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

'cast iron' is not compatible with cast iron unless you are certain the make up is the same. 40 yr old c/i is different than the new c/i. unless time and $$$$$$ is spent to see that they are exactly the same. it all becomes a can of worms and all we can do is a band-aid fix. and the metal changes everytime its used.

 

But, here is something I can't rap my mind around, Canton makes a billet main girdle for small block fords because they have the same exact problem as the big block Buick and there product works pretty darn good.. I understand your point on the band-aid part. I call it buying time Sincerely Gary M.

 

The blocks in question (Buick & Ford) were not built to handle the torque/horsepower that technology has made it so easy to attain so many years after they were first designed. Yes, you can do things to promote longevity, but in the end, an aftermarket block, built to handle more power, is the best solution. If I choose to go faster, with my Buick, I'll purchase a Tomahawk. With my Ford, I'll get a Motorsport block.

 

Can you describe or show pictures of "locating collars"? I have never seen or heard of them before.

 

I think what he is referring to is what i am calling "dowels".

Pontiac dowels their main caps via pin dowels, much like we have on our cylinder heads.

The main bolt dowels that i was referring to look like a collar that you insert either into the block or cap, and the opposite end has a bore appropriately sized to receive the coller. If you have seen aftermarket connecting rods that use the ARP 2000 series bolts, this is the method they use. It can be done to any block, you just need to ream the hole a bit bigger up to a certain dept.

http://www.corvetteactioncenter.com/specs/c6/2009/zr1/images/64228.jpg


Also the whole purpose of this thread when i posted a long time ago was to see if the TA girdle eliminated cap walk. My understanding is that it does not. On my halo girlde, when i torqued it down, i could tap the cap fore/aft and it moved. I think the same should be true for theTA girdle. Nothing eliminates the fore/aft movement. Although its so restricted, i bet its almost negligible. In the end the TA girdle has an immaculate track record, so it doesnt matter much what I think.

The TA girdle also does some things that others havent even considered. Cast iron like mentioned above. Know of any others that do that? Cant think of any, most are steel. I bet it makes a difference.


The other point i was trying to get at (with more subtlety) is that if the TA Girdle does NOT eliminate cap walk, what are the implications? Is cap walk really that bad? Or is it a design that we can live with, that the engine can in fact handle? The cap walking in and of itself is not usually a cause for failure.

 

one part of the solution on the girdle would be to have 'pockets' that would slide down both sides of the cap and each pocket would tie in together. draw that picture in your mind. yikes! then there are probably some more things to add for stability, but the damn thing would weigh how much......

 

No, this what I'm talking about, scroll down and look at the connecting rod end, http://store.440source.com/Platinum-Series-Rods/departments/138/ This will self locate everytime and stablize better ! Sincerely Gary M.

 

The self locating sleeve's (collar's) have been around for ages and work very well. I figured. this would stop main cap walk and help stop any wiggle at the top of main caps when implemented when using a block, main girdle. I would have this done when I have the block and mains machined for girdle ! Sincerely Gary M.

 

. Sincerely Gary M.

What I'm trying to show people will be plenty of enough for adding more power if you feel lucky

 

An example of the "locating collars" and hollow dowels referred to are used on BBC for heads, amongst others. A head bolt passes through there.


These are split. I would not recommend this on a main. Solid ones are available through suppliers like McMaster-Carr, etc.
Many H-beam rods have them.
You wouldn't use a pin dowel on the Buick or Caddy because there's no room.

I'm only guessing... but in the case of the Buick it looks like the main saddle might wiggle with the cap a bit. There shouldn't be any fore-aft movement anyways. The one that hurts is when they pinch inwards.
On the BBC, 2 bolt mains hold to near 900 hp for a short time (7000rpms with stock bob wt. heavy TRW's on a 275 shot). The block is much beefier than the cap, so the cap deflects and the bolts barely maintain clamp load. Those fasteners are set in relatively soft iron. Also have greater depth than the Buick. That's only one example...there are many others.

My point is that what is working and why is somewhat application specific.

