[BVR421]

Originally Posted by Tim Corcoran

Ok now that you have my name in lights and have me eating crow, when you say stroker, I suppose you mean a 4.21 or 4.25 stroke? Now that is a 455 not a 400. When I said 400 I meant an engine with a 3.75 stroke, a lot easier on the block. That is a very cool picture, I am sure it's not cool to the owner though. Tim C

Tim, I didnt want you eating crow I just wanted to illustrate a 400 split, no doubt the 4.25 crank added some side load, BTW, the trans looks even worse. LOL $$$$'s reconstruction. I havent even pulled the motor yet. Have to get my Bird out of the shop first. Jim Thompson suffered the aggravation in StLouis at the GTOAA race and I bought the car when he returned. He is bored with 10s and is half done with a low 8 car now.

HIS..solid factory type mounts to factory frame

[rfb92345]

Good info, Tom.

[242177P]

Originally Posted by Tom Vaught

deck plates that went between the block and the heads and used longer head dowels and head studs. There was one plate for each side.

Tom: What do you think about using something like 1/4" plate (forming the mother-of-all-valley-pans) attached to the intake faces of the head? Do-able or impractical? Just thinking out loud...

[Half-Inch Stud]

BVR421: "HIS..solid factory type mounts to factory frame"

More than just my opinion:
That would be the Worst-Case method to induce cracking-force on the #2 & #3 Mains.

Please don't blame the Factory Block alone, because the Block and Motor mounts beome a system of torsional force loading into the Frame cradle:
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Initial Driveline Free-Body diagram would show the Trans output shaft delivering a full MULTIPLIED output torque, while the Center-Support//Case takes 3/4th's of that torque force to the CROSSMEMBER. (((I make sure my Crossmember is Stiff, centered, rubber-isolated, the Trans Tail features the stiffening ribs, the mount and Shaft Loop are mounted well and the bolts have all the threads in use. The Tail cup is a good place for Half-Inch Studs. And good 6-bolt dry-attach to the case, and the Center-Support to include the "case-saver" to reduce case wear from peening.)))
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Engine System: Local Free-body force diagram shows the Crank flange having the full ENGINE output torque, and the Bell Housing has the full counter torque. IF we stop there we desire to install a rear motor plate to the frame. But we must read on:

Since the Crank has length, and includes torsional variation, we desire to include the Block countertorque to the Factory Motor mounts with a Rear Plate into rubber. I suggest the Factory rubber mounts and Rear Plate with same (Firebird or Big Car) rubber mounts attach rear plate to frame. Solid mounting all around the engine is best if the frame is torsionally stiff. Further, only if the frame is Roll bar-d or caged then the Rear Trans mount and crossmember can be solid attached.
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We should develop a Rear engine plate to frame. A pair of 1/4" steel or aluminum E-straps having attachments at the Bellhousing 3 places, and a single strap to attach to a motormount located at each frame turn-up. Ask me how I know it will clear the headers.
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After reading this (in agreement or not with above statements) a post-mortem observation on the split engine block reveals the torque transfer path FROM bell-housing TO the solid Motor Mount pair causes the COmpressed PS mount and PUlled DS mount to peel the block apart at the Main uppers as the Bell housing remains super-stiff. Crack progession occurs at #2 and goes back to #3 #4, the Bell, then #1 may go. Assume Steel Main Caps.

A rubber Driver mount, solid PS mount saves the motor for higher power levels.

Think of the Bell as a Steering Wheel and make a right turn with it. The PS mount compresses, the Drive mount pulls, the Cam tunnel in the middle wants to pull-apart or separate when the front Driver HEAD-CHAIN or Solid Driver mount are used. We think a stiff front Block web would save but the Motor mount is not pulling from #1. Further a Front Motor plate may be shown to increase the bow-force of separation at #2 & #3, much like a front DS Head-Chain does. We could learn something from the stiff Chevy valley cover or keep our Iron Intake COOL & bolted-down firmly. More effective to include a rear engine plate.

I won't go to a front plate for reasons related to Free-Body Diagram dictates, reliability, and leaks. A stiff Front plate with rubber mounts or perhaps steel mounts might also induce cracking without a rear plate. I still wonder if the Front Engine plate is worth anything.

HIS

[Half-Inch Stud]

good coffee today [Chock full of Nuts: Columbian@home , Original@work]. A GRReat day for physics. HIS

[RAIV55]

Originally Posted by Tom Vaught

Quote:


He told me that the aluminum intakes like he was making for the Fuel Injection years later actually made the block fail quicker. He said that the CAST IRON intakes tied the top of the block together very well (especially on the 64 and earlier blocks).

His thought was when you put an aluminum intake on the engine you took away a bunch of that upper strength. Cutting the water cross-over off and running the water hoses to the heads made it even worse. Running the split intakes like the after-market had in the old days with the rubber tubes connecting the two plenum halves was the worst. His FI intake needed to have some way to strengthen the block which is why he came up with the deck plates.

Tom V.

I could easily understand that, given the expansion charastics of aluminum. It don't take much imagination to see that could act like a wedge pushing the banks of cylinders apart. Guess it was something I had never given any thought to before now. Thanks for the tidbit Tom.

[Half-Inch Stud]

YESH, the aluminum Intake acts much like the Biblical Samson, busting the block down to its foundation. Filled crossovers help alleviate the additive separation force. Overall, despite stiffness, the aluminum lacks the ultimate strength of the Iron intake. 15yearas ago, I've seen a belly-cracked Torker I for sale at Maple-Grove. A large clue to the forces a large.

ANY takers on my prior posting? HIS

[Brian Baker]

Good post, Mark...except that what you said in the next to the last paragraph (ie - "Think of the bell...") would have sufficed. That paragraph condensed everything else you said before it in a manner that even a knucklehead could understand. There may be some hope for you yet.

