Wierd Question, Does the TA Girdle Prevent Main Cap Walking?

Over the last year and a bit, I have been farting around with a caddy 500 build, and dipped into girdles, cap walking, and all that jazz. TA seems to be waaaaaaaaaaaay ahead in the technology for our buicks, compared to what some of the other brands are using, or even aware of.

In any case, one of the things only a hand full of people are doing is doweling the main caps to prevent main cap walk. Other people suggest that this doesn't eliminate stress, it just moves it to a different spot. So if you ruined a motor because of cap walk, doweling will only make it fail in a different location so to speak. I designed a "halo girdle" of sorts for my engine, and there were all kinds of hurdles in the way to which I turned to the TA girdle for answers. It answered most of them, but in the end there's one thing that I'm not sure how the TA girdle addresses (if at all).

Whether or not it addresses them is somewhat irrelevant however, because of its immaculate track record.


How does it prevent main cap walk?

Just curious.

 

I'm not the engineer here but I would presume when you machine the caps to fit perfectly with the Girdle it is like interlocking them together when you torque it all up.


Just my idea.

 

While I'm sure there is a measurable improvement in cap deflection with TA's perimeter style girdle, you will get much more control adding the halo style girdle to that.

 

It provides way more surface area to bind the caps to the block. The girdle is actually stronger metal than the block itself. The main caps are machined to fit under the girdle, sandwiching them between the girdle and the block. The halo helps even further by adding rigidity to the girdle.

I think the block would shatter to pieces before the girdle/halo twisted any measurable amount. Those main caps aren't going anywhere. :Brow:


G

 

You should call Bob Makley @ Finish Line Performance in MI. They Have a halo that connects all the caps together and can machine the caps for the halo.. This halo does need a little front massaging to fit stock pans but for under 200.00 you cant go wrong..

 

And to Answer your question yes! :TU:

 

I personally think if the mains a cut
to fit girdle it should but here is my technical question , is the mains cut on top only or are they cut on the sides and top? I personal still would have locating collars installed top and bottom. This does stop all main cap walk. Am I over engineering the K.I.S.S. system ? Oh ya! But my caps will not move around at all when it has the mains done with locating collars to properly center the mains and girdle together. This eliminates all possibility of anything moving around. Yes, the main webs are still the weak link but it will have to destroy the block not just the main web now. Has anyone sonic tested the main webs yet? I personally want to try machine some material to fit the main web area and counter sink some bolts to it to add some strangth to it! Would that work ? Sincerely Gary M.

 

Only the tops of the main caps are machined for the girdle installation.

 

When you tie in to the pan rails and connect the mains to each other it spreads the moment of force some.
The flexing cap pinches inwards. On a BBB or BBO the main saddles themselves are flimsy, so you are trying to stabilize both the block and the cap movement.
Adding some beef across the top of the cap helps from distorting the cap itself.

To answer your Q's on doweling or which methods are effective, I think one needs to look at each engine type individually.
If the main saddles and caps were beefier, dowels would work great, think Pontiacs. BBF's do well with 2 bolts and dowels.
Hollow dowels are a pain to machine for because the caps aren't perfectly lined up to the block. If the cap is weak, that is a futile strategy.
Dowel pins like on a Pontiac, require room to place them. Can't do that with a Buick or Cadillac.

I'm not going to argue the chicken vs. the egg, but Oldsmobile has had these for quite some time.
This one is available from Bill Trovato. Beefy! Machined from a huge chunk of solid stock.


This was a limited run, very expensive. It's keyed and bolted to the base of the cap so it cannot move any direction.
Likely the best design out there.

 

85, I see where that worked great. But someone already did the locating collars on the bottom of the mains and drilled out block for alignment fit, now wouldn't it be wise to do the same on top of mains to stablize the block, main girdle? This is where the billet mains for Buicks could come in handy at Sincerely Gary M.

