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bgammie1 · Joined: 20 Mar 2011 Posts: 100 Location: Snellville, GA

adjusted the valve clearance because only 1 out of 8 was in spec
(4Ex was .40)
Spec cold engine .10 intake .40 exhaust.
Managed to adjust 7 out of 8 no problem.
All valve clearances are in spec now except for
2Ex most I can get out of it is .25 because if I back the adjustment screw out any further it will hit the wall of the cylinder head and I know that's not good.

How can I resolve this issue?
should I just go with .25 and consder it close enough. Before adjusting it was only .20
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BFG
1982 Porsche 924 NA

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

Pull the cam, remove the follower, and see how the bad ajuster is marked (either paint marks, or notches). Report back.
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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

bgammie1 · Joined: 20 Mar 2011 Posts: 100 Location: Snellville, GA

RM -- removing the cam shaft seems to me like a lot of work.
So I am going to ask what is probably a dumb question (I'm a noobie I think I'm allowed to). Can I just completely screw out the adjuster and look at it and if it is bad or the wrong one replace it with a good adjuster?
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BFG
1982 Porsche 924 NA

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

Hmm, maybe you can remove it but it might be tricky getting the replacement in.

The point is, that adjusters come in different thickneses, and if the adjuster doesn't give you the range of adjustment you need, you replace it with a thicker, or in your case, thinner adjuster.

P.S. Compared to some jobs on this car, pulling the cam is not that bog of a deal.
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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

emoore924 · Joined: 13 Apr 2004 Posts: 2822

If you leave the screw that screwed out (so that it is NOT engaged by both sides of the follower), you'll be pulling the cam and the head 'cause you're gonna mangulate the follower and the head and maybe the cam, and that is a bit of a big deal.

bgammie1 · Joined: 20 Mar 2011 Posts: 100 Location: Snellville, GA

Screwed in the adjuster enough to clear the cylinder head and have .30 clearance now. Is there any reason why I can not run the engine like this.
I'd like to know before I crank it up and damage something.
Thanks for eveyones input so far.
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BFG
1982 Porsche 924 NA

bgammie1 · Joined: 20 Mar 2011 Posts: 100 Location: Snellville, GA

I sure could use some detailed drawings and/or pictures to help me understand the mechanics of how the adjuster assembles into the cam follower.
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BFG
1982 Porsche 924 NA

porscheboy79 · Joined: 25 Oct 2010 Posts: 65 Location: Sydney , Australia

Hi bg

i hope that helps

regards
Shane

porscheboy79 · Joined: 25 Oct 2010 Posts: 65 Location: Sydney , Australia

porscheboy79 · Joined: 25 Oct 2010 Posts: 65 Location: Sydney , Australia

Hi BFG

I have had to deal with burnt Exhaust valves before due to miss adjustment in the belief i was gaining HP by the valve being open longer. ( young and stupid!)

So I would strongly recommend to remove the cam and source the correct screw.

I have t/belts on these down to 10 mins at the track. (dodgey cam gear).

Stop engine at TDC

Check in dissy for rotor alignment and mark.

undo 3x 10mm bolts for housing of dissy. Slide back out of way.

Mark with paint the cam gear and belt relation then the same at crank.

Belt off.

Valve cover off and loosen cam caps in correct order a bit at a time.( to avoid damage via bending etc.)

Cam out. while there check lobes. if stuffed don't bother reassembling get new cam! Then continue...

Slide out follower.

this will be quicker than trying to insert it blind with 2 cm room to move.

You may have had another follower with too much clearance swap them and refit cam correctly and measure.

once happy with clearances torque everything down make sure oil tube in correctly.

Valve cover on.

Belt on at painted marks.

Just my opinion but i have had the heads off these cars probably 20 plus times in the last ten years and as RM says a cam out is easier than a head!!

Regards
Shane

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

The main point here is you need to do things right on this car or you are "building" another parts car.
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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

fiat22turbo · Joined: 18 Jan 2006 Posts: 4040 Location: Portland, OR

Um, it's a screw. You screw it in to take up slack and screw it out to give it more slack.

There are different screws for different thicknesses to adjust for wear and tear. The different sized screws are marked on the ends with marks; they range from thinnest with 0 marks to thickest with 4 marks.

To adjust them properly, you have make sure the threads are engaged on both sides or the valve stems and that the flat edge of the screw is resting on the top of the valve stem. You'll know this because the screw will "click" into place.

If you're unsure about the position of the screw, etc or you need to change the screws, I would put the engine at TDC, note where the distributor is pointed/oriented and pull the cam belt off the cam (let it sit aside) and then pull the cam. It really is the only way to be sure the followers are correct.
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI

Each 360 degree turn of the grub screw will adjust the clearance by .05mm. Theoretically. If you are all the way in (on the thinnest part of the screw) and you still can't get to within spec, you need the next thinnest screw, which from memory is .05mm thinner than it's predecessor. As Stefan noted, they came in five varieties: 0 notches, 1, 2, 3, and 4 notches (reference porscheboy79's photo). New grub screws are NLA from Porsche, so if you need the next tolerance, your only option at this point is to source a used one from somebody. The first thing you need to know is what tolerance the screw is on the valve that you cannot adjust properly. If it's a 0 notch screw, you need to go to at least the next thinnest, i.e. one with a single notch, or possible 2. If you have a 2 notch screw in, you need a 3 or 4, etc.

I would strongly recommend AGAINST trying to replace the grub screw with the cam in situ because the valve will be under pressure from the springs, and the stem may go up into the bottom of the follower, you're unlikely to get the new grub screw reinstalled.

One thing I've learned is that it seems like the cam needs to be turned immediately after adjusting to allow things to snap and seat properly. So I'd recommend adjusting all 8 valves; turn the cam, check again; if you adjust, turn it again and check again. Continue until all valves are exactly within spec;

Bottom line, it sounds like you need a thinner screw, and the only way to do it is to remove the cam. It's really not as bad a job as it seems at first, and well worth it, as improperly adjusted valves can cause bad vacuum at a minimum. Once you get the the lifter removed, let us know how many notches are on the grub screw. I have several spares that I'm hanging onto with white knuckles, but could be persuaded to part with one, provided I have what you need.
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erstwhile owner of just about every 924 variant ever made

RC · Joined: 25 Mar 2007 Posts: 2637 Location: Australia

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI