[mrennie]

Hello,

I am installing a chain from the DS head to the frame to limit movement and prevent the DS mount from failing.

My goal is to hide the chain as much as possible and I have a perfect spot, everything lines up well, but I am looking for feedback on whether or not loading the corner of the aluminum head is likely to cause damage to it. The bolt hole is at the bottom outside corner.

If these were iron heads I wouldn't give it a second thought but being aluminum I'm just not sure if it is likely to hurt something.

Opinions?

[Jeff Hamlin]

If it were me I would make/use something similar to the old Chevy Lift Stop kits.
These were cables installed low and close to the frame/mount to prevent lift.
I would not go high and/or bolt to an aluminum part.
JM2C

Cheers.

[steve25]

I would have no question about using it if I first where to drill and tap it out for a 7/16” fine thread bolt .
Also a key detail when using a chain is that even when the engine is not running that there is some minor tension on it like you can apply from a turn buckle.

[78w72]

Originally Posted by mrennie

Hello,

I am installing a chain from the DS head to the frame to limit movement and prevent the DS mount from failing.

My goal is to hide the chain as much as possible and I have a perfect spot, everything lines up well, but I am looking for feedback on whether or not loading the corner of the aluminum head is likely to cause damage to it. The bolt hole is at the bottom outside corner.

If these were iron heads I wouldn't give it a second thought but being aluminum I'm just not sure if it is likely to hurt something.

Opinions?

it will work fine & not cause any damage to the head. i use a stainless chain with about 1/4" slack in that same location on a 500+hp stroker motor & it drops straight down to the frame where i drilled a hole with a grade 8 3/8 bolt & poly lock nut, & used a couple washers to space it off the head & frame. very hard to see behind the power steering pump. the chevy straps to the A-arm mentioned above will work too but are very visible & unsightly IMO. a nice turnbuckle is another option.

i also made my own mity mount since this is on an earlier 2nd gen firebird that doesnt have the later clam shell mounts. so far has worked great with lots of low 11sec drag strip runs.

[leeklm]

Here is my setup, bolted to the top outside hole. The seatbelt has a more sophisticated look than a chain lol.

Sent from my SM-G965U using Tapatalk

[Scott Stoneburg]

As others have said, I run an adustable rod to that bolt on my car. Edelbrock aluminum heads. Have for years with no issues.

[Tom Vaught]

I have had, as posted previously several engine block retaining set-ups over the years (with a manual trans drive-line) that I was power-shifting.

The version I am going to use with the 455 block will be a very simple piece of flat stock material 1/8" thick by 1 inch wide with a 3/8" hole very slightly slotted upward.
I am planning on making that a 7/16" tall slot. So about a 1/16" of clearance.

I will attach the lower part of the strap to the frame with a 3/8" hole and bolt.
The hole will just clear the 3/8" fastener.

Basically I want no twisting of the engine reacting on the Nash Transmission or
clutch linkage. I think it will work great and will not rattle.

I had the chain deal and the cable deal and saw too mush exhaust header swing with
excessive retention clearance. Engine could not break the mount but the rest of the
parts attached to the engine were getting worn by the engine/trans/exhaust movement.

Not a issue with a slip on collector exhaust but a totally welded exhaust system would eventually crack and need repairs. I have seen the same issues with Exhaust systems on some turbo applications. Two many Dollars on a custom Stainless Exhaust system to ignore movement of the driveline parts.

Tom V.

[Schurkey]

I really like the "seat belt" section. A fabric strap will do a great job of cushioning the initial "hit" when the block jerks under torque.

Same reason I like tow straps instead of--or in addition to--tow chains. The towed and the towing vehicle don't get the "impact" or "shock" of the chain getting tight, the tow strap provides some elasticity.

[BILL BOWMAN1]

You could fabricate a plate to incorporate two or three of the mounting holes.
then weld a nut or bolt to the center of that.

[mrennie]

Originally Posted by BILL BOWMAN1

You could fabricate a plate to incorporate two or three of the mounting holes.
then weld a nut or bolt to the center of that.

That was my plan B if it seemed to be a sketchy connecting point with only 1 bolt, but I would have to machine the back of the PS pump bracket an equal amount to keep the pulleys aligned.

Glad to see others have used that bolt hole with no issues, I'll carry on!

Thanks guys

[AIR RAM]

Originally Posted by leeklm

Here is my setup, bolted to the top outside hole. The seatbelt has a more sophisticated look than a chain lol.

