Majorly bummed out. Look at pics

[PHANTASM]

i was measuring thrust and was happy with the .004 i had.

was looking at the thrust mounting and seen one register side piece looking cracked. i tapped on the crack and a chunk fell right off.

the crank turns fine and no other problems seen.

will this be ok? or is the freshly machined block now junk?
my gut says it is a bad deal.
:frown:

 

[Squid4life]

Looks like the billet cap might have been longer than the stocker, and pushed the part out, breaking it. Isn't that surface used for making sure the caps don't walk, locating them in a way? That sucks man, sorry to see it.

 

[Nasty Wendy]

One thing is for sure. You don't want to just clean out the broken bits and run it. If it turns out that its OK to use like that (I'll let an experienced engine builder answer that) I would think that you would have to remove the cap and bearing and smooth out the jaggedness of the edges so that new cracks won't start there.

 

[PHANTASM]

wondering if it could be welded back up some?

anybody have any ideas. hate to scrap the freshly machined block over this.

 

[Nasty Wendy]

take it back to the machinist and see what they are willing to do for you

 

[BadAssGN]

There is no meat left in the register, The block is pretty much Junk in my opinion.

That is not an area you want repairs in. but they may be able to pin the cap into the block.
What kind of HP you plan to run?


Makes sense why you had trouble setting the thrust... the cap was machined wrong.

 

[TTipe]

Steel Cap

There is supposed to be a 0.007" interference fit between the register and the cap.A few shops just use the pile driver to install the cap.

 

[chopped39]

Is it me or does it look like the cap was staked. If so the machine shop has problems

 

[turbodave231]

Its common practice to peen the block around the register area to tighten caps when they are loose. That works on blocks that are not deep skirted. I've done it on SBC, BBC SBF blocks with no problem. From your pics it looks like somebody tried this approach on your block. NOT a good idea.

On a Buick block, I would either knurl the cap, weld it up (steel only) or replace it with another cap to tighten it in the register. Either way your situation is not good. Chances are that cap is gonna walk around under power unless you do something to prevent it. Pinning the cap is a good idea and might help you save this block.

Welding cast iron in a structural area is also a bad idea. Yeah lots of guys say they can weld cast iron. BS!!! it always cracks again in that area.

Pontiac V8's don't have cap registers, The caps are dowel pinned to the block. HIGH HP engines use this technique to keep the caps from walking around.

I've recently saw a LSX block in for repairs where the caps were dancing around. The engine was producing over 2000 HP so its no wonder they were moving. The fix is to pin the caps to the block and then hold the caps solid with the main 6 studs/bolts

I would be interested to see what your machinist says when you take it back to him He most likely created the problem. Let him figure out how to fix it!

 

[TurboDave]

Its common practice to peen the block around the register area to tighten caps when they are loose. That works on blocks that are not deep skirted. I've done it on SBC, BBC SBF blocks with no problem. From your pics it looks like somebody tried this approach on your block. NOT a good idea.

On a Buick block, I would either knurl the cap, weld it up (steel only) or replace it with another cap to tighten it in the register. Either way your situation is not good. Chances are that cap is gonna walk around under power unless you do something to prevent it. Pinning the cap is a good idea and might help you save this block.

Welding cast iron in a structural area is also a bad idea. Yeah lots of guys say they can weld cast iron. BS!!! it always cracks again in that area.

Pontiac V8's don't have cap registers, The caps are dowel pinned to the block. HIGH HP engines use this technique to keep the caps from walking around.

I've recently saw a LSX block in for repairs where the caps were dancing around. The engine was producing over 2000 HP so its no wonder they were moving. The fix is to pin the caps to the block and then hold the caps solid with the main 6 studs/bolts

I would be interested to see what your machinist says when you take it back to him He most likely created the problem. Let him figure out how to fix it!

Dave makes great points here! Peening is many times done, but on certain blocks, NOT these blocks.

I've seen it where there was a weld bead run along the bottom of the cap (steel) and machined to center it in the register. This was done on a couple stageII aluminum blocks I used to have. A weld bead was laid along the bottom/side if the cap and then machined away to a point to perfectly center it, and give the proper interference fit.

And I'm in agreement, I would NOT re use that block. See what the machinist is willing to do. I'll bet he tried to peen it.

