Gauging any interest? in 350 laser-cut exhaust flanges

I wouldn't know. It's been over 30 years since I've had a 350 Buick apart.

Jim

 

Any idea on the price of the girdle? I also sent you an email.

 

Woah!!! AWESOME STUFF HERE!:beers2:

 

Exactly what I was hoping to do.

Hey Tom - PM me with payment info (shipping to West Palm Beach, FL 33407 - business address).

 

I'm a machinist. At first glance it might look like about the only machine work required there is counterboring the holes but that's not really the case. The holes themselves can be cut with the laser and drilled to final size if a close fit is desired. (Waterjet is another option and probably a better one for thicker plate. I know a guy...) Am I right in thinking those holes at the front and back are for oil drainage? So that area can be opened up with the laser as well.

There are some pretty significant differences between the 340 and 350 block but they may be identical on the bottom end. If so I have an engine for test fitting if I could get some blanks in a reasonably short length of time, however I'm not planning to mill the main caps flush with the pan rails and I'm not sure that's a good idea anyway. The tallest cap looks to be around 3/8" proud of the rails so the the girdle could be recessed for clearance and tapped for 1 or 2 jackscrews to bear on the center of the caps if desired. Those holes could also be laserjet cut and then drilled to size and tapped. The washer face of all the caps is below the rails, the rear ones by probably over 1/4" and the others by less than 1/16" and there's no guarantee the blocks are uniform in that dimension. May not even be close. So you'd be on your own with the needed spacers. Longer main studs could be used, or the holes could be counterbored to use the standard ones with 1/8-3/16" of material at the bottom, except for the two at the rear which will need longer studs regardless. Also, I see that the plate is cut out for the pickup. Since the pan is being dropped shouldn't the pickup be also? That will require a separate spacer block because the mounting boss is cut at an angle. That spacer could be laser cut from one of the drop-outs at the same time the blank for the girdle was cut.

Jim

 

Hi Jim,

Thanks for your input! Great to have a "learned" brain looking over this.

Is a concern the strength of the remaining caps after the decking to block height?

If I remember the height of the caps is slightly lower than the rail and brass shims are used to preload the girdle. Hone the mains after fitting? I will source ARP studs to work with the block and girdle.

Yes thoses are oil drainback holes. I have seen these areas sloted on a V6 girdle.

I don't like the thin area of the girdle at the oil pickup. The cap is already cut and the girdle area is thin. If a tube could be press fit in a hole drilled in the girdle into the block, the pickup could simply be bolted to the girdle.

My MS Paint skills stink, but you may get the idea.

 

pm me when you get a price for the girlde, as by the time everything is thought out and quoted i may be back on my feet...hopefully

 

Yes, longer studs for sure, recessing the holes would weaken the cross straps too much. Using the existing rear main studs is probably fine, and possibly
the front ones. If the girdle is clearanced for unmachined main caps and fitted with jack screws, then those can be lightly tightened and locked, (not torqued down heavy) which will support the cap without requiring the block to be align honed. I'm thinking add-on here, and 2 jack screws spaced more towards the studs would be better. If you wanted to mill the caps on a build in progress you could leave the girdle with no recesses and skip the jackscrews. I would prefer to use at least a 3/4" thick plate and 7/8 or 1" would be better. Sump clearance on some cars might be an issue though.

But the pickup is a problem that will need some creativity because of the angle. You could cut the angle on the plate to mount the tube, but we still have to seal the plate to the block. The best option for that is an o-ring face seal but that would be a complicated piece since it has to seal to the block and the pickup also, while not interfering with the attachment screws and provide a reliable alignment, yet not compromise the strap strength in that area. Getting it right the first time isn't going to be that easy and it requires two additional complex (because of the angle) setups on the plate and an extra part requiring at least 8 lathe operations. Then you have a problem if there is any variation in the height of the angle cut in the block relative to the pan rails, and there probably is some. The solution used by the V6 guys is obviously the easiest, and it is probably good enough, especially with the thicker plates. Putting the tube through as you drew has problems too. Getting angle and position exactly right, differences in the hole diameter, and sealing to name the obvious ones and it doesn't stop there.

