98 L29 no oil to rockers. Help?

[Spareparts]

Mine did take a little while for sure to oil after first start up.
When i removed some pushrods and after i stick everything back together it will start oiling again in a few minutes but the next couple of days in the morning i'll have some tapping going on that stops after a minute or two.
After a few days i'll never hear another lifter tapping. Seems odd but that is just the way my engine is and this is with two different sets of new lifters.
My OP is 70psi cold and a hair over 25psi hot. Oil is Royal Purple 5/30. Gen VI with the front oil galley plugs drilled.
I replaced my engine because of extremely low oil pressure when hot. Upon tare down i also found some lifter with the disk that holds the pushrod sideways equating to a pressure leak.
Never once did i hear a lifter making noise and i would bet that is why i had low hot oil pressure. Old engine ran perfect btw.
From spinning my oil pump to pre lube the rebuilt engine i can tell you for sure the dizzy does need a snug fit or you will not get any oil to the lifters.
The GEN VI feeds oil to the crank first then cam and finally lifters.
What is your HOT oil pressure, What oil and what makes you think the crank bearings are bad?

 

[wb292]

Check your oil cooling line connector. One of them has a plastic part that breaks. It directs oil flow to the proper passage to the cam. It’s PN 1578022. The other line to the cooler doesn’t have this piece. I’ve had two of these fail on two different trucks.

 

[98BBC2500]

HOW are they not "exactly the same as OEM"?

You took them apart ONE AT A TIME for cleaning and inspection? Or did you take them all apart, and put the guts from one lifter into another--mix 'n' match style?

Did you put the metering valves back in correctly?


I know the oiling system changed between Mark IV and Gen 5, and the Gen 5 system carried-over to Gen 6.

I never considered the distributor "sealing" or not "sealing" the oil gallery on the Gen 5/6 engines, though. I just assumed that that part of the oil circuit was the same as Mark IV. Hoping to learn something here.


Yeah, you "should" have oil to the rockers by half-an-hour. Ten minutes...maybe not.

But Spareparts says it took his engine multiple hours to get oil to the rockers...which I would not have expected. I guess I don't know everything. Does make me wonder about plugged lifter passages.

I won't install lifters without pressurizing them with ATF (flows readily at room temperature.) It allows me to check the leakdown rate, and it verifies that the lifter will pass oil to the pushrod seat.

You must be registered for see images attach

You must be registered for see images attach

Having pressurized them, be careful and slow with setting lifter preload. The lifters need time to bleed-down as you adjust them.


You could. Are you sure you need to?

I'd at least run it long enough to warm-up so I could see what the hot idle oil pressure was, in-gear if an automatic trans.

What weight oil are you using? Not 20W-50, or straight 40 wt, or other no-flowing syrup, I hope.

I'm not sure how to set lifter preload. Gen 6 heads are positive stop rockers and not adjustable. The early big blocks required the distributor to be properly seated to get oil pressure to the top end. I don't think that's the case with a Gen 6. Oil is 10w30. I'm honestly scared to run it for fear of catastrophic damage.

 

[98BBC2500]

Mine did take a little while for sure to oil after first start up.
When i removed some pushrods and after i stick everything back together it will start oiling again in a few minutes but the next couple of days in the morning i'll have some tapping going on that stops after a minute or two.
After a few days i'll never hear another lifter tapping. Seems odd but that is just the way my engine is and this is with two different sets of new lifters.
My OP is 70psi cold and a hair over 25psi hot. Oil is Royal Purple 5/30. Gen VI with the front oil galley plugs drilled.
I replaced my engine because of extremely low oil pressure when hot. Upon tare down i also found some lifter with the disk that holds the pushrod sideways equating to a pressure leak.
Never once did i hear a lifter making noise and i would bet that is why i had low hot oil pressure. Old engine ran perfect btw.
From spinning my oil pump to pre lube the rebuilt engine i can tell you for sure the dizzy does need a snug fit or you will not get any oil to the lifters.
The GEN VI feeds oil to the crank first then cam and finally lifters.
What is your HOT oil pressure, What oil and what makes you think the crank bearings are bad?

You are the first person to say something about the sideways disc in the lifter. I found 4 of these on first teardown in original set. Hot oil pressure is 15 psi at idle. Rule of thumb is 10 psi per thousand I believe. I'll recheck the dizzy.

 

[98BBC2500]

Check your oil cooling line connector. One of them has a plastic part that breaks. It directs oil flow to the proper passage to the cam. It’s PN 1578022. The other line to the cooler doesn’t have this piece. I’ve had two of these fail on two different trucks.

Wow. Thank you. I'll check that. I wondered about the oil cooler playing a part in this. Did you have a leak? I do not.

 

[wb292]

Wow. Thank you. I'll check that. I wondered about the oil cooler playing a part in this. Did you have a leak? I do not.

No the line wasn’t leaking but I was getting low and erratic oil pressure. There are a few Ytube vids on the gen5 and 6 oil passages. This part is also explained.