fusion_ta66

iTrader: (1)

I am building an LM4 single 7875 turbo build. The LM4 is an 04 junkyard engine that has about 100k on it. I currently have it on a stand. Leaving as SBE with stock (but new springs) 862 heads. I am swapping the cam and gapping the rings.

I'm thinking while I'm at it, I should replace the oil pump and timing chain as well. Or is this a waste of money?

If replace with new, it seems that the general consensus is to just put in a Melling M295 and not a high volume or high pressure option.





For the timing chain, what is the preferred option? Just the standard Melling LS2 replacement?




​What about oil pickup tube? Anything else I'm not thinking about?

Thanks in advance

gametech

iTrader: (1)

Up to you, but I have seen more people cause problems putting new pumps in than I have ever seen failures on 100,000 mile pumps or timing chain/sprockets with these motors. Good news is taking it far enough apart to gap rings and change cam will make a good visual inspection easy. Should be obvious if other changes are needed.

Jake Wade

I would get new GM lifter trays, camshaft plate, pickup o-ring, barbell, seals and gaskets.

G Atsma

This, plus, depending on mileage, a fresh timing chain only. Sprockets stay pretty good, it seems...

grinder11

iTrader: (1)

The aftermarket, stainless steel barbell is a bit better than the GM OEM barbell. I mean, as long as the OP is in there. I agree with everything you've pointed out. I would say one of the most important things hes doing is to make absolutely certain he has the CORRECT O-ring for his pickup tube. Since the OP says it's a 100,000 mile engine, I'd also install new timing chain and gears, and since he's going FI/Turbo, I'd use some new beefier/hardened pushrods, too. Maybe new lifters while he's at it.......

fusion_ta66

iTrader: (1)

Thanks everyone thus far. I hadn't even heard of the barbell before, very interesting. I will probably swap out with the billet aluminum version. When I remove and replace the rear cover to access the barbell, should I always replace the cover seal and the rear main seal?

What about valve seals? If so, any particular ones?

Jake Wade

Definitely make sure you select the correct pickup tube O-Ring.
Yes, I would for sure replace the seal and cover gasket.

G Atsma

There is sort of a rule of thumb with oil pickup tube O-rings.
If the tube has a groove around it where the O-ring goes, use the thicker one.
If no groove (straight tube) use the thinner one.

grinder11

iTrader: (1)

This is one area of the LS game that GM dropped the ball, big time. It would've been easy to spec all the tube diameters the same, with or without a groove. Just make them all the same diameter. This is what happens when bean counters pick and choose outside engineering vendors......