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DonBurns
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I am having some issues and was wondering if anybody could shed some light.

This is a "new" 2.2 build with dellortos, Pertronix Flamethrower distributor and Flamethrower coil. "New" being relative because I've been trying to sort out issues for 4 years now.

Anyway - the engine has a slight backfire that I have been assuming was a tuning issue, but now I'm not so sure. When I watch the original tachometer, I have long noticed that there is a slight occasional dip or "blip". As I watch and listen, I am becoming convinced that the mis-fire and little dips in the tach are related. Not exact, because you tend to hear the mis-fire a moment after the tach signal.

In addition, i have an Innovate LM2 02 sensor. If I only hook up the O2 sensor, it works fine, but when I hook up the RPM signal (from the coil) the O2 reading freezes after a short time. I was assuming there was something wrong with the LM2, but am now wondering if the three symptoms are related. Maybe a bad signal from the Pertronix is causing the mis-fire, erratic tach reading and messing up the LM2 computer.

Has anybody experienced anything like this? Any suggestions appreciated.

The brand new Pertronix distributor is also leaking a little oil into the cap. I saw a thread on this a recommendations to get the McMaster-Carr 9505K17 oil seal. Does anybony know if these fit the Pertronics distributor as well as the original? I assume so since the shaft is the same diameter, but not sure about the actual groove for the seal.

-Thanks-

Don

Rick in Miami
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I’m not suggesting this as the solution for your particular oil leakage problem with your Pertronix distributor but there is a current auction on Ebay offering several used Lucas 41584 distributors (correct for horizontal mounting). At worst they would be good candidates for rebuilding. I have no financial interest in these.

https://www.ebay.com/itm/Lucas-41584-4D84-EL2-EC2-Lotus-Jensen-Healey-Used-Distributor-Points-Vacuum/173533009929?hash=item28675f9809:g:qKEAAOSw8D9bmnRx

DonBurns
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Thanks- I actually still have the original distributor for rebuild if necessary but am hoping to sort out the Pertronics system as I understood it to be an improvement. Will send in the Lucas for rebuild if that ends up being what it takes. For now trying to understand the issues I am experiencing. The leaking oil doesn't appear to be touching the areas between the rotor and Pertronics sensor (just messy), so I think that is not the issue, but maybe I am wrong?

Tim Murphy
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I have the same problem, a hiccup when idling. I am going to throw you a couple of curve balls here so be prepared :<) First, in my case, I have given up trying to get everything just right. If the engine starts, runs without overheating and the car stops when I apply the brakes, I am a happy camper. Now, I have an Allison/Crane Cams electronic ignition and ZS's. So maybe it is not in the ignition system. Maybe a sticky valve that takes a fraction of a second too long to close? Or engine vibration causing the carbs to deliver too much/or to little fuel. And my third option, which I favor, is a leaking brake servo causing the 3 and or 4 cylinder to be sucking air from the servo and not through the carbs. That could be tested by when the hiccup is happening, turn off the engine, disconnect the servo and cap the intake tube, then run the engine again. See if the problem continues. My servo is the original and needs to be sent in for a rebuild. How old is yours? I plan on going to the JHPS meeting tomorrow evening, maybe see you there. Take care.

Rick in Miami
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Don – I would try taking the taking the JH tachometer out of the equation by bypassing it. Power to the coil goes through it and the RVI just does not play well with electronic ignitions. If that eliminates your miss then you will probably need to convert your RVI (impulse) tach to (or replace with) an RVC tach (current).

When I converted to a Pertronix II my tach would hardly work at all. I tried several wiring alternatives to supply switched 12v to directly the coil while also keeping the RVI tach connected but the best results I could achieve was accuracy up to 3000 RPM. After 3000 it was worthless. I replaced with the RVC and now all is good.

Some background info may be found here https://www.tscusa.org/tech/4_RVI_to_RVC_Tach_Conversion_PhilipMillward_StagNews_2016_Q3_Summer.pdf

I would also recommend making sure the idle circuit on your Dellortos is clean and jetted correctly for your engine upgrades. Are they properly balanced? Are your progression holes properly closed at idle? Are the floats set to the correct height? Mixture screws evenly adjusted?

Some more background info is available here
https://www.mazdabg.com/ftp-uploads/Mazda/RX7/info/carb_book.pdf

Hope this helps.

Rick

DonBurns
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Rick-

Thanks for the suggestions. I will work through all of those and let you know. As far as Dellorto set up, I've fiddled with them quite a bit and taken to two local "experts" - three if you count the dyno tuner I paid over $10K for rebuild and set up (not including parts). I am not completely happy with the Dellortos. I have balanced as well as I could, but my 02 meter is saying that my ratio is about 10.5 - 11.0 : 1 at idle which seems too rich, with the leanest progression tube 7850.8 and 55 idle jets. But if I change to 50 idle jets it won't run.

