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Engine alignment

3K views 9 replies 7 participants last post by  jimfulco 
#1 ·
Hey you guys,
Not sure if this is the right forum for these questions, but here goes.
I have an '86 SS Monte Carlo with a 350 sbc that I plan on installing a 383 sbc into. I noticed when installing the 350 that it was difficult to locate the trans. onto the mount as if the engine mounts were not straight, causing the tranny to miss the mount by 1/2in. or so towards the passenger's side I believe. I managed to pry the trans over enough to bolt it up, but it wasn't easy, and I suspected something wasn't right(frame bent? Seems to drive straight). I couldn't see how to get a socket/wrench on the engine mount bolts, underneath inside the frame, so that they wouldn't spin when I turned the nuts on the mounts from the top to try to adj. engine alignment, unless I dropped the lower control arms, or even if thats what it takes to get to them, or are they pressed/welded studs. Even then I don't know if there is enough bolt hole clearance in the mounts to allow enough twisting/shifting of the engine to get the trans centered. And if it will, will it cause drive shaft/ujoint/rearend alignment problems?
Anyway, I forgot about it until about 6 months ago, when I noticed while I was changing the oil, that the trans mount rubber was broken. I tried to replace it with a urethane mount, but I could'nt get the trans onto it as it would't flex any like the stock rubber would, so I installed a new rubber mount with same difficulty prying it sideways, and caused an exhaust leak somewhere. I'm not to worried about the exhaust leak as it may be a broken rusty header tube/joint, and I'm going to install new headers/exhaust with the new engine soon.
I'm also installing a new double hump cross-member and urethane trans mount with new engine.
My questions are;
1: How do I get to the engine bolts inside the frame or are they studs?

2: Is there any clearance in the engine mount bolt holes, or in the frame to move the engine around much, or are the bolts/studs a tight fit?

3: Should I just enlarge the holes in the new cross-member to allow it to have enough play to bolt up the trans/urethane mount the way the engine sits now, since it seems to track ok without much if any vibration?

4: Anyone swapped out an '86 Monte's motor mounts?

Thanks for any input!!!
ssmonty
 
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#2 ·
Typically.
There are 2 sets of holes in the suspension cross member for engine mounting V~6 & V~8 .

Did the car have a V~6?
If so I would look to see if the Motor mount was not put in the wrong hole.

If it is that far off with a upgrade in power there is going to be busted stuff .

You need to find WHY there is a mis alignment & only then can you fix what is wrong.

It is possible like you said that the frame is bent . :confused:

I would start with a basic measurement test.
Measure from center point of wheels on the left them the right .
Then get under the car & do a "X" measurement , from side to side front to back in the same spot on each side measure all these should be the same if they are not ..you have problems.





R :thumbup:
 
#3 ·
Thanks for the reply Rob!
I figured someone on this site had swapped motor mounts in a Monte?
If memory serves, I did the "X" measurements 20yrs ago and it was close. I'll do it again to be sure.
I bought the car secondhand in '89 with a 305. Being that it was an SS I didn't think they cam with a V6. I could be wrong.
I guess I'm going to have to drop the control arms to get inside the frame to see if I can loosen/replace the motor mounts. I have a new set of motor mounts for a '75 Camaro. Any idea if they are the same?
Thanks again,
ssmonty
 
#4 ·
No Problem.

You can do the "X" in lots of different spots .

It will go faster if you have 2 people .One on the smart end & one on the dumb end. :D

I am 99% sure that Motor mounts are universal ,bolting them up is a BIG PITA.

If I remember right a Ball swivel socket is a life saver in this job.
Also some good magnets , to retrieve the nuts & bolts .

Here's a couple of trix. . .

If you take some paper & put it over the bolt then stick it in the socket it will hold it in places & still let you get your socket back.

If your swivel socket is loose a little electrical tape will hold it from flopping around.

It most likely easiest to drop the bolt down thru & nut it from underneath. this way there are no clearance issues with the "cup " on the Motor side of the mount.

Please let me know what you find out on the misalignment part.


Good Luck :welcome:






R :thumbup:
 
#5 ·
ssmonty said:
Hey you guys,
Not sure if this is the right forum for these questions, but here goes.
I have an '86 SS Monte Carlo with a 350 sbc that I plan on installing a 383 sbc into. I noticed when installing the 350 that it was difficult to locate the trans. onto the mount as if the engine mounts were not straight, causing the tranny to miss the mount by 1/2in. or so towards the passenger's side I believe. I managed to pry the trans over enough to bolt it up, but it wasn't easy, and I suspected something wasn't right(frame bent? Seems to drive straight). I couldn't see how to get a socket/wrench on the engine mount bolts, underneath inside the frame, so that they wouldn't spin when I turned the nuts on the mounts from the top to try to adj. engine alignment, unless I dropped the lower control arms, or even if thats what it takes to get to them, or are they pressed/welded studs. Even then I don't know if there is enough bolt hole clearance in the mounts to allow enough twisting/shifting of the engine to get the trans centered. And if it will, will it cause drive shaft/ujoint/rearend alignment problems?
Anyway, I forgot about it until about 6 months ago, when I noticed while I was changing the oil, that the trans mount rubber was broken. I tried to replace it with a urethane mount, but I could'nt get the trans onto it as it would't flex any like the stock rubber would, so I installed a new rubber mount with same difficulty prying it sideways, and caused an exhaust leak somewhere. I'm not to worried about the exhaust leak as it may be a broken rusty header tube/joint, and I'm going to install new headers/exhaust with the new engine soon.
I'm also installing a new double hump cross-member and urethane trans mount with new engine.
My questions are;
1: How do I get to the engine bolts inside the frame or are they studs?

2: Is there any clearance in the engine mount bolt holes, or in the frame to move the engine around much, or are the bolts/studs a tight fit?

3: Should I just enlarge the holes in the new cross-member to allow it to have enough play to bolt up the trans/urethane mount the way the engine sits now, since it seems to track ok without much if any vibration?

4: Anyone swapped out an '86 Monte's motor mounts?

Thanks for any input!!!
ssmonty
Was this car involved in a crash? Factory part alignments are pretty good as they haven't time on the assembly line to mess around with miss-matches.

Bogie
 
#6 ·
Rob Keller said:
Typically.
There are 2 sets of holes in the suspension cross member for engine mounting V~6 & V~8 .
Actually, there are more than just two sets of holes. All G-body frames came pre-drilled with all the holes for all the various engine mounts - Chevy, Olds, Buick, and Pontiac. It's pretty easy to get in the wrong ones.
 
#8 ·
Thanks for the input all of you!!!
You gave me a couple of things to think about! I'm trying to figure out how/where to put jack stands with the control arms out so that I can tighten the mount bolts after I get the engine and trans in. Its gonna be fun!
Its gonna be a while before I get my 383 together and swap engines, but I'll post with pics when I do. I'm sure I'll have more questions before then. I'm taking my time and triple checking everything I can.
Thanks again!
ssmonty
 
#9 ·
Mounts

I gave up on undoing the brackets on the frame and cut the heads off the bolts off with a grinder . I am changing from a 4.3 to a 350 in a 1989 pickup. I had to move the female part of the mount 4.5" ahead but the bracket stays where it was. I welded them on the bench. When the 350 goes in I will line up the holes and weld the bracket to the frame . Good welds for sure.
Clint
 
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