 

while you're on the girdle track, you might as well think crank scraper also... or at very least, some type of milled slot and "o-ring" similar to TA's newest 455 girdles..

On my turbo6 my (i think it was drivers side) pan rail at the block would pratcally POUR oil due to the crank slinging it in that area... the girdle didn't have provisions (milled in slot) for an "o-ring" or any other form of gasket. The crank scraper provided by RJC prevented the oil from slinging into that reigon with full force, stopping the leak.

ALSO, on the RJC girdles, the main caps were milled (the idea of doing that doesn't bother me one bit, I would think jacks screws would provide uneven pressure on the cap, in turn uneven bearing wear...???...) The rear mains on the v6 also have a large space between the original bolt surface and the girdle (about 1/2" or more). RJC provided spacers which were welded to the main cap before machining flush.

Might as well think of all of these things now, before they have to be fixed later.

wes

 

How about block the whole works off and come out the side of the oil pan?

 

I agree that milling the caps is the way to go then align hone once everything is torqued down.

 

That makes it a lot easier to make the girdle. But I'm not tearing my brand new, yet to be run engine back down for that so if I use one it'll be done the other way. As long as the jack screws are just snugged down there will be no distortion of the main caps and they will provide the same restraining force as a strap laying on the cap would, maybe more. Not a hard modification to make. I'm also not going to run an external line or a custom pan, though a scraper or at least provisions for the original windage tray would be nice. As far as using an o-ring, sure, if you can get someone to cut the groove for it. (An O-ring making kit was "only" about $70 the last time I checked, maybe closer to a hundred now, but happily I do happen to have one.) But I'll just glue it to the block with "Right Stuff" and there'll be no leaks there. Won't move either. Take a prybar to remove it, but that's OK. The spacers will require careful measuring and fitting and should probably stand a couple thousandths proud of the rails. There'll be that much flex in the plate and pre-tensioning it that way will actually help as long as the rail studs are tightened after the mains and then the jack screws snugged down. Probably locating them to bear on the lugs on top of the caps would be the best place. Better that than the other way around with the girdle having to be pulled down by the main studs. With a flat plate, yes, the entire block including caps and spacers should be milled as a unit to ensure flatness. Now just exactly how was it you were going to hold the caps in for that operation? If you just mill the caps independently there is no way you going to be able to make sure they are perfectly flush with the pan rails. So some sort of custom fastener maybe? Sounds expensive to me, and maybe not as effective. Since the straps are not pre-tensioned, in order to get any really significant strength from the girdle it really should be about 2" thick. Think of it this way, you are removing about a third of the height of the cap and replacing it with the strap. Overall the assembly is thicker but it is now laminated. Is a multi-leaf spring as rigid as a solid bar of the same thickness? Not even close, and 1018 is not anywhere near as rigid as cast iron. The real strength comes from tying the entire bottom end together, not by resisting downward force at the center of the cap.

And I think a stand-off for the pickup and the narrowed strap used in the V6 design would be just fine, and the easiest way to do it. Especially with 1" plate. (btw, the illustration "A" and "B" have the cutout for the pickup in the wrong place)

Jim

Edit: While you're at it, look into the cost of alloy steel plate as well as the 1018. I'd just as soon have 5/8" of Cor-Ten as 1" of 1018. The cost is probably comparable and it'll be cheaper to cut.
J

Here's an idea for you if you want to cut your caps. Cut 'em to size, assemble the bare block and install the girdle, and then sweat-braze the caps to the girdle in an inert gas oven. Then align bore your mains and you have the ultimate bottom end. One solid piece. If you want to get fancy, combine it with a dry sump. Some of those are around for the 215 in aluminum. It's a rare and expensive piece, but that's as good as it gets.
J

 

Shoot yea Alan, that works for me. I like it. I do not want to get the first girdles too complicated. If we left the girdle metal over the "oil up" area, it could always be machined away later if anyone wanted to make a way for the "oil up" to work.