I have also asked Pertronics about horizontal mounting of the distributor supplied by Delta Motorsports.


Tim-


I have been wanting to come to a meeting for a long time - afraid to drive this JH further than I can push it at the moment though. Almost talked myself into coming tonight, but the headlight switch chose today to fall apart permanently. It had been held together literally by threads. Ordered a new one today. I will shoot for next month.


I'll test the brake servo idea. I don't think so because I just had that rebuilt, but you never know.

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Don- I would fix the problem with oil inside the distributor first. Engine oil is an electrical insulator, so it could keep the spark from jumping between the rotor and the correct connection on the distributor. Also, if the oil is dirty with tiny metal particles, that could also cause the spark to jump erratically. This could not only cause the misfiring you are seeing, but if the spark is insulated from going anywhere, the power could feed back into the coil primary and cause a voltage spike in the ignition circuitry which could cause problems with sensitive electronic circuitry like the Pertronix and the O2 readout. When you fix the oil problem you should also replace the distributor cap and rotor. If there has been sparks getting redirected inside, the cap could be damaged which will continue to cause problems. The rotor is not likely to be a problem, but they are cheap, so I usually replace it with the cap just to eliminate one possibility.

Note on tachometers: The original JH tach measured the current to the coil and converted that to RPM. With an electronic ignition like the Pertronix, there is more power being delivered to the spark plugs, so there is more current going through the tach. So the tach will read high. Otherwise, the tach should not cause problems unless there is a bad connection somewhere in the system. It is a very robust design internally. If you are still using this tach, you should adjust the idle speed using a separate engine analyzer (which measures RPM by counting voltage pulses) so you are not trying to get a good idle a too low an engine speed. Replacing the original tach with a Spidya conversion, which also effectively counts pulses, will also give you a reasonably accurate RPM measurement. But this is a fairly time-consuming job.

If you did not already know, one of the banes of these cars is bad electrical connections, especially in the engine compartment. A quick way to check for this in the ignition circuit is to put a clip lead between B+ on the battery and the + terminal on the coil. If this gets rid of the erratic firing, then you need to go looking for bad connections.

Sorry for the long post. I hope I did not waste too much of your time with things you already knew. Hope it helped.

Tom

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Don, even if your JH isn't running you can come to a JHPS meeting, just drive another car. There are usually a couple of us there that didn't drive their JHs. If you just had your servo rebuilt, that probably isn't the problem. If it is easy for you to test, give it a try. My guess is that the oil seal o-ring should be the same. I remember I had to put oil on the o-ring and top of the hole to get my distributor back in. It is a very tight fit. I am not sure how oil leaks into the distributor. Does it migrate up the outside of the shaft and then is splattered around by the rotating plates? In any case, I agree with Tom Bradley to fix that problem first.

Tom Bradley-I don't know that much about electronic circuitry but I would be worried if I connected my battery b+ to the coil + that it would put too much amperage into the system and harm the coil or the electronic ignition. Is that an unwarranted fear? Could one run there engine for a long time with that connection? Also, I didn't think your post was too long and was, in fact, very astute and informative.

Take care all.

Tom Bradley
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Tim-Your intuition is good. In a standard mechanical points ignition or with Pertronix 1 the hookup should be to the side of the ballast resistor not connected to the coil in order to limit the current so the switch does not burn out. However, the Pertronix 2 has its own current limiting so does not need a ballast resistor. In this case the connection can be straight to the coil. If you look at the schematic for the ignition circuit you will see that it is essentially a long wire going from the battery to the ignition switch, through a bunch of connectors and then to the ballast resistor. Putting a jumper wire straight from the battery to the resistor or coil simply bypasses all this eliminating a bunch of possible failure points. This is how thieves used to "hot wire" a car back before there were things like steering wheel locks. The biggest danger here is that one end of the jumper wire could come loose and short to ground somewhere and cause more problems than you have already. So it is really only useful for quick checks or in an emergency. Back in college I ran my TR4 this way for a week when the ignition switch suddenly got unreliable, but it was not the smartest thing to do.

DonBurns
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Here is the response I got from Pertronics about the oil leak. My main question was whether or not their Dist was designed for horizontal placements. Obviously there is oil pressure against the shaft / bushing.


Don,

Oil in the mechanical advance area will would not be a issue. Most of the time oil around the ignitor and it's parts will not cause a problem. In less the oil has start to effect the grounding of the unit through the internal ground wire and plate attachment to distributor housing.

Oil in the distributor could be a bushing issue in the distributor. Or could be because of crankcase pressure causing the oil to push pass the bushing.

If you would like you can send the distributor into for inspection. I can send you a return number if you like to send in for us to inspect.
Your Pertronix Team,
Marvin Grebow Jr.


