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cams, valve timing and ignition timing  Rating:  Rating
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 Posted: 05-01-2016 07:57 pm
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subwoofer
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I don't know for sure, but I suspect that the closer timing would spit less. Some you have to live with, that is why we have air filters...

The best MOP for these engines is 104, 110in 97ex is basically that, just 6 degrees advanced. Advancing the cam is common on other designs, but they usually only advance 2-4 degrees.

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 Posted: 05-01-2016 09:27 pm
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westsideclay
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Thanks I really appreciate your help > I think it's time for this one to finds a new home as I really don't have anywhere suitable to work on it close to where I live and don't have the time to commute to where it currently is

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 Posted: 05-03-2016 04:14 pm
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subwoofer
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It shouldn't take many hours to get it running fairly well, if the rest of the car is in good nick it would be a good learning experience.

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 Posted: 05-03-2016 05:04 pm
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westsideclay
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the rest of the car is in good shape. The body is straight with very little rust I just put shocks tires and clutch into it. It needs an interior as its worn out and Healey dashpads did not play well with the Southern California sun I am in the process of deciding to keep the car or move on to something different. I truly appreciate your input on this but I'm really not looking forward to another learning experience. It would be different if ther was a good independent shop locally but unfortunately most have closed their doors

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 Posted: 05-10-2016 08:59 am
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Esprit2
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I'm late to this thread, sorry if I'm beating a dead horse.

Westsideclay, Subwoofer and Brett have given you good advice on how to time the cams, you repeatedly insist that is what you have done, but it's not.

> The cams line up with the correct firing order,
> everything is where it is supposed to be which
> is why I cant figure this out

No, it's not where it's supposed to be, which is why it doesn't have compression, and doesn't run. You're setting the cams incorrectly. Please clear your mind of what you have done, and please read through the following with an open mind.

You CAN NOT change the cam timing from 115-115 to 110-110 without first removing both pulleys from the engine, flipping them over front to back, and re-installing them. If you have not removed/ flipped/ replaced the pulleys, then you have not re-timed the cams correctly. Simply rotating the pulley 3-teeth without first flipping them changes the cam timing by 54 degrees, not the 5 degrees you seek. If the pistons have not hit the valves yet, then you are extremely lucky. Head for Vegas while you're hot.

Set the cams back to 115-115 where it runs.

Grab a felt tip pen.

1) For each timing mark on the pulley's rim, follow that tooth to it's opposite side, and there you will find another mark of the same number value. Or you should!! If there's no timing mark there, then put one there. At least temporarily with a felt tip pen.

On the INtake pulley, the front-facing 115 timing mark should have a little 'IN' stamped adjacent to it. On the back side of the pulley, the second 115 timing mark will have an 'EX' stamped by it. At least that's the way it should be. If the second 115 mark isn't there on the back side, use the felt-tip pen to put it there. And if the IN and EX marks are not present, write them in as stated above.

Similarly, on the EXhaust pulley, there should be '115' and 'EX' engraved near the timing mark on the front face of the pulley rim, plus '115' and 'IN" on the back side.

With the crankshaft set to TDC, make certain the pulley's timing marks aligned on the imaginary centerline between the cams. Simply aligning the dots with one another is not enough, they must also be on the imaginary centerline. If they're aligned but not on the centerline, then the cams are not properly timed.

2) On the INtake pulley, start on the pulley TOOTH that has the timing mark on it, and count downward (clockwise) three teeth. Counting the tooth with the 115 timing mark on it as '0' (zero), count down 1, 2, 3 teeth. Use the felt tip pen to color that 3rd tooth black.

3) Similarly, on the EXhaust pulley, start at the timing mark, count downward (counter-clockwise) three teeth, and color the tooth black.

4) For both teeth in steps 2 & 3 above, write '110' near that newly identified tooth.

5) On the INtake pulley, also write 'IN' next to the new 110 tooth.

6) On the EXhaust pulley, write 'EX' next to the new 110 tooth.

7) On the INtake pulley, start on the 110 tooth on the front side, follow that tooth to the back side (rearward facing side), and write '110' and 'EX' near the back side of that tooth.

8) Similarly, on the EXhaust pulley, follow the new 110 tooth to it's back side, and write '110' and 'IN' near the back side of that tooth.

Now, the 110 marks on the BACK sides of the two pulleys are what you want to have on the front side.

9) Remove the INtake pulley, flip it over front to back, and re-install it. 110 IN is now facing forward.

10) Remove the EXhaust pulley, flip it over front to back, and re-install it. 110 EX is now facing forward.

11) Rotate the pulleys three teeth to align those new 110 teeth on the imaginary centerline between the camshafts.

12) Re-install the timing belt and tension it properly.

Now both cams are timed to 110 MOP.

