Netrunnerz

I have had my 2000 Porsche 996 C4 for a few months now, and I have recently taken it to an autocross school as well as an autocross race. During these 2 autocross events, I have noticed that after a few runs, the engine starts ticking. It eventually goes away when the engine cools down.

During normal driving, even If I push it, I have never been able to reproduce the ticking sound. I obtained service receipts for the valve lifter replacement which were all replaced 2 years ago because the previous owner was complaining about the same issue although, I am pretty sure he was only driving it on the road and not at a track or an autocross event. When I bought it, at the inspection, I had them change the oil and they put Liquid Molly 0W40. The oil level is almost full (7/8ths). The first time it happened at the autocross school, I added a few 100ml of oil thinking that I was low (I wasn't) but the ticking did go away.

Has anyone ever had this problem? If you did, what did you do to fix it? Thicker oil?

Thanks.

dporto

Be prepared to hear diagnosis of everything from scored cylinder(s) to impending engine failure! Whatever you do, don't overfill your oil - it won't do anything to help your situation and it could cause damage. It seems that even though we carry over 9 qts of oil in these motors, if you make a lot of high g type maneuvers (which I guess you could do at an autocross) the oil gets in the upper and outer parts of the motor/heads, potentially leaving other areas drier than normal. The oil also gets really hot and thinner than it might like to be normally (thermal breakdown/shearing). This may be leading to your ticking noise. Keep the oil fresh and keep it clean.

Sneaky Pete

Not to start an oil thread........Go to a thicker oil.

Slakker

I have to ask, what's the significance of your screen name?

Netrunnerz

Combination of internet and Road Runner...Z at the end is because someone else already has it. Came up with it over 20 years ago and just kept it.

Slakker

Cool. My previous obsession was a silly little game called Netrunner is why I asked.

Macster

It reads like the engine is telling you it doesn't like auto-crossing.

That is the resulting hot oil, high g forces, high RPMs, aerate and thin the oil to the point one (or more) lifters get aereated oil and this is the result of the ticking.

If you want to continue to auto-cross you can try a "thicker" oil. There is an approved 5w-50 oil (not a typo for 15w-50!). I run this in both my Boxster and my Turbo. You can try this oil but it may not help. With this oil in my Turbo the oil pressure characteristics do not appear to change from those I observe when running 0w-40 oil.

I'm not a fan of oil additives but you can try Swepco 502 oil improver, too.

However, if these work, and there's no guarantee, they are just bandaids. The real problem is the oil is retaining air and getting pumped back to the lifters. The problem is this aereated oil is also gettiing routed to the main/rod bearings. These won't tick, though. One will just fail at some point.

So you need to address the oiling probably by installing a deeper oil sump with *proper* baffling. Whatever oil you end up running be sure it is fresh when you show up at the auto-cross event.

Don't overfill the engine with oil but do run the oil level at the max level with the max level obtained with the oil up to full operating temperature.

porschedog

Buy a Miata beater for A/X.
(J/k!!)

Netrunnerz

If all I wanted to do is autocross, I would probably have better lap times, and be less costly. However, I am planning on bringing the Porsche to a local track...

Netrunnerz

So, it seems that I need to add baffling to my oil pan to prevent aeration. After doing some research, it seems there are a few options available.
So far, I am leaning towards either the FVD Motorsport oil pan or the Mantis Sport oil sump extension kit. Anyone have any opinions?

With a 30% US/CDN exchange rate, these solutions are starting to get expensive for a few hours of track time here and there... but this is the reason I bought the car.

5CHN3LL

I was under the impression that the improved baffle design of some of the aftermarket pans was to ensure that the pickup tube remains submerged by controlling slosh, not necessarily affecting aeration.

I have also read that mesh is used in some oil pans to promote nucleation - is that a feature of any of the aftermarket pans?

Sneaky Pete

I had to look that one up........can't we stick to ***** and how sweat rolls down them?

Slakker

I went with the FVD and have been happy with it.

5CHN3LL

Nucleation probably isn't the right word, but I couldn't come up with one word that was "like when you stick your finger in a cup of fizzy Coke, but for oil."

rymerc

At least one other fast 996 at local autox events has this issue too, driver says his car has been like that for years. I'm on considerably less sticky tires now, but when I ran rs3s I heard it a couple times only when it was very very hot outside at a certain track.

Ticking is usually gone after a brief cool down drive. One of the other guys says his does it for a day or two after autox though.