djimenez993tt

hi guys,

again tapping into our HUGE collective knowledge of all porsche related things.

I attended a DE event and after some good laps my engine would develop a lifter knocking noise. after letting the engine cool down I would re-start it and it had disapeared, same thing happend twice.

some facts to help us out:
1. oil is about 1500 miles old (porsche spec, oil change done at the stealership)2. oil guage while at operating temperature was a bit under the halfway point.
3. oil temperature never exceded 9 o clock.
4. noise came from drivers side heads

thanks in advance,
David

Steve Weiner-Rennsport Systems

David,

A few Q's;

Precisely, what oil did the dealer install in there?? 0w-40?

How many miles are on your engine?

How often has the oil been changed since the car was new?

The answers to the above will help diagnose the problem.

djimenez993tt

Steve,

I would say that the oil might be too thin. I doubt the dealership would have 20w50 as they only service post 996 porsches.

the engine has abput 30k miles on it.

i would say the oil has been changed every 3-5k miles.

thanks,
david

Marlon

Steve - is 0/40W 'bad' for a street car???

993James993

https://rennlist.com/forums/showthre...llapsed+lifter

TheOtherEric

You probable have collapsed lifter(s). Not uncommon.

I have a theory about this too, that I've never investigated. I wonder if collapsed lifters might cause the engines knock sensors to think the engine is knocking due to the vibration. Then it would retard timing, causing lots of power loss. Just a hypothesis (which could be checked pretty easily, actually).

Steve Weiner-Rennsport Systems

David,

FWIW,.....Lifters fail from heat (hard, dried-up seals) and dirt (infrequent oil changes).

From your description, I'd venture that some of the lifter seals have hardened up and are allowing them to bleed down. All 993's are subject to this over time with the TT's being as bit more prone to due higher cylinder head operating temps. The slightly thinner oil exacerbates the bleed-off so you might do a bit better with a 15w-40 or 20w-50, expecially in south Texas,...

We usually pull the offending lifters to have a close look at them and if the seal is cracked or falls apart when they are removed, new ones are installed. Seals are not available for these applications. Personally, I would look at ALL of them.




Marlon,

Given the tone of the oil threads on the 993 Forum and Pelican, I think I'm going to refrain from offering oil opinions any longer since its akin to religious or political discussions and I'm sure you know how constructive that usually becomes and the normal outcome,...

To each his/her own and ultimately one should use (believe) whatever makes them happy.

AX993

Steve,
FWIW, I for one have & will always appreciate your sharing of your knowledge & expertise on any & all subjects !!
I only wish your shop wasn't all the way on the other side of the country !
Glenn

Pete Lech

Recently I had a stuck lifter after starting the car for the first time in several months. Hergie's recommended that I add a qt of ATF and see if that helped.The car had sat for a day when I added the ATF, so it went right into the sump. I drove it moderately and it came unstuck in about 2 miles. I drove the car for about 100 miles and I swear that the engine is much quieter than before.
I just changed the oil (using Motul 300V 15W-50 again) and the motor remains quiet.

I realized that I only had driven the car 2000 mile in the past 12 months since the last oil change - mostly autocross miles and to and from the track. Gotta drive it more!

TheOtherEric

Pete- What's the theory behind how that could work? AFAIK, they "tick" when they're collapsed, and nothing will bring a collapsed lifter back to life. Just trying to understand how that could help....

Perhaps yours wasn't collapsed, but rather "stuck" -- but what does "stuck" mean?

murfysflaw

If they are collapsed, aside from the noise and power loss, is there other damage that could occur from carrying on?

TheOtherEric

For a short time (weeks /months), no biggie. Just thinking out loud here, but I'd guess the affected cyliders won't be breathing as well and will likely run rich, with much more unburned fuel. And if the ticking causes the knock sensors to trigger (again, my pet theory) then the timing retard would cause that cylinder to run hot, which is not good.

murfysflaw

True... I have a bit of noise my mechanic noticed during the first oil change. Not bad at all. He just noted that we probably had a couple of lifters (drivers side IIRC) that needed some attention at some point.

Cy

I've had a similar situation with my car for the past 5 years. I live in NYC, but keep the car in Atlanta and only use it for a week each of the 3 or 4 times I make it home each year (so the car only gets from less than 1,000 to, at most, 2,000 miles per year).

Approx 50% of the first time starts from storage I get the clicking noise for maybe 5 minutes and then it goes away. It definitely sounds like only 1 lifter and it seems to go away faster if I actually drive it versus idle (which is probably due to the higher RPM and consequent pressure in the system). And the situation never occurs again after that initial start for the rest of the week or so that I use the car.

My thoughts were that it doesn't seem to be serious and to leave the lifters alone until I have some other work done at some point and then get them all replaced "while they're in there". But, as always, any thoughts otherwise would be greatly appreciated.

Regards,


(As noted before, I am a paying member but don't seem to be able to get my status updated.)

Pete Lech

You are correct in that it was stuck. i had one collapsed (while restarting a hot motor) and that was a lot louder. This was somewhat less noisy, the motor was cold, and the car seemed to run OK.

The theory is that ATF has very high detergent levels and will sometimes free a stuck lifter, as it did in my case. Glad these cars have 2 oil filters, especially that big one in the fender well.

Obviously i wasn't driving the car enough, although I do not use it for short trips. Based on the now much quieter motor, I must have had some slightly sticky lifters despite the thrashing on the track.