Thread: Motor mounts not lining up

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Some of the GM trucks had multi tranny cross member holes for different trannies.If you either swapped the tranny for a different one or have that cross member in the wrong hole,that would effect the engine mounts.

Originally Posted by cffisher

I was just out in the shop and looked at some spare mounts I have.....There is no way you could put them on wrong... They are made to be fool proof. You may have a bent one???/ Anychance you can get thwe old ones back off your old engine....If not Ebay has them

That's what I thought... I couldn't really put them on wrong. I'm going to try to get my old mounts back... spent all morning looking through old phone bills trying to find the guy's number

Originally Posted by rspears

Are you sure your frame hasn't been tweaked? Were the through bolts easy to pull from the old mounts on the old engine, or was it maybe binding a bit? Your pictures seem to point to the frame rails maybe being a little too close together which would tend to push everything up.

I'm pretty sure it hasn't been tweaked. I've looked at a lot of 4x4 frames, and it looks just like any other one. There are no obvious signs, at least. The through bolt was very easy to put on the mount (when the mount wasn't on the frame). When the mounts were on the frame, getting the one side through-bolt to go in was very easy, but the other side wouldn't line up.
I agree that if the frame rails were just a little bit further apart, everything would go in very nicely. But if my frame rails were off somehow, wouldn't everything else be off? My core support lines up properly, the bumper lines up, etc. I took the entire front clip off this truck, and didn't notice anything. If my rails were off, I would think my core support wouldn't line up anymore.


There's a guy down the street (who is also stumped by my issue) who has about 10 4x4 trucks without engines in them, I'll try and go up there today and take some measurements.

Originally Posted by 1gary

Some of the GM trucks had multi tranny cross member holes for different trannies.If you either swapped the tranny for a different one or have that cross member in the wrong hole,that would effect the engine mounts.

The tranny that was in the truck was a TH400, not what I'm putting back in, and not what came with the truck from factory, either. The transmission cross member is not currently installed (it will be once the tranny gets in). Are you referring to the crossmember directly in front of my motor mounts? I'll check it out tonight.

Thanks again for all the help. I'm going to get measurements off a different truck tonight, and try to call the guy I sold the engine to to see if I can get my mounts back.

Originally Posted by 1gary

Some of the GM trucks had multi tranny cross member holes for different trannies.If you either swapped the tranny for a different one or have that cross member in the wrong hole,that would effect the engine mounts.

Not sure how the trans mount would effect the engine mounts in the way he explains the problem..........If you have access to another truck I'd sure measure it and compare...ONE request when you figure this out post the answer cause there are a lot of us stumped..

Originally Posted by cffisher

Not sure how the trans mount would effect the engine mounts in the way he explains the problem..........If you have access to another truck I'd sure measure it and compare...ONE request when you figure this out post the answer cause there are a lot of us stumped..

I agree, Charlie. The tranny mount could affect the front to back MM position, but I cannot see how it could affect the spread of the mounts which is what's placing them a hair too high relative to the frame. How about if you slot your MM holes where they bolt to the block toward the top about 1/8" to 1/4", shifting your MM's down on the block a smidgen, which will put them just a bit closer together, dropping them down deeper between the frame rails. I cannot see that a minor slotting will affect your mount in any way as long as it's equal on both sides.

Man, this is becoming a case for CSI.

Ok, let's get it down to basics. It looks to me like your mounts do not go on the angled portion of the frame like I envisioned, but rather, they go straight up and down on a vertical portion of the frame. Is that correct?

If so, if you put weight on the engine mounts by taking some support out of the engine lift won't the frame portion of the mounts slide down that wall and line up with the holes?

Everytime you install a motor there is some fudging with a picklebar to get the holes to line up, and it looks to me from the pictures you took that those mounts are able to slide down that vertical wall the extra distance you need. Or am I missing something?

Don

No, scrap all of the above. The one picture you posted was throwing me off, I see they do go on an angled portion of the frame, in the other pictures. Hell, just redrill the holes a little higher on each side and be done with it. It's nothing us hot rodders haven't been doing for a million years and a 1/4 inch per side is nothing.

You might want to try a set from the local chevy dealer.

I will definitely let you guys know how I get this resolved. This engine is going in this truck, one way or the other! I'm just not about to get it in there the wrong way, not after all the money I've put in it...
I live in southwest Ohio, so about 4 hours south of Detroit.
I'm going to measure some other trucks in a few hours... Ill let you know what I find out.

Originally Posted by Itoldyouso

Man, this is becoming a case for CSI.

Ok, let's get it down to basics. It looks to me like your mounts do not go on the angled portion of the frame like I envisioned, but rather, they go straight up and down on a vertical portion of the frame. Is that correct?

If so, if you put weight on the engine mounts by taking some support out of the engine lift won't the frame portion of the mounts slide down that wall and line up with the holes?

Everytime you install a motor there is some fudging with a picklebar to get the holes to line up, and it looks to me from the pictures you took that those mounts are able to slide down that vertical wall the extra distance you need. Or am I missing something?

Don

No, scrap all of the above. The one picture you posted was throwing me off, I see they do go on an angled portion of the frame, in the other pictures. Hell, just redrill the holes a little higher on each side and be done with it. It's nothing us hot rodders haven't been doing for a million years and a 1/4 inch per side is nothing.

They definitely go on the angled portion of the frame. I have pictures of the old mounts still installed after I pulled the old motor, and they are in the exact same spot.
Honestly, I really thought about redrilling the holes. The reason I haven't done it yet.... First, there is a reason it's not lining up, I didn't want to rig it up. A 350 came out, a 350 should go right back in! Something's wrong, and i'd rather find the issue, if possible. Secondly, if I move my bolts up, that means the engine will sit a bit higher, and I'm not sure if I will have to worry about problems with the transmission and transfer case lining up properly.

Originally Posted by rspears

How about if you slot your MM holes where they bolt to the block toward the top about 1/8" to 1/4", shifting your MM's down on the block a smidgen, which will put them just a bit closer together, dropping them down deeper between the frame rails. I cannot see that a minor slotting will affect your mount in any way as long as it's equal on both sides.

I could also do that. I want to find the problem, first, though. There HAS TO be a reason this isn't lining up. It's almost the same engine going in as what came out. Only difference is they are about 10 years apart.
Let me measure some other trucks, and try to get a hold of the guy who has my original motor mounts. I think I got his number... I'll let you know in a little bit.
Thanks!

Ok im pretty sure it's in the block- side mounts. I can slide my hand between the motor mount and the frame mount on my current one, but couldn't on any other truck I seen. looks like if I get a shorter engine side mount I'll be fine. Unfortunately the guy I sold my block to sent my old mounts to the scrapper.
I'll let you guys know when I get new mounts if thats the problem.
Thanks again for all the help.

Hello,
I'm new here, but I hope I can help . Are you missing the 1/4" strut brackets for the trans support ? They go between the block and block side mount. I have an 85 truck with 700r4 and need to use the brackets to shim out mounts.

Welcome to the forum, looks like you are contributing good info already.

Don

Originally Posted by insidemic

Hello,
I'm new here, but I hope I can help . Are you missing the 1/4" strut brackets for the trans support ? They go between the block and block side mount. I have an 85 truck with 700r4 and need to use the brackets to shim out mounts.

Welcome to CHR insidemic

I have built a dozen of these trucks and never had to shim out a motor mount. thats new to me but his problem was he was already to wide.