Poly Motor Mounts Melted
Thread Starter
Pro
Joined: Dec 2000
Posts: 560
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From: Camino CA
Poly Motor Mounts Melted
I was under my car today and noticed a giant red blob hanging down from the engine compartment. I have the Energy Suspension red poly mounts, and it looks like the heat from my headers destroyed them. Is this a common problem with headers? Is there a different brand that doesn't melt?
I probably got these 6 years ago, but I hadn't been driving it much. I'm planning on making this my daily driver again. I really liked the poly compared to the old rubber ones, but I don't want to have to replace them all the time.
I probably got these 6 years ago, but I hadn't been driving it much. I'm planning on making this my daily driver again. I really liked the poly compared to the old rubber ones, but I don't want to have to replace them all the time.
Drifting
Joined: Sep 2006
Posts: 1,986
Likes: 21
From: Columbus MN
I had the same problem with stainless steel block hugger headers that were about 1/2" from the Energy poly motor mounts. I switched to fully length ceramic coated headers that are much further from the motor mounts, and I have not had any motor mount-heat problems since. My engine is better tuned now (including timing), so I can't attribute the solution to either the headers or timing exclusively...both changes probably helped solve the problem.
Thread Starter
Pro
Joined: Dec 2000
Posts: 560
Likes: 0
From: Camino CA
I'll check my timing, but I don't think I can change the fuel mixture on my 81, I'm pretty sure that's controlled by the computer. I do have the Dynomax ceramic coated headers and they are about 1-1/2 inches from the mounts. If I change to solid mounts would those eventually cause something to crack? The engine I put in there has about 300 hp.
I do remember the engine overheating because I had air in the coolant a while ago, maybe that caused it, I was driving it a lot at that time.
I do remember the engine overheating because I had air in the coolant a while ago, maybe that caused it, I was driving it a lot at that time.
Burning Brakes
Joined: Dec 2003
Posts: 1,004
Likes: 7
From: Adelaide South Australia
I have seen quite a few threads regarding molten poly mounts in the past...
even with heat shields fitted!
What's wrong with rubber mounts? If you have a lot of torque twist, you can limit the strain on the left mount by using some old hot rodder tricks...
... use a chain bolted low on the chassis to a left side header mount bolt ...
or fit a bolt through left mount plates to limit the extension distance....
both methods work.
Vibration insulation under normal driving, but limited torque twist under full load.
even with heat shields fitted!
What's wrong with rubber mounts? If you have a lot of torque twist, you can limit the strain on the left mount by using some old hot rodder tricks...
... use a chain bolted low on the chassis to a left side header mount bolt ...
or fit a bolt through left mount plates to limit the extension distance....
both methods work.
Vibration insulation under normal driving, but limited torque twist under full load.
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I have them on my BB with headers - no issues!
Thread Starter
Pro
Joined: Dec 2000
Posts: 560
Likes: 0
From: Camino CA
Timing is set correct, I think the poly melted when I had an overheating problem last year, and I just never noticed it. The solid mounts are cheap enough that I'm willing to give them a try.
1st Gear
Joined: Dec 2018
Posts: 1
Likes: 0
Mounts Melting
I was under my car today and noticed a giant red blob hanging down from the engine compartment. I have the Energy Suspension red poly mounts, and it looks like the heat from my headers destroyed them. Is this a common problem with headers? Is there a different brand that doesn't melt?
I probably got these 6 years ago, but I hadn't been driving it much. I'm planning on making this my daily driver again. I really liked the poly compared to the old rubber ones, but I don't want to have to replace them all the time.
I probably got these 6 years ago, but I hadn't been driving it much. I'm planning on making this my daily driver again. I really liked the poly compared to the old rubber ones, but I don't want to have to replace them all the time.
Desiging one now but will need to check out these other suggestion also! Hope this works too expensive to replace
designing
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
I agree. Moroso Solids, ARP bolts, Loctite Blue and never look back. Very, very, slight vibration in the steering wheel, but I can live with that.
Some of the older fellas & gals may remember the notorious, history making GM motor mount failure of the 70's. Thousands sheared apart, usually under acceleration. The recall fix was a steel cable to harness any separation.
Some of the older fellas & gals may remember the notorious, history making GM motor mount failure of the 70's. Thousands sheared apart, usually under acceleration. The recall fix was a steel cable to harness any separation.
Last edited by HeadsU.P.; Dec 17, 2018 at 01:06 PM.
Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
My friend had those Energy Suspension mounts and they melted....32' Ford with block huggers....went Moroso and called it a day.
Jebby
Melting Slicks
Joined: Mar 2008
Posts: 2,666
Likes: 289
From: Spring Park MN
I run the solid motor mounts also and I have a spreader bar. It eliminates the broken motor mount problem and tightens up the car. I also have my frame solid welded and gusseted, so the the overall difference from stock is stark.
Mike
Mike
Pro
Joined: Jun 2005
Posts: 583
Likes: 61
From: USA
on a C3, remember that the body is isolated from the frame: the body has rubber bushings for mounting to the frame. this means that vibration, noise on the frame is not transmitted into the cabin. So in the case of the C3, use of steel motor mounts does not result in a whole lot of engine noise, vibration being heard or felt in the interior of the cabin.
totally different story on uni-body cars, though, where the frame is integrated into the body.
I also put the Moroso steel motor mounts on my 78 with a BBC, and was surprised that there wasn't much noise/vibration difference. That then inspired me to install solid motor mounts on my 1990 Camaro (unibody). Whoa, big difference, totally, like night and day. But I got used to it, and now revel in the experience. Don't need no stereo in the IROC any more. total engine-sound, surround-sound "immersion".
totally different story on uni-body cars, though, where the frame is integrated into the body.
I also put the Moroso steel motor mounts on my 78 with a BBC, and was surprised that there wasn't much noise/vibration difference. That then inspired me to install solid motor mounts on my 1990 Camaro (unibody). Whoa, big difference, totally, like night and day. But I got used to it, and now revel in the experience. Don't need no stereo in the IROC any more. total engine-sound, surround-sound "immersion".
Safety Car
Joined: May 2004
Posts: 4,363
Likes: 1,587
From: los altos hills california
I was under my car today and noticed a giant red blob hanging down from the engine compartment. I have the Energy Suspension red poly mounts, and it looks like the heat from my headers destroyed them. Is this a common problem with headers? Is there a different brand that doesn't melt?
I probably got these 6 years ago, but I hadn't been driving it much. I'm planning on making this my daily driver again. I really liked the poly compared to the old rubber ones, but I don't want to have to replace them all the time.
I probably got these 6 years ago, but I hadn't been driving it much. I'm planning on making this my daily driver again. I really liked the poly compared to the old rubber ones, but I don't want to have to replace them all the time.
The scientist in me would put the remains in the oven and see at what temperature they became mushy!
Also if you replace the mounts with equivalents, you should make sure they have a travel limit.