MEEEEEEGA MOTOR MOUNT.
 

After braking another new stock motor mount (drivers side) im looking at other options. I dont want a 100 dollar magic bolt MightyMount. I have read that solids are a rough ride and can break a block in higher horsepower apps.

I was thinking about fabbing up my own for the drivers side. I would keep the stock passenger side and make a semi solid drivers side that uses pourable urethane. it also will utilize as many of the mounting bolts holes in the block as i can.

my question is the mounting hole in the block that is up higher than the 4 along the bottom edge of the block. Is that one a safe one to use along with 3 of the bottom ones? Im afraid i might pop it out of the water jacket.

http://www.highperformancepontiac.co.../photo_06.html

i know it overkill but i want to do this once and forget about it. im tired of chewing up fan shrouds lol

Regular Pontiac LEFT Motor Mount with a Link Chain and Eye-lets has held many engines making 1000+ hp and does not stress the block or allow the mount to fail.

One eye-let goes to the head, the other eye-let goes to the frame.
Typically one eye-let will have a provision to lengthen or shorten the chain.

Everyone always wants to invent something new. Try that vs designing up a whole new mount that may or may not work.

Tom Vaught

I use a 3/8 " turnbuckle, infinitely adjustable and about 3-5 dollar investment. It also looks more finished than a chain. Pretty easy to install too.

Do you think it would be a problem with aluminum heads ?

You can make a 3 bolt plate that will spread the load across the aluminum head bolt threads in the head and have an "ear" that connects to the chain or Turn-buckle mentioned by Sirrotica.

Tom Vaught

How about a picture of your turnbuckle and chain set-up???

I made a plate up and secured it too the head on drives side,,and then to the frame.. no issues so far..

The Might Mounts are just regular mounts with two flush bolts installed in each one.. that's the way the mounts were for our 68 Firebird..

Charles

Chains the head to the frame? Is a custom fit bolt on kit? Thats available in billet right? Color wont clash with my powder coated block and polished pump? LOL (8-)

The Chevy factorys solution to the 396 trying to jump out from under the hood was a very simple, clean, elegant tie wire of 1/4" aircraft cable and looped ends from frame to head. Hardly noticeable.
Never tried the chain deal myself, I always took a big hammer to the drivers side stock mount and bent the tabs over so it couldnt come apart. That worked ok for me. I dont know if it would work on the later model big flat mounts?
Anything with big power better have some kind of solid mount on drivers side IMO

Bmans deal is clean, easy to do. seen it on a 1000 cars.

Nice Picture, Bart, and totally understandable. That engine is going no where.

Tom Vaught

Back when I was racing turbo Buicks we used a small tie down that is used for like motorcycles and it worked great. We had several cars with 1,000+ hp and no failures. The webbing material isolated any vibrations. It was adjustable so worked on a lot of different combos.

Question. If you use a 3 bolt plate on the end of a head and use a stock mid 60's alternator bracket, does the bracket have to be machined down for the thickness of the new plate? My new motor is going together right now and not to this point quite yet.

Look in the picture where Bart's cylinder head bolt is, I used the studded head bolt that the ground cable usually bolts to and attached my turnbuckle to it. Also using a bolt with a stud on it you can use the front, middle or rear of the head to attach it to, my 69 GP worked better in the middle of the head due to the extreme setback of the engine, the upper A frame and shaft are in the way to mount it to the front of the engine. Of course if your using a studded block that wouldn't work out. I welded a 3/8' bolt to the frame and your done.

Mine was on my oval track car for 3 years and when I junked the car and pulled the engine the mounts were like new. I had broken brand new ones back in the late 70s when they weren't made in China, Korea, or Indonesia. My car was a 69 GP, and the left mount didn't have the limiters on it as the A bodies, etc. do. Actually those style mounts are interchangeable from left to right, one number fits both sides. That's how I did it when I didn't want solid mounts and thought I could find a better device than chain, the choice is yours....good luck with whatever you decide....:)

the only problem i have is room. i have an alternator, PS pump and stock exhaust logs facing backwards so they dump out the front of the motor in my turbo setup. i was thinking maybe the plate for the back of the drivers side head but there isnt much room there either.

