tap tap tap
- Thread starter Ryan944
- Start date
Oil viscosity may be a bit thick for this cold weather, is it kept outside,may try some thinner oil and sort it ? Put a large screwdriver on the fuel pressure regulator and fuel injectors then stick it on your ear the sound will be amplified as they can also tick tick.
Good flushing oil (or oil flushing agent before you change it - Wynns do something specifically for this). Change the oil when the engine is hot to get as much out as possible. The usual advice is to use a slightly thicker grade of oil, so less drains out of the lifters when the car is parked, but I'd not use anything too thick in this weather as it will turn to treacle in the sump! To a large extent, they all do this. Noisy tappets when cold is part of 944 ownership. As long as they quieten down within a couple of seconds of starting then it is nothing to worry about. Oli.
mr brightside
New member
Isn't it caused by some check valve thingy in the head failing, so as to let all the oil drain out overnight?
MrB, I have heard tell of this valve, but I think it rarely fails. Isn't it the case that they are all noisy on start-up, but those with the failed valve are very noisy? (And replacing/changing the valve is a very involved, head-off job, so much better to put up with the noise for a few seconds every morning.) Oli.
mr brightside
New member
I'll take your word for it, i'm actually glad the case may be that mine hasn't failed as i thought. It's only rappy on one when it's cold, it's embarrasing but i can put up with it if everyone elses is doing the same. I'm thinking of getting the head rebuilt this winter to try and stop it smoking, are the tappets cheap enough to be worth changing? I'm thinking of fitting one of those fast road cams from america (JW or something?) and a new cam is going to require a regrind and reshimming of the old tappets at the very least i suspect.
The internal valves in the tappets will be shagged letting the oil flow out of them. Worth nipping the cambox off next time the belts need done and checking them all. If you can compress the pad with your fingers, they are U/S. I have a big box of good S/H ones if you want any, £5 a go. New ones are rather pricey! Alasdair
MB, The tappets don't need grinding or shimming. They work with little hydraulic pistons, and 'pump themselves up' to the right size. Hence zero-maintenance, but if they drain all their oil overnight then they are noisy while 'pumping themselves up'. Google them for a better explanation. Downside is that if they get noisy then you either live with them (taking steps to make them as quiet as possible), or replace them. You can't adjust them by re-shimming them. And replacing them ... let's say you probably need to be sitting down when you learn the price of them. Which is why everyone lives with them being a bit noisy. I could be wrong about the valve preventing oil drain ... it sounds familiar (from what I have read on here), but I could be very, very wrong. Always a fact worth bearing in mind! [&:] Oli.
Hi Oli, complete pish puts it mildly. It is a mechanical part, just like a mini shock absorber internally to take up the clearance between valve stem and cam base circle or lobe so really not many wear parts. The only problem you get is the small needle valve to stop the oil flowing back under pressure. When these become damaged or worn, that's why you get noisy tappets. We changed a cpouple recently in Stuarts (scam75) turbo as 2 of his were soft. Car now a lot quieter. Alasdair
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mr brightside
New member
Cheers. Google's a bit light on technical images but there's just enough for me to get an idea of what one looks like, i had no idea they were so complex. I think i'd still have the cam end tappet faces polished up leaving a few witness marks just to make sure they were completely flat if i were fitting a new cam.
Thanks for your offer Alasdair. I've got into the habit of letting other people fiddle with my Porsche, i'm more of a push rods and carb person, but i'm sure i could stretch to removing the rocker top.
scam75
Well-known member
Hi Oli Cambox off then flip it over to remove/inspect them. Cam did not need to come out although we took it out to inspect it which is probably a good idea at that point. As Alasdair says, they are gubbed if you can compress them by hand (as 2 of mine were!). Then you get to play with them as you refit the cambox which can be amusing as they fall out when you flip it back over!! Some grease strategically placed ought to suffice! Stuart
david924s
New member
I found this link (OK for Calibra) but it shows the overhaul and reconditioning of INA Hydraulic tappets, I haven't tried this yet but I have a full set from a good car to try this on and maybe replace the 1 or 2 pairs that are noisy on my S2. Might be useful to someone, obviously if the spring is snapped or badly worn no amount of cleaning will help it I suspect. [link=http://www.nuvision.ndo.co.uk/tappets.htm]http://www.nuvision.ndo.co.uk/tappets.htm[/link]
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