Just had my motor rebuilt by a local place.
After 100 miles she lost oil pressure. so i take it apart and the 2,3,4 main bearings have made contact with the crank. 1,5 look ok.
i put a dial on the crank and all is good.
details-
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stock crank forged rods, piston arp bolts throughout and a ysi supercharger 18# boost.

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so the question is why did this happen?

 

Have you asked the machine shop that did the work that same question yet? How did you break it in? Hopefully not making 18#.

 

what were the clearances on them?? did the shop plastigage it before install? what oil did u run for break in?? when i put my fresh ls1 in my truck, on first start up i let it idle and come to temp, watched oil psi like a hawk. i then shut it down, let it cool, and did the same thing. Afer the 2nd start up, i drained the oil and put on new filter and oil. I have about 1700 miles on mine, and have used rotella 30 wt. sorry for rambleing, just curious about the oil used and if its been changed.

 

That sucks.

I see aftermarket main studs. Hopefully the block was line honed with the studs.

 

very true,did not notice that

 

The align bore for the crank is way off, have it align bored and the crank polished and try again. Wasn't the block checked for core shift?

 

the way he told me too, driving the heck out of it and he threw it on the dyno with 20 miles on it and took it to redline 755 rwhp.
30 weight oil

 

30 weight and its been changed 3 times in 100 miles, first right after start up

 

Have you checked what the oil pump pick up looks like and make sure its not clogged up with ****?

 

How about the align bore on the mains?

 

im not sure ill have to ask him.

oil pickup was clean

 

That's some of your problem there,try breaking it in a little easier.

 

I don't think that's the OP problem...

Easy break-ins are controversial, so I am not getting in to that, but my fresh 408 was/is getting the **** beat out of it every time it is up to temp. The few people I know outside of LS1tech that are car enthusiasts have all done this with success.

 

builder said Detenation will hammer the mains out of an engine. and he wants to take a look at it.
All the plugs looked good when i took them out.

 

Post close up pics of your plugs (as close/magnified/big as you can get).

When you ran it on the dyno, do you know what the wideband AFR was (at various RPM/load)...?

 

plugs are good, 11.5 afr to 12.0

well i might have found out why this happened. When i brought it in last time he said it would need to be lined honed, well when i talked to him today i found out that he didnt do it because i wanted my engine back as quickly as he could. so i believe this is on him.

 

I think the rod bearings take a larger beating personally (under detonation).

Did anyone cut the filter open on the engine shortly after you warmed it up (maybe put a little time on it) and dropped the oil right away? My guess is you would have already seen bearing material in your filter pleats but Im purely speculating. Point is thats a lot of bearing damage for an engine with so little time on it indicating something was probably wrong almost immediately.

What was the clearance of the mains and why are you running such thick oil?

Are you running excessive clearance that its necessary?

If they tuned it and they built it hopefully they are willing to take care of you....

Good luck with the situation

And a note to others that have a new motor going in their car or perhaps on the dyno.....buy a filter cutter for $25 or so and cut that filter apart almost immediately to get early detection of any problems. It can save you money in the event you catch something like this early.

-Tony

 

Oiling issue, builder mixed up main caps, or wrong clearance on bearing. I have seen bearing companys mix up sizes then whats labeled on box more then once. I now inspect every size stamp on bearing and dont take for granted. Line bore out is possible but I have never seen it on modern engines unless it had main issues before rebuild. Mains are usualy last thing to go. Tonys right, the rods take the beating. I have also seen beairing material from a blown engine and cleaning grit from machine shop block oil passages. I spend hours cleaning a block after a machinist does his cleaning due to this. If your engine was ok and you just did a freshen up I would lean towards them mixing up caps screwing up the line bore or bearings to tight. Check the sizes of crank journal and the bearing size stamp.

 

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