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Poly Transmission and Engine mounts.

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by MudFrog, Nov 13, 2003.

  1. MudFrog

    MudFrog 1/2 ton status

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    Who makes a good, decently priced set of poly mounts? I know Energy Suspenion makes them but I wanted engine mounts with the brackets already on them, I do not want to modify my current ones with a poly center.
     
  2. fortcollinsram

    fortcollinsram 1/2 ton status

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    I don't think anybody makes a polly motor mount with the clam shell around it already...Why don't you want to reuse the stock clam shell? It is REALLY easy to separate them: A proper sized drill bit and about 5sec for each rivit and your done...

    Chris
     
  3. 83ZZ502_Jimmy

    83ZZ502_Jimmy 1/2 ton status

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    I use these,

    Engine mounts

    and these,

    T-case mounts

    The engine mounts need to be left loose until you get everything lined up. Then when the big bolts are through, tighten everything down. I have these on two of my trucks and love them.

    John
     
  4. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I chickened out and used cheap rubber mounts because they had a lifetime warranty for my engine. I bought a complete poly kit so it came with a poly trans mount so I used that.

    I guess it's me being a usual cheapass, but when I had my body off, I just couldn't afford all the cool stuff I had envisioned. $10 for lifetime rubber mounts at AZ and a poly trans mount is what I ended up with.
     
  5. MudFrog

    MudFrog 1/2 ton status

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    I've got the lifetime warranty tranny mount from AZ and they will never honor it. I've gone through 4 in a year and they claim I'm "abusing" them.
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    Just make suer you have a set of STOCK motor mounts.

    Bought a set of the energy suspension ones, cut the "stock" mounts that were on my truck apart, put the poly centers in place, used zip ties to hold them together, and attempted to bolt them into my truck. Didn't happen. Motor wouldn't sit down, the mounts were screwed up somehow.

    Probably a one in a million chance, but the mounts on the truck when I bought it must not have been stock, because the metal shell was different than another metal shell I compared them with, and made them incompatible with the poly centers. The shell was actually stamped differently...bolted up normally, but the way it was stamped made it look like less rubber had to be used to produce them.

    Had to use rubber or buy some used motor mounts to put the poly's in. I went with the rubber. If it lasts me 5 years, I'll be happy, THEN I'll put poly in the shells I have now, which I know will fit the poly ones. Just an FYI so you don't end up with a vehicle down.
     
  7. bigmack

    bigmack 1/2 ton status

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    Not to hi-jack your post, but I'm also having problems with stock motor mounts. I really like the mounts that ORD has, but they are expensive. Does anybody know if there any solid motor mounts available ? If not, I will just make my own. I have seen some in Jegs and other places for older cars, but not for our trucks. /forums/images/graemlins/thinking.gif
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    I don't know that they ever WERE in favor, but it seems that solid mounts have gone out of style, at least for anything short of all out race cars, and even then...

    Something I read at one time mentioned that if the mounts can't move some, you end up distorting the cylinder walls, due to the location of the motor mount bolts. Not sure how true that is, since even with motor mounts, it will only move so far, but breaking the transmission mount or transmission is a possibility. Thats a common problem when combining poly and rubber...if one flexes, and the other doesn't, usually the aluminum or cast iron used at the tranny mount is weak enough to break if it sees enough power.


    Basically I think the moral is, whatever you end up using, use it in all 3 lcoations.
     
  9. k20

    k20 3/4 ton status

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    yeh i just got done putting poly in the mounts for my 496 swap. Lets just say I wouldnt do that again, i had to modify the tabs about 785 times, which involves, jacking the motor back up, unbolting the mount from the frame, then reinstalling it all only to undo it again. The poly tranny mount only took 5 to 10 mins to install. BTW these were energy suspension parts.
     
  10. stretch67

    stretch67 1/2 ton status

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    i also have the offroad design engine mount they are worth everypenny,bulletproof have less slop than poly stock replacement mounts they are more money but even if you wore out the bushing you can replace it! do not use solid mounts you are asking to break the tranny or transfer case also if you use poly on the engine use poly on the tranny mount to prevent cracking the tranny or tcase also the offroad design mounts include the upper clamshell part of the mount so it fits nice!
     
  11. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    I went the same route as 83ZZ502_Jimmy on my pulling truck and used Energy Suspensions poly on motor AND tranny on the other rig and love them both.

    Each were a BITCH to line up, but when I loosened the tranny/t-case mounts up a little and used a small pry bar, everything went fine. Keep as many bolts loose as you can and it will work.

    CAUTION: Initially on the pulling truck I noticed my t-case shifter moving ALOT when pulling. I decided to put new Rubber motor mounts in and Poly t-case mounts in. The very next pull (about 3 years ago) I snapped the adapter between the 700 and 205 ($$$$$) costly mistake. I then put the ORD motor mounts in and have not had an issue since. The Poly mounts did not allow flex, while the Rubber motor mounts did, and something had to give (the t-case adapter).
     
  12. Seventy4Blazer

    Seventy4Blazer 3/4 ton status

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    if you have the polly mounts in one of the 2 or 3 locations then you must have polly in the rest.

    i have seen many tranny to t-case adaptors broken and trannys broken from polly mounts and rubber in others.

    grant
     
  13. 84_Chevy_K10

    84_Chevy_K10 Banned

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    [ QUOTE ]
    I've got the lifetime warranty tranny mount from AZ and they will never honor it. I've gone through 4 in a year and they claim I'm "abusing" them.