Sent from my SM-G965U using Tapatalk

I used a similar set up on my 69 Bird... just used the turn buckle from block to frame. But installed it at the back of the head (EDL) drivers side to the frame.

On the street I kept a little slack to allow some movement. When I went to the track, I gave it a few twist to pre-load it to help minimize twisting.

It never rattled or made any noise. I went from changing drivers side motor mounts once every 3-4 months before to not having to change them for years.

Great low buck mod!

SPEED SAFE, NICK

[grivera]

Originally Posted by leeklm

Here is my setup, bolted to the top outside hole. The seatbelt has a more sophisticated look than a chain lol.

Sent from my SM-G965U using Tapatalk

Slick - do you have better pic where seatbelt is attached to frame?

[Sirrotica]

If you're worried about stressing the hole in the aluminum I would use a stud rather than a bolt. With a stud you can get maximum thread engagement of the depth of the hole. This point only has to hold the twisting force, it doesn't hold the weight of the engine at rest as the OEM mounts do.

The further the mounting point is from the centerline of the crankshaft, the more mechanical advantage (leverage) the tie down point has. The LS engine, for example, has 4 mounting points on each side of the engine to spread the stress of the mounting points over a wider area. It also is a skirted block and is a stronger design to begin with. The older Pontiac design needs as much help as possible to keep block distortion to a minimum, IMO.

I've used just a turnbuckle with just a very small amount of free play for many years. I had a problem with mounts breaking in my dirt track cars every couple of weeks. Installing a turn buckle stopped the mounts from breaking. After 2 years I pulled the engine from the car and the mounts were as good as new.

Transferring the holding of the torque from the oil pan rail area to the left cylinder head also takes stress from the older mount 2 bolt which uses only 2 mounting points, and straddles the #3 main bulkhead.

In 1970 with the advent of the 455 engine Pontiac engineers slid the mounts forward, and lengthened the mount so the later design used 3 mounting points with stiffeners cast into the block mounting points. This allowed the #2 and #3 bulkheads to share the load. With the 2 bolt system it has been documented that the #3 bulkhead will distort, and is subject to cracking in high HP applications. Transferring the stress to the front of the left cylinder head also lets the stress be transferred to the right cylinder hear by the coolant crossover tying both cylinder heads together.. I believe that lessening the forces from the pan rail area to the left front of the engine are beneficial to longevity of the block, especially in high HP applications, and also using a stock block, as opposed to the stronger aftermarket castings.

A front motor plate also is a more sophisticated way to distribute the twisting force to the whole block, rather than just a small area above the pan rail area.

[leeklm]

Originally Posted by grivera

Slick - do you have better pic where seatbelt is attached to frame?

Here it is

Sent from my SM-G965U using Tapatalk

[grivera]

Thank you

[OCMDGTO]

How about solid motor mounts?

[Sirrotica]

Originally Posted by OCMDGTO

How about solid motor mounts?

Knowing what I know about Pontiac engineers revising the mounts in 1970 to better handle the stress placed upon the sides of the block in the larger displacement engines. Plus seeing blocks break, and crack in the webbing of the #3 bulkhead, the last thing I'd want to do is remove any elasticity from the motor mount attachment points, especially on the older style 2 bolt mounts.

There are people that run them on this board that will tell you they're fine, but I'd rather use a limiting device attached to the left cylinder head than solid mounts placing all the stress on the left side of the block, especially stock blocks.

The mounting points may survive just fine on a low performance street tire application, but having sticky tires on a high torque example is going to start trying to distort the left side of the block and main webs.

There was recently a picture of a 69 GTO drag car that split the stock block into two halves posted on PY.

https://forums.maxperformanceinc.com...02#post6234402



After looking at this carnage there is some validity to the point of these engines will fail under extreme circumstances. Putting a solid mount on the left side isn't going to help any, at least IMO.

[Chief of the 60's]

W T F ^ ^ ^

[z man]

Had a 68 firebird 350 when I was a kid. Pulling into a gas station when engine starts revving up big time . Trying to brake, but rear tires are spinning. Finally slap it into neutral and shut key. Under the hood found motor mount broken which let engine rise on drivers side, which pulled the accelerator cable to carb and gave it more gas, which which raised it higher, which pulled it tighter...... Installed a section of chain from head to upper control arm foward bolt. Not pretty but effective