I installed the motor after doing a rebuild and I physically shake the motor by the manifold and it just jiggles back in forth. I just started the motor today and my idle is at 1,400 RPM so it doesn't shake that much, I don't know if it was set that high by previous owner so i wouldn't notice it. Mount brackets and mounts are tighten up. I noticed when it would decelerate it would shake.
Could it be worn mounts? Should I switch to polyurethane mounts?

 

sounds like worn mounts but actually if your tranny mounts wher tight and nice it should not me rockin forth and back! check tranny mounts first!

 

I thoughr FDs don't have tranny mounts??

 

He is referring to where the trans mounts to the PPF. If the trans bolted in securely and assuming the motor is bolted to the transmission properly you really shouldnt be able to move the engine much. If your mounts are completely shot I think it would be possible to move the engine side to side but not easily and not a whole lot.

 

Well its not that easy, i shake it with some force and it will just shake maybe like around 1/4 of an inch of play. Mounts looked good when installed...I might look into some polyuerathane mounts

 

1/4" is a lot since when?

 

Since I installed it like like a week ago, I just turned on the motor last night. Idle was at 1400 so it wasnt that noticeable only when it would decelerate

 

sounds like something else to me, like a loose PPF mount bolts or driveshaft bolts.

i once had a customer come in and the car had a vibration like you describe, while on the test drive to try and figure out what it was the driveshaft nuts all came out and the shaft slammed into the muffler. so double check that anything you removed gets put back in and tightened, his obviously only made it to the finger tight- if that, stage.

i sure was glad it happened while going 20, since he actually wanted me to road tune the car....

 

Well it use too be fine, I bought the car like 50 miles away ran fine, no problem but a couple of days later I found a little leak in the coolant seals so I sent the motor to get rebuilt. I installed it a week ago and notice that when I shake it with some force it would jiggle. But I will look at the transmission brace and driveshaft. Thanks

 

it will move to an extent, every engine has some give which is normal. problem i have is the FD mounts have straps that will prevent it from lifting up very much even with completely torn mounts. unless the mount was installed without the strap and the mount happened to completely rip through, then i am inclined to agree.

 

The mounts like fine before installing but all i can remeber is when installing I lowered the motor and few times the mounts stud wouldn't go through the hole so I caused to bind, maybe it git damaged then? What are the straps you are talking about?

 

there are metal straps around the stock mount!!! If your missing those that could be it

 

it's a stainless steel band strap that goes completely around the engine mount on each side. it acts similar to a solid mount when enough force is applied.

 

No they are fine, I just purchased some used ones from a fellow member. Whichever look worse I will install polyurethane mounts and see if that helps.

I do have them, they look good.

 

I installed some other mounts with less miles and it still shakes quite a bit without the torque dampener.