engine mount questions

Can a motor mount that looks okay really be bad? I have a bad vibration in my 96 firebird that split the engine block and I'm wondering if it could have damaged the motor mount in any way.

I have never had a car with bad motor mounts however when I used a come-along to tie the motor down on the drivers side this stopped the motor from flopping around considerably. I hate to think this vibration is trans/flywheel related but it still could be at the same time.

This vibration is bad and will shake the whole car, random missfires are seen by the ecm however I talked to a PCM programmer and he said the PCM could interpret these vibrations as random mis-fires.

Nothing else can be found wrong with the motor at all and it ran good in the firebird it came from. Could a bad input shaft/cluster gears cause this as well?

So post some of your motor mount issues that caused vibrations! The trans used to flop around but a new trans mount fixed that. I feel vibrations in the belklhousing and transmission case. This is not driveshaft related the car does it idling and clutch position does not affect it. I bought a remanufactured flywheel so that could be a culprit as well.

I dunno so much about vibrations, but put it in gear, brakes applied good, and hit the gas, if engine raises a lot on driver's side you have a bad mount....

but I have never seen a mount cause anything like excess vibration, just a clunk when you relax the gas/take it outta gear...engine settles down on the rubber mount....

:skeptic:

I had a bad motor mount cause a vibration at 60 mph, but not while idling

I've seen several broken mounts that looked fine when the engine was sitting still, but when it was revved the separation became apparent. On the same note, I've seen a rubber oil line on a vintage GMC engine split but close up so that it was completely invisible unless it was under pressure. Cracked rubber can be tricky that way.

Sam Cogley said:

I've seen several broken mounts that looked fine when the engine was sitting still, but when it was revved the separation became apparent. On the same note, I've seen a rubber oil line on a vintage GMC engine split but close up so that it was completely invisible unless it was under pressure. Cracked rubber can be tricky that way.

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Cause pregnancy too......:rofl::mullet:

mrvette said:

Sam Cogley said:

I've seen several broken mounts that looked fine when the engine was sitting still, but when it was revved the separation became apparent. On the same note, I've seen a rubber oil line on a vintage GMC engine split but close up so that it was completely invisible unless it was under pressure. Cracked rubber can be tricky that way.

Click to expand...

Cause pregnancy too......:rofl::mullet:

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No shit. :lol:

I actually really impressed an old-school mechanic when I found that broken oil line on the GMC engine and sourced a replacement part. He'd had it sitting in the yard for a week and couldn't figure out why it blew oil all over the damned place when the engine warmed up.

It was the flywheel

The flywheel scracked the engine block? Got-damn! :crap: Was it merely out of balance or was half it missing?

greg75vette said:

The flywheel scracked the engine block? Got-damn! :crap: Was it merely out of balance or was half it missing?

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I believe the flywheel was a 3800 series1 flywheel because prior owner said after he had clutch done engine started shaking. Apparently the series1 flywheel will physically bolt up to a series2 engine the balancing is way off.

After installing the correct flywheel my engine now sounds like the motor in my 97 camaro, has no vibration, exhaust and intake sound changed and now sound identical to my camaro and engine revs up a lot better.

Even the first initial cranking of the engine sounded different and with trans out motor vibrates less then when it was all together. I will start it again after trans is in and see if the vibration is gone in the trans case and bellhousing. As well.

Well everything is back together and all the vibration is gone. The vibration in the T5 is gone as well

Thanks guys!

The car has nice smooth acceleration and the random miss code doesn't come back.