Drive line vibration under hard acceleration question

[Vanne]

So, to finish off my new suspension install, I finally went and got an alignment on my car. (500 miles took a while)

Went for front -1.5 and 0.15 toe in rear -1.2 and around 0.06 toe inn

Car drives awesome , but (my friend who did the suspension install/upgrade) took it for a drive with me and gave it a few quick laps on the track, he builds race cars for a living (off road racing) so I guess he knows a little more about cars than I do... Anyways, he loves the setup, and was very, very impressed. But....

He noticed there is a very slight vibration towards the rear of the car under hard acceleration..

So after we got back we put the car on the lift and had a look.. 2 things he said it could be.. After looking.. The front right engine mount has a little play in it, and if you put a jimmy bar between the mounting points, you can lift it about an inch? Is that normal? I have new engine mounts and transmission mounts but have not installed them yet.

So thinking of going this route first and then open to suggestions if the engine and transmission mounts don't solve the vibration.

Any suggestions guys?

My mate seems to think if it's not the mounts, it could be the cv joint in the prop shaft???

[Shipkiller]

Being able to lift the engine that much is not normal. I believe your right side engine mount is faulty. My right side mount was completely sheared/separated at 35K.....
I replaced both engine mounts with Vibra-Technic mounts (do a search…). Never putting the OEM engine mounts back on the car………….They are that good.

[Nate4641]

because it might come up, and I swear I'm not thread jacking, when replacing the engine mounts (which sounds like you probably should do soon) I've read a lot of guys changing out some bolts. Is this necessary to do? What bolts get changed out and why do so many do this?

[1SerieStud]

Definitely sounds like a rubber/bushing problem. If the engine mount doesn't do it, check the other mounts (transmission as well) and the guibo.

[Shipkiller]

Originally Posted by Nate4641

because it might come up, and I swear I'm not thread jacking, when replacing the engine mounts (which sounds like you probably should do soon) I've read a lot of guys changing out some bolts. Is this necessary to do? What bolts get changed out and why do so many do this?

Changing out the bolt is not strictly necessary. The right side engine block to mount were not installed correctly and can backout.
Most of us are either using Nord-locks on the bolts and re-torqueing them or replace them (bolts) and use Nord-locks…. Do both sides…

Search is your friend here on this topic… and this was not really a thread hijack.

[StickMon]

My right side mount was cracked under the heat shield, which made it pretty much impossible to see until removed.

[Vanne]

wow ok, and these cracked/loose engine mounts did provide some vibration to the drive line? i am kinda hoping thats what the drama is..thanks for the input everyone. first stop new eng and tranny mounts

[007MCoupe]

The infamous engine mount strikes again!

Originally Posted by Shipkiller

Changing out the bolt is not strictly necessary. The right side engine block to mount were not installed correctly and can backout.
Most of us are either using Nord-locks on the bolts and re-torqueing them or replace them (bolts) and use Nord-locks…. Do both sides…

Yeah when I did my mounts I inspected the bolts and all 4 were intact and in place. no need to change...but i did both sides for peace of mind down the road since I used poly mounts.