You know you are lying to yourself, you will take the bait, you always do ...

Thank you, another post ... ding ...

Now if he only learns how to take the cheeze without springing the trap...

I have to much time invested in this thread to see it fade away :-)

Any resolution on why this happened yet??

Robert posts 20 times a day, when he knows the answer he will tell us.

Only 20?

Any updates?

I left him a message 3 or 4 days ago but I ain't heard back from him yet. the last time we spoke roughly a month or so back he said something about working on the interior & some other non engine related areas which was dissappointing cuz we need to get to the bottom of this but since it ain't my deal I gotta just go with what is presented to me but he does know that from me being involved in this deal that I also want resolution to this & that I am willing to help him achieve that & he has expressed appreciation for that interest/concern. I will post the outcome.

I spoke with him this evening. the shop that did the machining tore it down and ALL bearings are wiped smooth & clean (rods & mains) including thrust surfaces on #3 main halves EXCEPT the #4 main had spun. He (the owner) saw the bearings but did not take off the cap on the spun #4 main. this shop polished the crank (std), owner ordered std clevite bearings from Summitt. he recollected to the best of his ability that he plastigaged em at 2&1/2 tho. Assembly lube used. it was showing 80 lbs when we broke it in till it locked 4 minutes later. I told him either (1) wrong machining (2) oil psi or (3) debris & I wouldn't think debris cuz he said they were all smooth & it had 80 lbs at the sender but bearings can get starved especially the #4 main & rods on either side of it that feed from that main, but this was a 2200 RPM breakin, not high RPM & I said my money is on improper clearances. that's the latest guys, any thoughts? Oh & the #4 main cap was blued & he is going to source another cap & have another shop line bore it then the same (1st) shop that originally did the machining, put the short block together (not what I would do). I offered to put it together for him for free. EDIT He said the shop called in some other machinists to check it out & they are at a loss (I suspect they ain't miked anything yet, just visual.

No ideas on the cuprit, glad to see you are still engaged on this and thanks for the update!!!!

it is too challenging to let go especially with all the interest you guys have shown me on this and the puzzling development on the visual. I'm looking forward to eyeballing it in person as this is second hand info.

Since you mentioned blued cap and clearances checked: any chance the bearing saddle of either the cap or block had an edge ding.
Motor ran fine until heat built to the point of bearing failure.
I'm coming in late and I'd be suspect of foreign material in the bearing interface, or dome sort of block or cap defect displacing bearing.
Be interesting to find out how difficult assembly rotation was prior to start-up.

I ain't sure if startup rotation was mentioned priorly. He took some some pics that he is going to send & I'd like to be there in person before it goes together, I will for sure post any new info. EDIT what sounds strange to me & to them (& the people they called in) is that all the bearings are wiped smooth

IMO the bearing clearance was to tight. You don't wipe or spin main bearings with .0025" clearance on a new engine with 80# of oil pressure. If it didn't have oil pressure the top end would've been very noisy.

Id like to see the bearing pics, almost sounds like a machining error. I recently used PG to check for consistency but on the real measurement it was nearly .0015 off.

Interesting. Based on the autopsy it sounds to me like #4 was too tight due to the wrong bearing (undersize bearing in a standard bearing box) or there was insufficient oil supply to the #4 bearing. If the builder did indeed plastigauge all the bearings or the engine turned over at assembly, then I would guess an oil problem. 50 years ago I was working on one of the old babbit pounder 216 Chevys that have the oil dippers on the rods for rod lubrication. The engine was in the car and I got disoriented and got one dipper on backwards. The engine ran for about two minutes and locked up. The rod I had assembled incorrectly had fused itself to the crank and the rod was a pretty deep blue color. This sounds similar.

I think the tight or lack of clearance is why he had 80 PSI.

Robert

I think this is a good example of what can happen when someone lacking engine building experience is left to do it by themselves.

Unless there was no assembly lube, or a plugged feed hole to the #4 main, there is no way the crank would have passed the "feel" test for how it turned over.

I've seen where main journals on the crank or the main line itself is out if whack, to the point where the clearances measured fine, but the crank didn't feel "right" when turning it over........ And on a couple of occasions it actually locked up when all the caps were torqued.
I've had this happen twice. Once the problem was the block, once it was the crank.

good call on the psi & even tho it was a hi vol pump (not sure what spring), that number sure kinda points to minimal overall leakage. Evidently they did not mock it up/mike clearances after they did their work as he ended up plastigaugeing it himself (that had been bothering me from early on). I'm gonna see if I can drive up to the machine shop & take a look at the carnage.

With a 1st time engine builder, I have to wonder if the #4 main that spun was incorrectly installed. If the lock tabs were not in the grooves, the clearance at the bottom may have been OK, but the sides could have been very tight, causing the shells to spin as soon as the heat came up. The bearing shells could have begun spinning on start up, and it took 4 minutes to create enough heat to lock the motor. You are all assuming the new builder had the bearings correctly located.

If the #4 main bearing spun bad enough to lock the motor and turn the cap blue, and the other bearings look OK, how are you ever going to determine the real cause other then to point to #4 spun bearing and its blue cap? Gene