 

I'm not quite sure what the question is...
I'm not an expert at these girdles, just pointing out how other engine builders solve problems specific to their makes.
If I understand what you are getting at Gary, the last girdle shown has "billet" main caps.
Installing billet caps to the Buick might solve the issue of locating hollow dowels, but it still doesn't address the issue of the main saddles being thin and the need for more of a "bed plate" to add some structure.

Here's some more,
Replaces center 3 caps...ignore ugly welds,


New... not quite to the market. Bed plate from aluminum.

 

When we were drag racing in the early nineties with a blown and injected 350cui sbc running 42lbs boost via a hi-helix 14/71 blower, my father bought a new iron bowtie block, removed the main caps and made a one piece girdle out of a 4" thick steel block. Took him many hours of machine work, but when the engine retired due to a failed roller follower pin circlip, the crower crank bent before any damage to the block itself apart from the window.
Here between the pan rail and custom made oil pan you can see the girdle.

Cheers

 

You guys are on the rt track there but for the existing block girdle of TA's , this is me now ok. I would have the factory mains cut to size necessary for block girdle and have the tops of the main caps fitted for locating dowels while the bottom of the main caps fitted for locating collars. This keeps the main caps from moving around and at the same time it keeps the girdle from wanting to wiggle on top! Thus stablizes the block, mains, and main web to much higher level. But I like the one piece main cap and girdle system way better! Why hasn't come forward with that design and make it mass produced? I bet the Buick engine can be built to a much higher level then expected then! 85d, what engine is in that picture? Are those oiling lines or coolant lines? I'm a firm believer in oil control and coolant control! Look back at the Pro-Stock Buick cylinder heads that B.P.G. brung to the Buick nationals, you can see where they removed a soft plug from the front of the cylinder heads and threaded a pipe on it to cool the heads or both block and heads better ( Smokey Yunick stuff ). Sincerely Gary M.

 

The girdle will keep everything in the block when you break the main webs. :laugh::laugh::laugh: Yes, I am running one.

 

Gary, it would be a bad idea to take material out of the main saddle area to dowel the main caps. Any benefits would be cancelled out from making a weak area weaker by drilling for dowel pins. The halo girdle combined with the full girdle is supposed to keep the caps from walking. Kind of redundant but.......... That's what is available for the BBB unless you want to spend the time to build a better mouse trap. GL




Derek

 

Derek, I wouldn't use pins in the bottom of main caps because of that reason but would consider having locating collars around the main studs! This wouldn't hurt the main webs because I would be it thicker part of main webbing! The reason I brought this up because when you machine the main caps to be fitted to block girdle , you do remove some material off the mains making them thinner and weaker right? Sincerely. Gary M.

 

Smokey, I understand your point but that's not what the block girdle was designed for! It was designed to prevent it from breaking! The mains are still machined to fit the girdle but it doesn't do anything for the mains from walking side to side! By installing locating collars thus eliminates the possibility of moving any where. That alone would help stop bad harmonics getting to the weak main webs rt? Here is what I see in engines like sonny leonards engines and several other top named engine builders engines, almost everything has locating collars on them. These stablizes the whole system for a all around engine. Here is an esample, look at most of the top brand connecting rods, they have a locating collar, why? Sincerely Gary M.

 

one issue would be not all engines use the same iron and design. therefore there is not an one answer/design that fits all. and add any girdle of different material has a different stress level than the block. now what do we do. do we use a soft, hard, flexible or tough material to do the job. what metal treatment can we do to the block before we add a girdle. can we add or take away material on the block before fitting a girdle.
don't forget everytime the engine is raced, there is tiny changes regarding stress. just like an airplane engine.

my .02 theory

 

Gary, I know that. I am running one. Thus the :laugh::laugh::laugh:. In case you haven't gathered, I have a sick sense of humor, kid.

 

This is true but once you find out what you are dealing with, you can find the different materials that are compatible . Here id another thing, age of cast iron has a lot of dealings too.