I have been playing with the car a little today. One strange new thing is that when I turn the key the starter does not immediately turn, but if I hold the key in the start position it will start after 1-2 seconds. I don't remember it doing this before. I verified with my meter that there is that delay before the starter solenoid sees the voltage. With my ohm meter I verified that connection at the ignition switch seems to be instantaneous. Odd, but I am ignoring for now. BTW - I just recently finished installing new wiring harnesses (all three - main, engine, instrument) and went through and checked the relevant connections and added dielectric connector grease.


I learned something new. I went back to basics and attached my Carbtune Pro and fiddled with the idle mixture screws. The Carb Tune readout has not been very sensitive to the screw adjustments. Don't know if that is a sign of an issue. But I started adjusting them by 1/2 turns and happened to look at the O2 meter. This was very sensitive to adjustment. I had been seeing O2 at idle of 11:1. About a 1/2 turn of the screws brought it to about 13:1. That adjustments to the screws would affect O2 ratio should have been obvious - just didn't think of it.


I was adjusting the timing as it seems to hate 10 degrees and below, and I was adjusting to get 12 - 13. The engine very hot at this point and I managed to let the distributor slip out of the mount. Will probably be a couple of days before I get back to it.


Thanks for all of the suggestions and I will work through everything when I can.

answerman
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DonBurns wrote:
The brand new Pertronix distributor is also leaking a little oil into the cap. I saw a thread on this a recommendations to get the McMaster-Carr 9505K17 oil seal. Does anybony know if these fit the Pertronics distributor as well as the original? I assume so since the shaft is the same diameter, but not sure about the actual groove for the seal.
Late to the party, but I believe I can answer this for you.

I went through the same thing a few years ago: I was troubleshooting some ignition issues and decided the easiest thing to do was to replace the original Lucas distributor with a Pertronix Flamethrower distributor purchased from Delta. It solved my ignition problems just fine, but started leaking not long after.

I lived with it till last winter and finally called Delta about it. I basically was asking the same question about the seal. Mike from Delta actually chased around at Pertronix until he got an answer, which is that (a) no, there is no seal, and (b) no provision for one.

So, I ended up having an original distributor rebuilt (that's a story in itself) and fitted it with a Pertronix Ignitor II.

DonBurns
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Thanks - I ordered a rebuilt Lucas from the club store yesterday. None in stock so will be 2-3 weeks. I went with the new Pertronics originally because new seemed better and they were cheaper than the rebuild- not so much in this case.


Was there a problem with the rebuilt Lucas?

DonBurns
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So have now ordered rebuilt Smiths 25D which Greg has guaranteed not to leak AND a Spiyda conversion kit to convert the tach to RVC. Will update in a few weeks when I have these done.

answerman
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No, the rebuilt Lucas has been perfect. Problem was that my original distributor, the one that came with the car, was a 45D4, not a 25D4, and Greg was pretty sure it was an MGB distributor. So, I had to scour the group for someone who had an actual JH spec 25D4 that could be rebuilt (thanks Stephen Luckett). That worked out fine once I got the correct one: I still have oil leaks to track down, but not from the distributor.

Last edited on 09-22-2018 07:28 am by answerman

DonBurns
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While waiting for the distributor and tach conversion, as I said I am going through with relooking at some of the basics. Rebalanced the carbs and tried it from a different direction. Adjusted all of the idle mixture screws to the same turns (ended up at 4 turns) after very small adjustments to the air bleed screws on 1 and 4 to give equal CarbTune readings. Getting to 4 turns was what it took to get an 02/fuel ratio average of just under 14:1. The reading is bouncing around much more than I remember in the past though. Not sure if that means something wrong with the meter. At 3000rpm average is about 12.7 also with a lot of variation, somewhat less. For those with O2 meters are your readings reasonably steady?

Did a compression test, with engine warm.

1- 200
2- 208
3- 184
4- 200


That's a little disturbing. This engine still has very few miles and I did a test when new and they were closer then.

The plug condition seems to indicate that cylinders 1 and 2 have been running rich and 3 and 4 lean. I'll check again to see if these latest adjustments even that out.

CDA951
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DonBurns wrote:
While waiting for the distributor and tach conversion, as I said I am going through with relooking at some of the basics. Rebalanced the carbs and tried it from a different direction. Adjusted all of the idle mixture screws to the same turns (ended up at 4 turns) after very small adjustments to the air bleed screws on 1 and 4 to give equal CarbTune readings. Getting to 4 turns was what it took to get an 02/fuel ratio average of just under 14:1. The reading is bouncing around much more than I remember in the past though. Not sure if that means something wrong with the meter. At 3000rpm average is about 12.7 also with a lot of variation, somewhat less. For those with O2 meters are your readings reasonably steady?

