New 383 high oil consumption

[Daveo91Burb]

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I’ve been hoping for something simple for a while now, have actually been in denial. But I can’t deny 1/3 to 1/2 quart in 300 miles any longer. Funny thing is plugs do not look oil fouled to me at all, and the (hot) compression is good and consistent in all cylinders (approx 180 at three hits and 200-210 at five hits). And there are not clouds of smoke going down the road, even when I get on it with high load. It will puff smoke if I gun it at idle, though.

Only thing I can think of is oil rings are wrong for the application, installed wrong, or didn’t seat correctly. I followed the instructions that came with the Hastings set to a T. First start up I didn’t do anything special for break-in, but everything I’ve read said you don’t have to with roller cam. First start up was on an engine stand with a carb. I had water in the water jackets, but it wasn’t circulating and it was steaming out the water neck after the less than 2 mins of running I did. There’s a back story: I had to switch machinists mid-build. The first one was hitting the sauce pretty hard and he had about five missed deadlines. He also bought pistons that would have given me 10:1 CR with vortec heads. So I found a new machinist and bought some KB pistons that lower my CR half a point. Second guy, who has a good rep building high end motors, said the rings would be fine with the new pistons but now I have some doubts.

Anything else I should check before I start pulling the motor and tearing it down? Any other theories of what’s wrong?

 

[shiftpro]

How many miles now Dave?

 

[Daveo91Burb]

Only about 1k. Too soon to tell?

I’ve taken it out in the rolling hills a few times and gotten on it hard - read that it could possibly seat the rings doing that. Didn’t seem to help

 

[77 K20]

What oil did you use for break in?

 

[Daveo91Burb]

What oil did you use for break in?

Nothing special, I believe it was Chevron Delo 10w-30. I changed oil 300 miles ago and used Mobil 1, 5w-20. Also eliminated the factory oil cooler, stalled a standard oil filter adapter and went to the 2 qt AC delco filter.

 

[Frankenchevy]

I do know you don’t want to run synthetic in anything until the rings have seated/worn into the cylinder.

 

[QBuff02]

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I’ve been hoping for something simple for a while now, have actually been in denial. But I can’t deny 1/3 to 1/2 quart in 300 miles any longer. Funny thing is plugs do not look oil fouled to me at all, and the (hot) compression is good and consistent in all cylinders (approx 180 at three hits and 200-210 at five hits). And there are not clouds of smoke going down the road, even when I get on it with high load. It will puff smoke if I gun it at idle, though.

Only thing I can think of is oil rings are wrong for the application, installed wrong, or didn’t seat correctly. I followed the instructions that came with the Hastings set to a T. First start up I didn’t do anything special for break-in, but everything I’ve read said you don’t have to with roller cam. First start up was on an engine stand with a carb. I had water in the water jackets, but it wasn’t circulating and it was steaming out the water neck after the less than 2 mins of running I did. There’s a back story: I had to switch machinists mid-build. The first one was hitting the sauce pretty hard and he had about five missed deadlines. He also bought pistons that would have given me 10:1 CR with vortec heads. So I found a new machinist and bought some KB pistons that lower my CR half a point. Second guy, who has a good rep building high end motors, said the rings would be fine with the new pistons but now I have some doubts.

Anything else I should check before I start pulling the motor and tearing it down? Any other theories of what’s wrong?

The plugs actually look ok. depending on timing and fuel type. But the concern about the oil consumption.. a couple of things to note. And in my opinion is the engine (rings) is still not broken in yet due to oil type and grade. I just rebuilt the 454 in my truck last year and used brad penn break in oil (for comparison) and then switched to Valvoline vr1 20w50 with about a half a bottle of zinc additive at the change when I hit right around the 200 mile mark. (Flat tappet cam) My engine used about a quart in the 1st 150 miles and then leveled off and didn't use but a little more in the next 50 miles. I had some puffing of smoke in the first 50-75 miles of running it but that slowly went away. You say you put in Mobil 1 5w20 which if I'm not mistaken is a synthetic oil, and if you were still having problems with oil consumption at the time you changed the oil, certainly would've been the last thing I put in the engine. Your compression is good, so I wouldn't say the rings are damaged, but depending on tolerances in the cylinders, I'd say need more time to seat. If it was me, but I'm not a mobil1 or Pennzoil fan at all. I would dump the oil in favor of a classic "dino oil" of Valvoline 10w30 or shell rotella 10w30 and change the filter and run it for a 100-200 miles and see what happens. I bet your oil consumption drops off. We could get into piston to wall clearance, ring types, plateau honing, standard honing, type of machining and all sorts of internal goodies. But if the guy that built it is reputable like you say, I would think he would have made sure the parts and pieces were compatible and clearances were set how they should be. But back to the problem- If it was in my truck, I'd get that oil out of it in favor of a conventional oil and drive it for a few hundred miles before going back into tear down mode and see what happens. All things considered, if everything else is good the worst you're out is a half dozen quarts of oil and a filter. Cheaper than going back into full tear down mode, which is worst case scenario. Best case, the oil consumption goes away and it's off to happy motoring.

