mix & match poly eng/trans mounts

[Jon325i]

So here's my situation:

I pulled my M20B25 drivetrain on Sat due to a spun rod bearing (have a lower mileage M20B25 almost ready to drop in) and I discovered the IE poly trans mounts I was running were sheared in half.....just the weight of the equipment was holding it in place My present motor mounts are IE poly as well (they are just fine).

My friend helping with the task suggest I call AKG to inquire about their poly (75D rated) trans mounts which have a thru-bolt design (which I did, very helpful & knowledgeable folks). My question is: how do the poly IE motor mounts compare to the AKG items in terms of hardness? IE doesn't rate their poly items for stiffness/density. Would I be ok with this mixed set of poly mounts or should I just go with one brand (and known desity) for engine & trans?


Jon

[Smelser]

I know on our race car, and this goes with our BMW and also with our Chev 350 race car.

BMW we use poly on the engine and stock rubber on the trans

in the Chev, we used solid steel for the engine and a single stock rubber on the trans tailstock.

reason: hold the engine tight in place, there is still some flex, the rubber allows for a sligfht amount of flex and does not wear on the weak aluminum mounting points of the transmission.

this reduces the chances of breaking the weak transmission and holding the engine solid in its place.

just my thoughts, but thats what we run and its been no issues.