aero_ub

I started with a new LSA block and built a forged engine. I used the stock forged crank, forged Diamond pistons and Callies H Beam rods. I'm planing on being around 700 whp on 93 and built it so it could also take e85 and/or a shot later if I feel the need.

I've got about 200 miles on it and the ONLY thing so far that I slightly question is my oil pressure. It's not climbing much with the rpm's as I would have expected it to. I think that the LSA piston oil squirters have check valves in them that opened up in the low 40s? Started with some 5-30 break in oil and then went to a 10-40 conventional oil and it did bump the hot idle (about 890 rpm) pressure from about 23 psi to 31 psi. by about 2500 rpm i'm in the 40's but from there up to 5500 it isn't going much past mid 40s. When I built the engine, I set the mains at about 2.7 thou clearance and the rods at 2.4 thou. Not 'tight' so I figured I would need at least a 40 weight but I'm thinking now that I should try a 50 weight? I used a Precision Oil Pumps ported Mellings high volume pump. It is the 10355 and though this is quite high flow for most LS applications, this LSA has 8 piston oil squirters and takes a whole lot more oil flow than most LS applications. My understanding is that the 10355 is pretty much a direct replacement for the LSA pump, not much of a gain in flow but the Melling pump is probably more reliable and then getting a ported and blueprinted one from Precision is about as good as you can do.

Should I try a 20-50 or are my mid 40 psi oil pressures ok with my setup? If I go to a 50 weight and it jumps to mid 50s, does that really matter and is it really 'better'? Maybe it's the same exact flow volume but just generates more pressure because it's a little thicker and doesn't really matter? This I'm not sure about.

Would love input from some guys more experienced with this or experienced with the LSA. Aside from that, the WOT 3rd gear pull made me giddy, she is going to be nasty for sure. So strong it's a little unsettling at first, and it's purposely running a little rich (commanding 11.12 a/f) and only 16* timing. The traction control still kicked in at the top of 3rd and about 90 mph.


Thanks for any input!

KCS

iTrader: (20)

aero_ub

Thanks KCS, appreciate your input. I was also thinking, once the engine is 'broke in' and I switch to a good 10-40 synthetic then that might push it up a little as well.

pdxmotorhead

If your clearances were at the loose end get that second number higher.. like 20w50.. For daily driving,,
its just enough higher shear to keep stuff happy.. 10w40 is basically a 30weight ,, thats light for engine
oil temps above 195. But the engine guys I work with all set motors up via the main and rod
clearances to run a specific range of viscosity.. YMMV..

stevieturbo

Strangely my LS2 is similar.

It has had oil squirters for a few years now and at first ran a Melling 296 ( also feeding a pair of turbos ). Oil pressure was never fantastic but always consistent.

I rebuilt a couple of years ago and threw in a 355 pump instead in case it needed more flow, again with the stiffer Melling spring.

Oil pressure didnt change a bit, Both those times had King bearings fitted.

I had to rebuild again a few weeks back after a head exploded and threw in some ACL Race bearings and shimmed the relief spring a little. FFS if anything now warm oil pressure is a little worse !

Initial cold start it can make 65psi or so with a little rev but it drops to 25 or so warm.
But rarely ever goes over 50 warm and is prone to pressure drops after a gear change etc for some reason. If anything pressure will drop a little as revs climb. Only been logging pressure for 3-4 years or so so no idea what it was like prior to that with other blocks I've used over the years.

Even despite that, the bearings that came out werent terrible looking by any means. Maybe a slight lack of cleanliness but still decent surface etc.