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-   Porsche 924/944/968 Technical Forum (http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/)
-   -   Vibrations (http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/1034123-vibrations.html)

fsufsu69 07-08-2019 06:45 AM

Vibrations
 
Any ideas what to look for??? I have a 1988 16v 944s with 62,800 miles on it. Quick background sent it to get water pump replaced it was leaking and ended up doing the entire timing belt change, rollers ect... at the same time. Got the car back and noticed a vibration in the manual shifter, the local shop said it was the motor mounts, less than 800 miles after the work was done the engine lost compression in cylinder #2. Went to a different shop and had a complete valve job done (exhaust valves broke), change the motor mounts and a bunch of miscellaneous items fixed by recommendation of the mechanic. He said the balance shafts were off by a notch that was the vibration and everything is now good, the car runs strong but there is still a vibration in the shifter. Doesn't matter what RPM's your at, idol, revving to different RPM's and holding it steady, and also happens when driving in any gear. Could it still be the balance shafts, or torque tube, maybe motor mounts not installed right??? Does anyone also know of a good mechanic in the New Orleans area I haven't had much luck with the 2 I've used in New Orleans and the last one was 75miles away in Baton Rouge. Thanks

v2rocket_aka944 07-08-2019 07:40 AM

ill send your post to a master 944 guru in Plaquemine, maybe he can help.

Spring44 07-08-2019 09:25 AM

I used to use Greff Motors in Metairie when I lived in the NOLA area, but I’ve been gone from there for many years.

djnolan 07-08-2019 09:55 AM

The shifter linkage may be worn. Try twisting the shifter to check for play. There is a plastic anchor that can wear out and the shifter itself might have a worn metal bushing.

9FF 07-08-2019 10:15 AM

Only vibration Iíve felt at all rpms was a kind of buzzing through the shifter of an S2 caused by a bad harmonic balancer. Does a 944S have a harmonic balancer?

universeman 07-08-2019 12:07 PM

There's a bit of vibration in my shifter almost always, it was definitely worse when the balance shafts were a bit misaligned. If you can check the alignment (it's easy to do, just remove the timing cover and look at all the notches while the engine is at TDC) you can eliminate that as a possibility.

951and944S 07-08-2019 12:47 PM

Quote:

Originally Posted by fsufsu69 (Post 10516284)
Any ideas what to look for??? I have a 1988 16v 944s with 62,800 miles on it. Quick background sent it to get water pump replaced it was leaking and ended up doing the entire timing belt change, rollers ect... at the same time. Got the car back and noticed a vibration in the manual shifter, the local shop said it was the motor mounts, less than 800 miles after the work was done the engine lost compression in cylinder #2. Went to a different shop and had a complete valve job done (exhaust valves broke), change the motor mounts and a bunch of miscellaneous items fixed by recommendation of the mechanic. He said the balance shafts were off by a notch that was the vibration and everything is now good, the car runs strong but there is still a vibration in the shifter. Doesn't matter what RPM's your at, idol, revving to different RPM's and holding it steady, and also happens when driving in any gear. Could it still be the balance shafts, or torque tube, maybe motor mounts not installed right??? Does anyone also know of a good mechanic in the New Orleans area I haven't had much luck with the 2 I've used in New Orleans and the last one was 75miles away in Baton Rouge. Thanks

I think I know this car, or know of it.

You just had the head part of the job done at Loupe European...?
You wanted to sell car after..?
I got a call about this car I think.

Not many 944s around the vicinity that I don't see or know about.

Did you try Jon Sheurich at NOLA Motorsports...?
Shop is in AVondale, right at the NOLA Motorsports track premises.

Randy Greff at Greff Motors..?

Really in the middle of too many side jobs or I'd offer to look at it for you.

T

DannoXYZ 07-08-2019 06:13 PM

Drop oil pan and measure all rod-bearing clearances.

951and944S 07-09-2019 08:49 AM

Quote:

Originally Posted by DannoXYZ (Post 10517161)
Drop oil pan and measure all rod-bearing clearances.

More like, chunk missing out of stock rubber centered disc of stock 31 year old car.

T

IdahoDoug 07-09-2019 10:49 AM

You didn't really cover what was done for the engine. I suspect shop 1 did the timing and balance shafts wrong, so the valves hit the pistons and broke exhaust valves. That's a pretty big deal and could have damaged piston(s) by removing a chunk or damaging the wrist pin. Or frankly other things. These would cause a vibration.

So perhaps some detail on what shop 2 did. Hopefully a full teardown, measurement for damage, and a proper full rebuild with new bearings. If they did something different because you told them you were going to sell, such as did not remove the pistons and/or reinstalled a couple dented pistons with chunks missing just to get you down the road - there's your possible issue.

There's plenty of other mistakes they could have made on reassembly, such as the balance shaft belt. It's not that easy to do that correctly and super easy to do it "almost correctly".

So, perhaps take a photo of the shops invoice so the knowledgeable here can say things like "aha - they did not bill you for a new timing belt and reused the almost new one that likely sustained some damage." etc..

Doug

Huleboar 07-09-2019 02:57 PM

Im new to 944, got mine last week! But a local Porsche guru told me that I could remove one of the balance rollers, maby the idle pulley? Cant remember the name on this one but this would give me 8hp more but the downside was that it would cause the shifter to vibrate.



Sent fra min H8324 via Tapatalk

9FF 07-09-2019 03:15 PM

Quote:

Originally Posted by Huleboar (Post 10518165)
...it would cause the shifter to vibrate....

...and eventually...

1. the oil pick up tube will fracture causing the engine to seize, and

2. the fuel rail will crack causing your car to burn to the ground...

If 1 happens first your engine will die, if 2 happens first you may die.

Huleboar 07-22-2019 06:39 AM

Ok, thanks. But im not into to get the car as fastes possible anyway. Just enjoying the ride :)

DannoXYZ 07-24-2019 03:24 AM

Quote:

Originally Posted by Huleboar (Post 10518165)
Im new to 944, got mine last week! But a local Porsche guru told me that I could remove one of the balance rollers, maby the idle pulley? Cant remember the name on this one but this would give me 8hp more but the downside was that it would cause the shifter to vibrate.

Dyno-tested and proven to be more like 2.5-4 hp. Not worth it for damages it causes in long run. Only racers remove balance-shafts since they're rebuilding every year anyway. Even then, many of them don't make it to end of season before snapping oil pickup tube.


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