Did a compression test, with engine warm.

1- 200
2- 208
3- 184
4- 200


That's a little disturbing. This engine still has very few miles and I did a test when new and they were closer then.

The plug condition seems to indicate that cylinders 1 and 2 have been running rich and 3 and 4 lean. I'll check again to see if these latest adjustments even that out.


Before freaking out too much about the relatively low compression on cylinder #3, how many miles are on the engine, and have the valves been re-adjusted, and if so, how long ago?

I would do a leakdown test to make sure the cylinder is sealing properly. If so, I would then check the valve clearances (which I know is no small task on the 907 engine). I tend to set the valve clearances on the loose side on an engine with a fresh valve job, because they will tighten up once everything seats in during the break-in process. If the clearances get too tight, the valves are open for a longer duration than normal, and this affects the dynamic compression.

I am currently assembling the engine on our (somewhat) recently acquired '74 Jensen Healey (#19250 for those keeping score), and while this is my first 907 engine, I have a good amount of experience building/breaking in engines as a professional Porsche/BMW technician.

The usual routine at my shop is to install and run the engine with break-in oil, do the initial break-in run (say ~100 miles, and make sure the engine sees some load to seat the piston rings, no babying it!), change oil, re-adjust valves. Then re-adjust the valves and change the oil again at the 1,000 mile mark, and go to normal service intervals after that. Whether Porsche 356, VW Type IV, Porsche 911, or BMW M10/M20/M30, this routine has always worked well.

I did the same on our '81 Alfa GTV6 after a fresh valve job, and the shim-and-bucket intake valves (same concept as a Lotus 907) certainly tightened up after the valves seated in!

DonBurns
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Thanks for the reality check. Essentially no miles on the road. Hours in the garage. I still remember driving a Lamb Miura and being told "it was not a car you should drive further than you can tow it" I hope that is not the case with a JH but not sure yet. This is my second and at over $45K into it and still undrivable. Starting to think that with the engine from my first car - a Ford Pinto - this would be a pretty decent ride. Please don't take this too seriously - just giving voice to the dark place that I suspect many JH owners get to now and then.


BTW - had a '74 Alpha 1750 GTV Iniezione, and a '74 BMW 2002 TII. Hindsight, right?

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I also own a '73 BMW 2002tii. Great car, though it is currently awaiting some overdue rust repair . . . .

Another point I wanted to make (somewhat unrelated to the original post and sub-section of this forum) is that while modern wideband O2 sensor controllers can be a great asset for tuning older cars, they are only as good as they are set up to be. Have you properly calibrated your sensor in free air? Are you 100% sure there are no exhaust leaks? It can be easy to obsess over minute changes in A/F ratio and lose sight of the big picture . . . .

Make sure that the mechanical and ignition side of the engine are good, then make sure your wideband setup is properly calibrated and leak-free, then circle back to the fine-tuning.

Last edited on 09-27-2018 04:09 am by CDA951

noomg
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Don,

You have 45 thousand dollars in your J-H, seriously? Not judging, actually I'm impressed, you are truly a man of dedication. Reading your thread it seems to me you may have inadvertently created a witches brew of upgrades and performance parts so when a malfunction occurs it can be difficult to isolate it.
I'd say generally speaking based on my experience the J-H is pretty reliable. I've driven mine from Long Beach to Reno for the air races with a buddy driving his J-H, a distance of 1000mi roundtrip, twice. Both cars ran flawlessly. Aside from Pertronix ignition and an MSD unit my motor is basically stock with 120,000mi on the clock.

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I agree with noomg: too many variables. The original distributor should be oil free if you replace the internal seal(the very early cars did NOT have a seal but could if one pressed the upper steel bushing down for a seal).
A Petronix ignition system(minus the dizzy) would make for a long reliable system; their distributor with NO seal apparently was not designed to be placed on its side.
As noomg said they're reliable; I have driven my car twice across the U.S. and twice have driven cars back from CA. to Atlanta.

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Come to our JH meetings each month at Round Table Pizzain Costa Mesa and bring your JH. We usually have from 3 to 6 JHs there with 6 to 10 folks in attendance. Great pizza and just a nice evening with friends. Join us. Randy Clary - 909-938-2090

Also most of us in attendance have a great deal of experience with the striker crank 2.2 L mod and the Delorrto 45s so give us a call. I live in Riverside and there are others that live closer to you in Fullerton.

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Don,

I'm curious, while you've got a number of niggling, frustrating problems(tach, oil leak, backfire)has your Healey ever stopped running and left you stranded? Or is it just not running they way it should.

