Anyone break the updated non clamshell motor mounts?

[burnin oil]

Posting this here for discussion and traffic.

I noticed that the trans tower was moving around alot so I checked the trans mount while I was under the truck. It was broken so I replaced it and the problem persisted. So yesterday I pulled the drivers side motor mount and it was busted right at the threaded nut for the frame bolt. This is the new style non separating old style mount. I ripped the metal plate in two horizontally across the entire mount! OOPS. New mount works great but I never saw a mount that ripped the steels apart. It looked to be around 1/16" steel. Possibly thicker. Oddly the motor passed the rev test for visually checking the mount and looked good until raising the motor. Anyone else have this happen?

[dmjlambert]

It would be great to see pictures of what you are talking about.

[burnin oil]

I never posted pics on here. I think I got it figured out so I will snap a picture tomorrow.

[burnin oil]

It's a little hard to see but that crack is through a steel plate with a rubberized coating.

[burnin oil]

Second pic

[Wizo]

I use to have motor mounts like that, then i burned all the rubber out to them, cut and fabricated 1" metal bars to fit in place of the rubber, welded it all together
and now i have solid motor mounts. That was 5 years ago and haven't had a problem since.

[burnin oil]

I originally did a 30 day rebuild on this truck about 8 years ago and went back with these mounts. I was on vacation at the time. Next time I will update to clamshells but that is another few years away when she gets the frame off.

Has anyone else had this happen to this style mount? I have seen some come apart at the end but not actually rip apart like this.

[burnin oil]

No one else has a comment on the way these broke? I know that some of you have run these for a long time. It seems like a wierd failure to me.

[Palf70Step]

It was pretty common on the farm trucks (or race cars) torque seems to tear them up. Probably cheaper build of the replacements don't help either. I have done one set on a daily, but I did tend to repave the road with black strips off the rear tires too. The last couple folks I know with work trucks took them out and made solid mounts like explained above.

The older 67-72 style mounts were even worse. GM even added a torque cable to keep it from jamming the throttle linkage wide open.

[burnin oil]

Thanks palf,
I know of the failure of the original designs and only seen them rip apart at the ends for the redesign. I have also seen the ones with a stud pull out. Just never ones that ripped the steel in two like this. This truck is a high HP toy that is also a work truck around the property. Heck the 4.10s are about to come out for 5.14s. Waiting on the new brake shoes (14 bolt upgrade). Once I am done hauling water to the reclaimed field she goes under the knife. Be detroit rear with a spartan front. Should be a beast then.

[garyd1961]

I went old school with mine, chained the motor to the frame.

[Captainfab]

Those '63-'72 mounts are just not a good design. They last a little better when you have a manual trans with the crossmember mounted bellhousing. I have heard that the urethane version of those hold up better, but I have no personal experience with them.

[crazy longhorn]

The urathane mounts do hold up good! Ran a set on my 383 (385 hp/440 ft ls), with stick shift. The same mounts are on my 5.3....no bell crossmember, the old longhorn was born with an auto trans Longhorn

[burnin oil]

Thanks guy's. She has been rolling on a stock replacement that I had laying around. So far so good but will be upgraded next time the truck goes under the knife. She was rebuilt several years as a good looking work truck but will get the full treatment sometime in the future.

[garyd1961]

My old 307 had the cables around the exhaust manifolds so when I put the L31 in with headers I just chained the motor down to the frame. Haven't had a problem in 5 years now. Leave a little slack in the chain and you will never know it's there. To me it looks a lot better than the old cable tie downs.

[burnin oil]

I have seen and owned a few with chains. I just thought ripping steel apart in the mount was strange and not where you normally see a failure.