 

[Daveo91Burb]

The plugs actually look ok. depending on timing and fuel type. But the concern about the oil consumption.. a couple of things to note. And in my opinion is the engine (rings) is still not broken in yet due to oil type and grade. I just rebuilt the 454 in my truck last year and used brad penn break in oil (for comparison) and then switched to Valvoline vr1 20w50 with about a half a bottle of zinc additive at the change when I hit right around the 200 mile mark. (Flat tappet cam) My engine used about a quart in the 1st 150 miles and then leveled off and didn't use but a little more in the next 50 miles. I had some puffing of smoke in the first 50-75 miles of running it but that slowly went away. You say you put in Mobil 1 5w20 which if I'm not mistaken is a synthetic oil, and if you were still having problems with oil consumption at the time you changed the oil, certainly would've been the last thing I put in the engine. Your compression is good, so I wouldn't say the rings are damaged, but depending on tolerances in the cylinders, I'd say need more time to seat. If it was me, but I'm not a mobil1 or Pennzoil fan at all. I would dump the oil in favor of a classic "dino oil" of Valvoline 10w30 or shell rotella 10w30 and change the filter and run it for a 100-200 miles and see what happens. I bet your oil consumption drops off. We could get into piston to wall clearance, ring types, plateau honing, standard honing, type of machining and all sorts of internal goodies. But if the guy that built it is reputable like you say, I would think he would have made sure the parts and pieces were compatible and clearances were set how they should be. But back to the problem- If it was in my truck, I'd get that oil out of it in favor of a conventional oil and drive it for a few hundred miles before going back into tear down mode and see what happens. All things considered, if everything else is good the worst you're out is a half dozen quarts of oil and a filter. Cheaper than going back into full tear down mode, which is worst case scenario. Best case, the oil consumption goes away and it's off to happy motoring.

Thanks for the info and thoughts - good stuff. I’m definitely realizing my mistake now with the Mobil 1. I guess I thought the 400-500 miles I already had on the motor with Dino oil was sufficient and I also was hoping it would help the situation not make it worse. Bad assumptions. I’m going to dump it and put in the Rotella or Valvoline and go from there. Funny thing is I’m not a big fan of synthetic for older motors that weren’t designed for it. My ‘76 vette has a 355 that I put together myself (flat tappet) and I only run Lucas or Joe Gibbs hot rod oil that is conventional. I’m going to go back to conventional for this motor and may keep it that way.

I’ve also thought about a quart of Marvel Mystery Oil when I change the oil. Any thoughts on that?

 

[DoubleDingo]

I'm guessing the 5w20 is too thin. Even the new cars are having oil consumption issues with the thin oils. The thinnest I've run in my square was Rotella T-6 5w40 because that was all I had when I replaced the heads to vortec. That's the oil I run in my Forester, and it doesn't burn a drop. The truck didn't burn any or use any while it was in there, but it was mainly for breaking in the new parts. But I did switch to the recommended weight 10w30 after about 500 miles. With your engine being new MMO isn't needed, but you could run it for a 100 or miles before an oil change to keep things clean. I run MMO in all of my vehicles like that. I have even done an oil change in my Forester, added some MMO with the intention of changing the oil in 100-300 miles to clean out the turbo oil passages. Since I ended up not going out of town like expected, I ran it for a week in town, and the oil was pretty black.

So try running 10w30 something heavier and see if the oil consumption stops.

 

[Frankenchevy]

I agree with the 10w30 Dino. Some oil “experts” say 5w30 is too much of a spread for conventional oil and it shears and/or breaks down quicker.

 

[richard A lindner]

Could be valve seal or a valve guild out of spec

 

[yevgenievich]

Mobile 1 5w40 would likely be better vs 5w20 for it. My TA gets 5w40, wagon runs on 5w50, and suburban been decent on 15w40 rotella(non roller)

 

[Daveo91Burb]

Thanks all for the input. Just to be clear this is a roller cam. L31 stock vortec cam, lifters, pushrods, spider/retainers, etc. to be exact. And CompCams roller tip rockers, 1.6 ratio.

I'm guessing the 5w20 is too thin. Even the new cars are having oil consumption issues with the thin oils. The thinnest I've run in my square was Rotella T-6 5w40 because that was all I had when I replaced the heads to vortec. That's the oil I run in my Forester, and it doesn't burn a drop. The truck didn't burn any or use any while it was in there, but it was mainly for breaking in the new parts. But I did switch to the recommended weight 10w30 after about 500 miles. With your engine being new MMO isn't needed, but you could run it for a 100 or miles before an oil change to keep things clean. I run MMO in all of my vehicles like that. I have even done an oil change in my Forester, added some MMO with the intention of changing the oil in 100-300 miles to clean out the turbo oil passages. Since I ended up not going out of town like expected, I ran it for a week in town, and the oil was pretty black.

So try running 10w30 something heavier and see if the oil consumption stops.

Yeah, I'm thinking 10w30 Rotella now. I agree with @Frankenchevy about the spread between the winter weight vs summer weight. I like to try to minimize that spread since I've heard that concern many times in the past. I'm about half a quart low right now so I may top off with MMO and drive it a bit as you suggest, then change the oil.

Could be valve seal or a valve guild out of spec

Possible, but I think one spark plug would be worse than the others and/or I'd be puffing blue smoke on cold start up?

 

[Daveo91Burb]

Well changed oil and filter this weekend. 6 qts of Rotella T4 (conventional) and 2 qt AC Delco oil filter. We'll see what happens.

 

[Matt69olds]

What are you running for valve covers? My brother in law bought some really nice cast aluminum valve covers for his 455. I guess I should clarify, the machining and casting look top notch, my only issue is where the cast the hole for the breather and PCV valve. It’s directly above one of the pushrods, it basically squirts oil directly into the PCV valve. On the other side of the engine, it will fill the breaker element with oil after a couple minutes run time. The engine didn’t use a drop of oil before the valve cover swap, now it’s a smoky leaky mess. I told him he needs to either put the stock stuff back on, or fabricate some baffles to keep the oil out of places it isn’t wanted.

If your engine has the PVC vacuum source located in The carb plenum, every cylinder could be burning just a little oil. Maybe that’s why all the plugs look clean. Is the PCV valve hose oily?