Make certain the timing belt's orientation on the auxiliary pulley doesn't change (ie, the same teeth engage after the timing belt is replaced. Any change of tooth mesh at the auxiliary pulley will require a corresponding change to the distributor's timing, so it's less work to make certain the aux pulley's registration on the timing belt doesn't change.

If nothing else has changed, then expect the idle rpm to be slightly higher with the new cam timing. Let the engine fully warm up, then re-set the idle speed to 900 - 1000 rpm.

Good luck,
Tim Engel

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 Posted: 05-10-2016 02:39 pm
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westsideclay
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Thanks for your input but as I stated previously I'm on hiatus while I decide if I want another "learning experience" with this car I shouldn't be having this problem as I built the engine in the first place and drove the car for eight years before this. When I decide what I'm going to do I'll get back into this.

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 Posted: 10-06-2016 11:18 am
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qwerty
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Hi All,  I'm a new JH owner and learning the ropes, i request your patience.

I'm trying to work out this timing, it was done by my late father. I know my way around an engine but not specifically cam timing, it's a little over my head for the time being.

Would anyone know what the MOP timing of the white marks are? I understand MOP yet it's the why i don't understand. I remember when we first drove it home it was terrible but after a few months it was running very very good!

I'm yet to turn over the enigine, even by hand as it's been sitting for a while so i have some work to do.

Not sure yet how to post two images in sequence yet, i will post another below of his thoughts at the time which may help.

Attachment: WhiteMarks.jpg (Downloaded 88 times)

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 Posted: 10-06-2016 11:20 am
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qwerty
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Camshaft Drawing

Attachment: Camshaft1.jpg (Downloaded 89 times)

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 Posted: 10-10-2016 06:57 am
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Esprit2
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The second file, the camshaft drawing, is pretty illegible. I've reversed the color bias so that it has a white background, but the resolution is still low, fuzzy. Can you re-write the notes in a message here?

What cams are installed in the engine? Can you confirm what MOP pulleys are used. From what I can see, I presume they're the standard Lotus dual MOP pulleys, 110 red dot and 100 blue dot. But it's not good to guess when timing cams, so please confirm the starting point... what cams and pulleys are installed?

For the sake of conversation, let's say the pulleys are the 110 MOP (red)/ 100 MOP (blue). In that case, the first thing for you to understand is that there were separate single-MOP pulleys that were true 110 MOP (red) and 100 MOP (blue). But 110 and 100 do not fit on the same pulley, so the 110/100 dual MOP pulley cheats, and the blue dots are really 97 MOP, not 100. If your father had tried to reverse engineer the pulley's math based on 110 and 100 being 4 teeth apart and the pulley flipped over, it would have driven him nutz... it doesn't work.

Also, there are 40 teeth on the pulley, and 360 degrees in a circle, so 9 degrees per tooth. However, cams are timed in 'crankshaft degrees', and there's a 2:1 ratio in crank & cam speeds. Therefore, each tooth is 18 crankshaft degrees. One tooth beyond the red dot 110 MOP advances the cam timing 18 degrees, or 92 MOP, which is not a useful value with the OEM cams.

The white marks in your first photo have no value in timing the stock J-H 907 cams.

If the cams are stock C-cams, and the pulleys are 110/100 (97), then the best cam timing to use is 110 IN and 110 EX. The Lotus 100 (97) and JH 115 MOPs were emissions settings, and results in a loss of power compared to 110 IN/110 EX.

The photo shows the pulleys to be installed the correct way around. The raised bump on one spoke faces forward on the exhaust pulley, and backward on the intake pulley. That's correct.

Now, rotate the crank until it's at TDC. Then the red dot next the the IN mark on the intake pulley should align with the red dot next to the EX mark on the exhaust pulley. That will give the design-correct 110/110 MOP.

The original JH 115/115 MOP reduces power output about 10 Hp. If you want to use that setting (why ??) it's also on the 110/100 (97) pulley, just not marked.

In your first attachment, the photo of the pulleys, refer to the intake pulley... it's the most straight-on shot, and the easiest to read.

The timing dot farthest to the left/ counter-clockwise (nearest the white mark) is red, or 110 MOP. The alternative blue timing dot is 4 teeth clockwise, and is 100 (97) MOP... EXCEPT it's next to an EX mark. Follow that tooth to the back side of the pulley, and you'll find a second blue dot next to an IN mark. To time the cam to 100 (97) MOP, the pulley must first be removed, flipped over front-to-back, and re-installed (ie, raised bump facing forward on the intake pulley, or facing backward on the exhaust pulley). Then rotate the INtake pulley until the blue dot next to the alternate IN mark aligns with the dot next to the EX mark on the EXhaust pulley.

