BOTH heads cracked!!
I'll give you details in a PM on KYFbodies
<small>[ August 23, 2002, 11:38 AM: Message edited by: sweetTA ]</small>
<strong>Thats a casting flaw, either sand or air caused a pocket beween those cylnders and de-shrouding them exposed the problem. I saw that problem here while porting a set of heads and caught it before they were installed.
Joe.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">While I'm not an LS1 Head expert, I run a testing lab for Aerospace and Automotive castings. Those are not cracks. They are either miss-fill, or weld voids.
You can tell if the casting has been welded by looking closely at the machined surface. The aluminum will be a slightly different color with a sharp transition, often with very small pockets (0.1mm) in the welded area. Take some 600 grit paper to it and look under a loupe.
A welded casting is inferior to a correct casting. It is weaker, and more prone to cracking due to thermal stresses imparted during the welding process. Many castings fail penetrant inspection or X-ray. Some non-critical application allow for welding. Some casting are rejected for "core-shift" where the inside and outside of the casting are misaligned. In critical applications, they scrap them. Usually they saw the casting in 1/2 or do something to keep it from accidently being used prior to melting it down.
If it is a casting that failed due to core-shift, penetrant or X-ray testing, DO NOT USE IT. Unless you know why the casting was rejected. The wall thicknesses could be too thin, there could be internal cracks, etc.
If I was going to buy a suspicous head, wheel, crankshaft, block, or any casting or forging, I'd shell out the money to have it MagnaFluxed, X'ray'd, or Penetrant inspected. Because a failure under load can be expensive and dangerous.
Brent
Speedaholic
Engines and Cylinder heads.
<small>[ August 23, 2002, 11:24 PM: Message edited by: One Monkey ]</small>
So if you ask me just weld it it will be fine.
It was not welded It was like that from the factory I am sure of that.
the shop that did your heads should of seen the pitt when there deck your heads... If it was our shop I would of have it fixed before I sent the head out.. so you might want too just have them take care of it for you.
Brent
Speedaholic
Engines and Cylinder heads.
<strong>Look at the bubbles in picture #3.
Are you going to tell me that ISN'T welded?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Nope not welds!!!
the first time I saw it thats what I figuer it was alos... but after seeing it in as many heads as I have it's a casting defect. trust me.
Brent
Speedaholic
Engines & cylinder heads
The Best V8 Stories One Small Block at Time
If I were you I might would pull my short-block down and put new bearings, etc. in. I have had some bad experiences with blown head gaskets(ruined the bearings and spun a couple of rods..... on a couple occasions)
Josh S.
Those heads were welded. No doubt at all. The last picture has the characteristic bubbles and you can see the line on the deck where the weld starts and ends.
<small>[ August 23, 2002, 12:21 PM: Message edited by: McRat ]</small>
Me personally, I'd be really pissed if the seller knew they were welded there and sold them anyways.
Some of my 98 ls1 heads look like that after I smoothed the chambers.
You don't see it with raw casting surfaces.
So the pock marks do not automatically mean they were welded IMO.
Steve
I've seen 100's of welded cylinder heads. Probably thousands. I used to rebuild cylinder heads at SIR, a Volkswagen shop. Granted different heads, but still welded/cast aluminum.
And I've also inspected thousands of other castings. Welded, not welded, voids, cracks, core-shift, etc.
While I can't say for 100% sure without looking at the head under high magnification, those pictures depict what a welded head looks like. Even if there was no voids, I'd still say they are welded.
I'm not saying welded heads are all bad. But many are. I've seen many heads crack during the welding process. If you do weld aluminum heads, always store them in a hot oven before welding, and weld them while still hot to reduce the chance of cracking, then check them throughly after welding for cracks.
I could go take pictures of some casting sitting on the floors of probaly everyshop that has the exact makings..
Now if there are damage from the factory, (it will have too be a machine because of the similarities in the damage) and say Suan (Valve god) had them welded. by the same person who can't weld for ****. then maybe... however the heads that I have seen them on have being heads that have being run on production trucks. So there could not be outcast from the factory.
Later
Brent
Speedaholic
Engines & Cylinder heads
<small>[ August 24, 2002, 02:32 PM: Message edited by: One Monkey ]</small>



