Black LS1 T/A

I've been procrastinating for weeks and weeks now. I hate to tear all the away down to the oil pump (low pressure: 8 PSI at warm idle, 25 at cruise), replace it and reinstall everything ... only to find it still has low oil pressure and needs a rebuild.

It drives fine (the oil pressure reading is the only thing that says something is amiss). No noises, no reduction in power that I can tell (of course I don't race it with the oil pressure low like that). And yes, I've verified the oil pressure with an external gauge.

Is there a way to get a better feel if clearances are excessive because of a problem like a spun bearing, etc.? Is it possible to have such problems and not hear something wrong?

Thanks for your input.

brad8266

iTrader: (23)

damn its that low?? You probably spun a bearing or something.

Steve Bryant

iTrader: (1)

1. How many miles are on the engine?

2. Have you done a compression check on the engine? This has nothing directly to do with low oil pressure, but it if you have low compression or a big differential from cylinder to cylinder, this really favors a tear-down/rebuild.

3. What were the circumstances and time line leading to the current oil pressure levels?

My gut feeling is that something serious has happened beyond your oil pump . . . but, maybe not. For instance, the oil pressure regulator piston could be stuck at or near the maximum oil return position, thus dumping the oil before it goes into the oil galleys. Answer the three questions above and let's see if we can help you make an informed decision.

All my best,

Steve

Black LS1 T/A

1. This engine only has about 20K at most. Maybe less.

2. No low compression problems

3. I was driving back home frorm the drag strip when I noticed the lower oil pressure. With the supercharger, often the oil is thinned out after racing and I always change the oil after a night of racing. This time, though, the oil pressure did not come back up.

BTW, I have a 98, and my l pressure has always idled around 40 PSI, rising with RPMs, and sometimes lower at idle. I never had one of those 60 PSI cruising oil pressures. Also, my oil pressure has always varied with the type of oil I ran.

Thanks!

Black LS1 T/A

If there are no noises, no power loss, why come the oil pump could not have just failed? Just wondering ...

97Rob

I assume you checked the oil and magnetized plug for metal shavings. Good luck. Damned if you do and Damned if you don't. Seems like a spun bearing would leave evidence.

Black LS1 T/A

I know, right. I found no metal parts/shavings in the oil.

Z28_DAD

iTrader: (18)

what kind of oil pump do you have now? if you dont have a high volume/pressure, id say give it a try. its easy enough to do and cheaper than a motor.

Steve Bryant

iTrader: (1)

I think that you are at the point of pulling your engine and do a teardown/inspection. Since you mention oil dilution from the supercharger and it happened after runs at the dragstrip, that says that something failed under higher than normal stress . . . and the lubricity of the oil was compromised. At a minimum, I think that you will find at least one bad rod bearing. Do something now before you further damage the engine! That's my advice.

If you want to try something first, change the pump and don't run the engine too much until you know if this fixes the problem. You're still going to have to do a good bit of work to change the pump. I'd be concerned about what else may be going to fail next and when . . . even if the oil pump brings back the oil pressure.

Your signature doesn't tell much about your car and setup. Is your engine bored and stroked? If so, how much? Are you running FI? How much boost are you running? You need to address the oil dilution issues. Also, If your rings are not gapped properly for FI and your rings are not seating well, you probably are washing down the cyinder walls with blow-by. This will also expalain the oil dilution. What kind of crankcase ventilation are you running?

All my best,

Steve

WhosNXT

Change the oil pump, with that low of miles its unlikely to be a bearing, but possible just my .02

Proud2bSS

iTrader: (2)

Good suggestions. I would add that the extra costs and "inconvenience" of upgrading the oil pump to a higher pressure/volume unit (and then analyzing the results) is far outweighed by the insurance and piece of mind obtained (and possible solution) by the process.

DONAIMIAN

iTrader: (18)

If you still have the oil you took out, I would send that in for an annalysis(sp) and go from there.

03 BUSA

iTrader: (25)

Is it possible that something happened to the oil pump seal? Wouldn't this cause low oil pressure?

Black LS1 T/A

ATI Supercharger, about 12 PSI Boost, 4.030 Bore, 4.125 Stroke (422 CID) from 6.0 Liter Iron Block

half-n-half

iTrader: (7)

i didnt either...no visible signs minus the knocking..haha

no shavings or anything along those lines but sure as **** it was spun bearing

Irocss85

iTrader: (1)

its very possible the pum is bad. I would def. start with replacing this. it'll cost less than $100 after you buy the gaskets, oil pump, and new oil and worst case scenario, if it doesnt fix it, you would be buying a new oil pump for the new rebuild anyways. who did the eng. rebuild? alot of things can cause short bearing life. poor surfaces on the rods/crank, high rpms, alot of stress (hello supercharger and long stroke), high heat from the supercharger could also lead to alot of bearing wear too. maybe you should invest in an oil cooler for that sucker.
good luck though, hope its just the pump.

Black LS1 T/A

Hmmm ... whatever the problem, an oil cooler sounds like a good investment ne ways

Black LS1 T/A

I trust the builder did an outstanding job. Too outstanding.

After I fixed the belt slip problems, I either needed to drop the boost level or kill timing... the thing would make a set of ET Streets slick on the drag strip like glass.

I should have not been greedy and lowered the boost. Fueling would have been easier and I would have gotten some traction. I probably could have stood to get a lower stall, too.

In a way, I almost feel like I let the builder down, because I ran out of steam money-wise to do quickly what I needed to to feed this monster and get a hook-up.

Black LS1 T/A

The biggest thing I regret is the weight of the Iron block, and the heat it retains.

If I were going to do another build, I was hoping it would come when I could afford a C5R block. But, that costs almost as much as my engine completed ... and I got it at a discount!

Irocss85

iTrader: (1)

I think the new LSX block is alum., buts its arount $2k just for the block, prolly much like the c5r block is. that extra 100 lbs on the nose isnt helping you hook up either. what suspension mods do you have? and your saying your running out of fuel press. in the upper rpms? if so you should get a boost-a-pump. it worked for a customer of mine that has around 11lbs boost with a d1sc. and put a fuel pump hotwire kit on your list of must have's if you dont already.