 

[PHANTASM]

the marks are from me scratching at the pieces to see if they were loose.
the cap still fits fairly tight.

a few local machine shops that do high perf work said they have seen the piece i had break off with steel caps.

out of the three local shops i talked to and seen the block said they honestly didnt exspect an issue with the cap as long as it was still fairly tight in the register.

hopefully having the main studs,caps and a steel crank with a good balance job will pay off maybe not.


i didnt have an issue setting thrust i remeasured and was at .004

i think i am just going to put her together and run the damn thing.
i dont want to sink anymore money into this car.

dont really plan on draging the car other than a few blasts now and then.


the buick curse continues for me. hopefully i can shake these demons

 

[Jerryl]

......... Welding cast iron in a structural area is also a bad idea. Yeah lots of guys say they can weld cast iron. BS!!! it always cracks again in that area. ........

Dave,
Not going to argue with your wealth of experience. cool: No pun intended)
Just a question. In general terms . . . . . In your experience, is welding repair effective if a block is correctly welded (Preheat, correct rod/technique) . . . and correctly post weld heat treated?

Edit: I am talking about localized pre-heat and post weld heat treat to minimize warpage etc.

 

[TurboBuRick]

i would be interested to see what your machinist says when you take it back to him He most likely created the problem. Let him figure out how to fix it!

x2!

 

[joey316g]

ALot of times the caps are manufactured with extra material and need to be fittied to the block. Im not sure now much experience your machine shop has with billet cap installs but ive seen quite a few people force them on right out of the box and crush/break the end of the register just like yours. Ive done many cap conversions at my last job and step one was to always chamfer the cap and block and then fit it to the register. Dowel pin the cap. It will work and it will be as good if not better than rlying on the registed to prevent cap walk. If that cap walks, your mains will go away in a hurry.

 

[turbofabricator]

I agree with using dowel pins. The block is fine, just need to provide a new register. Doweling the block and cap will work fine.

 

[Nick Micale]

.................a few local machine shops that do high perf work said they have seen the piece i had break off with steel caps.

If a machine shop did that to a block of mine, they would have a SERIOUS problem with me that would most likely cost them a new block. If they do not have the experience or knowledge, they should have passed on the job.

We set up a block in a mill to machine it for proper register fit. Once that is done, it must be align bored and honed for proper crank fit and clearances. This is NOT a cheap shop process, labor alone is ~$500.

Having done more than 100 turbo 109 blocks with steel caps, and many other brands as well, never had this happen. It is very poor workmanship to say the least.

If you are using a stock cast crank, and plan to go to an RPM range over 5K, it would not be surprising to see the caps walk due to crank flex.

 

[Michael McCoy]

You can believe it if Nick says it.

 

[A2000RICH]

the marks are from me scratching at the pieces to see if they were loose.
the cap still fits fairly tight.

a few local machine shops that do high perf work said they have seen the piece i had break off with steel caps.

out of the three local shops i talked to and seen the block said they honestly didnt exspect an issue with the cap as long as it was still fairly tight in the register.

hopefully having the main studs,caps and a steel crank with a good balance job will pay off maybe not.


i didnt have an issue setting thrust i remeasured and was at .004

i think i am just going to put her together and run the damn thing.
i dont want to sink anymore money into this car.

dont really plan on draging the car other than a few blasts now and then.


the buick curse continues for me. hopefully i can shake these demons

only thing worse than throwing the block away is having to throw that nice crank and everything that is connected to it when it fails-------your instincts are right that it is a problem, thats why you asked in the first place--------step back and think about it-------does it really make sense to take the risk of almost certain catastrophic failure???------if you were not going to run it hard you would not have put a steel crank and steel caps in it, right????------just make sure next time you find someone that knows how to fit a set of raw machined caps to a block and get it right--------i feel for you................RC

 

[PHANTASM]

If a machine shop did that to a block of mine, they would have a SERIOUS problem with me that would most likely cost them a new block. If they do not have the experience or knowledge, they should have passed on the job.

We set up a block in a mill to machine it for proper register fit. Once that is done, it must be align bored and honed for proper crank fit and clearances. This is NOT a cheap shop process, labor alone is ~$500.

Having done more than 100 turbo 109 blocks with steel caps, and many other brands as well, never had this happen. It is very poor workmanship to say the least.

If you are using a stock cast crank, and plan to go to an RPM range over 5K, it would not be surprising to see the caps walk due to crank flex.

THEY have done 2 other blocks for me with no problems. the register edge on that particular main register is extremely thin on the edge that broke , so i assume taking the cap in and out a few times it just broke. the other caps are fine.
the shops i talked to said they didnt think it would be a problem.

so what do i do throw away the fresh machined block or run it and see? i am 50/50 on it.

****ing buick curse lives on

 

[davinci50]

I agree with using dowel pins. The block is fine, just need to provide a new register. Doweling the block and cap will work fine.

No,you don't just run it, you put a dowel in it like turbofabricator suggests and have peace of mind to not turn more parts into junk unecessarily.