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answerman wrote:
No, the rebuilt Lucas has been perfect. Problem was that my original distributor, the one that came with the car, was a 45D4, not a 25D4, and Greg was pretty sure it was an MGB distributor. So, I had to scour the group for someone who had an actual JH spec 25D4 that could be rebuilt (thanks Stephen Luckett). That worked out fine once I got the correct one: I still have oil leaks to track down, but not from the distributor.Don't focus on the "25D4" as being the answer. It's the "JH spec" part that is critical. When the JH-907 came out, Lucas was making the 23D4 & 25D4 distributors. Later ('74 ??) Lucas introduced the 43D4 & 45D4, and dropped the earlier models. Which distributor your engine came with was a simple function of where it was in the timeline, and for which market it was destined (emissions or non-emissions).

Standard Lucas distributors (23/ 25/ 43/ 45) didn't have shaft seals for horizontal operation. 907 distributors were specially configured with shaft seals, and no non-9XX replacement (MG/ most Britcars) will have the seals. That includes the various aftermarket Lucas-clone distributors, like Pertronix and 123. It's unfortunate that JH/ Lotus specialists sell those modern aftermarket distributors for the 9XX... they're not appropriate as they come.

In general, the 43/45 distributors are superior to the 23/25 units. Nothing big, just evolution. One difference to notice is the size of the distributor cap. The 23/25 cap is very small, which places the plug wire terminals close together. If you run a 'hot', high performance coil (ie, 45k volts), the spark can arc between the terminals inside the small cap. For a 23/25, it's best to stick with stock coils. If you want to use "hot" coils, then it's best to install a 43/45 JH-907 distributor.

Regards,
Tim Engel

Last edited on 09-30-2018 05:19 pm by Esprit2

DonBurns
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My JH has never stranded me, but I have not driven it much. I am grimly determined that it be absolutely 100% sorted out before I take it to paint and body. I rebuilt my first JH myself, but on this one I decided to have a professional speed / machine / dyno shop do it, and then opted to have them install the engine and do final set up and tuning. They ended up charging quite a bit more than the estimate and delivered a car that was barely drivable. Took it back a couple of times and finally decided to give up on them. I do not recommend Superior Automotive in Placentia. Have since taken to two different tuners who made some improvement, but I'm still not happy. With this much invested (time and money) I want it perfect.

I will try to get to the next meeting. Maybe it's not as bad as I think - a reality check might be a good idea. I received the RVI - RVC kit for the tach yesterday, and hopefully will have the new distributor by then also. I have asked Greg about supplying a 45D instead of a 25.


I was under the impression that you needed to use the hot coil with the Pertronics Ignitor? Is that not true and the combination of 25D, Pertronics Ignitor and standard coil is better?

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Many of us are retired and have taken the time to get the cars right mechanically and electrically for the sake of reliability. We have either done it ourselves or with the assistance of our JH friends (both local and remote). I’m interested in getting my tach to read accurately. I know how to calibrate to a running GPS device and working backwards based on tire size, transmission and rear end ratios. I also have work to accomplish in getting a working speedometer that I can calibrate to my custom gear ratios. I have a 4!speed and am using 205/60/15 wheel/tires on the rears.

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Being retired and then not is why I ended up going the "throw money at it" route. I retired mid 2014 just as I was starting on this project. I did a bunch of suspension and cosmetic work thinking the engine was OK. It's a long sad story but I started finding some serious mechanical issues that the previous owner had clearly gone to pains to hide. After the third potentially fatal discovery (as in possibly fatal to me) I decided it all had to come apart. About that time my old company talked me into coming back for two years. It seemed like free money at the time, and since it looked like I now had more money than time, I went the route of having other people do the car. If I could do it over I would have stayed retired and done the work myself.


Anyway - if you are looking for a good speedometer shop - Gail's Speedometer in Costa Mesa is reliable and fair. http://www.gailspeedo.com/

I have never calibrated a tach, but once I do the RVC conversion I will need to. There are instructions on Spiyda.com site. A cable came with the kit that you can borrow if you need it. It's really just a stereo headphone jack connected to two alligator clips to input a signal.

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For a local super expert, I would recommend you call Richard Reyman of West Coast Cylinder Heads in Van Nuys, about an hour away.
(818)996-5673
info@proheads.com

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I contacted West Coast Cylinder Heads in late 2015. They used to support Jensen Healey but have since decided to focus on Corvettes. They scoured their shelves and I am told I got the last full set of the "big valve" set with Viton seals that they produced.

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Don,

It sounds like it's got very few miles on it. If it were me I'd drive it, take it to the grocery store, run errands, drive it around close to home to gain some confidence in it's reliability. Putting some miles on it just may reveal the answer to one or more of your problems. Also when problems crop up as they always do on Brit cars I find it best to tackle one problem at a time, I try to start with the easiest first and sometimes that even leads to a solution for the next.

