Hey guys and girls,

I've been a 928 owner for several years and learned most of the in's and out's of the water cooled cars, but have now bought a 1989 C4.

I have ordered a maintenance kit from Pelican and am planning on adjusting the valves once it comes in. Has anybody used the alternate method of checking the valves that doesn't require the Porsche tool where you can use a normal set of feeler gauges? Are the results as good as using the regular procedure in the books?

Thanks for any insight!
Jim

 

The feeler gage cost is practically a rounding error in the cost of a major service. It is possible to snake a flat feeler into place, and of course some feeler gage sets come with the tip bent at a 45 degree angle.

It is more accurate to use a dial indicator. There is a z-bar holder for that purpose. Of course that is far more expensive than the feeler gage. I use both methods and don't quit until I am convinced the valve is adjusted within a micron or two of the specification. The 0.1 mm setting is 100 microns, so there is not much room for error.

Do a search. Unless you have a lot of experience, setting the valves correctly is tricky. You will see when you are in there that you don't want to button up and discover you have a noisy valve and need to go back in. Buy the right tool and take the time to do the job right. It is so important that it is not a bad idea to run through a second time to verify all valves are spot-on. You will have no regrets if you spend the extra time to get it right. You will suffer considerable heart ache if even one valve is out and you hear it.

 

I have been told that the engine needs to be COLD...

 

In other threads it has been suggested that the correct setting is tight enough that the feeler gauge must be pulled out rather than having it slip out with some drag.

If so, how do you go back and check them all a second time? I have trouble enough getting the feeler in when the gap is loose! I've found that I pretty much have to loosen the gap to get the gauge in and then tighten down.

I'm still trying to get a proper understanding and feel for the valve adjustment.

Thanks,
Dave

 

I cross check with a dial indicator, and I do not agree that the feeler gage needs to be forced in or out. There should be friction, but just enough to prevent gravity from moving the feeler gage. The valve spring is starting to compress if force is required to remove the feeler gage.

I agree it is a bit of a chore getting the gage in. If the valve is correct, it will go. Otherwise, you would need to back off every valve to check it. Trick for getting the gage in: there is a ball end on the lash adjustment stud that lets the tappet stay flat on the end of the valve. You can tilt the tappet just enough to get the feeler gage started, and then it will slide in.

 

I'm assuming on the back side of the rocker arm. What value do you use?


That's a good tip! Thanks.

 

I did the back side method.... it is supposedly very accurate but a pain in the *** nonetheless. I think i had to do it about 3 times to get it to where i thought it was good. It is still more foolproof than the original way though. You can print it out on pelican if you did'nt already know. Good luck.

HEY SPRINGER WHATS UP????

 

The Z holder positions the indicator on the top of the adjusting stud - no way to adjust the valve with the indicator in place, but a good way to cross check. The value is 0.1 mm - same as putting the feeler between the tappet and the valve stem.

 

Not much, just busy all the time lately. I was afraid you would be in the Middle East by now. How is that going?