Mark71

I've decided to replace my motor mounts before I do anything to my manifolds or headers. Currently, one manifold is leaking badly, so I've got no choice but to do something which I thought would be headers. But maybe not. Then again, maybe.

Anyhow, does anyone know if they make poly motor mounts for SBO's?
All I've found is the relatively cheap rubber mounts. I've been told they won't last very long (2-3 years, max) so... I was looking for an alternative.

This is an example of the rubber ones: http://www.summitracing.com/parts/PIO-A2328/

Opinions or ideas welcome!

Thanks!

Mark

rocket1889

hey when i did my headers i replace my mounts with the ones you show there from summit....nd hey if the life on them is only 2-3 years then i change them out again..it wasnt a difficult task at all altho i enjoy working on my car

Mark71

Really? I thought it was going to be a tough job. Can I just lift up the motor with a jack and block of wood under the pan? Or do I need an engine hoist?

I am more worried about the mounts getting weak and causing the headers to sag onto the frame...

Rickman48

Unless the rubber on the mounts gets saturated with oil, they'll last indefinitly!
The polyuerethane mounts are impervious to oil and stronger, and will outlast the rubber ones!
Labor is the same, but do one side at a time, and be careful of the fan shroud.

joe_padavano

There are no poly mounts for Olds motors available unless you have one of the Firebirds or Cadillacs that use the Chevy clamshell mounts with the metal engine-side brackets on the Olds motor.

Mark71

Hmm... Sounds like rubber is the way to go for me. Considering Joe's comment that they don't make poly versions for the stock mounts, it might be the only way for me to go.

That brings me back to my other question... How do I need to lift the engine for a mount replacement?

I've been told a jack and block of wood under the pan might work, but might also damage the pan. I don't have an engine hoist, though.

rocket1889

NOOOO...i wudnt recommend doing it from under the pan at all! too much risk of damage

the way i did mine was very easy....i first started with the passenger side mount, loosened the thru bolt. Then i took a floor jack with a piece of wood and there is a spot on the engine tht u can put the wood on the block so it wont damage. Next i took the thru bolt out and jacked the engine about 3 inches high...removed the mount replaced and reversed the process!

i will try to snap you a pic of the jacking points i used on the engine block...but if ur mechanically inclined im sure ull b able to find it ...its in the front of the block

Mark71

Heh... I thought I was at least a little mechanically inclined, but I had a quick look around and I am not sure what spots you are talking about.

Then again, I also don't know what you meant by "wood block" in this case. I found an area further up on the engine block that would probably work, but I'd need a short length of 2-by (or something similar) to get to it...

rocket1889

ill go snap the pic right now for you =)

and by wood block yes i meant a short 2x something ill show exactly how i did it

BRB with pics

joe_padavano

I've changed a boatload of Olds motor mounts using only a length of 1x8 or 2x8 on top of the floor jack. Jack under the oil pan sump. Be sure the wood is longer than the width of the sump so the load goes into the sides of the pan, not just the bottom of the sump. Never had a problem.

Bayou Olds

That's exactly what I did when I changed mine.....due to header contact with the old ones.

rocket1889

i went outside to take pics but it was raining so hadda pull the car into garage then found a leaky battery =(

anyway i got the pics but what Joe just suggested is what i had to do on the driver side....the pass side has a lip tht u can jack it up from but just using the oil sump (which im guessing is the part where the oil pan bolts get bolted to the block) and ull b in good shape

Mark71

So, this way, the entire weight of the engine (and the accessories, alternator, etc.) is on the pan sump, right? My pan is just a sheet metal one, not a cast type. Will it hold the weight?

Also, can I do one mount at a time this way or do I need to remove both through-bolts to lift the front of the entire motor?

Oh yeah, and are the bolts going through the motor mount and into the block really supposed to be 80 ft. lbs? They seem pretty small for that kind of torque...

joe_padavano

Yes, you can jack under the sheet metal oil pan so long as you ensure the load goes into the sides of the sump and not just into the sheet metal bottom. That's what I posted above.

Yes you can and should do only one motor mount at a time. Note that this way you are not lifting the weight of the motor, simply tilting it.

Yes the mounts should be torqued to what the Chassis Service Manual says. Don't torque any bolts until both mounts are replaced and all bolts are loosely installed, otherwise you'll have difficulty getting the motor mount to line up with the frame mount.

MDchanic

If you want to get really fancy, you can use a speedbore bit to drill a relief in the piece of wood you're using, to accomodate the filler plug .

- Eric

Mark71

Joe - I have to admit, I thought you were crazy when you said that, but you were right. I needed some convincing, but jacking up under the pan sump worked like gangbusters. I was able to swap out the mounts much, much more quickly than I expected and even got some other work done while I was under there.

Here's how I setup the jack:


Up close you can see that I did support the bottom of the pan - and yes, that's a 4x4. I didn't have a 2x8 and the 4x4 covered most of the bottom of the sump, up to the oil drain plug.


The pan flexed a little under load, but it didn't crack or split and jumped back into shape when I let the jack down. Here's the passengers' side mount before.


I'll try to get an "after" pic up as well.

Bottom line: I need to have more faith in your instructions. It worked great. Thanks again!

Mark71

Eric - that's a great idea cutting a hole or relief for the plug in a nice chunk of 2x8. I think I'll end up doing that for next time.

Man, I gotta do something about those rusty, leaky exhaust manifolds...