 

Gary, Tony(8ad-f85)basically told you the difficulty of installing those with the old not so accurate factory production machining of the late sixties to mid seventies and how accurately those would have to be installed. Ideally those would be installed in the same setup when the original holes were being tapped. Can it be done? Sure, with enough of these, $$$$$$$$$.

On another note, has anyone ever doweled the caps to the girdle? Would that even help? Drill and tap the tops of the caps and use collar dowels to bolt the caps to the girdle? Would that stop cap walk? Seems like a better fix than throwing a halo girdle on top of the full girdle?

Anyone?



Derek

 

Thanks Derek, I should have re-iterated that an accurate aftermarket main cap or purpose made jig would need to be used to locate everything.
If you're not the one doing the machining, you might as well use what's out there and accept safe limitations or go aftermarket.

Good idea on pinning the girdle to the cap, it's always the machinists that see these things.

 

For what it's worth, I purchased a TA block girdle and TA halo girdle from an ex-NHRA class racer about ten years ago. The package is still on my shelf. The combo is doweled between the halo girdle and the block girdle, and in my opinion, it only makes sense, since the function of the halo would be pretty much null if stacking those pieces together and expecting the fastener stretch to stop things from moving around had been attempted. I feel the same way about using a halo by itself on any engine. Doweling is the savior for location with this stuff. Bolt stretch can't do it alone. It works in one axis only.

To reply to the original question, I don't know with any experience if the TA block girdle helps to lessen cap walk, but intuitively I think it may as long as cap register is robust.

PS by "dowling" or "dowels", I'm referring to the cylindrical pieces added that surround the fastener like Azeem mentioned. Not solid pins as seen as cylinder head locators.

Devon

 

Lol, guy's were all talking about the same thing. That pic i was trying to show isnt loading for some reason, but here it is.

 

Too bad nobody makes main studs knurled to fit the caps snug, (like the connecting rod bolts do on the stock rod and cap) but only knurled far enough up the stud to stabilize the movement of the cap. One downside to that would more than likley be that the main caps would really be a major pita to get on and especially to remove. Though one could incorporate a designated cap splitting (separator) tool like the ones we use on connecting rods. The other issue would be that the only way to really get a true alignment so the caps could side up and down the studs without a fight, if at all, would be to have had the caps and block drilled together, in place, at the time of the initial machining back at Buick. Everything would have had to be in perfect parallel alignment especially with tight fitting registers. Seems like I'm overthinking this. I like the (dowel girdle to cap) idea more..... Larry

 

Some of the aftermarket caps I've seen are tapped for slide-hammering out. They want them fitting the registers tighter than factory.
The bolt holes in the factory caps are probably not accurate or consistent enough for an enlarged area on the fastener...that would do it otherwise.

 

Larry, funny you say if anyone can have a self locating system! Just think long and hard about that! Any well established machine shop has a free floating cylinder head valve machine that can hold any block, by adding a threaded rod that is smooth on the opposite side would be a self locating fixture, once located in the rt position , release the air table and drill to predetermined depth, its simpler then anyone can think! I know this because I have done it several times. Larry, look at the aftermarket connecting rods, if the collars didn't work so well, why are they using them? A connecting Rod takes a 100 times the abuse of any part of the engine. Yes, the design of the rod has a great deal of influences too. Look for a machine shop that does amazing valve jobs, you'll find the table I'm talking about. This all has to be done before have the mains align honed. After that you don't have to worry about it! Sincerely Gary M.


P.S.
I might be over engineering the girdle fitment but I look at it this away, I don't have six grand to blow on a block that needs machining too

 

Again, that alone causes a stress area! We are trying to eliminate stress... Sincerely Gary M.

 

Devon, its like brake calipers and the locating sleeves! Self aligning! This keeps things from moving around and causing mayhem! Sincerely. Gary M.

 

Derek, any well established machine shop has the rt machine for it. Time in doing it, maybe an hour tops, is it worth it? Do you have six grand for a TA block that still needs machining ? I sure don't! Ya, the factory iron piece can't handle no where near what a TA block can but, are you planing on screamin the thing and producing 1200 hp? Dang, I'm only asking for tops on any of the engines about to build is 850! I like the extra insurance that's all... Sincerely Gary M.