CitznFish2

( I haven't posted here in over a year or more. I couldn't remember my original password or email for my acct here, so this is a new one, sorry)


I finally went and spun a bearing on my 98 LS1. The engine has 140,000 miles on it and I guess the oil pump went out.

Would the following seem like an oil pump failure?

I was driving down the freeway when my car started knocking. I saw my oil pressure drop to 0, then back to 45, then back to 0, then back to 25. I pulled over and the car had 0 oil pressure. had the car towed to a dealership, restarted teh car and the oil pressure came back up. drove it down the streeet to a friends shop and the oil pressure remained. At the shop the oil pressure went back down to 0.

When there is oil pressure there is no knocking at all, but when the oil pressure is at 0 there's def. loud knocking.

So we took the oil pan off and found 1 rod bearing that was extremely loose. the others were all tight and seemed OK. There was minimal metal shavings in the oil pan. the crank seems fine except for the single spun bearing:







We are debating if the symptoms described could be caused by a bad oil pump (or relief valve in teh pump), or if you could get intermittent oil pressure with a spun rod bearing? We were thinking sometimes the bearing would be in place and the oil pressure would go up, but once the bearing spun it dropped the oil pressure in the engine. Sound feasible?

Where there any TSB's on the early LS1's for bad oil pumps? I read somewhere there was, but i don't know who lists all teh old TSB's these days.

I would like to avoid doing a complete rebuild, so we're thinking we could get the crank polished in the car. Does anyone know of a company that does this? Similar to how they can bore cylinders while the engine block remains in the car. (I know of only one company that made the equipment to do this though)

failing that we're just going to take some 600 grit sandpaper and try polish it that way and replace the 2 bearings, and the bearings next to it.

I'm not sure about replacing the oil pump, i would only want to do that if I found that TSB, or if it was acknowledged that the characteristics of the oil pressure problem were pump related as opposed to bearing related.

Any opinions?

I just want to get the car up and running again so I can sell it(with full disclosure of course). I think if we replace the bearings the engine can last another 10-20K miles if it's not driven extremely hard.

as a side note, the cylinder walls all show very, very little wear. cross hatching is still easily visible, the cam doesn't look worn, and the other rod bearings seem to be within tolerence. Dunno about the main bearings, but I'm assuming they are OK.

If I get this car running again, which seems like I can, how much could I reasonably expect to get for it? It's very clean with only the typical rock chips you'd get after 140K miles. Interior is clean. driver seat as the usual wear on the left bolster.

1998 Artic White Z28 M6 fully loaded
Ported TB
MTI lid w/ K&N
SLP SFC
BMR STB
Bilstein Shocks
Eibach Springs
SS Rims
Pro 5.0 shifter
Random Tech. catback Exhaust with MF rolled exhaust tips
clutch 50K miles ago

always garaged at home and at work




Cliff notes:

Intermittent oil pressure, spun a bearing.

Was there a TSB for Oil Pumps on early LS1's? (Can I get a copy of it?)

Would my oil pressure problem be a symptom of a bad oil pump, or spun bearing?

Anyone know of a company that can polish cranks in the engine block in the car?



sorry for the long post, but there's a lot of info I need to find out. TIA!

-CF

Crazy Man

iTrader: (6)

As far as the cause I would say the oil pump was going out when I spun bearings in my motor the oil pressure dropped to a constant 15-20 psi but never dropped more than that and I had 2 spun bearings... Good luck

CitznFish2

thanks. So you think a spun bearing could cause intermittent oil pressure problems?

MeentSS02

iTrader: (11)

I would think the intermittent oil pressure problems would cause the spun bearing.

Randy WS6

iTrader: (69)

Make sure that you check your main bearings because that were your oil comes from to oil your rod bearings ,each main oils one rod jernal or two rod bearings side by side rods .A rod bearing can be fixed farly cheep but a spun main can cost you a block if not real bad, just a line bore witch can cost some bucks.

ACW

What was your original username?


Here are some possible causes of oil pressure problems:
Oil pump worn or dirty
Oil pump-to-engine block bolts loose
Oil pump screen loose, plugged, or damaged
Oil pump screen O-ring seal missing or damaged
Malfunctioning oil pump pressure regulator valve
Excessive bearing clearance
Cracked, porous, or restricted oil galleries
Oil gallery plugs missing or incorrectly installed
Broken valve lifters

I don't see any TSBs about oil pump problems on 98-02 F-bodies, unless I'm overlooking something; this only goes up to 2003 so there could have been something issued since then, but I'd think that kind of thing would have shown up by then.

Race Car Driver

There is no doubt that too much bearing clearance will result in lower oil pressure readings. Depending upon the position of the bearing, oil pressure may or may not be effected.

CitznFish2

thanks eeveryone for your help.

P.S> my original name was CitznFish

ACW

CitznFish = https://ls1tech.com/forums/member.php?u=863
Was registered with email account of c1tznf1sh on aol.

Please make a thread about this in the User Support forum to get your old account merged with the new one.

gollum

iTrader: (1)

Remove oil pump and inspect.

Measure crankshaft surface for excessive wear. If too much clearence exist, you will have to remove your motor to repair crank.

The connecting rod will have to be rebuilt or replaced. You can do this by removing the head. Did you check the breakaway torque measurements of the rod bolt nuts? The 98 LS1 had the weaker rod bolts.

Big end rod measurements and bearing crush are "very important".

BLA BLA BLA

Camaro99SS

iTrader: (4)

I have a hard time seeing how a spun bearing would cause erratic pressure. That sounds more like the oil pump to me. Worn bearings cause constant low pressure, not from 0 to 40 lbs.

Jason

Tech

iTrader: (1)

My oil pressure did that to me a few times. I didn't hear any knocking though because I killed it when my check gauges light came on. I had some fancy "lifter unsticker" stuff in the oil at the time. Changed the oil and haven't had any problems since.

PhoenixLS6

My motor had a low oil pressure problem also, then it went. So now i gotta get a new one. Building it bigger and better than stock though.

family sedan

iTrader: (3)

Check the main bearings ... Oil starvation just kills them.

If they are ok, I'd go with the cheap fix. Just polish the crank and install a new pump and bearings.

Bow94z

iTrader: (3)

crappy LS1 oil pumps

lbm13186

iTrader: (4)

had a problem with the oil pressure on my 2000 ta. i was driving down the highway at 70 mph in sixth and everything was fine then i heard a knocking and lost all oil pressure. the engine has 70,000 miles on it and have a mti x1 cam with headers. the person that had the car b4 me ran nos in it for a little if that matters. and the car sat for a year. i had the oil sucked out and have gone threw 3 or 4 oil changes since then and have drove it for a year. i think its the pump, but wanted to get some ideas... if any one has any thing to say please let me konw i would like to know what to replace it with if thats what i need to do. that what i think im going to start with and go from there. how would i konw if i spun a bearing when i pull the oil pan. if im going to replace the oil pump, iv come to understand that i have to pull the cam and to get to the pump is that the case? and should i pull the motor to do all of this or should i take it step by step

SSmoked1

iTrader: (21)

Should of just made your own thread instead of bumping a 6 year old one and hijacking it.

lbm13186

iTrader: (4)

just did sry man didnt konw how to do it, new to the site but thanks

chrisfrost

iTrader: (8)

Hello , bummer dude , if You do end up sanding/polishing the crank , I would suggest going to an automotive paint supplier and buying 2000 grit sandpaper to sand with . As far as polishing goes , I have no idea , someone else can help with that . Good luck

AutomagicLS1

iTrader: (18)

Just find a used crank and a rod and re bearing it & be done with it.