944, possibly trashed... please help

SirThunder · 10:12 AM

hey all,

i'm a newbie on this forum, and i am actually a gm man myself, but i am hoping you guys can help me with my dad's 86 944. last summer (it wasn't driven much) and now this summer, the car has an obnoxious tapping noise, but i can't feel it when i touch the block. its a different sound than i am used to, but then again its a very different engine than i am used to tearing down... please review the following video and tell me if we have a spun cam or main bearing, or a bad rocker, etc.

thank you all very much,

Jason

HondaDustR · 05-26-2008, 10:01 AM

Put it on Youtube. It won't show it on there.

SirThunder · 05-26-2008, 10:30 AM

done

HondaDustR · 05-26-2008, 10:35 AM

These motors use an overhead cam with no rockers, just hydraulic bucket lifters. How is the oil pressure? If it's nice and high and doesn't bounce around or drop when driving under load, then the bearings are probably fine. It could be a stuck or collapsed lifter. If it is more of a ticking sound, then it's probably the fuel injectors firing. They can be quite loud, but the video sounds more like a dull clunking sound. It could be a loose cam sprocket bolt. There's all kinds of stuff that "could" cause it.

Does it change at all when fully warmed up?

SirThunder · 10:45 AM

i can hear the injectors... they are more of a lighter clicking... this is also at a different frequency than the injectors

the first few seconds when oil pressure is coming up to level it is louder... that is what it quiets down to. the oil pressure is good... between 4 and 5 at idle.

is there an easy procedure to check the lifters? can i pop the valve cover off with this type engine and see if its a stuck lifter, or does it spray oil in such a way i cannot do that?

i'm used to gm pushrod engines, so i gotta ask the dumb questions

on a side note, while its a duller clacking sound, it carries pretty far... its audible as you are walking up to the car.

HondaDustR · 05-26-2008, 10:48 AM

That is (unfortunately...) not a valve cover but the cam housing which carries the camshaft and the lifters inside of it, which requires a bit of disassembly to remove. That gasket is prone to leaking, which is why I say unfortunately.

I've heard of people here using seafoam added to the oil to try to flush out gunk in the hopes of unsticking lifters, and I think some have been successful with that, I just don't remember exactly.

I'm sure some of the more "lifter experienced" pelicans will be able to help.

Porsche-O-Phile · Porsche-O-Phile's Garage

Sounds like a lifter that's not pumping up.

SirThunder · 05-26-2008, 11:17 AM

ok, as 2 of you feel its a stuck lifter, i will lean towards that as the issue. what are the chances that something will be damaged by driving it this way?

what is the "sea foam" additive that is supposed to help?

Vfourfast · 05-26-2008, 12:14 PM

Your "problem" does sound like lifters.

If it is a lifter you will not damage anything to drive it for a while. In my street car I have a lifter (or more) that bleeds down if I haven't driven it for a couple of weeks.

If it is a lifter it should clear up if you let the car warm up and then drive it for a short while (5-10 miles). It will return if you let the car sit for a few days. Other than the noise it is not a big issue. You don't say whether you have driven it for any length of time. It takes a very long time if ever to fill while idling.

Heres a list of potential sources of the noise.

Connecting rod excess brg clearance - not likely because you have good oil pressure.
Piston wrist pin clearance in connecting rod - not likely if it was ok when you stopped driving it.
Piston slap - should clear up as the engine warms up. probably not the case as the car was never really known for this.
Lifter - most likely as this is a common problem.

It is hard to figure out a specific lifter that is causing the problem. If you can live with the initial noise while it fills with oil it should be ok.

SirThunder · 05-26-2008, 01:23 PM

the car sat for the whole winter, so that definitely sounds like the issue. another thing i have noticed is that the oil pressure tends to read high... and on other threads that is attributed to an oil valve that sticks open. this is also supposed to cause the lifters not to fill correctly. what are your thoughts?

jmd_forest · 05-26-2008, 01:32 PM

+1 on its a lifter. Invest $5 in a can of Sea Foam, available from any NAPA auto part store as well as many others. The stuff works wonders on stuck lifters, and I'm speaking from experience here. Just follow directions on the can. If it doesn't work, all you've lost. is $5.

jmd_forest

SirThunder · 05-26-2008, 01:51 PM

i have been doing more reading, and there appears to be a major battle regarding the use of seafoam, atf oil, etc to clean these cars out. this is the first time i have heard of seafoam, but i have heard from many other car forums of a quart of atf fluid being used to purge crap out of the engine. did the seafoam cause any issues in your car?

flashgordon13 · 05-26-2008, 02:18 PM

I have used sea foam on this engine and several others and always had good results. If it is a lifter problem the sea foam will likely fix it. I have never had any problems with using sea foam and as already stated, if it doesn't work you are only out a few dollars.

Vfourfast · 05-26-2008, 03:06 PM

SirThunder,

If you have not yet driven the car I would try a short drive before using an additive. I have not used seafoam or atf but I can't see they would do any harm if used for a short while and then dumped.

5 bar oil pressure with cool 15W50 oil at idle is normal for the Porsche front engine cars. If the RV is stuck open you would experience low oil pressure, especially at idle. I would not worry about an RV being stuck closed unless the oil pressure doesn't fall to between 3 and 4 bar at ide when the oil is hot.

I think it is more common for the RV to stick open or the spring to get weak and give low oil pressure.

Good luck

bholmes · bholmes's Garage

I'm goin w/ lifters. I too am a GM man as well so welcome, darn shame gas prices has rendered my truck worthless other than to sit in the yard. What weight of oil is in it? I'd flush it a little and then put a heavy weight oil in it and drive it a little. When i started mine up for the first time this spring it made alot of lifter clatter which is virtually all gone now. Good luck and let us know how it goes. Also if you haven't discovered it clarks-garage.com is an excellent resource for repairs on these cars.

twofoldtyranny · 08:00 PM

That's the oil pickup tube not getting oil man. I had the same problem on my 944 N/A, so I replaced the tubes and it fired right up, minus the knocking.

So long as it hasn't been running for a long period of time, you should be alright without a rebuild, otherwise go to task. If you need any help, or have any questions, hit me up.

kameron@sweentech.net

Check out the project pics:
http://www.facebook.com/album.php?aid=2000404&l=2f062&id=1481010015

Also, DCAuto are your boys for wholesale or cheaper Porsche parts.

http://www.dcauto.com/

Regards,
Kameron

SirThunder · 05-28-2008, 06:13 AM

thanks everyone! I will work on the car this weekend and see how she does..