Thinking about oil?.....Have you guys seen this guys conversion to do away with our pump off the cam to a Gerotor oil pump? Looks simple if you had a mill, (which I do not). :rant: I have bought the pieces from a junkyard, just need to modify them. Wack off the lower half of a Gen II V6 and add it to the top half of my buick 350 timing cover, modify the pump/balancer.... Also it gives me options of where I want to put the oil filter. If I stick the turbo low on the passenger head, I can use the oil filter mount that pushes the small oil filter to the side of the block. I like the options. This may need its own thread.

http://www.turbomalibu.com/oilpump.htm

Jim, I do not know much about the metal candidates? 1018, 1026, 4140ANN, 4340ANN, Cor-Ten? May have to come back to this after getting a drawing and potential fabricator to cut the initial design out. There is a Mopar girdle on Ebay made out of 3/8's steel. :blast:

That was a good idea about cutting with a waterjet instead of a laser. I found this and will stop in sometime.

http://atlantawaterjet.com/index.html

Back to the exhaust flanges: After the flanges are shipped to me and I am sure they are worthy, I will collect funds and ship out. That is what I would like to do. Thanks to all.

T

 

I'm not trying to pee out anyone's campfire, but how many guys have launched the mains out of a 350, or at least flexed the bottom enough to cause bearing wear issues thus requiring a girdle?

Again, not picking any fights like CASON does just truly curious. If there are such experiences I hope they come to the surface so we can collectively pursue a stronger combo, based on where failures have already occured.

I was thinking about making a stepped girdle that just uses jack screws to put preload on the main bolts. If this flat one is the better option, I might be inclined to save myself the hassle and just hop on this batch.

Bill, care to offer up any experiences here?

 

Mark, good point. It’s a welcomed open discussion. The girdle is not for everyone, and there are very few (any?) cases of crankshafts letting go at naturally aspirated horsepower levels and low boost levels. Even if I have them made there may only be 2 or 3 takers at a target price of $250.00?

I hope I can venture my 350 into Bills territory. My goals start at 18 pounds. The Buick V6 turbo guys pushing big air have already given us a historical warning. There are many members in "The Drive Over The Crank Club" on the turbo Buick V6 sites. Lots of pictures of scattered engines. This simple flat steel girdle idea seems to work fairly well for them. Maybe this design helps better with side to side cap walk? or who knows? Anyway, I am looking at their experience and solutions to problems they encountered.

If it was stock parts, I would not care. I am hanging big $$$ on a cast crankshaft. I would like to make sure it stays in the block....at least for a pass or two.

Thanks for your input.

 

If I remember correctly, I think Bill M. only used a mini girdle on his procharger build. It wasn't near as nice as the girdle shown in this thread. However, I may be wrong.

 

OK back to the exhaust flanges what are the advantages?

 

Cason is correct. The halo we fabricated only tied the 2,3, and 4 caps together. The only issue we had was some evidence of twist above the 700 hp level. Some minor "scuffing" along the bearing edges on the 3 center mains. We didn't see the need for a full girdle until we were above 15# boost.
That is when the cracks in the webbing above the mains appeared.
In my opinion, either style girdle, flat or stepped will help with both situations if it is tied together with the pan rails.
I think Tom's thoughts are on the right track. There will only be a few who may need this piece and those will be high dollar builds. If there is a need for some extra machine work or modifications to the oil system then that will just be part of the build. We aren't talking "drivers" that will need a girdle.
One other note of interest. With a girdle, we will need a fabricated oil pan and pickup.

 

and theres a guy on this board that i'm sure wouldnt mind doing the pan/pickup

 

Whadd'ya mean Bill? I'm gonna drive mine on the street!

Oh, and I wouldn't mind doing pans and such either!