Solid motor mounts?

I see ads for solid motor mounts. What would be the dissadvantage of that?
Right now I have a piece of plate steel with the 3 bolts into my 350, and in the opposite direction there is one bolt through a deuce and 1/2 motor mount (doughnut) into the frame horn. This works on a SBC as there is space between the plate and the actual block and in this space is the head of the one bolt that goes into my frame horn.
The problem I have is that my BBC has no space between the plate and the block to fit the head of the bolt.
I was pondering just welding the plate to the frame horn as I always plan to run some sort of GM motor and this way would be alot easier.

Would this be a solid motor mount? Would this work? Is this too ghetto to be discussed seriously here?
-B.

Do you mean to eliminate all rubber or vibration dampening material and just go engine to frame? If you do, then it will just be a lot of vibration and noise. No real harm except for what gets shaken up.

Don't.

Lot's of vibes, will probably break apart, and if you ever get loose anywhere and hit some with enough force to tweak the frame you are putting ENORMOUS strain on the engine casting. It IS possible to distory the block under severe circumstances.

Good point about the frame acting on the engine. I was only thinking the other way.

However, I have always wanted to build a car that has the engine and transaxle as the frame, like the Indy cars. Kind of a Can-Am Hot Rod.

My 6.2 diesel has solid motormounts. I don't notice any more vibration then usual and I run it pretty hard.
Novak's orginal Chevy V8 kits all had solid mounts, so I would bet there are quite a number M715's out there with solid mounts.

Rollie

Ah! HA! And there is what I was hopeing for.

Rollie, not to pry- but what kind of mounts are they? They something you made of bought?

I don't figure that if I wreck my rig bad enought that the frame is tweaked that I'm gonna be freaking out over the motor being stressed. And I think what I have now is about as close to solid mounts as you could get.

I appreciate it all,
-B.

Solid motor mounts are used in drag racing to stop the clutch linkage from binding, or comming apart, while doing high torque power shifts. You are asking for nothing but problems if you use them. Besides the vibrations that they transfer, I have seen the sides of the block cracked from their use. Remember that the weakest link in the chain always breaks first. M1028

I have been running moroso solid mounts in mine for two years mounted to the stock frame horns. no vibrations. I do monitor the condition of the block and frame. Be sure to run a rubber trans mount so something gives instead of your bellhousing.

I also used to have a '72 chevy pick up with a radical 468, It also had solid mounts. I drove it hard everyday for 8 years with no problems or vibrations. I have seen problems with some home made mounts breaking up block castings and causing vibrations, I don't think they were set up properly. Good Luck!

Stupid question, but aren't all solid mounts like made out of poly something or another? So in effect they absorb the vibration? Or are they like rock solid chunks of steel?

solid mounts are just steel

As strong as our frames are...why do you think you can't get the doors open when you've got the suspension all crossed up on a hard trail. Frame Flex. As that flex acts on the cab, that flex acts on the engine block casting which is very stong, but is CAST iron, not steel, which makes it not want to give...ANY, but just flat break. If you've got a driver and no lockers and it's a road truck...solids will be fine. I'm with Barry on the new weaklinks...you bust that rat motor cause you didn't want to adapt a pair of cheap GM captured pin mounts and you'll feel pretty stupid.

Indeed. I guess you hippies are right- the only reason that I'd do it was to save some time. I looked at the mounts again last night and it seems that it would be just as easy to change my current mounts as it would be to weld on solid mounts.

Just tossing out ideas.

Thanks all,
-B.

Brian,

After all the good advice listed so far, I'm not going to suggest the solid mounts are the way to go, but if you are interested there is a close up picture of mine under Rollie715 in the Members Gallery. I did not cut the original frame perch and found that with the bigblock there was very little room to make a large rubber encased mount. I cut down the pieces that bolt to the block and drilled a new hole in it for the big bolt. The part I fabricated you can barely see consists of about a 4" square of 1/4" plate with a piece of pipe welded to it. The 4" square bolts to the frame perch using two bolts through the original perch holes and the pipe piece is bolted to the Chevy mount using a long bolt. You can see the head of the long bolt in the picture. This style is almost an exact copy of what Novak had been selling for years.

Rollie

Rollie,

I see what you mean. I wonder how much different that mount would be than what I have now as far as vibration dampening. Yours sits about 2" higher than mine does as my mount is just a pieve of plate steel with a bolt through it, a doughnut, and then through the frame horn. The only spacer is the doughnut and it is only about 1.5" or so thick.
Hmmmmm....
Thanks for the idea. I need to pull the motor and see what I can do about it all.
-B.

Brian,

I think your donut idea will work fine, but you might want to add a second donut and large washer on the bottom side of the perch and use a longer bolt. Then you would have a cushioning affect in both torque directions. Also a locking nut or cotter key to hold the nut on might be good.

Rollie

DaveA has e-mailed me with the option that he's looking into- a '72 Chevy 2wd pickup with the v8. He said the motor mount is stuck to the frame horns via a large bolt and that they use your style of horizontal bolt.
He pointed out that that bolt could be replaced with one that has a pointed end and thus it would be a slide in to help alight the motor. Nice. He said they were cheap too.

I'm gonna pull my 350 saturday and then check into all this and try to get some sort of cheap motor mount that is easy to use. I think it would be nice if a newbie could get a part number from here and walk into any auto parts store and get a motor mount that needs no mods to use and is simple.

If it all goes the way it did last time I swapped my motor and I end up using the motor mounts I have now, then I'll use your double doghnut idea. The bolt is already as big of one as will fit through the horn slots and is grade 8. I'll also add the safety wire.

Thanks,
-B.