I recently did the headgasket on my 968.
Ever since then I have had what sounds like a tappet noise, but unlike
most hydraulic tappet noises this one isn't there on a cold start-up, but only
appears, when the engine is properly warmed up. Anyone ever heard
of a problem like that?

Any suggestions as to what to investigate next? I don't really want to
replace all the tappets, if i don't have to.

Paul

 

might just be the injectors, they are pretty loud on these cars

 

I track a 968 and if it sets for a few weeks it will make a tappet noise that goes away after about 5 minutes. Doesn't make much noise after that, I changed my head gasket due to a timing belt issue a year or two ago and haven't had that problem. What oil are you running? Mileage? Oil pressure? Mine is at 5 cold and goes to 3 for idle warm. My fuel injectors have just been serviced and sound the same as before rather quiet compared to the rest of the motor and this is a noisy motor! You should be able to put a stethoscope on the head and see if it’s just one or two, doubtful it would be all of them.

 

Car has 148K on the clock, and before the headgasket change it was pretty quiet. Oil is mobil 5/30. Oil pressure is 5 on a cold start and 2.5ish on a hot idle. The engine is very quiet on a cold start and interestingly its about the point where the oild pressure starts to drop that the tappety noise starts. Don't know if thats related or coincidence. It sounds like the noise occurs at about 10Hz when I hold it at 1200rpm, that means it should be happening every other revolution right?, would that coincide with one of tappets being out.
If I get cam cover off is there any way to tell which ones are bad? Though if I have to get cams out I would probably replace all followers, rather than just some, avoid risk of having to get them out agina at some point.

P.

 

Your lifters aren't bad.

Your oil is the problem, 5-30 is way too thin.

The 30 is much too thin at temperature, you need an x-40 minimun, but you should really use 20w-50.

Use 20w-50 and it will stop.

 

I was going to say the same thing although if the car isn't tracked the reccomended oil for all water cooled Porsches is 0W-40. I'm actually running this in my track car and don't have any issues although my friends are running 15W-50. For everyday driving you need a lower winter weight particularly during the colder months to minimize engine wear at start up.

 

I can't find a 15-50 or 10-50 anywhere...where do you get those weights and who makes them?

 

Mobil 1 Extended Performance comes in 15W50.

 

Your oil is too thin! 15-50 or 20-50 of your favorite brand, and it should quiet down.

What oil was in it before?

 

Sorry typo on current oil, its actually 0-40, which is what I have always used, I don't think its the oil.
Took the cam cover off today with engine warm and car making tapping noise. All followers apart from one were rock solid when I tried pushing them down with a rod, one of them was quite soft, with probably 3mm movement with not too hard hand pressure. Turning it over with cover off and there was a distinct tapping noise coming from that region just as cam started to compress that valve.
So new followers, now question is just the one or all 16....
P.

 

Whe doesnt everyone just run 10w-40 mobil 1 synthetic. Its the best oil and you can run it all year round, and it can go all day long at the track.

 

Because these cars are supposed to use 20w-50 and for the track you should without a doubt use xx-50 and even xx-60's are used. The xx-40's are too thin an oil at temperature for these cars.

You should only use 10w-40 in these cars when it's below 30F

 

Oil is like religion. Why isn't everyone a Catholic? It's the best religion! But it is fairly well established that these 4-cyl water cooled Porsche engines "like" 20w-50 in temperate to warm climates and given my location, that's what I run year-round. I won't get into brand choice.

 

Most of the mechanics and racers around here will only use 20w50.

jamie@944online.com

 

roccap,

Before you go any further change your oil to 20w-50 take it for a drive, and tell us your results.