Porsche Enthusiasts Club Forum

Hi All,

Spent some time this morning removing my cam tower on my 2.7 project 944 to replace some collapsed/failed hydraulic cam follower valves. Can someone confirm that a bad cam follower valve will be firm when you try to depress the valve? I have 5 that I can squeeze under finger pressure and 3 that are solid and do not compress at all under finger pressure.

Thanks
Ian

Hi Ian,


No, the ones you cannot depress are the good ones!


These are the duff ones.


These are the good ones.

What are you doing about replacements? If used is OK, I have loads in my garage...

HTH,

Jim.

really? got my thinking back to front...
I have some spares but not sure I have 5...
How much for some serviceable cam followers?
thanks
ian

TBH depends on how much oil they have in them! The ones you can depress are dryer than the ones you can't pop them in a vice with some wood to protect them & see if they compress then. The dry ones are the ones that clatter when you start it after it has been standing. Make sure if you are replacing them they stay in the same 'oles.

Hmm. Now confused.
The car had not been run for approx 4 years when i got it- and when i finally got the engine going, it was of course very clattery. The engine did quieten down a little with some use, but clearly I think several cam followers are not pressurizing - without going to the expense of buy 8 new ones (>£300!)- is there a foolproof way saying 'this cam follower is a dud'? I'd hate to strip the cam tower twice....!
thanks
ian

They do fail but rarely. It can take 2-3 cooling fan cycles to stop the clattering. Even more so if it has been standing a long time. There are various additives for hydraulic followers that can help, sometimes an oil change & a good run can help.

Hi
Yes thanks tr7v8 - I have changed oil and run through two top end additives (one in old oil and one with new oil) - but still no joy on a quiet engine. Having run VWs before with similar hydraulic valves - even on hgh milage engines, the clatter was not as bad and they would quieten within 5-10 minutes as the engine warmed.
Cheers
Ian

I have some noisy tappets in my S2 which do quieten down after a short while, I had an engineer while looking at some other stuff check the cams, chain and tensioner, and balance shaft bearing for something else and we decided at least those cam followers on No. 3 & 4 cylinder inlet valves were probably the culprit of the noisy tappets. These were shiny on the outside edge and could be rotated in the head (not easily but still moved where the others were tight) when the cam was not in full compression.

I know I need to change at least these but my concern is would new cam followers be any tighter in the head i.e. is it the head that is worn not the followers as these look harder material than the head unless they fit in a toughened sleeve, which I do not think they do and if I went to the trouble of removing the cams and belts etc I think I would want to replace all the cam followers for piece of mind but with 16 at around £30 ea this is a bit too expensive at present.

Cam followers should rotate when the engine is running. If you mean they are loose then that is an issue, as they'll drop pressure. Oversize followers are available for some engines but not sure about Porsches.

Thanks Jim, for the piece of mind there, they do rotate when turned by hand and some turned easier than others but are not loose in the seats.

Just keep my eyes open for 16 replacement items almost had some twice now but missed the chance (Porsche ones rather than INA items I think).

Just a quick update - for info - with help from Jim on here, I have managed to replace the hydraulic cam followers and after a few seconds of clicking on restart - the engine is now much much quieter - just other noises to worry about!
Thanks again
Ian

Glad I could help.