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Just finished with the Tach conversion to RVC. I'm pretty certain I followed the procedure exactly. Nothing is happening though when I follow the calibration procedure. Needle doesn't even twitch. Are there any instrument places that might be able to help sort it out? Maybe I am not applying the calibration signal correctly.

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Don,
If you are sure that the assembly is correct, that you have a good 12V power to the tach and have tried reversing the signal polarity, then the most likely problem is that the calibration signal is not large enough. Have you tried listening to it on the speakers or headphones? The signal should be extremely loud for it to work. Some laptops or tablets might not have enough signal strength. When I calibrated mine I used the speaker system a desktop computer which still needed to be turned most of the way up. Does your DMM have an ACV measurement? When the signal is hooked up to the tach the signal voltage should be close to 12VAC peak-to-peak or something like 9V RMS.

Another possible approach is to wire the tach into the car 12V and ground and to the coil. It should at least respond, if not accurately. If you have an accurate tach on your engine analyzer you can use that to calibrate the spiyda. Or hook it back to the computer and figure out what is wrong there.

Last edited on 10-02-2018 04:35 am by Tom Bradley

noomg
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Don,

I don't know what RVC is but it sounds like you may have just added another problem to your list.

answerman
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Don, I did the Spiyda RVC conversion on mine and I never got the calibration signal to work either. I ended up just using my automotive multimeter (which does RPM among other things) to calibrate the tach instead.

DonBurns
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Noomg- RVI tachs use an Impulse signal as the signal to drive the tach, RVC uses contacts signals from the distributor (I think that's close anyway). The consensus, not just on this forum but others is that RVI is very often a problem when used with electronic ignition and it seems pretty common to do this modification. The issue I am seeing with an unstable tach has been fixed by others by converting to RVC. My understanding is that all modern tachs are RVC.


Tom- How did you supply 12V to the coil? It looks like the easiest would be to run a white wire from the now unused white wire that used to go to the tach to the + side of the coil. And I understand that the White / Slate wire from the tach moves from the + side to the - side of the coil, but I see some recommendations to run new wires all the way. I have all new wiring so the connections should be pretty clean. If you did not use the old white female connector, where did you splice into? I always worry about adding to a circuit that can't handle the current and anyway hate to butcher my pretty new harness. For the aux fan, O2 meter and Accusump I used relays and ran power straight from the battery. It's getting really challenging to feed more wires through the bulkhead grommets, though.


Apparently my problem with my practically new Innovate 02 meter suddenly going wacky for stability isn't that rare. I found references to this on a number of forums for different cars (BMW, American Muscle, etc etc) with no solution but to buy a new one.


My oil leak through the Pertronics dist seems to be getting rapidy worse. Before barely a sheen of oil before now a puddle. Probably won't make much progress until rebuilt Smiths arrives.

Tom Bradley
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Don,
Standard 14 gauge wire to the coil is perfectly OK. The only thing I get worried about is the connectors. This is where I have had most of my problems over the years. When I re-did my ignition system I got rid of as many as I could, especially inside the engine compartment. The spade terminals like on the coil, alternator and starter are the worst. If you have these, even if they are new, make sure that they are very tight. They should be difficult to push on and pull off. If they slide easily they are too loose and you should tighten up the connector on the end of the wire with a pair of pliers. People who are in a hurry to put things together sometimes wiggle the connectors to get them to slide in easier. This does not usually cause problems right away, but often cause intermittent problems down the road as they loosen up some more.

I once had an intermittent problem that only occurred after I had been driving for 15 minutes or so that I finally tracked down to a loose spade connector inside the Lucas alternator. Apparently after the engine compartment got hot the connector loosened up enough so that the alternator randomly stopped working, but then was fine when everything cooled down enough for me to work on it. One minute with a pair of pliers fixed the problem.

On the coil I got rid of the spade connectors and put ring terminals on the end of all the wires to get rid of the problem, though I think I may have been getting carried away there. As long as the connectors are good and tight they should last for many years.

The weakest link at this point is probably the ignition switch itself. With the original points, the ignition switch could get burnt just like any switch. I ended up replacing it with an electronic switch of my own design which has worked well for many years, but that is a pretty major undertaking and butchers up the wiring big time. Since the Pertronix 2 has built-in current limiting hopefully that will extend the life of the ignition switch as well.

CDA951
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Esprit2 wrote:
answerman wrote:
No, the rebuilt Lucas has been perfect. Problem was that my original distributor, the one that came with the car, was a 45D4, not a 25D4, and Greg was pretty sure it was an MGB distributor. So, I had to scour the group for someone who had an actual JH spec 25D4 that could be rebuilt (thanks Stephen Luckett). That worked out fine once I got the correct one: I still have oil leaks to track down, but not from the distributor.Don't focus on the "25D4" as being the answer. It's the "JH spec" part that is critical. When the JH-907 came out, Lucas was making the 23D4 & 25D4 distributors. Later ('74 ??) Lucas introduced the 43D4 & 45D4, and dropped the earlier models. Which distributor your engine came with was a simple function of where it was in the timeline, and for which market it was destined (emissions or non-emissions).

