Zedo- Check this out

[Gach]

Tell me what you think coz this problem, here's a little
information from the owner. I have my idea what the problem
is, but wanted to see what you think.

Quote:
posted January 26, 2005 03:48 PM
Ok now what? I think I am going to burn this thing....does anyone want to buy some E-heads and a matching victor intake

The crank is a factory unit that was done by lunati....I have ran this crank for 5 years now, originally in one block for 3 years until that block developed a couple small cracks so I had another block machined and put the same crank into the new block, which I have ran for the last 2 years now.....I did not have these problems with the last block, every thing that came from the old block looked like new....I will deffinately be checking the block very carefully to see what I can find, and yes I do assemble my own stuff I have done it in the past and never had any problems.....like you can see in the picture I did check clearances but I did not check to see if the bore was straight I did not realize it would be that hard to get straight....maybe it is not the machinest fault but right now I am leaning that way....

Pic of where I used a dial bore gauge to check clearance as you can see it never touched the bearing here

Like I said in a previous post these have 2 years on them along with the rod bearings and the rod bearings look good.....is it the line bore? The way the rear main bearing looks like it was never touched on the front half but the back half looks like.....well you know makes me think that the line hone is tapered across journal......HELP

[Gach]

He had steel caps and studs put on, check out the
dowel pins. Here's more pictures

[sprint250]

a precision ground mandrel that is just slightly smaller than the finished main bearing saddle bore and as long as a crank shaft should be passed through the assembled and torqued bores to check for binding.
Just the rear main suffered this?
Bell housing misalignment can cause rear main to wipe out early and take the seal with it.Crank center and transmission center lines not true and /orExtreme stress placed on block by engine mounts due to high torqe and horsepower twisting chassis on car.

[sprint250]

Is that rust , old RED GLYPTAL paint that got left behind from a previous build or something else?
Thrust surface is wiped out too.
Lou , what was the oil PSI on the engine?

[Gach]

Oil pressure ? don't know he didn't say. So basically they screwed
up the line bore, is what your saying.

[sprint250]

It is quite possible this could be the case.
The mandrel would reveal a lot of it.
Improper ,too tight, clearances can cause the bearings to wipe out.
Only the machinist responsible for setting up the operation knows for sure if an error was made .

[sprint250]

if the parting surfaces on the main caps were not ground "true" when the material was removed to set them up for the align bore or align hone operation the hone or boring bar would graze the loose spots and remove too much material from the tight sides.

[sprint250]

heating and cooling cyles over time will cause a block to warp and distort.

since this takes place over a long period of time the original crank and mains will compensate by wearing unevenly and on teardown everything looks good.
Put a new or reconditioned crank shaft and new bearings in the warped block and the result is binding and rapid bearing wear.
It could be the align bore or hone operation was never performed at all by the machine shop.

[Gach]

Ok the verdict is back from the machine shop....the block appears to be crack free and a light line hone and cylinder hone she will be race ready again. Now the crank on the other hand was not so lucky, it failed the mag. test #3 main has a crack running through the front radius that is about 2 1/2" long and the rear main is heat cracked from the bearing contact, the machinest figures that the cracks would probably clean up after cutting the crank, but he also said that he did not think that running this crank would be a good idea for what I do, hmmm I would have to agree....So anyway I am guessing that the crank was flexing around alot...One more thing that I know I said earlier and that was "why did I not find this in my oil filter?" well I got to thinking about this problem and I realized that I never cut open the last oil filter since I had just pulled it out with engine so the oil filter was still attached to my adaptor, well I cut it open and guess what I found......bearing not alot but enough to concern me that I would have pulled the pan anyway.....well I guess I can consider myself lucky, I was going to make the 5 hour trip to the 1/4 mile track at the end of last season and maybe make some bottle passes just to see 9.0's or maybe a 8.90 (just guessing and wishing) but the event was cancelled due to the threat of snow. I would guess that the bottle passes would have pushed the crank over the edge, maybe not but no way to know now...well talk to you all later...

Chad Dammen

[chris percival]

Lou.
The crack on #3 main you said it was 2 1/2" long and in the rad or did run 90 deg. from the rad? Any crank that has a crack that runs around the journal in the rad the crank is JUNK! But I have polished many cranked c/s for customers that under stand and are ok with building a bomb. Not to say all cranked c/s are junk but 2 1/2" Long sounds a bit past the stage of using.

The rear main sounds like heat checks. Seeing the pics above I would agree, do not usually see heat checks on a cast c/s. In most after market c/s (forge steel @ billet) you find heat checks on the journals after loss of oil and c/s is blue in that area. If the all the cracks are across journal and not around journal you can grind .050 to .060 under and weld and regrind. I Have ground .100 to .200 under and have never seen a crack go a away. The crack may not be in the rad but is still in the counter weight and still will break sooner or later.Take a look at some pics of a 428 ford that is cracked in #3 throw.sorry no luck on attach. pics, will try later.

[chris percival]

pics of a dead 428 "F"liped "O"ver "R"eservation "D"ecoration
I will get some good pics showing heat checks and post them

[Gach]

Thanks Chris, good pictures. I say his crank crack, and
was wobbling around and that's what cause the bearing issues.
I'm I right in your opinion.

[chris percival]

No way to besure, but I would agree with you. I have seen c/s come out of race engines that I have checked out, that look perfect ,stright,size is bang on, bearings were good enough use over. Only to clean @ mag find a crack, sometimes find 2 or 3 cracks.