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Dellorto set up  Rating:  Rating
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 Posted: 01-03-2007 12:33 am
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Dave Shively
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I just got a set of Dellorto carbs off eBay and I'm not sure how to set up the linkage or for that matter, anything else.  Is there a diagram available to show the proper set up?

Any help would be greatly appreciated.  I've looked at the other posts on Dellortos and realize I need basic help before even trying to tune them.

Thanks,

Dave

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 Posted: 01-03-2007 04:05 pm
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Greg Fletcher
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The Jensen Healey Parts Catalogue should have a schematic of the various bits. Any linkage that fits the JH is tough to find, but you can always fabricate your own. I prefer the original factory parts and that's even harder come across. I'm planning on getting sets remanufactured one of these days.

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 Posted: 01-04-2007 12:29 am
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Dave Shively
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OK, who has a parts catalog with a diagram or schematic?

Thanks,

Dave

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 Posted: 01-04-2007 06:47 pm
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John Finch
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http://cgi.ebay.com/Dellorto-DHLA-Weber-DCOE-tuning-manual-NEW_W0QQitemZ300065722756QQihZ020QQcategoryZ48444QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Try this link to purchase an excellent book on Dellorto Carbs

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 Posted: 01-05-2007 12:55 am
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Dave Shively
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Thank you John.  I just bought one outright on eBay.

Dave JH 12579

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 Posted: 01-05-2007 08:07 pm
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John Kimbrough
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Dave, I have instructions on conversion with lots of photos on my web site. 

http://home.comcast.net/~jrkengr2/index.html

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 Posted: 01-06-2007 02:56 am
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Dave Shively
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WOW!  Thanks John.  This should be a big help if and when I can find the throttle cable hardware.

Dave

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 Posted: 01-08-2007 03:25 pm
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j23mau
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I just found this website.  Very helpful with some basic operational instructions and maybe someone can use it for parts/linkage.

http://www.racecar.co.uk/dellorto/

Jeremy Mau

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 Posted: 05-03-2007 03:29 am
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DeDub
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I'm taking off on a thread from a year and a half ago on the DellO 40 vs 45 forum (last used a year and a half ago) and posting here because I think my need better fits this forum subject line AND this forum has seen more recent activity.  We'll see who is still monitoring this forum (besides you of course, Greg).

My car: a 74 era mutt made up of at least 3 bodies, now titled 19377 with a mutt of a motor with an unknown history.  But it's sound, good even compression and hasn't smoked noticeably after sitting for several years.  It was purportedly good when parked.  I had 104/107 cams and towers from another motor, put those on instead along with a new set of DellO 45s from JHPS.  They came set up as follows:

37mm chokes
160 mains
7772.8 emulsion tubes
230 main correction jet
62 idle jet
7850.9 idle jet holder
50  pump jet
95  cold start jet
7482.3 cold start emulsion tube

I mention the above because I think I have a fuel problem rather than ignition.

I first ran the car briefly as soon as I put on the DellOs; they didn't have air cleaners or even velocity stacks on them yet so the car ran poorly and was very balky.  Then I got around to putting on the stacks and went for a first drive but still without the air cleaners.  It ran amazingly well for not having balanced carbs; even and strong with only a hint of hesitation once in a while.  I'd read that DellOs must have the stacks on to run right.  But as I drove it, it would occasionally stumble on mid throttle, erratically, increasingly as I came home.  Yesterday I put on K&Ns and went for a drive that started well but it increasingly would bog down mid throttle as if it was running out of gas.  EIt worsened and eventually I could barely drive and only got home the last bit in first gear.  It would idle but would only run with the slightest crack of the throttle; any more and it would act like it was out of gas and die.  Since then, I've checked the fuel pump; it had plenty of pressure and flows plenty of volume (though I didn't try flow under a few pounds of pressure).  I checked and blew out all lines; they were completely clear.  Went for a drive, no change.  I pulled the tops of the DellOs to look for fuel level (it looked fine), water (none), and debris (none).  Went for a drive, no change.  I decided maybe it was ignition so I put a Pertronix I had lying around on a spare distributor and installed and timed it.  No change.  Pulled the plugs and regapped them to 40 thousandths, no change.  I swapped out the coil for one off a parts car, no change.  It's already got new wires and cap so that's the whole ignition system.  By now, I'm starting to get a bit testy.

Data points:  It always starts right up.  It runs better when cold and becomes more undriveable as it warms up.  When I hit the throttle part way, it initially very briefly surges, then completely bogs down and will die if I don't let off the throttle.  BUT, once I couldn't quite get home and sat on the side of the road for a minute with the motor idling, and it was then better enough to get me the last few feet home.  It acts as if the fuel pump can't keep up but there's definitely pressure in the fuel line at the carbs and will hold that pressure for a few minutes after I turn off the key.  It also acts like as if it might be heat related.  It's not a vacuum in the fuel tank problem.  I'm not losing coolant and the car doesn't run hot.

At this point, I'm looking for a fresh perspective. What am I missing?

David,
quietly, so far, going nuts in Sebastopol

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 Posted: 05-03-2007 03:39 pm
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Jensen Healey
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What do the plugs look like? I think you're running rich. If you give the throttle a quick goose the accelerator pump will squirt fuel. If this makes the engine bog or die, it's not lean.

Your idle jet seems way too big, especially for a low compression motor. Try a 53 or a 55.

Tuning Dellortos is a complex process that even Jensen never got right. Do you have the Des Hammill book?

Balancing is required using a 4 tube manometer.

