Let it knock until it dies?

On my 93 1500 350 TBI with 143,000 niles, I just had the tranny rebuilt. Got it out of the shop yesterday. I was driving around getting my emissions test. I passed emission. The guy pulls my truck
out of the emissions testing bay and all of a sudden it's knocking.
Now it knocks upon start-up and doesn't get better after it warm. Won't hurt if I put heavier weight oil in there will it? Just for kicks and giggles.
My oil pressure is real low. Under accelration I can get it up to about 20-30. Someone suggested main bearing is gone. I heard oil pumps don't fail often.
I'm thinking I should drive it until it croaks. Been without the truck for a long time. I've got another 350 out in the shed ready and on stanby.
I've got extra parts from a third engine was well.
Any advice?
Brian 93 1500 Damn, daddy.
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wrote:

Main bearings do not knock they can rumble a bit though when well worn but typically the main result is low oil pressure. The bad thing about that is that the rods receive their oil supply from mains via cross drilling in crank so when mains get worn and pressure drops the rods will fail eventually and start knocking from lack of proper oiling. You might be able to nurse it for a while though if it is not too bad. If you are using 5w30 in it STOP using it now!!! Try some 15w40 (not 10w40) as this is a HD diesel oil that does well in worn engines and it will boost oil pressure. Sometimes in extreme case a can of STP or Motor Honey will help too. Do not keep driving it as is with current oil and try as above with a fresh filter too. (WalMart brand 15w400 is fine for this) ----------------- TheSnoMan.com
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Tell that to my old 6 cyninder Buick. It had a spun main bearing and knocked like crazy! It was just as cheap to have it rebuilt as it was to buy a remanufactured engine.
The bad thing about

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On Tue, 3 Apr 2007 13:14:55 -0500, "Mike Dobony"

You may of had a uneven fire versionof the V6 which can rattle the crank around when bearings are loose. Normal even fire engines generally do not "knock" on main bearing. ----------------- TheSnoMan.com
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wrote:

With worn mains the oil pressure will go up if you decelerate, and down when you add power. Like to get some of that Wal*Mart 15W 400:)
Al
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We had a 94 Z-71 with 200,000 on it. The oil pressure dropped down to 20 psi. We pulled the pan and were going to just roll a set of bearings in and unload it. We dropped a main and a rod down and they looked great. We pulled the pump apart and it looked like it had something go thru it and leave a good score in it. We put a new HV pump in and thru it back together with the old bearings fired it up and had 60 psi cold and 40 psi hot at an idle in gear. Ran it for another 100,000 + miles and sold it with still great oil pressure... Might be the pump...

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I had the same issue on a 92 4.3L V6. The local dealer noticed a bit of a leak arond the oil filter housing and sealed it with some sealant. It wasn't 100 miles later I was at 20 PSI on the highway. To this day I believe a chunk of the sealant somehow partially blocked a line but they were not going to admit it was their error. Since it was 8 years old and at 145K miles I traded up rather than fight about it.
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We pulled the pan and were going to just roll a set of bearings in and

I've heard about "rolling in" new main bearings several times. Can you run down that process for me?
Mike T
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Basically drop oil pan, loosen all main caps pretty good, drop one at a time and the bottom bearing is in the cap and the top one you just "roll" it out of the block and "roll" the new one in, install bottom half in cap and put back up loosely until you get them all done, Also on the back one roll in a new rear main oil seal if it is a two piece one while your at it. (easy on Chevy a pain in the ass on a junk Ford with the rope seal) The rod bearings are just as easy...
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