I am having block girdles made for the Buick 350!

I am thinking it would not be a problem to have your girdle made with the material over the cap as you describe. The only hang up might be getting detailed enough info for the main holes into the auto-cad.

If you can get the holes drilled yourself then I could likely provide the girdle its self for you to work with.

What thickness are you looking for?

I will call the guy who is doing the auto-cad and see what he says.

 

.5 to .75... .75 would prolly be better. I would prefer the holes to already be drilled, but it is not a huge issue, as I have a Bridgeport style mill and some transfer screws.

So for the 300, the measurements is as follows (measurement is APPROXIMATE):

3.55" center to center on main cap bolts

The spacing between main caps is the same as the 350.

The 300's caps are scalloped at the top (see pictures) and only protrude .25" above the pan rail. The bolt lands appear to be below the level of the pan rail (though I may be mistaken, it was a quick check on the protrusion aspect), so washers will need to be made to make up that space, OR use a billet cap for a 3.8 and mill the top off. I believe the bolt lands are even with, or protruding above the pan rails on those.

 

OK, I will see if we can get a girdle made for your 300. The only reason I am hesitant to have the holes drilled is that I want to be sure 100% they are in the right spot. The guy doing the auto-cad has a 350 block to use so I know that he will have precise info for that.

The mains are lower than the oil pan surface on the 350 as well. Shims/washers will be required for sure.

Like you say, the cap has far less height above the oil pan surface compared to the 350 so even 1/2" should be plenty in my opinion.

Let me know what you think.

 

Sounds good Sean. I can drill the final main holes myself.

I suppose cutting it out of the same 1/2" material as the rest would be fine. The 300 block is heavier and, I'm assuming, stronger anyway.

I would like to suggest you have a groove for an o-ring milled into the pan rail like the newer TA girdles. The girdle on my v6 leaked like a sieve.

Would save a lot of headache down the road with your own project as well as the publicity associated with parts causing leaks. :TU:

 

Yeah, I was thinking about that O-ring as well:TU:. I will keep you posted!:beers2:

 

It looks like we will do a 3/4" girdle and make it extra beefy! This way there will be plenty of security for the 350 and 340. For the 300 we will have it set up to cover the main caps, only holes would be required for the mains.

 

Sounds great Sean! Any tentative pricing?

Before someone jumps all over me for that question, I would like to explain that I am asking so that I may budget for it as it is the off season and I'm currently not working. I'm sure some people can appreciate that.

 

I agree. An idea od price gives a better idea on how to budget your spending and saving habits

 

No worries... I do not want to throw out any numbers until I get the estimate for the price. I will let you all know ASAP when I find out how much it will roughly cost and then we can go from there.:beers2:

 

Cost of the steel alone will be significant.

JB

 

I hope to find out soon....:3gears:

 

Bolt the girdle to the block around the perimeter, and through all the main caps except one. Leave that cap off.

Install a dial indicator to read off the girdle up 'n' down, next to the empty hole for the missing main bolts/studs.

How much pressure can you load on the girdle "tab" before it flexes one thousandth? Five thousandths?

 

bump!!!!!!!!!!!!

 

Not a bad idea. Another thing worth considering would be to install 1 or 2 threaded holes over each cap, say a 3/8" UNF and screw in a locking setscrew. That could then be used to preload the caps, using a dial indicator to determine how much preload is applied. If Schurkey's method was used to determine poundage/movement then the indicator could then be used to show how many pounds are applied to the cap.

Personally I would relieve the girdle for cap clearance but I know not everyone agrees. And, maybe the V6 billet caps machined to match the girdle would work very well. Even so, I think the preload screws would help.

Glad I was able to assist in moving this project along.

Jim

 

All we need is to fit the girdle and then use a feeler gauge to see what thickness of spacer is needed between the cap and the girdle. This will work out really nice, should be no problem. The studs will some through the caps, spacers, and girdle. Things will be tied together nicely, no need for set screws. The pre-load on the caps, if desired can be determined by the spacer thickness. We can get any thickness spacer required after mock up of the girdle.

We will provide the girdle and if anyone wants to do custom caps or whatever then they can....

I am keeping it simple and effective. Our engines already stay together really well, so I just want add support to the mains and keep them where they are.

 

What's the approx. Eta on production and quote?

 

I'm not sure you understand what I mean about the setscrews. It is true that you can apply some preload at the studs. When I made my spacer plate I think I spaced it up .005" so the plate would help clamp the caps. But that isn't the same thing. You are applying more clamping force at the studs, which already are adequate, but that doesn't effect the strength in the center of the cap.

Whether you mill the caps or relieve the girdle for cap clearance, the weakest point is dead in the center of the cap. (or possibly in the web of the block but the girdle already addresses that) What I'm suggesting is the use of a jacking screw right at that weak point (or else just on both sides of it, say 3/4 to 1" apart) which apply a predetermined amount of force to the center of the cap. What this does is to pre-stress the strap across the top of the cap, and takes out any micro-movement of the cap before the strength of the girdle is brought to bear. In essence it is very similar to tensioning the cables through a pre-stressed bridge's roadway section. It removes the freeplay and makes the structure more rigid. This reduces movement and flexing, and since we're talking about cast iron here, any reduction in flexing is a very good thing.

Bear in mind also that when you set the spacers at the studs proud of the pan flange you induce flex into the strap, creating a gap above the (milled) cap's center.

Jim

 

I am not worried about the center of the cap... I just want to give support to the studs in the mains to keep them from moving front to back in the engine... This is what was happening when Bill M was dyno testing his 350 in the 1000+ range... Some bearing scuff due to the mains moving front to back a bit.

Mike, not sure on the time frame yet... I will let you know.

 

Thanks sean. ..only think I'm worried about is crank flex/walk once we get into/past 600hp range. Too bad they didn't test or mention any issues with stock crank at the 600 750 hp range

 

They said the stock crank seemed fine in the 700+ HP range but they had a forged version made just to be safe.... I guess we may find out if we get up into that range.