Solid motor mount help

Need some advice guys.I am going to fit solid motor mounts on my project and need to clear up a few things 1: If I have solid mounts using the factory placing can I still use the rubber trans mount or does this also need to be solid mounted.2: If I use a front motor plate do I need to use a mid plate also or will a front mount plate and the reg rubber trans mount be enough.This is a 351m with c4 strip only car Thanks Andy

 

btt

 

If you are going solid mount, and especially using front and mid plates, use a stock type rubber trans mount. You will have some chassis flex between the front of the engine and the trans, and it will likely break the bellhousing off at the pump.

Also, if you're going with front and mid plates, be sure to add a locating link from the frame to a stock motor mount bolt. This will keep the engine weight from bending the plates on launch and braking.

 

Don't ever use a front mount engine setup with a tailshaft trans mount, no bellhousings were designed to handle that sort of stress and you're likely to stretch your bellhousing bolts or crack the bellhousing itself...always use a front/mid plate setup, or the side motor mounts with a tailshaft mount trans...

 

So the locating link stops forward and backward movement of the engine.One on each side ?

 

I think I will go with solid mounts in the stock location and a new rubber mount on the trans

 

Urethane bushings on the sidemounts will give a very positive location to the motor, without trying to find the weak link structurally. I can't imagine the tiny bit of deflection you get in them would degrade performance at all.

 

Strip only car will NEVER be on the street !!!!

 

Solid motor mounts and rubber trans mounts usually result in broken bellhousings/trans cases. You cannot allow any flex on the trans with a solid mounted engine...something will crack/break. good luck..................

 

so i ask again if I have solid mounts in the stock position I have to have a solid trans mount ?

 

I've never had issues with solid motor mounts and a rubber/urethane trans mount...I'm either lucky or have never had chassis or drivetrain flex issues that caused failure...I've never solid mounted a trans, so I've got no opinion on that...

 

I've had several cars come to me that had problems breaking bellhousings and or cracks in the trans case that were running solid mounts on the engine with original style rubber trans mounts. These cars are all race cars with cages, so chassis flex is/was minimal. I'd replace the trans and use a solid mount and never had one come back. I cannot comment on urethane mounts, I do know they tend to be better/stronger than oe rubber style ones therefore they may be ok...or not.

 

You can run a solid trans mount, but ONLY if you have the engine solidly mounted- and that's IF your chassis is a full effort to kill frame twist.

A rubber, poly, or urethane trans mount will allow the frame to react to the launch without putting severe torque to an aluminum trans case/bellhousing/tailshaft, which will be solid mounted to the front of the frame.

MOST "track only" Hot Rods dont have max effort "race" frames, and exhibit some frame twist- and that is death for a solid mounted trans.

So if your frame is PERFECTLY rigid, then you can get away with a solid trans mount/solid engine mount- My buddy's 69 Nova is just a body shell draped over a full tube frame supergas chassis, and he runs a poly transmount.

 

Thanks 69fury
I am running a 2x3 box frame with a 10 point cage so I think I will put solid motor mounts in place of the factory and a new poly trans mount. I just do not see the point of rubber motor mounts on a race only car as I know that it will fail eventually and every hard core race car I have seen has ether motor plates or solid engine mounts but I never took much notice of the trans mount. Just want to do it the right way first time and not have to go back and fix it later
Andy

 

I am a "Race" only guy and currently race a nostagia Pickup (9 sec) am part of the crew on a mountain motor pro-stock team (1400+ hp) with a powerglide as well as help with a pro-mod (3000+ hp) that uses a clutch/lenco setup.

All of these use the same set up....

Solid mount front and mid plates with urethane or rubber trans mounts.
Engine limiters for front to rear movement.

No problems ......

 

WRONG (sorry) BAD ADVICE.

If your going to use solid motor mounts YOU MUST USE STOCK STYLE TRANS MOUNT. POLY STYLE TRANS MOUNT WILL NOT WORK EITHER. Stock RUBBER trans mount.

If you use solid mount on the trans you WILL BREAK SHIT!

 

Da Tinman,

Agree and have "done that".....

Solid tranny mounts will break stuff !!!

 

Thanks for all the replies chaps !!
The problem was sorted today and I am glad to say that I managed to do what I needed to do without resorting to solid mounts of any kind. Viva the Plasma and welder.
Andy