L98 oil distribution question
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Heel & Toe
Joined: Mar 2005
Posts: 20
Likes: 0
L98 oil distribution question
I havent had too much experience working on these chevy motors, But last winter I rebuilt my L98 in my 87. When I got it all finished I am having a problem with oil getting all the way up to the top end. My gauge says I have 60 psi at idle and there is plenty of oil going to the mains and the cam. But then when it goes to the lifters it stops there. Right now I have the motor back out and on the engine stand. I want to know if I turn the oil pump with the priming tool should i get oil out the top center whole in the lifter. or does oil only come out there, if the lifter is being pushed on by the cam? also what is the proper way to prime the lifter prior to installation. Like i said I know my way around an engine but havent done too many chevy's. The way I always primed lifter was to submerge them in oil overnight before install. Now these are the newer roller lifters, so is this the correct way? I also wanted to know what is the correct height to set the oil pickup relative to the pan? i.e. one inch up from the bottom, 1/2" etc. Any help would really be appreciated. Thanks
Melting Slicks
Joined: Feb 2006
Posts: 2,753
Likes: 15
From: backwoods upstate ny
if your pre-oiling tool is not made from an old distributor you will not get oil up to the rocker arms...the hi-buck nothin-but-a-shaft type primers allow the oil to bleed off without goin to the top end...in this case the crude ole backyard tool is better
i have set oil pump pick-ups at 1/4--3/8 above floor of oil pan on hundreds of small blocks with great results....i have heard some recent reports of going higher, but i'll stick with what is proven
i have set oil pump pick-ups at 1/4--3/8 above floor of oil pan on hundreds of small blocks with great results....i have heard some recent reports of going higher, but i'll stick with what is proven
Last edited by redrose; May 22, 2006 at 12:18 PM.
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
The oil galley rises up to the rear cam bearing housing and oil flows
around the perimeter of the housing to openings on either side
that feed the lifter galleys.
The pass side lifter galley enters the hole that supports the bottom
of the dist housing. If the housing is in place, oil flows around it
to the galley on the forward side of the dist housing hole and goes
forward to the pass side lifters. If the housing is NOT in place, there
will be a massive leak where the cam bearing-to-dist housing galley
terminates at the back side of the dist housing hole. The oil will
flow down into the crankcase.
Aftermarket tools have a casting at the bottom to seal the housing
hole in the same manner that the dist housing does.
.
around the perimeter of the housing to openings on either side
that feed the lifter galleys.
The pass side lifter galley enters the hole that supports the bottom
of the dist housing. If the housing is in place, oil flows around it
to the galley on the forward side of the dist housing hole and goes
forward to the pass side lifters. If the housing is NOT in place, there
will be a massive leak where the cam bearing-to-dist housing galley
terminates at the back side of the dist housing hole. The oil will
flow down into the crankcase.
Aftermarket tools have a casting at the bottom to seal the housing
hole in the same manner that the dist housing does.
.
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
I don't know each of the answers but perhaps I can help by making your
questions more visible for those who do
3/8 - 7/16 from the pan.
I have not worked with hyd roller lifters. I recall that priming flat
tappets resulted in oil moving up the pushrods from the center holes
in the lifters but it's been so long since I've done it, I'm really no
longer SURE of this.
I used the overnight procedure for flat tappets, and spun a priming
tool in the distributer opening immediately before starting. I ran the
tool long enough to see oil pressure build and stabilize on the gauge
- if I couldn't build pressure, the engine didn't get started.
Incidently, the 18V cordless drills are GREAT for priming, IMO.
.
questions more visible for those who do
- I want to know if I turn the oil pump with the priming tool should I get oil
out the top center whole in the lifter. Or does oil only come out there,
if the lifter is being pushed on by the cam? - What is the proper way to prime the lifter prior to installation. The
way I always primed lifter was to submerge them in oil overnight before
install. Now these are the newer roller lifters, so is this the correct way? - What is the correct height to set the oil pickup relative to the pan?
i.e. one inch up from the bottom, 1/2" etc.
3/8 - 7/16 from the pan.
I have not worked with hyd roller lifters. I recall that priming flat
tappets resulted in oil moving up the pushrods from the center holes
in the lifters but it's been so long since I've done it, I'm really no
longer SURE of this.
I used the overnight procedure for flat tappets, and spun a priming
tool in the distributer opening immediately before starting. I ran the
tool long enough to see oil pressure build and stabilize on the gauge
- if I couldn't build pressure, the engine didn't get started.
Incidently, the 18V cordless drills are GREAT for priming, IMO.
.
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
Originally Posted by bogus
that is interesting. Didn't know that.
I preoiled all but my last BBC with a home-made shaft made from a bit
of round stock (no collar.) There was pressure on the gauge each
time so that tells me that the main and rod bearings got oil. The cam
and lifters were probably short-changed but I was always generous
with EOS and moly during assembly so perhaps that helped me
avoid trouble back then.
Actually, I think I primed my first with a big screwdriver, now that I
think about it. No pressure, but at least there was oil in the galleys.
.
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Melting Slicks
Joined: Feb 2006
Posts: 2,753
Likes: 15
From: backwoods upstate ny
when i prelube an engine, i run the primer for about 5 minutes, rotate the crank manually 180*, prime 5 more minutes, rotate crank 180*, prime 5 min, rotate 180*, prime 5 min.....after 2 complete revolutions/priming , oil usually is trickling out all the rockers...occasionally need a second prime cycle...i don't fire the engine until all the rockers are wet
Race Director
Joined: Jun 1999
Posts: 14,924
Likes: 9
From: Merritt Ils Fl
Originally Posted by redrose
when i prelube an engine, i run the primer for about 5 minutes, rotate the crank manually 180*, prime 5 more minutes, rotate crank 180*, prime 5 min, rotate 180*, prime 5 min.....after 2 complete revolutions/priming , oil usually is trickling out all the rockers...occasionally need a second prime cycle...i don't fire the engine until all the rockers are wet
FWIW, I recently read a piece that said that as a SBC winds up thre will be from 3 1/2 to 4 quarts of oil distributed throught the engine. That means only 1 to 1 1/2 quarts in the pan. This is the reason for the pick up to be 3/8 to 7/16 from the pan.