G Atsma

Exactly!

gagliano7

Did you put the pump on in one piece on the motor or did you take it apart and put it on body first then the gears? If you did take it apart the gears only go one way so if you reversed them that could be a problem.

Rroyall415

I took it apart then put it on there was a dot on the gear

G Atsma

Why take the pump apart?

07NBSChevy

iTrader: (1)

For alignment purposes, to be able to measure the pump gear to housing clearance with a feeler gauges.

G Atsma

OK, thank you!

Rroyall415

Found our the reason the main bearing was worn causing crank wobble

LLLosingit

iTrader: (4)

Not saying it couldn't be the cause but I have my doubts. I have a 408 that literally broke the main cap in two pieces and still didn't hurt the pump or chain.

qweedqwag

Use the ls 2 timing set and a GM performance hi flow pump, problem will be solved.

LLLosingit

iTrader: (4)

How is that going to solve his problem? He was already running a Melling pump and you can't get much better than that, His issue isn't a bad pump, There is something else going on.

qweedqwag

What's your suggestion other than something is not right, I believe he knows that .

LLLosingit

iTrader: (4)

Well considering I'm not there I cant speculate other than what it's not likely to be and since it was a new melling oil pump (that he had apart) and cloyes gear and stock chain I can't see the brand of part being the issue. Maybe it was installed incorrectly I have no idea but he stated a worn bearing as being the cause and that's highly unlikely. I literally have a 408 that broke a main cap at over 5,000rpms (920+hp)under load on the dyno, It was pulled apart and although it junked the crank and there was no bearing left the pump was still intact.

joecar

The pump's gearset can slide around inside its housing... crank wobble shouldn't break the pump.

S10xGN

iTrader: (11)

Might just be me but when zooming in on the 2nd pic in post #1, I see what looks like a rocker trunnion needle in the mix. Of course, it may be a pin from the chain or other related debris. So, OP, have you had any previous rocker arm destruction? No other instances of parts coming loose and maybe not being 100% cleaned out?

KCS

iTrader: (20)

Bent crank?

jayyk31

iTrader: (2)

Op when you took apart the pump did u put it in a vise at all to hold It? Possibly warped the casing? Are there any burrs on the block on the pump mounting area possibly caused it to be bolted up on an angle of sorts?

00pooterSS

iTrader: (40)

He said he replaced it for an o ring problem then the next pump went 100 miles and then this one went immediately

I wonder how much of that time the engine wasn't getting oil pressure, maybe it wiped out all the lower end and the crank is all over the place

By the way OP, did you check the thrust on the crank? Forward to rearward movement? Crank could be moving back and forth pushing on the pump...?