Motor mounts
 

What is everyone else using that works? From the archives it sounds like most are happy with the Mity Mounts.

Anyone modify the factory mounts himself?

Can I see pics how you chained or turnbuckled your motor?


I need to change something.
http://i1305.photobucket.com/albums/...pshmdpuip7.jpg

I had no idea there was this many options

http://www.jbp-pontiac.com/products/...otorMounts.htm

This is still going to be a street car. The poly mounts look tempting but I would guess they would transmit as much vibrations as solids. This has me leaning back to the MightMounts even is they are just a bolt through a stock mount.

What mounts did you end up with?

For you guys that use limiting straps can you share your pictures?

I have subframe that I need to get blasted and painted and wondering if I need to do any more welding to it for a limiting strap.

I went with a solid mount on the driver side and a cheap Chinese mount on the pass. I don't feel any added vib because of it. I just recently changed it out and I would've noticed. Still have to have the shims installed to keep the pan off the crossmember but I expected that. If you have that clearance issue new mounts probably won't fix it.

A side note, these straps (on a 69 Canadian 2+2) were installed by the dealers as a factory recall on all 69 SBC 350 big cars (chevy and canadian pontiacs). apparently motor mounts were failing even when the cars were new.

north

That is really interesting.

If you go junkyard hunting you can find full size chevys with the update still intact. Of course they are only going to fit chevys, Pontiacs will require a complete engineering for our engines. The GM retrofit shown in the pictures was to keep the left mount from separating as well as keeping the engine in place front to rear. Those cars had solid rods for accelerator linkage. If both mounts broke and the engine slid forward in the chassis the carb would open up causing (Toyota phrase) unintended acceleration.

I have an idea along the same lines for Pontiacs, I just don't have enough time to sit down and make a prototype, transferring the idea, into metal, that you can lay your hands on. It would be many times better than mity mounts that members here have broken in short order. $15 dollar mounts with a couple of $85 screws in them...…….:pound:

My idea would let you use the stock mounts for vibration dampening and only come into play when someone was accelerating at or near WOT, saving the stock mounts by limiting engine movement. It would also remove the strain of the motor mounts on the left hand side of the engine where in the past some people have seen cracked main bulkheads and #2 and #3 main bearings with unusual main bearing wear. Transferring the limiting of the engine twisting from the pan rail area to the left cylinder head area may get you some longer engine life, especially with a stock block.

I’ve seen it on lots of virgin big chevies, some only have the drivers side.

Apparently the recall was driven not so much by the mounts themselves failing but by the engine fires caused because of flexible fuel hoses failing when the mounts failed.