Standard Lucas distributors (23/ 25/ 43/ 45) didn't have shaft seals for horizontal operation. 907 distributors were specially configured with shaft seals, and no non-9XX replacement (MG/ most Britcars) will have the seals. That includes the various aftermarket Lucas-clone distributors, like Pertronix and 123. It's unfortunate that JH/ Lotus specialists sell those modern aftermarket distributors for the 9XX... they're not appropriate as they come.

In general, the 43/45 distributors are superior to the 23/25 units. Nothing big, just evolution. One difference to notice is the size of the distributor cap. The 23/25 cap is very small, which places the plug wire terminals close together. If you run a 'hot', high performance coil (ie, 45k volts), the spark can arc between the terminals inside the small cap. For a 23/25, it's best to stick with stock coils. If you want to use "hot" coils, then it's best to install a 43/45 JH-907 distributor.

Regards,
Tim Engel


Thanks for the info, Tim.

Here is a link to a chart with a part # and description of pretty much any Lucas distributor known to man:

https://mgaguru.com/mgtech/ignition/pdf/lucas_distributor_specs.pdf

According to a chart, the distributor that came with our '74 J-H is a 41623 43D4, which is from a '78-83 Lotus Esprit/Eclat, so it should have the appropriate shaft seal. I noticed a couple of small shaft seals in the bag that I got from JAE months ago when I ordered all of the relevant seals for the distributor and the auxiliary shaft/oil pump housing, which I am sure will require distributor disassembly to replace.

redracer
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A word of caution: the 5 digit # stamped on the distributor casing will be misleading if you plan to have a "professional" shop rebuild it:
if you notice the "arrow" that was on the top (where the vacuum retard capsule goes) was "filed" off because the direction of rotation for the shaft is OPPOSITE what the 5 digit #s stand for.
In the late '90s, I sent 4(Lucas #41634 25D4) to a place in Pennsylvania for rebuilding. When I installed one, as the engine sped up the engine "died". After putting a timing light on it, I saw the "advance" was going the wrong way. I called the shop to get my original weights back and springs but they had been thrown away.

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Not to worry - I am not having mine rebuilt but am exchanging it for a club rebuilt unit. Greg says he has them bench tested somehow for proper advance and oil seal.

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Don,

Thanks for the explanation on the different tachs, so let's see if I can add to the confusion. Sometime in the '90s I installed the Pertronix unit in my distributor, it ran great but the tach didn't work. I don't remember where I got the info(maybe at the monthly meeting)but someone told me to install a ballast resistor from a '71 Dodge Van(I think), it worked great and has ever since.

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I've been pulling what's left of my hair out, and I am hoping someone can help me with some trouble shooting. I had finally gotten 15800 running pretty well. It seems most of my issues were due to the connections to the distributor cap. The leads were secure but the metal connectors had been pulled into the rubber, so the spark had to make a jump. So that fixed I moved to another issue, which was that after my conversion to RVC the tach isn't working and the speedo was never right so I decided to replace both - and maybe get the originals working later. Went with a GPS speedo from SpeedHut and a basic tach. Anyway, got them installed and now the car won't run. Seems like it wants to fire when the starter motor is turning, but then stops when I release the key to the run position. Replacing gauges should have nothing to do with anything, so I assumed I bumped a connection somewhere under the dash. Spent many hours tracing the circuits through to the engine compartment.

One suspicious thing that was going on before this was that when I turned the key to "start" there was usually a delay before the starter kicked in. Always started though, so maybe related? The switch seems to be OK. If I use my meter I get instant continuity from the brown wire to the ACC, run and start wires as appropriate.

When I use my meter to check voltage to the coil, I get 10+V in the "start" position, but only 0.7 volts when in the "run" position. That's the + side of the coil which has the wire from the starter solenoid. On the negative side is about 0.3 V, I assume due to the 3 ohm built in resistor. I am assuming this is the issue, since I should see 12+V at the coil?

Just to make sure I didn't mis-wire when I connected the new tach - There are two wires from the Pertronics, red to + side of coil, black to - side of coil. WY wire from engine harness pin 2 and wire from starter motor to + side of coil. Wire to new SpeedHut tach to - side of coil.

Does it sound like the fault is in the starter motor, not supplying 12V to coil? I have had many starters go bad over the years, but the problem has always been that it doesn't turn the motor over, not something like this.

Thanks for any suggestions.

