Engine Mounts - Poly or Rubber?

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Sharecropper

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Just curious to get experienced opinions on the pros and cons of using original rubber engine mounts versus Polyurethane. I am approaching the point in time to acquire these parts and would like to know other folks' thoughts after using each. In addition to the engine mounts, I will also need to replace the transmission mount.

After reading online, it seems the rubber absorbs more of the vibrations of the engine and road, while the Poly is stiffer and transfers more of the vibrations to the cab. Rubber will last a few years, but Poly will last indefinitely. Rubber doesn't require lubrication, however Poly needs to be greased every few years or so. other than that, I can't see much difference.

Summit and Jegs sell the Poly from several brands however I did not see OEM rubber. It seems Energy Suspensions owns the market. I'm not sure anybody is offering rubber mounts.

Thanks in advance for your experienced opinions.
 

cucvrus

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You ask. May I give my highest recommendations to the Energy Suspension. I had a new rubber set fail in 1 weekend at Rausch Creek. The engine sat down on the fuel line inlet of the fuel pump and cut the hose. Was hard to figure out what was going on. I changed the hose and it happened the next week. From that point I installed the Energy Suspension mounts You drill the rivets from the steel clam shell of the stock mounts and install the new polyurethane mounts. I don't know that it vibrated more. Never took notice dragging logs and pulling trailers. Along with a lot of hi hill climbs and deep mud holes. Good Luck. Others opinions may vary. Be Safe.
 

Sharecropper

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You ask. May I give my highest recommendations to the Energy Suspension. I had a new rubber set fail in 1 weekend at Rausch Creek. The engine sat down on the fuel line inlet of the fuel pump and cut the hose. Was hard to figure out what was going on. I changed the hose and it happened the next week. From that point I installed the Energy Suspension mounts You drill the rivets from the steel clam shell of the stock mounts and install the new polyurethane mounts. I don't know that it vibrated more. Never took notice dragging logs and pulling trailers. Along with a lot of hi hill climbs and deep mud holes. Good Luck. Others opinions may vary. Be Safe.
Thanks Rick. I knew would have advice. I'm leaning towards Energy Suspension.
 

cucvrus

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Very easy to install. Just drill the rivets out and use short 5/16" and tack weld the clam shell or grind the bolts flush. Your choice. They give you wire ties. I discard them. But wire ties would work after they are tight in place.
 

sneekyeye

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Don't waste your time with the oe style rubber ones. Do the polyurethane once and forget about it. Get the trans mounts too while you are at it. You will probably need to notch the little u plate that it comes with the Energy Suspension trans mounts to clear one of the mounting bolts, but its not hard to do. I made the mistake of getting the stock style and they collapsed after less than a year, rubbing my power steering hard line on the frame. Unless you have the worlds most sensitive ass, you wont be able to tell the difference anyway over all the other vibrations.
 

Sharecropper

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Don't waste your time with the oe style rubber ones. Do the polyurethane once and forget about it. Get the trans mounts too while you are at it. You will probably need to notch the little u plate that it comes with the Energy Suspension trans mounts to clear one of the mounting bolts, but its not hard to do. I made the mistake of getting the stock style and they collapsed after less than a year, rubbing my power steering hard line on the frame. Unless you have the worlds most sensitive ass, you wont be able to tell the difference anyway over all the other vibrations.
Actually, my donkey is not sensitive at all. ;-)
 

richingalveston

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I like the ORD motor mounts that I used in my truck. They are smaller. using them with their high clearance cross member allows the cross over pipe to pass over the crossmember between the oil pan and motor mount.
But since you are not doing a turbo it should not matter but you may want to look into the ORD mounts.

Just get that engine in the truck as soon as you can, I am anxious to see how it runs. I should have mine back rolling in a few weeks.
Rich
 

chevymike

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Very easy to install. Just drill the rivets out and use short 5/16" and tack weld the clam shell or grind the bolts flush. Your choice. They give you wire ties. I discard them. But wire ties would work after they are tight in place.
So which model are you using? On both Energy Suspension and Prothane, I am not finding engine mounts listed for the 6.2. Are you using big block (454) or what?
 

Rutjes

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So which model are you using? On both Energy Suspension and Prothane, I am not finding engine mounts listed for the 6.2. Are you using big block (454) or what?
I think the mounts are similar to that of a 350 block if I remember correctly? I bought the Energy Suspension 31116R mounts. 31106R for the transmission and 34116R for the body.

Please note, I did not use them yet, but I came up with these part numbers after intensive research on this forum. The R in the partnumber stand for red, they also have B for black. I figured using the red ones it's easier to see and visually inspect them once mounted.
 

Sharecropper

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Thanks everyone for your replies. I bought Energy engine mounts and Prothane transmission and radiator mounts. Bought the Energy on their website and Prothane on their website. Both sites had the option of entering your vehicle information (1984 K30 diesel) and the correct item popped up. While I was on Prothane’s site I went ahead and bought the cab bushings as well. I will post photos in my rebuild thread over in the CUCV Modification forum.
 

cucvrus

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So which model are you using? On both Energy Suspension and Prothane, I am not finding engine mounts listed for the 6.2. Are you using big block (454) or what?
The truth be told the correct Energy Suspension motor mount inserts for all GM CUCV's are for a 1983 350 gas motor on the pick up and K5. 3.116G is the Energy Suspension part number.


OK that this as a word of advise. If you needed to bend the fitting on the fuel pump to get the hose on. That vehicle needs motor mounts or Energy Suspension motor mount inserts. Take my word for it. You can probably see where the fuel line was laying on the frame and it made a mark in the paint. Change the motor mounts. If the motor flexes it will cut the fuel line. It will wear a small hole in it and suck air. I learned this last April while wheeling at Rausch Creek. I changed the motor mounts before I went and the night before the truck shut off while idling in the parking lot. it seemed strange but I ignored it. The next day the trouble got worse and worse. I have used the Energy Suspension Autozone part number 353700. 3.116G is the Energy Suspension part number. Get 2 short 5/16" bolts and nuts. It beats the wire ties they give you to use to install the inserts. They work but the short bolts are 99% easier and better. Good Luck. Do as you wish. I just put a pair in a plow truck last week. The Jersey Indian. Thanks for looking.
 
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