Is it early blocks or oil pumps that are the problem?
05-28-2005, 06:02 PM
#1
Is it early blocks or oil pumps that are the problem? I've always assumed that early oil pumps were the problems with lubrication in our blocks. I finally tear apart 3 pumps: a 1998, 1999 and a 2001 (stamped in September 2001, so I assume this was a 2002 model year car).
I measured everything with calipers: the relief valve piston & bore, pump body intake and exhaust along with several other things. All measurements were the same between the three pumps!
The only thing I havent checked is the spring pressue between the 3 pumps. The 01 pump pump did feel a little stiffer when compressed with my fingers, but I'd like to check with a spring pressure measuring tool. I now see why shimming the spring helps.
Now I'm thumbing through the May 2005 issue of Hot Rod magazine and on page 104, in the upper left hand corner I see this:
"Here's a good bit of info to know: The '97 to mid'99 LS1 block should not be used for high performance applications. These first version had two holes in the back of the block for the pressurized oil coming from the oil filter making them more susceptible to starving the passenger side lefter galley of oil. "
They show two blocks side by side. Should I open this up with a grinder before closing up the motor? I could use the old gasket as a template. Has anyone done this?
I know the older blocks had smaller sleeves and I'm not talking about that. I just want to know what others have to say about the block or pumps.
Hey, my 396th thread! what a coincidence
I measured everything with calipers: the relief valve piston & bore, pump body intake and exhaust along with several other things. All measurements were the same between the three pumps!
The only thing I havent checked is the spring pressue between the 3 pumps. The 01 pump pump did feel a little stiffer when compressed with my fingers, but I'd like to check with a spring pressure measuring tool. I now see why shimming the spring helps.
Now I'm thumbing through the May 2005 issue of Hot Rod magazine and on page 104, in the upper left hand corner I see this:
"Here's a good bit of info to know: The '97 to mid'99 LS1 block should not be used for high performance applications. These first version had two holes in the back of the block for the pressurized oil coming from the oil filter making them more susceptible to starving the passenger side lefter galley of oil. "
They show two blocks side by side. Should I open this up with a grinder before closing up the motor? I could use the old gasket as a template. Has anyone done this?
I know the older blocks had smaller sleeves and I'm not talking about that. I just want to know what others have to say about the block or pumps.
Hey, my 396th thread! what a coincidence
05-28-2005, 07:04 PM
#2
the old pumps actually came apart (the teeth on the gear-rotors would disintegrate).....I think it had something to do with the heat threat.............
the oil "ports" in the back of the block are a problem but by themselves are not a problem.....the problem comes when the oil pumps volume becomes marginal which results in a pressure drop..........with enough pressure the holes wouldn't be a problem......
the oil "ports" in the back of the block are a problem but by themselves are not a problem.....the problem comes when the oil pumps volume becomes marginal which results in a pressure drop..........with enough pressure the holes wouldn't be a problem......