10 LBS of oil pressure, what did I break?

**excrider121** · 08-31-2012, 03:58 PM

Car info: 98 t/a with LS1. Just been rebuilt, has less than 500 miles on it. I currently have 5w30 valvoline with the Lucas Zinc additive.

Prior to the engine rebuid, I had 20-30lbs of oil pressure at idle, and 40-60lbs the moment you touch the gas.

After the rebuild, I've 10-15 at idle, and it barely makes it to 20lbs when the gas is touched.

The engine was completely gone through, new rod/main bearings, new Oil Pump, Cam, Cam bearings, Lifters, Pushrods, Trunion rebuild kit, intake and TB.

The oil pressure never gets lower than 10lbs but that's scary low on a new-ish engine. Any ideas would be appreciated.

**tatertot91** · 08-31-2012, 04:03 PM

I'd check the oring on the oil pump

**excrider121** · 08-31-2012, 04:50 PM

Thanks!!

That was the only idea that I had. The rebuild kit came with 3 sizes, and I used the one closest to the size of the one that I took out. When I put the pick up tube back in, it went in firmly, with minimal play, but still. Thankfully, I've got solid motor mounts (more clearance) so removing the pan shouldn't be too difficult.

**2002ssslp** · 08-31-2012, 07:19 PM

Did you plastigauge the bearings before you put them in ?

**excrider121** · 09-02-2012, 02:13 PM

Sadly, no I didn't, and I just started it up a few minutes ago to go to the store, I've got what feels like a dead miss or a knock :/

Looks like the motor is coming back out.

**2002ssslp** · 09-02-2012, 06:33 PM

You know what they say. Measure twice and cut once.

**Wfolsom** · 09-02-2012, 07:13 PM

If your crank or rods were turned or refurbished and you put stock bearing back in in stead of an oversize bearing that could be your problem
If your unsure of a how to on a rebuild always buy a book and follow it step by step

**2NDSLPSS** · 09-03-2012, 06:57 AM

between the not measuring, wicked low pressure, and knocking. . . . im really sorry to say but main bearings. but you never know considering you just had it all apart, obviously try O-ring and ign. system before yankin her back out again.

***SMWS6TA*** · 09-03-2012, 03:37 PM

I'd also check the OPSU. It is easy to crack and simple to check when compared to oil pump o ring and bearings.

**2NDSLPSS** · 09-04-2012, 11:58 AM

i def 2nd the
10-15$ 10min sending unit job 1st

**tatertot91** · 09-04-2012, 05:26 PM

Originally Posted by 2NDSLPSS

i def 2nd the
10-15$ 10min sending unit job 1st

Where are you getting them from? Last I remember its like 50 bucks

***SMWS6TA*** · 09-05-2012, 04:26 PM

I paid $58 for mine.

**2NDSLPSS** · 09-07-2012, 05:42 AM

Originally Posted by tatertot91

Where are you getting them from? Last I remember its like 50 bucks

oh . . . that may be the only part i have not bought for a ls1. when i worked at advance i think the avg price i saw for other cars was wayyyyyy cheaper. my bad. lol

**excrider121** · 12-10-2012, 05:59 AM

Well, I took the engine apart, and from what I can see, it looks like the low oil pressure killed the bottom of the engine....what do you guys think?

This is cylinder 1 right after we unbolted the connecting rod main cap.

This is the same connecting rod cap with the bearing set inside it. I'm holding part of the bearing flush with the rod cap. I think the rod will be trash too...

This is the 'prettiest' crank journal

I think it's interesting. If low oil pressure ate up the bearings, why are the score marks tangent to the oil feed holes, and not more towards the outside of the bearing? One would think that low pressure would have the inside of the bearing looking pretty good, with the outside of the bearing surface looking burnt/scored/fked.

I now have two options (I think). If my stock crank can be turned, I can have my rods stretch tested to see if they are toast. If they aren't toast, just do oversized bearings and toss it back in the motor. But since the grooves will hang your fingernail, I'm think the crank is trash too.

Or, I have a friend with a 6.0 iron block just sitting in his garage. It came in a lot that he bought online. We know the engine is still good, its been verified by an engine shop. If I have to buy a rotating assm, why not just stroke the 6.0?

***SMWS6TA*** · 12-10-2012, 06:57 AM

Your crank is toast....rods too, not worth the effort to salvage the rods. Crank maybe but looks like you'll be at the limit.

