Polyurethane Engine mounts Help

1981zapper

Veteran Member
Apr 28, 2009
1,447
Great White North
I'm using Prothane Polyurethane part # 7-506-BL Engine mounts with the factory shells and clamshells. I am using a bare block and a empty turbo 350 transmission to get everything lined up, before I drop my engine in. I followed there instructions to a T as to engine mount orientation.

I have left the subframe mounts loose and can not get the mounts to line up, I can start the driver side bolt but it will not go through. I've tried prying and using a lady bar but no luck, I even pulled the block back out and tighten the subframe mounts thinking they were not getting compressed enough but it made things worse.

any advice

image_67198977 (1).JPG

image_67200513 (1).JPG

image_67510273.JPG


image_67229953 (1).JPG
 

Twisted_Metal

Administrator
Staff member
Lifetime Gold Member
Feb 26, 2004
31,446
Bloomington, MN
Are you using clam shell mounts with one mounting hole in the center/bottom instead of three corner holes?

IF so... Those are the wrong mounts.

They should mount like this:

1656858766791.png




I battled for hours trying to get the "performance" mounts to work and it wasn't possible.
Use this style.
(Four mounting holes in the corners but you only use three of them.


If you want to use the poly inserts, open them up and replace the inserts.

I see you put the bolt heads on top.
That's "factory correct" but it's a lot easier to pull the bolts up through the frame and put nuts and lock washers on top.
An impact wrench will usually tighten them without the need to put a wrench inside the frame.

Good Luck!!!
 

1981zapper

Veteran Member
Apr 28, 2009
1,447
Great White North
Are you using clam shell mounts with one mounting hole in the center/bottom instead of three corner holes?

IF so... Those are the wrong mounts.

They should mount like this:

View attachment 143593



I battled for hours trying to get the "performance" mounts to work and it wasn't possible.
Use this style.
(Four mounting holes in the corners but you only use three of them.


If you want to use the poly inserts, open them up and replace the inserts.

I see you put the bolt heads on top.
That's "factory correct" but it's a lot easier to pull the bolts up through the frame and put nuts and lock washers on top.
An impact wrench will usually tighten them without the need to put a wrench inside the frame.

Good Luck!!!

what do you mean by "one mounting hole in the center/bottom instead of three corner holes"

mine are orientated the same just as your picture. Before removing the factory mounts I made sure I took a picture as to which mounting holes they use in the frame so I know that is not the issue.

these are the polyurthane inserts I am using,

here is my set up, I am using factory Clamshells with zip-ties and factory engine mount

image_67197953.JPG


image_67237633.JPG

image_67177985.JPG


image_50439169.JPG
 

Twisted_Metal

Administrator
Staff member
Lifetime Gold Member
Feb 26, 2004
31,446
Bloomington, MN
Okay... That apparently isn't the problem.

Some auto parts stores sell two different frame-side mounts.
The ones with three mounting holes don't fit.

I don't see a problem with the way yours are mounted.
 

suds788

Member
Dec 26, 2018
65
Fort Morgan, CO
just a thought - is it just not lining up to go in the nut thats welded on the upper mount half? if it is grind that nut weld off get the bolt though the mount hole the put your nut on. don't recall any of my mounts having a nut welded to the upper half is is shown in the one pic.
 

1981zapper

Veteran Member
Apr 28, 2009
1,447
Great White North
just a thought - is it just not lining up to go in the nut thats welded on the upper mount half? if it is grind that nut weld off get the bolt though the mount hole the put your nut on. don't recall any of my mounts having a nut welded to the upper half is is shown in the one pic.
i did not weld the nut, the previous owner did that, i guess it was done because the mechanical fuel pump is close to put a wrench in-between.

like I said above, I can start the driver side but the passenger side is off a lot,
1656899996168.png
 




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