Left hand engine mounts keep breaking

[Rodney Gold]

My 80 vette is breaking engine mounts on the LH side when the car is used in serious anger on the street ..not strip...2 gone so far -- est 350-375 hp , high 2600 stall and 3.55 rears?
I have also noticed my windscreen seems to have cracked due to the car "twisting" , also LHside , crack radiates up from the base of the windscreen..
Any ideas or solutions..all the other mounts are 100% (including gearbox)
Is there any strenthening strut arrangement I can add?

 

[DINO1970]

Try a length of cable

I had this problem with my 64 Chevelle. Just get a length of wire cable, and four clamps. (The factory actually made a kit to deal with this problem in sedans, and who knows, there may be on for the Vette as well.) But you can make one by running one end through the base plate of the mount on the left side and secure the other end to some solid part of the frame or even the upper control arm mount. Make it short enough to keep it snug, but not in constant tension, so that your not transmitting engine vibration to the chassis. It does the job.

 

[navy2kcoupe]

When I raced my 1969 SS-396 Chevelle back in the day..........make that WAYYYY back in the day,
I used 2 pieces of chain with a turnbuckle in between to do that job. Bolted one side of the chain to
the block and the other side of the chain to the frame. Used the turnbuckle to tighten up the chain on
race days, and loosen it up for street driving. Never broke a motor mount on that car as long as I had
it, even before I put the chains and turnbuckle on it. Great car........wish I still had it, but as great
as it was, my C-5 beats it hands down in every way except drawing a crowd. The Chevelle would win
THAT contest like there was NO contest.

Andy
(One for the old Chevelle too....)

 

[Crimson Thunder]

You could run a solid mount on the left side and keep the rubber mount on the right. You will feel some vibration at idle with the solid mount though.

 

[damoroso]

You might make sure you're using good quaity motor mounts. I had the same issue with another vette I had and I was replacing it with a part from NAPA. I went to the dealer part (NAPA part was $10, the dealer part was $30 in the early 90's no less!) but it never broke again. Lakewood puts out some good mounts that still have some rubber in them too...