Kurt

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 Posted: 05-03-2007 04:14 pm
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Greg Fletcher
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I think Kurt's right. Those settings are for a high compression, big valve 2.2 liter engine that's pumping some goodly amount of air through the head. What kind of fuel pump are you using?

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 Posted: 05-04-2007 12:27 am
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DeDub
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Thanks for the quick reply, Kurt and Greg,

I was using a stock SU fuel pump that I took apart and cleaned up.  It was pumping plenty of fuel and had good pressure.  I don't have a pressure gauge that will read 0 to 5 pounds so can't test it but it feels, in my experience, completely satisfactory.  I tried swapping in a known good pump from a friends MG but no change so it doesn't seem like fuel delivery.  The plugs look mediium dark tan, not real dark or black, but not the light tan I would want.  I agree that the idle jets seem way too big, though I don't understand why that would affect everything ABOVE idle but not the idle itself.  It idles just fine all the time with the idle screws turned out 2 to 3 turns.  I just got back from trying a run with the brake booster disconnected, in case I had an air leak there but still no change.  Nothing I've done has improved or changed things a bit.  I've thought I was running lean but maybe your right and it's too rich.  The plugs don't give me as good an indication as I hope.  

Yes, I have Hammill's book, it's GOOD.  Very thorough.  I wonder why my idle jets are big and the holders are lean (see below).  I also wonder whether I should put in a pressure gauge and/or an adjustable pressure reducer.  The fuel level in the bowls doesn't look like the carbs are being overwhelmed with pressure.

Hammill's book, on page 70, regarding idle jet and air bleed selection, says at one point that 7850.8 is the leanest but later on when giving the entire range, he listss 7850.8 as the richest.  Do you know which is right?  Is my 7850.9 the 3rd richest or 3rd leanest?

I had my floats set to 17mm but I dropped them to 15mm with no change in how the car ran.

So, shall I first try, as you suggest, a 55 idle jet, then perhaps a 7850.7 holder?  And after that, depending on how/if it's improving, consider dropping the mains down quite a bit, to 145 or so?

I wish I knew why the car ran so well at first and only slowly got to this problem; that's what's got me so flummoxed. 

One final question: where is the vacuum take offs on the 45Es?  I have a couple of manometers but don't know where to plug them in.

OK, one more final question: is there a west coast DellO supplier that has these things in stock?

And thanks again for your attention,  I *really* appreciate it.

David


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 Posted: 05-04-2007 01:33 pm
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Jensen Healey
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The idle jets actually control the mixture from idle to about 3000 rpm.

There's CB Performance in California which has some Dellorto parts.

Weaker ................................... Normal .... Similar  .......... Richer
   7850.5,     .10,     .9,     .4,     .1,     .3,     .6,     .7,     .2,     .8


A neat trick is to drill out the holes on the .8 to allow more air to pass, (weaker mixture). A mini machinists bit set is about $10.  I would get the smaller idle jets first. Re-read the idle jet selection part of the book.

If your car runs well when cold and then bogs down it's probably running rich.

Kurt

Last edited on 05-04-2007 02:33 pm by Jensen Healey

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 Posted: 05-04-2007 01:42 pm
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John Kimbrough
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This may be stating the obvious, but I had the same thing happen to my car and found that it was rust chips in the fuel tank slowly clogging up the fuel pump intake and limiting the fuel supply.  Ran fine at first and then starved.  When I stopped, the flakes fell away from the intake and the car would start and run for a while, then stall out.  Fuel pressure and flow looked fine when I tested it, but it choked out while driving. 

Finally took the fuel tank out and had it coated.  No problems since. 

Then again, it might be the carbs.........

 

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 Posted: 05-04-2007 03:28 pm
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DeDub
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The flakes in the tank story is a good one.  My tank is unknown, tho I did look it over well with a mirror before I installed it and it looked good at the time.  No visible rust  or loose stuff, even tho it had sat in a parts car for several years.  My guess is that it dried out before it had time to rust and the bottom outside looked fine, too, and the car was under a tarp so the trunk stayed dry.  I'll keep it in mind, but I think I'm going more towards the running rich idea now, so I'm ordering some leaner parts and we'll see, eh?

David


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 Posted: 05-14-2007 02:18 am
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DeDub
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Well, well.  I figured out why my JH wasn't running right.  And this is a good one.  Sometime before I installed my brand new DellOrtos an insect crawled into the fuel intake spigot of one of them.  From the sodden parts, I'd say it was a couple of earwigs or a cockroach.  As the body slowly disintegrated in the fuel, it turned to a sludge which mostly plugged up the tiny little screen inside the float needle seat, something I didn't know was there til I pulled the seat.  So that carb would slowly starve out as I drove.  I'd stop, fiddle with it and it would run again because the bowl would slowly fill while I was stopped and idling and every time I pulled the top off the bowl the fuel level was different.  I could still blow through the spigot but less than I thought I should.  It was driving me nuts and just on a whim I pulled the needle seat and there it was.  That fr@#$% insect took up several hours of my time before I found it.  My guess is that the chitonous exoskeleton was slowly turning to jelly in gasoline and there was just enough of it to coat that little screen with paste.


Of course, there's a dark cloud, too.  As I was putting the second carb's needle seat back in (that carb didn't have a blockage but I decided to check it anyway) the carb top flew out of my hands and landed on the concrete floor, breaking not only the float but one of the hinge pin ears.  Ah, the words I said......  So  I just ordered a new top and float from the UK at well over a $100US.  One step forward, one step back, eh?

Dave

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 Posted: 05-14-2007 10:01 am
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John Kimbrough
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Dave, glad you figured it out.  The most bizarre things happen to JHs for some reason.  Sorry about your misfortune with the flying carb.  I know the words you used well.  John.

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