Rick in Miami
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When you removed the JH tach, the white wires to the back of the tach need to be connected together as power to the coil went through the original tach. The sense wire to the SpeedHut tach needs to be connected to the negative side of the coil. The red pertronix wire needs to be connected to a 12v source. If using a ballast resistor, wire the pertronix to th 12v side.

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Thanks Rick - that was the problem. Actually half the problem as I had neglected to attach the end at the coil. For some reason the white wire from the JH tach to the coil is a separate wire that was added. I don't remember doing this so I think the shop that helped set up the new engine must have done it. Since then I have replaced the main wiring harness. I should probably figure out what's up with the white wires in the harness.

Back to spitting though. For those of you with O2 meters, what ratios are you shooting for at idle and above idle? I have read that you have to run a little rich to be safe. Is the reading steady? Mine bounces around a lot.

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It could be your Pertronix momentarily shuts down, try wiring the red wire from the Pertronix directly to the battery through a relay and a fuse, naturally.

--
Joachim

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I recently had the same issue with my car (#19250), and it turned out to be restricted idle jets. I know this sounds odd, but let me explain.

I rebuilt the engine over the course of last year, put about 1,200 miles on it and the engine ran great and pulled well throughout the rev range (2.0 engine, Dellorto DHLA45Cs, 9.5:1 CR, stock cams). The car sat for a month or more until I had time to re-adjust the valves, and I got it going again last week.

The original Smiths tach did not work (needle was physically sticking and I have a Pertronix Ignitor), so last week I also installed a universal Auto Meter tach, which worked, except I would get missing/hesitation during light load/cruise, but only at about 3000 RPM, and only before the engine had fully warmed up. The tach needle would "blip" at the same time as the miss/hesitation, which would normally point to an ignition issue. I double-checked everything ignition-wise, and re-wired the primary circuit, which I had planned to do anyway: no change. The next plan was to take the car to my shop and use the oscilloscope to properly check the ignition primary and secondary circuits.

However, as I drove the car a bit more, I noticed the hesitation/tach blips would really only happen during part-throttle and in the RPM range during which the Dellortos transition from the idle to main circuits. The engine would pull cleanly to redline once out of this range. Furthermore, the engine would occasionally pop back/spit during a long period of closed-throttle deceleration, and the tach would blip then as well.

I pulled the idle jets, and while they weren't completely plugged, they were restricted. Once cleaned out, the hesitation and "blips" were completely gone. The restricted idle jets would allow the engine to idle and run normally in the low-RPM range, but would cause a lean condition in the upper reaches of the idle circuit. Because more fuel condenses on the walls of the intake manifold and ports of a cold engine, this effect was more pronounced before the engine had completely warmed up.

I already run two fuel filters (one upstream of the fuel pump, one in the engine compartment) and an in-tank strainer on the fuel pickup, but I might add another EFI-type fuel filter as well. I cleaned out the fuel tank as well as I could before I ran the car, but CA environmental regs make it difficult to properly clean a fuel tank . . . .

Interestingly, the slight bog/hesitation that I get during brisk acceleration from a dead stop is slightly worse with de-restricted idle jets, which tells me that my 58 idle jets are probably too much for my particular engine setup. The carbs are otherwise balanced and tuned well, and my engine setup and carb jetting pretty much mirrors Lotus "Spec 5."

I am not 100% sure why the tach needle would blip during a lean hiccup, but it might have something to do with how the Auto Meter tach is constructed:

https://www.autometer.com/resources/index/faq_view/id/49

Last edited on 06-16-2019 03:53 am by CDA951

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For what this is worth - I replaced both the original tach and speedo (which was not reading correctly in spite of rebuild by speedometer shop, replacing the speedo cable and "new" transmission) with new units from Speed Hut (GPS speedo - I highly recommend!), and have not seen any of the tach "blip" issues since. Limited miles since, though, so I'll update if this changes.

CDA951
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DonBurns wrote: For what this is worth - I replaced both the original tach and speedo (which was not reading correctly in spite of rebuild by speedometer shop, replacing the speedo cable and "new" transmission) with new units from Speed Hut (GPS speedo - I highly recommend!), and have not seen any of the tach "blip" issues since. Limited miles since, though, so I'll update if this changes.
Interesting. In reading your first post, it seemed like you had slight misfires that would coincide with tach blips, but are you saying that it was tach blips only without misfiring?
It also seemed like your carb balance/tune was nowhere near ideal, so I was hoping this would help. My carbs were well balanced and sorted before this issue cropped up, but it goes to show that these old carb'd engines need regular care and feeding!

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Wasn't thinking clearly last night - might have had a beer by then. I think the blips went away when I discovered the wires to the distributor cap were not pushed far enough through the silicone boots, and the sparks were jumping, building up carbon on the contacts. In the meantime I had messed up the original tach trying to convert it from RVI to RVC.



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