Which weight oil???

[no tree to big]

this is an old post but for future readers I figure I'd throw this out there

oil weight cant just be determined by the engines intended use/time of year I can build three motors using all the same components except the bearings. If I had one set of bearings -.001, one set std. and one set +.001 resulting in say .0015/.0025/.0035 of clearance on the mains and rods and each one of those motors will use a different weight oil to maintain the same oil pressure. so first question is what are your bearing clearances?

the tight side of clearance will like a 5w30 in the winter 10w30 in the summer while the loose bearings would require at least a 10w40 maybe stepping up to 20w50

just for reference I have a 383 LT1 in my 94' camaro fully forged rotating assembly big cam ported heads...I turn it to about 6500 rpm at the moment (needs better tuning) the mains are .0025 on 1 thru 4 .0035 on #5 all rods are at .0025 and I have found that 10w40 gives me my best results so far, hot idle is ~35 anything over 1100rpm is 55+. during start up when its cold(less then 40) it sounds like it needs thinner oil the valve train is very loud, when its over 40 it pegs the gauge at 80 until it gets up to temp. and keeps everything fairly quiet. I have tried 5w30 and 10w30 and the hot pressures were about the same when the motor was reved up but sitting at 800 rpm it was only producing ~20 which was unacceptable to me for a brand new motor so I stepped it up a weight to accommodate the looser bearings.

 

[olyman]

Marine oils, so I have been told, still have higher zinc content.

I ran 10/30 Castrol GTX in my 11.5 to 1 383 chev in my Toyota. It is an all roller engine. I had a machine shop assemble the bottom end. It is currently sitting on an engine stand in my garage until I figure out why there is metal in the oil. It had one hour break in time. The fist attempt of this engine ended in a spun rod bearing (assembled by a different shop).

I have a 350 in it now. I will run 10/30 marine oil in the 350 engine with the flat tappet. I should have it running soon. It is in the truck, but I have to plumb and wire it. I have to finish splitting my wood pile first.

I hope I can learn a little here. I am tired of swapping engines in this truck.

guy by the name of gary--used to frequent the forum--he built a warmed over 350--and it near destroyed itself in less than 40 miles!!! cause??? not near enough zddp in the oil for break in--flat tappet engine!!

 

[Nick359]

The 383 is an all roller engine.

The first shop told me they had to assemble it to have a warranty. They told me to run 10W30. It only had 20 psi at an idle. They said run 20W50. It showed better pressure, I can't remember exactly, but oil pressure would drop to 0 in the high rpm ranges.

They told me to put an oil accumulator on it. I did, same problem. Then I changed the oil pump and the same thing.

I took it apart and everything looked great except one rod bearing. I showed them the problem. "We don't warranty race engines" was the response I got. We exchanged words and I never went back.

I took it to a new shop. They were getting it cleaned up. Work sent me away for a few months, so I had them assemble the bottom end.

After one hour of run time, there is a ton of metal in the oil. I think I will get into the engine over the winter and do everything myself.

 

[chowdozer]

The 383 is an all roller engine.

The first shop told me they had to assemble it to have a warranty. They told me to run 10W30. It only had 20 psi at an idle. They said run 20W50. It showed better pressure, I can't remember exactly, but oil pressure would drop to 0 in the high rpm ranges.

They told me to put an oil accumulator on it. I did, same problem. Then I changed the oil pump and the same thing.

I took it apart and everything looked great except one rod bearing. I showed them the problem. "We don't warranty race engines" was the response I got. We exchanged words and I never went back.

I took it to a new shop. They were getting it cleaned up. Work sent me away for a few months, so I had them assemble the bottom end.

After one hour of run time, there is a ton of metal in the oil. I think I will get into the engine over the winter and do everything myself.

20 psi at an idle is ok. Rule of thumb is 10 psi/1000 rpm. 0 psi at higher rpm is not good. Accumulators are great but it's not going to help you.

There isn't much to go wrong on a small block oiling system. You're running the pan dry. Are you running a high volume pump? Winding it up before it's warm? How high are you spinning?

These are things I would do. Port the rear main oil passage and match the ports. Put a deep sump pan on if it will fit and a long pickup. Set the height on your pickup and weld it in place or buy the Moroso pickup that has a bracket off the oil pump bolt to hold the pickup. You got a roller top end, so you can restrict oil up there and keep a couple quarts out of the rocker boxes. Little Chevys need oil to the top end to keep the ball and stud rockers cool. You don't need all that oil. Port and smooth the drainback holes too. Blueprint your oil pump. Pull all the oil plugs and run a piece of welding wire through all the oil passages and feel for obstructions. Get some of those super magnets and put them wherever oil is draining back. Magnets are your best defense against oil pump problems farther down the road. Steel kills oil pumps, aluminum and bronze not so much. It's not necessary but I always pressure balance the oil pump and then try it out with an electric drill (a big drill) in a bucket of oil. I like to know the pressure it goes into bypass. If you want to raise the bypass pressure, a #10 washer behind the bypass spring is worth about 5 psi. Yeah, I've blown a few oil filters off when I was young. 6 quarts of oil on the ground is a shame.

 

[Nick359]

All of the oil ports in the pump and rear main are matched and the drainbacks have been ported.

It has a high volume pump and I turn 6500 rpms.

I put the accumulator on bc I have a stock pan and can't fit deep pan.

I never ran it hard the second time it was built, so I don't know if it still dropping pressure at higher rpms.

I have the engine on a stand in the garage. I am going to tear it down this winter and do everything myself. If the same rod is bad, there is probably something going on in the block.

The truck weighs 3800 without me in it. I ran 12.53@112 at 5k feet and over 100 degrees. The plan is to sell the truck with the 350 and put the engine in a car or my boat.

 

[chowdozer]

All of the oil ports in the pump and rear main are matched and the drainbacks have been ported.

It has a high volume pump and I turn 6500 rpms.

I put the accumulator on bc I have a stock pan and can't fit deep pan.

I never ran it hard the second time it was built, so I don't know if it still dropping pressure at higher rpms.

I have the engine on a stand in the garage. I am going to tear it down this winter and do everything myself. If the same rod is bad, there is probably something going on in the block.

The truck weighs 3800 without me in it. I ran 12.53@112 at 5k feet and over 100 degrees. The plan is to sell the truck with the 350 and put the engine in a car or my boat.

A stock pump will do you fine to 6500 rpm if you restrict oil to the top end. Which rod went bad? Number 1 and 2 rod journals will be the first one's to starve for oil.

Not sure why you can't fit a deep sump pan, a truck should have plenty of room unless you're dragging the frame rails. If you can't fit a deep sump pan, get your welder out and make some kickouts on the pan you have.

At 6500 rpm you have a lot of airborne oil too. Consider a windage tray minimum and maybe a crank wiper.

What height did the shop set the oil pickup too? Should be 1/4-3/8". To measure it, put a piece of clay in the oil pan, throw a piece of cellophane over it and bolt it on. Unbolt the pan and measure the thickness of the clay.

 

[Nick359]

The #3 rod went bad.

I put a crank scraper in it and the block was studded for a windage tray.

I put the pan on and verified the pickup height at 3/8" with clay.

The first shop was jerking me around, so I am not ruling out improper assembly. They put more effort into avoiding the problem than fixing it. I should have known better, but I listened to them. I am just build cars for fun, and they do it professionally. I was afraid to assemble it, because I didn't know how to check all the clearances for the longer stroke.

The second shop told me to be wary of the longevity of the 383. He said I should build a 400. Since I had a lot of money in the engine already, we decided to redo the 383.

The engine is out and I am off on Sunday. I will pull the pan and see what is going on in there.