Could a Flywheel cause the engine to shake at idle ??

Ddubb

Registered User
Im still trying to help a local SC owner with his 1995 5 speed.

It developed a shaking about 2 years ago after the rear differential went out making a bad noise - another mechanic diagnosed it as the clutch, so he replaced the Flywheel, and Clutch .. and when the noise didnt stop, he figured out it was the rear differntial. So it's been shaking ever since then, enough to break the power steering lines and a few other things.

The car only shakes at idle, when it gets revved up it runs smooth and everything is ok. Since it started breaking, he replaced the Motor mounts, spark plugs, wires, etc ..

Im just wondering ( Before I pull the whole engine / transmission out of the car ) .. if anybody has any second thoughts on the flywheel being the cause of the problem ?? The shaking does seem to be more visable in the rear end of the engine, it's just hard to tell what is "normal" shaking and "out of balance" shaking. :confused:

Flywheel ? Pressute plate ??

- Dan
 
How's the timing I have seen cars out of time and shake at idle, and as soon as you rev it up it will smooth out. Depending on how fare the car was out of time played a role on hp a little you really did not notice , but enough to make the engine shake . If the motor mounts was replaced , and installed properly one would think it might be timing, or a fuel injector not opening correctly under idle , maybe even the crank balance. If it were me that the next places i would look. I'm sure you will get other members opinions that might solve your problem so i would give it a few before you pull the motor ....
 
Yeah .. its been two years already, no big rush to pull the engine.

From what it looks like the harmonic balancer and pulley spin straight, dont look like they wobble at all - they are still the original parts but the thought has crossed our minds.


- Dan
 
Yeah .. its been two years already, no big rush to pull the engine.

From what it looks like the harmonic balancer and pulley spin straight, dont look like they wobble at all - they are still the original parts but the thought has crossed our minds.


- Dan

Did HG's ever fail and been replaced? I've seen{in the dealership} people bringing in thier 3.8 after someone else did HG's, only to tear it down and find a slightly bent rod causing the rough idle/shake.
 
Since you indicate the shake came with the clutch and flywheel exchange my vote is an out of balance assembly.
When you raise the RPM's the imbalance is self cancelling somewhat.

My thoughts,
Rob
 
Never had a HG problem, and yeah .. it smooths out as the RPM's raise .. just shakes at Idle.


- Dan
 
OH .. got a little more Information.

He says he does not have the part number, but the Flywheel and Clutch are AC DELCO PARTS !!! ...

Doing a little researching, I can not find an AC delco flywheel for the 3.8 Thunderbird SC ... but I can find PLENTY for the Mustang 3.8.

Does anybody know if there is an AC delco replacement for the Super coupe ?? Or am I right in assuming they are using a counterweighted flywheel that should be a 0 balance ???


Anybody else have any thoughts ?

- Dan
 
Just to update .... 6 months later, I have the 95 5 speed back in my garage and the engine / transmission were removed - slave cylinder went bad so we decided to take a look at the flywheel now that its all apart.

Now that the engine is out of the car, I can also tell that the head gaskets have been replaced at some point in time.

Flywheel pulled off .. it is an OEM Ford Tbird Flywheel, but after doing a little searching on here, I found the part number is most likely for the early 89Duracast crankshaft engine - so there is a large relief area cut into the flywheel for the counterweighting ... going to be re-balancing and hopefully it cures the vibrations. I narrowed them down to 2 major vibrations, one around 800 rpm and another right about 1100 rpm, the rest of the rpm range is fairly smooth but we will see .. :cool:


- Dan
 
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Not 100% sure, but it doesnt appear to be out of balance.

The part number on the Flywheel is E9SR 6380 CB

.. it looks the same as the one in this thread .. http://www.sccoa.com/forums/showthread.php?t=109891&highlight=flywheel+balance



- Dan

Dan,

From what I've read the one on the right is the part number you listed, and it's not a zero balance unit. Pretty sure it should look like the one on the left.

attachment.php


David
 
Dan,

From what I've read the one on the right is the part number you listed, and it's not a zero balance unit. Pretty sure it should look like the one on the left.

David


Thanks for posting the picture.

Yeah I could never see the recessed area / part number until I actually pulled the flywheel off the engine. I dropped it off at a machine shop yesterday and the tech was insisting this came off an externally balanced engine. They are going to drill out some more material to make it neutral.


- Dan
 
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