    [/ QUOTE ]

    That's ridiculous. Go to a different store and get them to swap it out or give you a refund.

    I have had no issues with having poly trans and rubber motor mounts nor has anyone I know, but just for cheap insurance I might swap my tranny mount to a rubber unit.

    I just don't understand how it could make a difference. They say if you run a solid motor mount not to run a solid trans mount because something has to allow movement. I figured I could allow movement at the engine and have the poly be at the tranny.

    I dunno maybe I'll just leave it. It's going to be a tough decision to pull poly out and put rubber in. I know I'm not going to buy ES's poly motor mounts. They don't even know how many sales they've lost not including the metal part, and ripping their customers off for what they charge.
     
  14. big pappa b

    big pappa b 3/4 ton status

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  15. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Thanks, however:

    1. I boycott Summit because they piss me off, and

    2. Rubber is cheap and I get an AZ discount, so I'll probably go that route and sell my poly mount. /forums/images/graemlins/thumb.gif

    Now that I see they're moroso, I could order them at work anyway. /forums/images/graemlins/smile.gif
     
  16. Seventy4Blazer

    Seventy4Blazer 3/4 ton status

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    [ QUOTE ]
    I have had no issues with having poly trans and rubber motor mounts nor has anyone I know, but just for cheap insurance I might swap my tranny mount to a rubber unit.



    [/ QUOTE ]
    AJtatted broke his tranny of on the back side. i will put money on it from having polly motor mounts and rubber tranny mounts.

    a few things that can make it so it doesnt matter as much is if you have the braces that run from the motor mounts to the TQ convertor cover alont with the torque bar that runns to the t-case.

    they make all the connections nice and solid and prevent a lot of flexing.

    running rubber and polly in any combination is bad. the rubber will wear out a lot faster that the polly and in time it will break something.
    Grant
     
  17. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    I don't know about that. The engine mounts control engine torque. Stock is generally ok, but poly generally better in most cases. But for tranny case longevity, I think that in general the trans mount needs to be no stiffer than the engine mount. Stock mounts on the engine and poly on the trans forces the trans case to try and restrain engine torque. This is especially true of the custom cross members with outboard bushings. IMO, the trans mount is really just to support the weight in the back. A simple single mount with NO tortional control would probably be best for most rock crawling applications. Poly on the engine and stock in the back puts the torque control on the engine block where it belongs while avoiding using the case and rear mounts to control the twist. IMO, stock rear mounts in good condition should be fine.

    But, there are exceptions. Due to the off-center front drive portion of heavy cases like the 205, something needs to be done to control impact loads such as those that occur when jumping. An offset mount or something similar could be used, but I don’t think making the tail tortionaly rigid is a good idea at all…
     
  18. 84_Chevy_K10

    84_Chevy_K10 Banned

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    [ QUOTE ]
    AJtatted broke his tranny of on the back side. I will put money on it from having polly motor mounts and rubber tranny mounts.

    a few things that can make it so it doesnt matter as much is if you have the braces that run from the motor mounts to the TQ convertor cover alont with the torque bar that runns to the t-case.

    [/ QUOTE ]

    1. I have rubber engine and poly tranny mount. I'm probably gonna just put a rubber tranny mount in. I'd rather have a mount go out than crack a bellhousing or something. Big deal, they're rubber, they wear out, I'll just go to the store and swap myself out for a new one then, they're lifetime.

    2. Don't have any rods on my torque converter cover because I don't have a torque converter. I have a 4 speed, and I'd bet with its cast iron case, cracking isn't really an issue. Either way, I think after what I've just read here I'm going to get rid of my poly trans mount which is brand new and go rubber everywhere. I would rather see the give be in the mounts instead of the bellhousing of my tranny.

    Thanks guys for the heads up...although I'm worried now and I'm gonna get this stuff swapped out right away!!
     
  19. Klink K5

    Klink K5 1/2 ton status

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    We'll this may be a long, but true story, but I farm in Northwest Iowa. I can give you a true testamate about engine/trans mounts. We farm about 1600 acres of farm land corn & beans. WE USE Chevy pickups to pull our loads of grain to town that weigh in over 45000 pounds on the scale and about 12000 pounds empty. I personally use my 1984 K10 4x4 pickup 1/2 ton long box with a 350 v-8, 700r4 trans (I am on my third rebuild). 208 t-case and 2:73 GEARS in the axles that were stock from the factory. Anyway, I pull the loads from the field to town in 4 low at 25mph. (There is alot of torque going though the driveline at this point). I have pulled loads every fall for the first three years I have owned this truck with the origional mounts with no problems. The fouth year was a diffrent story. Starting into fall, I had a banging noise on the start of the pull of the wagons and looked it over to find the stock mounts to be bad. I called my GM dealer and priced some New GM mounts and they were $60.00 dollars each. I SKIPPED BUYING THEM AND WENT AND BOUGHT SOME ENGINE MOUNTS FROM NAPA that were $9.95 each. I ran them two years pulling them and this year they shelled out. So I would recommend buying Factory GM mounts or going totally polly on the engine and t-case. Bottom line, if you are having problems with engine mounts and t-case mounts, buy a good mount and not the cheaper stuff. It does not pay! Also, I run Energy Suspension mounts in my 1978 Malibu Drag car on the transmission and motor mounts. The motor mounts are a bitch to install and line up, but they are worth there weight in gold when you are finished with the end result. It made a diffrence in my 60 foot times as compared to the origional mounts. /forums/images/graemlins/thumb.gif
     

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