Post 454 rebuild and oil consumption

[txaggie]

Howdy all,

We had our 454 pulled and rebuilt in the c20 suburban. We used king bearings throughout and converted to a hydraulic roller setup through Howard’s Cams. The engine was bored .030 over to 461 cubic inches.

So far I’ve put around 1000 miles on it and it’s consuming around .5 to 1 quarts every 300-500 miles. No smoke, no Pcv issues (Wagner with a catch can), and the engine has tons of power. We did a compression test and all the cylinders are excellent. Plugs look clean, etc.

Howard’s recommended a GP1 10w30 oil. Our oil pressure is awesome, (55-60 at cold idle) and then when warm 30 at idle.

Do these big blocks like thicker oil? Wonder if I need to change to 15w40?

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[Ricko1966]

I wouldn't be worried at this point give the rings time to seat,keep monitoring it it should start to taper off. If you don't see consumption decreasing,then worry. I'm also assuming you have the pcv hooked up correctly and 1 valve cover vented.

 

[txaggie]

I wouldn't be worried at this point give the rings time to seat,keep monitoring it it should start to taper off. If you don't see consumption decreasing,then worry. I'm also assuming you have the pcv hooked up correctly and 1 valve cover vented.

Correct. Wagner Pcv fixed orfice settings on the driver side cover, monster breather on the passenger side.

 

[bucket]

I wouldn't be worried at this point give the rings time to seat,keep monitoring it it should start to taper off. If you don't see consumption decreasing,then worry. I'm also assuming you have the pcv hooked up correctly and 1 valve cover vented.

You don't think a quart in 500 miles is a bit excessive, even for a very fresh engine?

I do agreed though, just continue to monitor the consumption and go from there.

 

[txaggie]

Engine shop said they will back their work so I’m not worried about that. Just the hassle and expense of ripping this engine out and being down again.

What are your thoughts on moving to the heavier oil? The machine shop did mention they don’t like synthetics (this Howard’s recommended oil is a semi synthetic). However curious if the heavy weight might help on consumption.

 

[Vbb199]

What was the piston ring gap

 

[txaggie]

What was the piston ring gap

Not sure. They put it all together as a long block. I supplied all the parts.

 

[mlsceo]

Heavier oil probably won't change consumption but won't hurt either, Give it a try if you're so inclined.

 

[Ricko1966]

I didn't want to start a big discussion about break in oils,because everyone has their own opinion. Mine is, I'd run Dino oil until the rings have seated and then switch to synthetic,if I was going to run synthetic. And monitor your consumption it should start going down.

 

[Fat 454]

I didn't want to start a big discussion about break in oils,because everyone has their own opinion. Mine is, I'd run Dino oil until the rings have seated and then switch to synthetic,if I was going to run synthetic. And monitor your consumption it should start going down.

yeah - I would "start" with break in procedure. Hopefully the shop will have given you a list of "do's and dont's" when you first picked it up. If the bores have glazed over, you will never get it back( ie it is the mechanical seal developed between rings and bore, not oil viscosity that will set performance ).
I would go back to the shop that did the work, and have a detailed discussion with them about how the truck was first run in. The first 20 mins can affect the performance ( or lack of ) for the rest of the remaining engine life. You may be able to get it back with a hone ( and new rings ) etc. - but I would get the shop that did the work to advise you on options...

 

[Ricko1966]

I built an engine once, bored,new pistons,rings,everything, it was all top notch and no machine work was skimped. Rings wouldn't seat for what seemed like forever it blew blue smoke,I was almost ready to try bon ami down the intake, and then they just decided to seat. No more oil consumption. Never happened again,still can't explain it.

 

[Craig Nedrow]

I run the thinnest oil I can, determined by mechanical clearances in your engine. I use Schaffer. Do not over fill the pan. I generally leave mine 1/2 qt. Low and watch my oil pressure. I go to great lengths to keep the oil off the crank, drilling two extra holes in the front of the block and one in the back. Internal engine back pressure inhibits ring seating. Look at Mark Jones post, he runs, it looks like, a Moroso pan evac system, which has excellent vacuum, but not street able. Here is my build with some pics that visually explains the previous post. https://www.gmsquarebody.com/threads/bbc-489-build.45389/page-3 Believe post 37 shows block mods.

 

[txaggie]

I built an engine once, bored new pistons,rings,everything, it was all top notch and no machine work was skimped. Rings wouldn't seat for what seemed like forever it blew blue smoke,I was almost ready to try bon ami down the intake, and then they just decided to seat. No more oil consumption. Never happened again,still can't explain it.

What’s weird about my situation is the engine is blowing no smoke at all and running great. Just keeps drinking a half to 3/4 a quart ever 300-400 miles.

I guess I’ll try to get this thing to 2000 miles and see what happens. The machine shop said they’ll back their work if something is wrong.

Maybe I need to perform a leak down test?

 

[Rusty Nail]

I wouldn't be worried at this point give the rings time to seat,keep monitoring it it should start to taper off. If you don't see consumption decreasing,then worry. I'm also assuming you have the pcv hooked up correctly and 1 valve cover vented

This ^

*rings still seating*
Run it harder.

 

[Bextreme04]

What’s weird about my situation is the engine is blowing no smoke at all and running great. Just keeps drinking a half to 3/4 a quart ever 300-400 miles.

I guess I’ll try to get this thing to 2000 miles and see what happens. The machine shop said they’ll back their work if something is wrong.

Maybe I need to perform a leak down test?

I can't imagine a situation where an engine loses that much oil and doesn't smoke like a SOB or leave a LARGE puddle of oil everywhere it goes. My truck leaks a bunch, leaves lots of drops of oil everywhere I park... whole underside near the engine has oil on it.... maybe 1 quart every few months. My honda daily was using up a quart every month or two also and that is with ~250 miles a week of driving. It smoked like crazy because the rings had totally gummed up and stuck in the piston ring grooves. I pulled the head and pistons, put new valve seals in, installed new rings after cleaning everything up and running a ****** ball hone through it... no more smoke or oil consumption since.

A quart every 500 miles is A LOT. You are either leaking it or burning it. If burning it, you would be smelling and seeing it. Plugs would be VERY fouled.

For a fresh rebuild, I'll usually run break-in oil for the first 500 miles. Because its a roller cam, I would go out and do the partial acceleration and deceleration pulls for the first 20 miles with a few heat cycles. Then swap oil filters and cut it apart to make sure no big chunks of metal. Change out the break-in oil at 500 miles for conventional oil. Run conventional for the first 5000 miles and then switch to a synthetic.

I'm a little concerned that the shop that assembled your long block didn't provide a build sheet. Did they just throw in the parts you provided without any measurement or adjustment? You should be setting bearing clearances for the usage and desired oil viscosity. If you are running tighter clearances like .0015" - .0025" on the mains(Gen VI BBC production spec), then GM calls for a 5w-30 synthetic. If you are closer to .0030" and only drive in warmer weather... then go to a 10w30. If you have gone full racecar and are running .0035" or something, then you really need a 15-30 or 10w-40 depending on the weather.