In my case I needed to space the alternator bracket forward by 3/8" because of the use of an early style '64 alternator bracket on a '74 455 engine with the later style front cover, balancer and water pump pulley setup.

In your case you can mill the back of the accessory bracket down. Do this only after making sure that after removing the material needed for the thickness of the engine tiedown bracket the accessory bracket still has the structural integrity it needs.

You can use 1/4" steel plate and it will be plenty strong, keeping the amount milled off the back of the accessory bracket to a minimum. Also you might consider just milling down only some of the backside of the bracket leaving part of it intact, using only the 2 outer bolts instead of all 3 bolts to secure the tiedown bracket to the head.

Read post #13 if you haven't already, and I addressed an alternate way to mount it, unless you have a block with studs instead of head bolts.

Vic,

Perhaps you can make up a longer more elaborate tiedown bracket out of 5/16" or 3/8" steel plate (depending on bracket length) attached behind the accessory bracket on the front of the cylinder head that will reach over and past any obstacles, like the front-dumping exhaust manifold.

Mill down the accessory bracket on the backside to match the new bracket material thickness. You can then attach a chain or turnbuckle to the frame. I used a long 3/8-16 Grade 8 bolt and drilled through both walls of the frame to attach the bottom link of the chain.

Get out some heavy cardboard and start making a bracket template.

Good luck, Bart

You could go strait vertical from the frame to the extra holes in the block allowing some movement to cushion the hit with the original mount. My engine straightend the safety catches out the metal is not near as thick as original mounts.

I had thought of that set up but became concerned about the torque applied to the front of the head. I figure that a 6 to 8 inch lever plus the torque of the motor at full squirt, 10 pounds of boost etc would/could cause some problems with the head lifting, twisting or distorting? i dont know, am i being too much of a puss here? am i over reacting on the forces at work here?

There is another mod where you weld a piece of steel rod across the tab interlock. It allows about .03-.06" travel and then it is basically a solid mount. i found a pic of it once upon a time, very inconspicuous and simple.

Yes. ;)

Check out post #8 in this thread:http://forums.maxperformanceinc.com/...in#post3555937

yes, that is what i had envisioned. i took a look at it today. looks doable but i will have to mess with moving the power steering hoses a little bit. I still havent ruled out the back of the head. with exception of a tight fit against the firewall and alot of fuel injection wiring i have a ton of space...... and just as i wrote that i had an idea....what about the utilizing the bell crank pivot hole to mount up something?

Bolt your own motor mount?

Only problem with a regular bolt is clearance to the frame bracket. Can either notch that, or shave down the bolt head...

http://img820.imageshack.us/img820/9339/mounte.jpg

I'm not sure if the block casting is stout enough in that area. I wouldn't put all that force on only one bolt attached directly to the block casting, a stout bracket bolted to either the front or back of the head with 3 bolts would be a much better choice in my opinion.

Vic,
I'd make a cardboard pattern off the passenger side head's front (mirror of driver's rear), add in a tab to mount the chain/turnbuckle/cable to, cut it out of 3/8" steel, and mount it to the back of the driver's side head w/ 3 bolts. should be low profile, clean, and almost unnoticed if painted black.

Found this posted in another thread by 1971warbird a while back. Believe it's the Jim Hand mod...credit shows a "Joe Hand" ??

Forgot picture...getting old damn it !!:)

While that works for an A body mount, it doesn't cover the many other mounts Pontiac used throughout the V8 years.

Here's what I did (Pics). I used a 1/4" turnbuckle and a piece of 5/16" chain. It runs from the driver's side, front, head bolt to the rear steering box bolt head (outside of frame). I welded the eyes on the turnbuckle shut for good measure. I run it with just a little slack.

Joe is one of Jim's sons.

Someone mentioned the Chebby cable...

http://cgi.ebay.com/ebaymotors/NOS-1...Q5fAccessories

Why not a solid mount on the drivers side and a rubber mount on the passenger side

Guys, if you read the first paragraph of the original post he's trying to avoid stressing the block where the factory motor mount attaches.

