andystaiger

I had my ls1 rebuilt a while back and it was reading lower oil pressure than i would have liked it to.(Probably around 25lbs. cold and at a low idle it dropped into the red) The machinist said it would be fine. Well less than a year later the cam bearings went out. I took it back to the machinist had it rebuilt again and as soon as i got it back together it was reading even LESS oil pressure than the first time and I upgraded to a Melling high volume pump! My machinist has never touch a modern ls block before is there any kind of error that could be made on these to cause this issue?

Sales2@Texas-speed

iTrader: (5)

Loose bearing clearance would be my first guess, but it's hard to say for sure without inspecting the assembly.

andystaiger

Sorry, should have pointed that out.. He checked clearance and we're good there...
However I have heard from a few people in my area that he may not have installed the cam bearings properly.. Do they take some special talent to install? haha because I can't afford to tear it apart a 3rd time..

82cetuner

iTrader: (9)

that pressure is definetly way to low, if you drive it you will be rebuilding it but sounds like your ganna have to go back into it anyways I would be taking it back to the guy and make him fix the issue

SVTconfused

oil pump pickup tube cloged?

Sales2@Texas-speed

iTrader: (5)

What is/was the main and rod bearing clearance?

PowellSixO

iTrader: (1)

What about an oil galley plug?

gMAG

iTrader: (1)

I'm gonna take a guess and say that he installed the oil pump o-ring incorrectly.
On the pickup tube, where the pickup tube meets the oil pump, there is a flange. The o-ring should be sitting ON TOP of the flange, not below the flange. If the o-ring is mounted below that metal flange, the pickup will not seal completely.
Did the rebuilder install the pickup tube? If so, ask if he remembers how the ring was mounted.
Otherwise, you might do the investigation yourself, by pulling the balancer, timing cover, then lowering the pan. From here, remove the four oilpump bolts, then remove the pump.
If the cam bearings were installed incorrectly, I would think that oil pressure would either not be affected, or oil pressure could be higher than normal.

gMAG

iTrader: (1)

Oh, yeah...as Powell asked, the oil galley 'barbell' might not be fully inserted in the back of the block.
Don't allow the rebuilder to use the excuse that 20lbs (or, less) is ok. After a few WOT runs, you'll be in trouble. I know firsthand

andystaiger

SVT-No everything is brand new oil pump pu tube and such...

Matt-I have no idea what the clearance is..

Powell-The machinist also checked that and it's in there..


On another note.. he also checked the o-ring and it's good too

PowellSixO

iTrader: (1)

Correct me if I'm wrong, but aren't there 4 oil galley plugs?
1) Semi-permanent plug about 2" to the right of the oil pump under front cover.
2) Plastic "dogbone" style plug under rear cover
3) M16 plug on front drivers side of block behind alternator
4) M16 plug on rear drivers side of block above oil filter

The last two would be very noticeable though. Lol.

andystaiger

@ Matt- I called the man up and he said the clearance is .0027

There's a little room there but not near enough room to be causing the problem

andystaiger

The motor is out of the car right now anyways..
He's going to strip down to a bare block once again and start over..

The reason i'm freaking out is because he told me today that if we get it put back together and the problem persists it's my problem and he's washing his hands of it..

SWEET98SS

iTrader: (8)

Something is definetely messed up. I have .002 on all my bearings. My oil pressure is 40 psi warm idle.

andystaiger

Tell me about it.. haha.. It's been almost 2 yrs since i've raced it. I'm itchy..

Anyways I'm still leaning towards cam bearings.. That's what my intelligent friend from SHO-ME Speed says..

Sales2@Texas-speed

iTrader: (5)

.0027" on the mains of an aluminum block will have crappy pressure at full operating temp for sure...likely cold/cool as well! Remember the clearances expands/grows more on the aluminum blocks than it does on iron, so most builders old them to a tighter tolerance to ensure good pressure.

ABQ99TA

iTrader: (17)

So what is the proper clearence for the main and rods on an aluminum block i.e LS1?

Sales2@Texas-speed

iTrader: (5)

For an NA aluminum street build you'd like them closer to .0020" on the mains (There are other variables to this of course).

SteveDoten@ARH

add another M16 plug, right next to the main cap side bolt out back

Is it possible to install the 2003 or 4 style cam bearings into an older block or vice/versa??

I don't machine LS blocks, but I'd research the OD of the old vs new cam bearings to cross off the sht list