[Half-Inch Stud]

Perhaps: "if Brian grabbed the bell and torque a right turn... he might see the mains split BEFORE splitting his pants."

What worries me is: I don't think the Main Girdle is gonna do much on anything to keep the Main uppers intact. Because the Steel Main Caps are Dowled & in Compressin for the torque system described. More and stiffer metal down there does not change the peel-apart forces at the cam web. Just a darn-grouped Main Cap array. HIS

[Brian Baker]

Originally Posted by Half-Inch Stud

Perhaps: "if Brian grabbed the bell and torque a right turn... he might see the mains split BEFORE splitting his pants."

What worries me is: I don't think the Main Girdle is gonna do much on anything to keep the Main uppers intact. Because the Steel Main Caps are Dowled & in Compressin for the torque system described. More and stiffer metal down there does not change the peel-apart forces at the cam web. Just a darn-grouped Main Cap array. HIS

Agreed, to a point, as this type of girdle has certainly helped the 5.0/Windsor Ford boys several years back that were spraying the bejesus out of them with nitrous. Best effort however would be more material between the two cylinder banks in the lifter valley and cam area.

And if Sears still sold Tuffskins in my size...I'd wear 'em.

[Jack Gifford]

H.I.S.- Good points. Although I know what you're saying about front plates, please don't be too general about it. The front plate on my mini-puller extended downward in a 'V' shape and had a single pivot point connecting the bottom of the 'V' to front of frame. Not many people understood it, even if they noticed the full bulkhead (frame-to-frame) sandwiched between the in/out box and the QC box. But then, not many understood the chrome-moly torque arm attached to the differential housing with a vertical link at its front to the main bulkhead. Even some competitors couldn't figure out why my frame didn't get all twisty during a pull.

[rfb92345]

There's one in every auto forum.........a so called know it all that hijacks everybodys thread...................Bye to this forum.

[Brian Baker]

Originally Posted by rfb92345

There's one in every auto forum.........a so called know it all that hijacks everybodys thread...................Bye to this forum.

Alot of good info here, all on topic, from every poster, so I don't follow your logic.

[RAIV55]

Originally Posted by rfb92345

Thanks for the link.......we are going along with the project anyway. We just like to do things ourselves. We're kinda weird that way. The pictures were interesting. I know that the 403 is weak in the main area and requires all the support possible. I do need some input from you guys as to what is really needed for the Pontiac engine. We are at the point now where we need to determine if we need to go with a 3,4 or five main halo girdle. I really don't think it is necessary to tie it to the pan rail. I may be wrong though. One thought, though, is that it could be tied to the block, at the three center mains, via the bolt holes provided for a 4 bolt cap. Just thinking out loud here. Give me some input on this one.

Not sure if you are still around, but since you asked for input, thought I'd put my .02 in.

I'd try making it to tie in to all five mains. I know cost will go up with the added material and machining but I'd consider it worth the price.

For those that have problems with what ever comes up, (ie. chassis or pan issues) they could cut the offending portion of the girdle off and proceed on as if it was made for 3 or 4 mains.

For example I'm sure with my 3rd gen camaro, the first main cap could be an issue because of the centerlink.

[Jack Gifford]

Originally Posted by rfb92345

There's one in every auto forum.........a so called know it all that hijacks everybodys thread...................Bye to this forum.

You're right, and I apologize. Hope you return, as I had planned to keep watch of your results with the girdle. I should have confined my remarks to your efforts. Speaking of which- did you consider a combination main-caps/girdle deal? (Is that what the "halo" term is all about?) I have a specific reason for asking- one thing that helped my fragile old aluminum block survive a blower and hemi heads, was making 5-bolt main caps (just #2/3/4) that extended out to just shy of the passenger-side pan rail, spanning the area where my first block cracked. I'm sure that a combination caps/girdle would do even more good for my setup. Although my interest would be in a 7075 aluminum piece, I assume the same CNC program could be used (although I'd probably choke on the cost of a 21"x12"x4" billet of 7075-T6!)

[rfb92345]

No apoligy necessary Jack. I was not directing the comment to your post. Actually I had a piss poor day and was overreacting to a previous post that I misread anyway. I think I need a few days off, I've been wound way too tight this week.

[Half-Inch Stud]

rfb92345,

I was just trying to help. Such "help" can stop a train already set in motion. I know that can hurt if one were interrupted in the restroom. With renewed planning, the Main Girdle project can contine with vigor and steady direction. HIS

[rfb92345]

I recieved the prototype main girdle support today. Looks good. I will post pics as soon as we mount it to the block. The first one is a 3 main support. We will be designing 4 and 5 main prototypes also. We want to have the 3 main work with a stock pan. I will keep everyone posted.

[GoatRider]

I have talked to Steve B. about his engine girdle that he uses on his Nitro motor, and actually saw one bolted onto a modified '59 block. It looks pretty darn effective! He didn't share any of the secrets that he put into it, nor would I repeat them if he did, but I got the impression there was more complexity in the machining and attachment to the block than meets the eye. I also think it was made of something harder than iron or mild steel.

Good luck with the one you guys are making, I know Steve will sell his kind to anyone who really bugged him for one, but he is not making them as a business as of when I visited his shop.

[PONTIAC DUDE]

If it gets to the point that you need a girdle to hold things together, then you need to step up to the IA 2 block. Because when you try and locate the stress at one point........... it justs moves to another in an already overtaxed block to begin with.

Plus the difference betwen a billet cap block with a girdle, then add another on at the top, plus all the other things your gonna have to do.............

I just don't see the point and Playing with the Gods and hoping your block will still hold together.

Before the IA block deal this was an viable option. Now???? Someone please explain this topic to me?