924Board.org

[brupska]

Well I have found the information in my Haynes manual on what to adjust the valves for my 81 NA 924. The thing I am having problems with is which way to turn valve adjuting screws to loosen the valves up. When I turn them counterclockwise my exhaust valves don't seem to loosen up any at all. All the valves seem to be really tight!!! Any help would be great!! thanks Brad

[ideola]

Turn the screws IN (toward the RHS fender) to tighten, turn them OUT to loosen. One thing that Haynes doesn't explain is that you have to turn the lifter screw 360°. If you're using an allen wrench, it will take about 4-6 mini-turns to get the screw all the way over, and it will be quite stiff until you get the last turn, when it will pop back in place onto the flat of the grub screw. My guess is that you have several of the screws not completely turned over. Each complete turn = .05mm of adjustment.

You also have to be careful that the screws don't turn too far in or too far out. You need to make sure you have thread engagement on both ends of the screw, otherwise, you risk damage to the lifter. There are five different sizes of screws, indicated with notches etched into the opposite side of the allen head (zero to four notches). If you're finding that you have to turn the screw WAAAAY in to get proper adjustment, you need to move to the screw with one more notch on it than what is currently in the lifter. If you have to move the screw WAAAAY out, then you need to change to a screw with one less notch.
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erstwhile owner of just about every 924 variant ever made

[Martijnus]

[brupska]

Well I think the PO took the head off and the cam out. He must have mixed up the tappets and ajustment screws. When I started adjusting the tappets I couldn't find all of the openings in the tappets. So I took the camshaft out and turned all the screws toward the intake side to access them. I think I am going to take all of the tappets out and look at which screws are where. If I need different screws. Where can I find them? Thanks Dan and Martijnus

[Paul]

Assuming that the tappets were once correctly adjusted, you need to determine which one goes where.

I'd start but measuring and writing down the clearances for each valve. Then pull the cam and tappets and swap the tight and loose ones, and reassemble. Repeat until all can be adjusted correctly and all the screws are within range in the tappet bores.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

[Martijnus]

[Paul]

A proper machinist measures the installed valve height before any work is done, then grinds the end of the valve stem when the work is done to restore the same height.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

[brupska]

I know there has been no machine work done to the head, so I think the PO took the camshaft out and mixed up the tappets when he reinstalled them. I am going to take the camshaft out for a second time and all of the tappets too. I know the intakes valve lash is set at .004 inches and the exhaust are set at .016 in a cold engine. I am wandering which screw to go where? My best guess would be to install all the screws with the least amount of marks on the intake valves and the screws with the most marks on the exhaust valves to get the proper clearances. I am also going to back all the screws out before I install them again. If that doesn't work then I will have to put them in with the most marks on the intake and least marks on the exhaust valves. I want to thank everyone for all the input!!! If you have anymore sugestions please let me know. Thanks Brad

[ideola]

I can get 4-notch screws for anybody who needs them, $15 each. At last check, there was still decent availability of the 4-notch screws. The 0, 1, 2, and 3 notch screws are NLA.

Also, I just sent a full complement of these out to ARP last week after finally rounding up one of each flavor. They are going to take a look at the feasibility and cost effectiveness of reproducing them. I'll post when I have more info.
_________________
erstwhile owner of just about every 924 variant ever made

[brupska]

Thanks Dan, I do have intake vavle one set at the right .004 in. So I am going to take the cam out and compare the adjustment screws to this one and go from there. Right now I am stuck on #1 exhaust. It has less then .004 in clearance and I have backed off the screw more then 4 or 5 turns with out any difference in clearance. I was affraid of backing it off to much and loosing a adjusting screw into the engine. I would turn it a half turn and check then a full turn and check. That is why I am asking so many questions. Sorry. Brad

[Martijnus]

[brupska]

So if I am having problems adjusting my valves. I might need to take off the head a have the valves seats redone? Man this thing is making me crazy. I keep running into problems everytime I try to do something else!!!!

[ideola]

Get the lifters set to some sort of a baseline before you worry about removing the head. You have to start somewhere, don't worry about what it might be until you know what it is. Do as Paul suggested and take some copious notes measuring each valve carefully. It will be tedious and will require some time, but no use fretting about the head until you know where you stand with the lifters. Likely, it's just a matter of getting them put back into the correct order.
_________________
erstwhile owner of just about every 924 variant ever made

[brupska]

Ok I am going out in a few mins. and start measureing where to start!! thanks Brad

[Paul]