402 stroker follow up.

[sscrazy]

Hey all I am just following up to a thread that I posted in september. I had just built my 402 stroker, had it tuned and dyoed. And it started knocking in september, i just got around to tearing it apart and yep, sure enough, #4 rod bearing spun. It is repairable though. Does any one know why just one rod bearing would do this? I mean I guaged everything before assembly. They are Howards forged rods, I hope that it wasnt egg shaped or anything, and i know I torqued everything right. I am thinking maybe something got into the oil port and plugged it. Well anyway the crank is in the shop as you read this, I should have it back on the road again by end of march!!

[davered00ss]

Is this the SLP one? I have heard of a few failing.

[sscrazy]

Is this the SLP one? I have heard of a few failing.

oh i forgot to put my sig. it is a callies 4" forged crank, Howards rods, Mahle pistons, 598 598 comp cam. I built the motor from scratch myself. I have never seen a rod bearing let go like that.

[408WS6]

When you rebuilt, did you upgrade your oil pump?

I spun a rod bearing as well and suspect my stock LS1 oil pump is the culprit.

I'm upgrading to a ported LS6 pump on my new motor.

[Sarge]

Oil starvation caused by lack of oil flow or a clogged port...or too thick of a viscosity of oil....bearing clearances of .002 to .003 should have no more than a 10-40...
What installation lube did you use? What break in pattern with the oil did you use? Oil Pump? Viscosity of break in oil and running oil?

[sscrazy]

i used a ported and polished blueprinted oil pump. I used normal assembly lube. Technically there is no "break in period" with these ls1's. I bought all my parts from wheel 2 wheel powertrain. These guys are the ones who did all the testing on these motors for GM. They just recently opened up to the public, now they are probably the best ls based motor shop out there. They put together motors, start them up and put them right on the dyno with Mobil 1 oil.

I used mobil 1 for break in. and normal use. Like I said I think there may have been a problem with that rod before I put it in. Maybe out of round or something like that. I have never had this happen to me. If it was an oil problem then I think that it would have hurt more than one bearing. I am just glad that it didnt and that this didnt hurt my engine any worse than it did.

Any way thanks for your input guys, I will keep you posted when I finish it "again".

[Sarge]

Well...sounds like it very well may have been bad out of the box as you state....it happens....

[310stanger]

and oil problem likely would have caused a problem on more then one bearing. but not necessarily spin more then one. check the other bearings and journals for scuffing.

[sscrazy]

alll the other bearing surfaces were chewed up, but that was from all the bearing fragments from #4. There were copper pieces everywhere in my oil pan, and stuck to my oil pickup screen.