So you say you have a 6.0L....You are in in interesting position. Rebuilding the LS1 will be real close to getting the 6.0L ready.

You got to ask yourself what is more expensive?

Other things to consider with the 6.0L -

What yr/LQ? Is it a LQ4 or 9? Yr - >04 or 05<?

It matters because of the reluctor wheel. All >04' LQ4's & 9's are 24x reluctor wheels, were as 05< LQ9's started using 58x reluctor wheels.

If you have one that has a 58x reluctor wheel you can still use it but you will either need to use a 58x to 24x conversion kit to work with your pcm or replace the 58x reluctor wheel with a 24x wheel.

LQ4's have around 9.4 compression (great for boost applications), while the LQ9 has around 10.5 compression (close to LS1)

All of your accessories, heads, headers & intake will work on the 6.0L.

If thinking of a cam/heads upgrade now is the perfect time while the engine is out because if you swap over to the 6.0L you'll need a full tune.

I have a 04' LQ4 short block that I hope to work on in 2013. I also picked up LS2 pistons and connecting rods for almost free. If they check out I plan on swapping the LQ4 pistons for the LS2 ones. Will up the compression to 10.5.

**2002ssslp** · 12-10-2012, 07:52 AM

I would go back to your "Engine Rebuilder" and have him give you a correctly built and balanced LS1 short block or have him build the 6.0 to match your topend. He put in the wrong bearings and trashed your short block, time to pay up.

**35th-ANV-SS** · 12-10-2012, 08:00 AM

Based on all the information stated in the thread, he rebuilt the engine himself.

**cpop98ws6** · 12-10-2012, 09:29 AM

No need to run the Lucas Zinc additive in these engines. On a fresh engine I use Shell Rotella T 15W40, it is a high detergent oil and will help clean out all the assembly lube. Run it with the rotella t for 15 min then change the oil and filter with the oil of your choice. After about 500 miles change it again.

**excrider121** · 12-10-2012, 06:30 PM

Originally Posted by SMWS6TA

Your crank is toast....rods too, not worth the effort to salvage the rods. Crank maybe but looks like you'll be at the limit.

So you say you have a 6.0L....You are in in interesting position. Rebuilding the LS1 will be real close to getting the 6.0L ready.

You got to ask yourself what is more expensive?

Other things to consider with the 6.0L -

What yr/LQ? Is it a LQ4 or 9? Yr - >04 or 05<?

It matters because of the reluctor wheel. All >04' LQ4's & 9's are 24x reluctor wheels, were as 05< LQ9's started using 58x reluctor wheels.

If you have one that has a 58x reluctor wheel you can still use it but you will either need to use a 58x to 24x conversion kit to work with your pcm or replace the 58x reluctor wheel with a 24x wheel.

LQ4's have around 9.4 compression (great for boost applications), while the LQ9 has around 10.5 compression (close to LS1)

All of your accessories, heads, headers & intake will work on the 6.0L.

If thinking of a cam/heads upgrade now is the perfect time while the engine is out because if you swap over to the 6.0L you'll need a full tune.

I have a 04' LQ4 short block that I hope to work on in 2013. I also picked up LS2 pistons and connecting rods for almost free. If they check out I plan on swapping the LQ4 pistons for the LS2 ones. Will up the compression to 10.5.

The block is a 02-03.
It is a LQ4
I have Trickflow 235 CNC Ported heads with a big lift cam that I'm thinking will be transported to the new engine. Only issue I have with the motor at this point is it's been sitting inside without heads or oil pan for a year or so, so there is rust a-plenty. I've been told that acid dipping will take care of all of it?

The plans for the engine would include stroking it to a 408 or 421 so rust on the cylinder walls would be a minute worry.

I've got HP Tuners so tuning would be on me as well...

Originally Posted by 2002ssslp

I would go back to your "Engine Rebuilder" and have him give you a correctly built and balanced LS1 short block or have him build the 6.0 to match your topend. He put in the wrong bearings and trashed your short block, time to pay up.

I did the rebuild myself. My mistake was the oil pump pick-up tube o-ring. When I purchased a Felpro head gasket kit, it did not include the paper work that explained which of the three included o-rings went back in the engine. The one I removed was black, so I put a black one back in. Apparently the one I was supposed to use was green. As a result, I had 20 lbs lower oil pressure than I had before the engine rebuild.