Shimming front engine mounts

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Shimming front engine mounts


Post by panwars » Tue Mar 24, 2009 1:59 am

Hi all,

I searched the knowledge base and didn't find an answer to this problem.

I have set the engine in the frame (no paint and clean surfaces), snugged the rear bolts and have some expected air-gap under front mounts. Here is the rub...on the left front, which has been repaired some time in its life, I have an un-even gap. It measures at its tightest .010" to 015" at its loosest point. This is not a front to back taper it runs kind of left front to right rear.

I dont think I can make a shim that thin with a taper. Other than pulling the engine and attempting to file the frame pad (1949) level (good luck), does anybody have an idea?

The right front runs about 001" to 003'.

Maybe Sikaflex ? LOL



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Re: Shimming front engine mounts


Post by mbskeam » Tue Mar 24, 2009 3:10 am

why not take .005 off the high side of the engine pad....
use a set of calipers and a big felt pen, this will let you see your file job...
measure, do a few strokes, then measure again, repeat till you get it the way you need, then your shims will a whole number...
I have used pop can material stacked unevenly in the past, these held up till I finally did the pads on a mill. just kept putting them in till it would not take anymore then moved over with a bit more, till the gap was filled then torqued it up....

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Re: Shimming front engine mounts


Post by lockdoc » Tue Mar 24, 2009 4:59 am

A soft aluminum or copper shim would tend to compress to the desired shape and thickness.

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Re: Shimming front engine mounts


Post by panwars » Tue Mar 24, 2009 5:34 am


I think I knew the answer was going to be to try and get the pads closer to true, I just don't want to lift that thing out again.

I don't think soft shims will live there for long, just like paint. I plan on using stainless shim stock if I can get these things straight, or close to it.


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Re: Shimming front engine mounts


Post by steinauge » Tue Mar 24, 2009 11:46 am

Chevy starter shims make good motor mount shims.Steel and available in different thicknesses.

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Re: Shimming front engine mounts


Post by Ripley/Fla » Tue Mar 24, 2009 10:44 pm

I just went through the same exercise. Unfortunately the right way is the only way as you don't want bust up a front engine mount. Remove the rear dishpan and you will have a bit more room to work with. I'd straighten out the .001-.003 and get that pad to sit firmly - then start on the .005 taper. That's not a lot to file so go slowly.

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Re: Shimming front engine mounts


Post by LittleAl » Wed Mar 25, 2009 8:07 pm

this discussion is pretty timely for me. Sometime over the next few days I'll be putting my motor into a new frame, new to this motor anyway, lol. I've been a bit concerned about it because the front mount (frame) was repaired and no motor has been in it since. The motor came from a different frame.

so the correct procedure is torque the rear bolts then measure & shim the front, each "pad" individually?

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Re: Shimming front engine mounts


Post by RICOCHET » Wed Mar 25, 2009 8:42 pm

This may sound redneck but it's easy and will get you there safely. Get some sandpaper strip like maybe 220 or 320 1 inch belt sand belts cut so you have a strip you can pull back and forth with your hands. I have this material and it comes in rolls. Same stuff. Put it under the uneven tab between the tab and the frame and work it back and forth until you've cut what's needed. If the frame's painted stick paper or anything under the sanding strip to protect it. Keep in mind to hold the strip flat to the frame while working it to keep from rounding the mount. Your using the engines weight to sand off the high spots and I'll bet it goes quickly and fairly accurately on the aluminum. You can actually do both mount pads at the same time being careful to only take the minimum needed off. Shim as required.


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