That rules out using any kind of solid engine mount, a rubber mount modified so that it locks up or a rubber mount that's been bolted through.

I like the cable idea. Looks like it would be a clean install. Can anyone tell me how much the engine still moves (approx) with stock mounts and one side tied down? Thanks

How about a piece of angle iron bolted to the back of the head. Make 2 holes to bolt to the head or weld a piece of flat iron to it to hit a 3rd hole. Easy to make. Just use a piece thick (strong) enough.

Just stick a front engine plate on it like the allPontiac one...providing he has room for access. drives. Otherwise a cable or chain is in order ..:2cents:
I know to well about stress on DS mount. I lost a motor over it..IMO.
This is pic of #3 cylinder in old 462..there was stress cracks inside & outside block by mount pad..However block was not filled.

Being B-Body Mount Is diffferent, can A guy just use a chain under the cross member and attach it to the thru bolt on the mount securing the back of the chain with a nylock Nut on the end of the bolt?

Look like there is plenty of room behind my drivers side head. i already started to weld up the bracket that bolts to the head. I ll post a pic of it later.

I have an idea to use sway bar stabilizer bushings to help take some of the shock out of the setup when the slack in the chain is taken up at WOT.

any thoughts?

What is the bolt thread on the bolt that goes thru the mount? How long also

Just that it seems (to me anyway) your over engineering it, The mounts are going to give you the elasticity, and the torque restraint (whichever one you decide on) stops the mount from breaking due to twisting too far. You already have the isolation from the mounts for vibration etc., the torque restraint is only going to be in use a very small percentage of run time and isolation isn't really needed. It's your car, you do what pleases you. I'd put a turnbuckle on it and call it done.

If anyone wanted to take the time to do it ideally a strut that could have some pre-load adjusted into it and to tie both cylinder heads together and the a mounting point of the left side to tie the torque restraint to secure the torque restraint to the frame. The Pontiac engine is trying to push the cylinder banks apart while splitting the block. Tying the heads together would help with this force while providing a fixture to equalize the twisting force on both cylinder banks, but that's a lot of work, although it may help block longevity down the road, who knows?

im looking at a 1/2 inch bolt coarse thread, length to be determined.

Sirrotica, lol, yes, my curse. i always try to make things juuuust a little bit better than before.

It drives my wife crazy whether we are planning something, making dinner together or remodeling the house.

so that is why i see that a chain bolted to the frame has worked for countless people but i just want to take it to the next level. it seems easy enough to incorporate a urethane bushing and as i mentioned earlier i feel that it will still take out the shock when the chain runs out of slack as im banging through the gears.

here id a pic of the bracket. this will be the view if looking at the back of the drivers side head from the driver seat. the chain will be welded to the 1/2 bolt with a nylon locking nut on top. the chain will be bolted to a bracket welded to the frame. with the nylon locking nut, it will make it adjustable. i also plan to weld in a shallow bucket top and bottom to keep the bushing centered.

over engineered...yes..better than a chain bolted to a motor? time will tell. ;)

Looks good, Vic!
That's exactly what I was describing.

I tried a 1/2 nut last night was too big, 7 /16 ?

I think we are talking about different things. im using a 1/2 bolt for my custom mount seen in the pic..

Like this??

I welded a 5/16" bolt to the underside of the tab. Without the bolt, I dont see how the tab does anything?

More importantly, will this work?

I don't think the tab does anything, unless the rubber fails. Then it is a safety.

Couple of thoughts. For the dragstrip, I would prefer the turnbuckle because of its ability to prevent engine movement - the less stuff squirming around, the better. On the street, I would go with the chain (or preferably cable) and maintain about a 1/4" slack to prevent transmission of engine vibration to the frame, to the steering shaft, and finally to the steering wheel. This will allow the engine mount to do its job of isolating vibration, and also put a specific limit on engine lift. Only time you want the chain tight is under acceleration. If I felt any vibration at idle or normal cruise, then I would add just a bit more slack.