CRAZZ28

iTrader: (13)

Ok sorry in advance for the long post.

I have been fighting this for a while now and i guess its time to ask for some oppinions. I just installed some ported stock casting heads and a custom grind hydraulic cam. I am using comp OE style lifters, stock length hardened pr's, and 1.6 NSA promags, with comp guideplates and comp double valve springs. The cam is a 234/234 .576lift on a 110 lsa. I also switched to the new style opti and went with an electric waterpump.

At warm idle the oil pressure was bouncing between 6 and 0. with 10-30 oil. Verified with a mechanical gauge. So i threw in some 20-50 and it was the same story. so i replaced the oil pump with an HV pump. When the pan was down I pulled a couple main caps. and number 1 and 5 rod caps and the bearings looked brand new almost no wear on them at all.

The new oil pump didnt seem to help at all. the odd thing is with with the pressure that low at idle (750rpms) if you bring the rpms up to 1000 its got 27-35lbs of oil pressure. So that leads me to believe that i am bleeding pressure off somewhere in the top end hence no oil pressure at idle.

Again sorry for the novel. And thank you to anyone with some insight.

My95Z

iTrader: (8)

Really sounds like one or more cam bearings have been damaged and you are losing pressure there. It is odd that even with a HV oil pump and 20W-50 it wasn't a huge improvement though, must mean its more than one cam bearing gone bad to leak that much. Sorry man, low oil pressure is never a good thing.

CRAZZ28

iTrader: (13)

That was my first thought, but would that not cause low pressure at any rpm? Its just odd that its got almost nothing at 750rpm and around 30psi at 1000rpm

JAKEJR

What if there's a problem with the new lifters? Perhaps their OD is too small for the bore diameters in the block.

How about re-installing the stock lifters to see if they'll make a difference? They're a lot easier to swap out than changing cam bearings.

How did the oil pump drive gear teeth look? You could change that at the same time as the lifters.

A few weeks ago I just finished doing the same mods on my son's 96 LT1 - heads and custom cam and rockers - but I re-used the stock lifters. Oil pressure wasn't effected.

Just trying to brain-storm this.

Jake

West Point ROCKS!

Wicked94Z

iTrader: (26)

none of that would affect oil pressure

the_merv

iTrader: (88)

Sounds like a Cam Bearing went to ****.. do it make any wierd noises?

JAKEJR

Sure it would. Excessive clearance between the lifters and the lifter bores is like an internal leak, reducing oil pressure.

Worn teeth on the stub shaft causes erratic, ubnstable and reduced oil pressure. Ask me how I know.

Jake

West Point ROCKS!

My95Z

iTrader: (8)

The higher rpm drives the pump faster thus pushing more oil through the engine, enough to "override" the leaks from the cam bearings while your at higher rpms. Cam bearing lose oil pressure mainly at idle unlike rod/mains which seem to be everywhere especially at high rpm's.

CRAZZ28

iTrader: (13)

no odd noises whatsoever. I was starting to think along the lines of the lifter idea also. or possibly a bad cam journal? I should have mentioned that i bought the cam used. I was told that it was in an afr headded 383 for around 3k miles and then they decided to go SR.

edunegan

my car did the same thing a few days after i did my cam swap in my car the new cam literally ate the drive gear that runs the oil pump off, bought one of the phenolic ones from comp been great ever since.

JAKEJR

Are you talking about a gear that's made of the same material that the stub shaft is made of?

Do you recall the part number of the new gear or a link so I can find it. I'd like to read up on it.

Thanks,

Jake

West Point ROCKS!

SS RRR

iTrader: (2)

Oil pressure is dependent on most every internal component in an engine...

Wicked94Z

iTrader: (26)

hm should have said it a little better, but its extremely likely that none of those reasons are the cause of his low oil pressure in this case. worn drive gear teeth would cause no pressure at idle, but then decent pressure a few rpms higher? not likely

and where in the world do we come up with mismachined lifters as a possible culprit? Fine I say the cam was misground, the fuel lobe was switched with one of the bearing journals. Or his old oil pump was on its way out, and the new one just so happens to have loose internal tolerances. Exactly.... not likely.

What is likely, is the OP didn't do a very clean install or nicked the **** of out those cam bearings and they're toast.

CRAZZ28

iTrader: (13)

This is not my first cam swap by far. And the work was done on a lift in my shop, so you can rule out a dirty install.