Similarly, the missing 115 MOP dot would be three teeth to the right/ clockwise from the red dot, on the tooth next to the tooth with the blue dot... next to the EX mark. Again, follow that tooth to the back side, and that's where the 115 dot would be next, to the IN mark.

So you have your choice of three MOPs with the pulleys shown in the photo. But, IMHO, unless local emissions inspections will not allow the OEM cam timing to be altered, there's no desireable reason to use either of the alternative MOPs, 100 (97), or 115. The engine will run it's best if you time the stock cams to 110 red IN / 110 red EX.

But before taking all that to the bank, first confirm what cams are installed in the engine, and look for any marks stamped on the pulleys that indicate the MOP. Normally, the MOP would be stamped on at least one side.

Good luck,
Tim Engel

Attachment: JH Cam Timing for qwerty - White Background.JPG (Downloaded 65 times)

Last edited on 10-10-2016 06:52 pm by Esprit2

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 Posted: 10-10-2016 07:30 am
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Esprit2
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JHPS allows file attachments up to 102kb, and your drawing is only 17kb. Do you have a higher resolution version that you could post?

Regards,
Tim Engel

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 Posted: 10-10-2016 08:13 am
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qwerty
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Thanks Tim, that sheds a bit of light on the subject.

I'm sure he knew that the 110/110 timing was correct for the engine without emissions and is why the white marks have piqued my interest, maybe he messed about with the overlaps as seen n the drawing allowing it to breathe a little better. It has DHLA45's on it. I doubt is has a different Cam but i will check ...how do i check?

I'm sorry i can't get it any bigger that the attachment without going over the limit.

The Notes to the bottom left are:

RED DOT        110 MOP
BLUE DOT       100 MOP
YELLOW DOT  102.5 MOP
GREEN DOT    104 MOP

EUROPEAN SPECS  INLET 102.5 A.T.D.C.
                              EX   102.5 B.T.D.C.
NORTH AM SPECS  INLET 100    A.T.D.C.
                              EX   110    B.T.D.C.

Attachment: CAM.PNG (Downloaded 63 times)

Last edited on 10-10-2016 08:39 am by qwerty

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 Posted: 10-10-2016 08:37 am
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qwerty
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Absolutely no numbers on Cam wheels, front or back.

Attachment: IN.JPG (Downloaded 62 times)

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 Posted: 10-10-2016 08:37 am
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qwerty
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Ex

Attachment: EX.JPG (Downloaded 62 times)

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 Posted: 10-10-2016 08:46 am
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qwerty
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"If the cams are stock, and the pulleys are 110/100 (97), then the best cam timing to use is 110 IN and 100 EX. 100 (97) and 115 were emissions settings, and results in a loss of power compared to 110 IN/110 EX."

Is that a typo Tim, should that read 110 IN /110 EX?

I apreciate your knowledge Tim, i've read quite a few of your posts regarding cams in order to understand them.

Regards
Peter

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 Posted: 10-10-2016 09:56 am
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subwoofer
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You have both cams installed with Red Dot (110MOP) as the valid timing mark, but if I am not much mistaken they have been timed one tooth advanced (if the white marks are anything to go by).

--
Joachim

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 Posted: 10-10-2016 10:38 am
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qwerty
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That's what it looks like yet for anyone reading please note  i am a complete novice when it comes to Cam Timing.

I wan't to get it running with this timing first. I remember spending a lot of time on this and at the end of it all the JH ran very very well. Dad without doubt knew what he was doing, i know that much. Timing it to Red dots 110/110 would have been a no brainer for him as i have already learn't through reading and he would have done through calling people in the know. He didn't have access to internet resources back then, only a bunch of manuals sent over from Cropperby Bridge and AutoCad. This is the whole reason i'm exploring this. Maybe it does have non standard cams, as yet i do not know. Maybe it's to let the DHLA 45's breathe.

For now though i have to get over the damned Manflu. Greg's box of goodies (ps thanks for packing the inside rad hoses with styrofoam haha, i'm assuming this is so they wouldn't be crushed in transit??), a Gates blue belt, wheels, tyres, tools and steering wheel came in last week and i was all set to have a dirty weekend untill the sniffles happened!!

Last edited on 10-10-2016 10:43 am by qwerty

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 Posted: 10-10-2016 11:33 am
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qwerty
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Tim,

Thinking out loud here, Could this be the end result of the Aux pulley being out by 1 or more teeth and correcting for it?

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 Posted: 10-10-2016 11:43 am
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subwoofer
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That would make things even worse, as the ignition timing likely would be out as well (although that can be corrected by turning the dizzy).

