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How much clearance should there be between motor mount and motor mount bolt?

2K views 7 replies 7 participants last post by  cdminter59 
#1 ·
I have what I consider quite a bit of clearance between the motor mount and the motor mount bolt, is this typical?



seems to me that at most there should be a few thousandths, but it is more like 1/4" to 3/8"......thoughts, nothing to worry about? I can just see the motor reving up against those bolts and getting a good chance to run up at it....comments??????
 
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#2 ·
firstgear said:
I have what I consider quite a bit of clearance between the motor mount and the motor mount bolt, is this typical?



seems to me that at most there should be a few thousandths, but it is more like 1/4" to 3/8"......thoughts, nothing to worry about? I can just see the motor reving up against those bolts and getting a good chance to run up at it....comments??????
You will never know it , if it were in the thousands , you would never get the engine lined up on both sides.
 
#5 ·
I dont think you have any thing to worr about ,it has to have some clearance .dont use washers or bigger diameter bolts ,the ones you have are much stronger than the rubber bonded to your mount ,just a note i had to change my frame mounts also ,but mine is an 88 it is not a bolt in like everyon said when i started . Good Luck
 
#6 ·
I have to go with the point on fitting the engine. Try putting those bolts thru the mounts when dropping a motor into a 70 Camaro or something like that with the front sheetmetal on and you are laying under the car with it on jack stands. You would be damn happy to have that little wriggle room and it would be perfectly clear why it HAD to be there. If it was a few thousands you would NEVER get that bolt in! There has to be a little room to make up for flaws in the location of the mounts on the frame and motor. There is no way there can be absolute perfection in where those mounts are mounted on every frame in every car, even from the factory. A little sagging of a frame over it's life, different brand mounts, etc, there are way too many variables to ever have a perfect hole for that bolt to go thru.

Use the larger, thicker washers and tighten it up well and there you go.:thumbup:

Brian
 
#7 ·
This makes up for the fact that chassis are really pretty sloppy when it comes to assembly so the stack-up of tolerances requires some give when it comes to the engine and transmission's attachement. They take the adjustment at the engine as that's fewer oversize holes. Once the bolt is torqued the engine isn't going anywhere, so this isn't a problem. If you use a hardened washer between the underside of the bolt head and the mount, it won't distort like a regular washer so it will insure the bolt's clamping force is well and stablely transfered into the mount.

Bogie
 
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