On December 4, 1971, General Motor (GM) announced it would recall over 6.68 million 1965-70 Chevrolets with defective engine mounts. The recall covered 1965-69 full-size Chevrolets, 1965-69 Chevy II’s and Novas, 1967-69 Camaros, and 1965-70 Chevrolet/GMC light trucks, all with V8 engines. (NHTSA Recall 71-0235, now 71V-235.)
Engine mount breakage causes a self-perpetuating chain of events. When the left-side mount breaks, engine torque causes the engine to rise up, pulling open the accelerator linkage; this causes even more upward movement, and consequently more opening of the accelerator linkage, until the engine’s movement is stopped by the closed hood. Moreover, the engine’s upward movement pulls the power brake booster vacuum hose loose, thus greatly increasing the force needed to stop the car. Also, the automatic transmission “PRNDL” quadrant would shift itself over one position to the right (e.g., from D to L), affecting all gear positions; this meant that the car no longer had a Park position, and could be started in Reverse.
The National Highway Traffic Safety Administration (NHTSA) received its first report of a broken Chevrolet motor mount in September 1969, and contacted GM a few weeks later. However, even before it received GM’s reply that indicated a total of 14 reports on 1968 models Chevrolets alone, NHTSA placed the investigation on “inactive status.” NHTSA informed GM of this “inactive status” in a June 1970 letter.
The case (IR 162) remained in abeyance until NHTSA received a second report in late August 1970. Only then did the agency begin to arrange independent tests of effects of broken Chevrolet motor mounts on driver control, but even these tests (in October 1970) were flawed. The test facility used a Chevrolet without power brakes or power steering, thus preventing an examination of brake assist loss. Nonetheless, the tests demonstrated the throttle-opening effect that consumers had noted.
In December 1970, NHTSA sent a second, more comprehensive information request to GM. The company’s January 1971 reply indicated a total of 172 reports of failed motor mounts, with 63 accidents and 18 injuries; GM also advised that it had been using the same mount since 1958. Despite this clear indication of a widespread defect, NHTSA did nothing further on the matter until June 1971, when it sent questionnaires to 63 consumers who had reported broken Chevrolet motor mounts. NHTSA sent a third information request to GM that August. On September 1, 1971, Ralph Nader sent an extensive letter to NHTSA about deficiencies in NHTSA’s investigative procedures, including the handling of the motor mount defect. Robert Irvin, long-time automotive writer for the Detroit News, took interest in the matter after receiving a copy of Nader’s letter, and subsequently wrote over 70 articles about the motor mount case. Irvin’s articles, many of which appeared on the front page played a key role in putting public pressure on GM and NHTSA to force a recall.
On October 15, 1971, NHTSA issued a consumer protection bulletin advising motorists of the “potential risks” of broken GM engine mounts. Around this same time, GM President Edward Cole declared that a broken mount was the equivalent of a “flat tire or blowout”, and that anyone who could not control a car with a failed mount at 25 mph “shouldn’t be driving.”
A few weeks later, NHTSA sent two staff members to GM’s engineering facilities in Warren, Michigan to witness more tests of failed motor mounts; their findings corroborated the results of the earlier tests. Around this same time, NHTSA Administrator Doug Toms visited GM headquarters and test drove Chevrolets with severed mounts with GM President EJ Cole in the test vehicles, but NHTSA did not place a record of Toms’ visit in the public files.
NHTSA sent a letter to GM on December 1, stating that it was close to determining that a motor vehicle safety defect did exist. Three days later, GM announced its recall, but the company refused to admit that the vehicles contained a safety defect.
One irony of the recall is that on over 95% of the vehicles recalled, GM did not replace the defective mounts themselves, but rather installed a bracket and cable to restrict engine movement if a mount broke. By avoiding replacement of engine mounts on all 6.68 million cars, GM managed to cut its recall costs considerably; the cable and bracket assembly cost about $1 per car, far less than the $50 cost of new motor mounts.
For a comprehensive report and materials on the failure of NHTSA to obtain a more timely recall, see Hearings on Auto Safety Repairs at No Cost, Senate Commerce Comm, 93rd Cong., 1st Sess. Pp 200-58 (Jan. 30-31, 1973) including Oct. 11, 1972, letter from Chairman Harley O. Staggers, House Interstate & Foreign Commerce Comm. to NHTSA Administrator Douglas W. Toms.


As I said unintended acceleration. I was twisting wrenches at that time for a living.

I didn’t realize it was such a big recall. However now that I know that Nader had his nose in this I will be removing those straps tonight. ;-)

https://forums.maxperformanceinc.com...1&d=1568488280

69 Camaro

I originally had a solid on the driver side, got spooked by cracked block horror stories and put a normal mount in. I welded a half chain link to the frame as a anchor point to make a chain setup to the back of the driver head. haven't got around to completing it yet.

Reading though this gave me a thought though. I, as others have noted, have to shim my mounts to keep the pan off the crossmember. Currently I have about an 1/8th of clearance, I need to shim it up a little more.

If I used the solid mount on the driver and cut say a 1/4 piece of hard rubber, similar to normal mount content, and used that as a shim rather than metal shims. Would that not provide the block a little flex and some relief from the possibility of cracking?

Just a thought.

not a bad idea IMO.

Very similar to the isolator pads that you can buy with solid body mounts.
https://scandc.com/product/scc-body-...-68-74-x-body/

I ended up drilling a hole and installing a nutsert in the main crossmember on the sub-frame. I plane to keep rubber mounts and use aircraft cable from the head to the frame. I want to paint it black and make it as inconspicuous as possible.