But I know for a fact that a 907 with C cams (standard issue JH spec) will run two teeth off on the cams, just not well. Open the cam covers to look for the cam markings, IIRC the standard JH cam will have a number of 'C's stamped in somewhere behind the pulley seal, later Lotus spec cams will have an 'E' (Eclat/Esprit S1), '4' (104-cam, intake side on later NA engines) or '7' (107-cam, turbo spec).

Any aftermarket cam would not be ground one tooth off for sure.

--
Joachim

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 Posted: 10-10-2016 01:10 pm
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qwerty
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Thanks Joachim,

I will be taking the cam covers off later this week or on the weekend. I will look for markings.

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 Posted: 10-10-2016 07:52 pm
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Esprit2
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qwerty wrote:
(Snip)... I doubt is has a different Cam but i will check ...how do i check?
On the stock, OEM cams, there were marks on the bit of exposed cam between the pulley and the cam carrier's front seal. The first marks were grooves cut around the cam, none, one, or two grooves. Later, the grooves gave way to a series of numbers stamped around the shaft.

No mark = C-cam, the J-H OEM cam, 272° duration, 0.340" Lift, 110 MOP. This was also the original Lotus cam used for Federal 907 engines.

1 Groove = D-Cam, Orig Lotus Euro 907 cam, 270° Duration, 0.350" Lift, 110 MOP.

2 Grooves = E-Cam, Later Lotus Euro 907 cam, 260° Duration, 0.344" Lift, 102.5 MOP. The 907 was designed by the same motorsports enthusiasts who brought us the berzerker Seven, Elite Mk 14, Elan and Europa, and the Lotus-Ford Twin Cam engine. And they were still in berzerker-mode when they designed it. They did not anticipate that their new customers for the 3rd Generation cars (4-seat Elite-Eclat, and Esprit), would not appreciate having to drive the cars with their foot mashing the throttle to the floor.

When they began to see the light, the E-cam was their first attempt to make the 907 more mild, with a stronger low-end torque curve... at the expense of top-end, balls-out power. It's the same design philosophy use in the later 107 cam, but the E-cam was a smaller step in the mild/ torque cam direction. The 107 took the idea further.

7777777... stamped all around the cam = 107-cam, 912LC & 910 cam, 252° Duration, 0.378" Lift, 104 MOP. This cam goes even further in the direction of improving low-end torque and driveability in commuter traffic, but at further expense of top end power. A 9XX engine with two 104 cams will still reach redline, eventually, but it clearly starts to run out of breath above 5000 rpm... definitely above 5500 rpm.

4444444... stamped all around the cam = 104-cam, 912HC Intake cam (along with 107 on exhaust), 272° Duration, 0.410-0.420" Lift, 104 MOP, 64 Overlap.

5555s, 6666s & 88888s indicate the 105, 106 & 108 competition cams that are not appropriate for street use.

The trouble is that a lot (most) of the non-stock cams now found in 907s are re-ground. Some vendor took an original C-cam and re-ground it to meet E-cam, 107 or 104 specs. And most of them didn't bother to alter or add an identifying mark. You really can't tell just by looking what it is. In that case, measuring the "Lift" will give you some clue whether the cam is stock, or something else. If something else, then does it match the lift given for one of the other 'Lotus' cams given above. If not, and it's a totally different aftermarket grind, then your guess is as good as mine.

*~*~*
Early on, Lotus used one part number for all cams, but with a different Alpha prefix identifying each cam... hence the C-cam, D-cam, E-cam naming. Later, Lotus changed the part number format, and each cam got it's own discrete part number, and the common name became the last 3 digits of the 'serial number' portion of the part number... ie, 104 & 107 cams. The fact that the 104 cam also has a 104 MOP is purely coincidental. The C-cam, etc, also got new part numbers, but the fans still use the old alpha-names.

(Snip).... The Notes to the bottom left are:
Here's your notes with some info added:
RED DOT ....... 110 MOP = design correct MOP for C-cam & D-cam
BLUE DOT ...... 100 MOP = Federal emissions timing for C-cam & D-cam
YELLOW DOT .. 102.5 MOP = design correct MOP for E-cam.
GREEN DOT .... 104 MOP = design correct MOP for 104 & 107 cams

EUROPEAN SPECS .. INlet ....... 102.5 ATDC .. YELLOW Dot
............................. EXhaust .. 102.5 BTDC .. YELLOW Dot
That's the yellow-dot pulleys for the early Euro 'torque' cam, the E-cam.

NORTH AM SPECS .. INlet ....... 100 ATDC ..... BLUE Dot
............................. EXhaust ... 110 BTDC .... RED Dot

That's the red-blue dot, dual-MOP pulleys for the Federal emissions 907s, with the C-cam. The Red-Blue pulleys could also be used to time the D-cams to 110 MOP.

Regards,
Tim Engel

Last edited on 07-11-2017 05:29 am by Esprit2

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