924Board.org

[Pezman]

Hi everyone this is my first time on here and i'm hoping someone can help me with a little info. My father is the mechanic in my family and we do most of the work on my '87 924S together. However, i'm usually the gofor and bolt tightener. With everyone help i'm hoping i can offer him some advice on how to fix my current problem. As for the problem, there is an awful vibration at idle. We did a tune up and got new spark plugs,wires, rotor and distributor cap but that didn't help. Has anyone else had a similar problem and if so how can i fix it?

[rkunk]

Welcome aboard first of all. I also have a slight vibration at idle speed. If I hit the gas a little it goes away. I have asked several people and they say it is probably the motor mounts. My car has approx 60k miles on it and they are the originals. I have not replaced them yet but it will happen down the road. Perhaps a winter project for e because mine is not really all that bad yet.

[Lizard]

also i would suggest that you should put your foot to the floor then take it completely off if there is alot of backlash then you know your motor mounts are bad

[carnut280]

any chance your balance shaft is outa sync?

[gohim]

Lizard,

You don't check for bad engine mounts in a 924S/944 engined car like you can in many other cars.

Infact, burying the throttle pedal, and suddenly releasing it is not a safe test on many other cars as well.

On a Ford Taurus or Mercury Sable FWD car with bad engine mounts, this type of action/test usually results in damage to the radiator, and/or heater core, because the radiator, and heater hoses are what anchor/locate the engine if the engine mounts fail.

Heavy vibration at idle, that smooths out when the throttle is advanced is a classic sign of one or two engine mounts failing on a 924S/944.

If one of both balance shafts are not timed properly, then the vibration would get worse with increased rpm.

[carnut280]

gohim, your smart

[Paul]

Vacuum leak?

[jcope]

My 2 cents:

When I first bought my 87 924S (it had 53K miles at the time), I had the same problem. A harsh, annoying vibration from the engine at idle and just over. Everything was perfectly smooth from about 1500 rpms up. It was the motor mounts. I read that the original motor mounts were prone to failure, and the 924S engine is pretty hard on them.

I remember reading that Porsche made improvements so that the replacements last longer.

[Mike]

Anyone know the part number to the latest version of the motor mounts?

TIA

Mike

[Lizard]

http://www.performanceproducts.com/product_page.asp?attFlag=0&appFlag=1&productname=Engine+and+Transmission+Mounts&productfamily=&subcat=&category=&make=PORSCHE&model=924&submodel=+&series=&year=1978&vehicletype=CAR&keyword=&vendorid=&search=keyword
performance products has them and i dont really recommend doing what suggested earlier in a front whell drive car but in this vehicle you arent going to do damage to the car if you do that

[swami]

Pezman,
I am sure you need to replace your motor mounts. The motor mount problem is pretty serious. I recommend replacing the mounts as soon as you can. I think they are about $110 each. It is a bit of work to replace.

Check out some of the engine is sitting on the radiator hoses or if the struts are OK. A faulty set of mounts might cause damage to these.