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Topic: Can I do this??

in Forum: C3 Engines

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Can I do this?? (1/14)
5/25/10 10:43am

BlueX2

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Posts: 2168

So I have smoke coming out of my exhaust. I can't really tell if it's blue or black, but since the car is losing oil and there's none on the floor, I'm guessing it's burning oil. When I first turn on the car there is a cloud, and there is a nice puff everytime I down shift or excelerate.

History: The car is a small block 350, numbers matching. About five years ago I had the engine rebuilt. I know it was completely broken down and bored out at that time. The guy who was doing it had issues with the owner of the shop. The reuslt was that they had my car for a year, the guy got fired, and as part of the agreement with the owner, came back, put my engine together, and put it back in the car. I now know that the first part of the rebuild was done correctly, the slapping it together was not.

So from reading I think my rings might be bad. They were probably the cheapest that could be found in a hurry, and it was literly slapped together. Is that something that I can do? I do have basic knowledge of engines, I have done some work on them, and I can read and understand manuals. I just don't know if this requires special tools, can the engine stay in the car, am I getting in over my head??

Thanks all!

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Can I do this?? (2/14)
5/25/10 12:29pm

ebo

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Holland Patent, NY - USA

Vette(s):
#1 *1980 White, Red interior 14,000 mile #2 *1980 Red, Oyster interior 93,000 miles Resto project car, rebuilt to 383 stroker

Joined: 6/3/2008
Posts: 4421

There is a bit of work involved ut not rocket science. You most likley will have to do some honing to the cylinders. But there may be alot of while I'm in there...........

ebo

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ebo

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Can I do this?? (3/14)
5/25/10 12:49pm

Adams' Apple

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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

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You can re-ring with the engine in the car, but....why? Ken(ksyter) swapped the crank out of his car with the engine still in it...on the ground...in his yard!
My opinion is, I would pull the engine and do it right. There's no telling what else might be ready to take a doo-doo on it. The cylinders need to be measured for out-of-round & taper, as well as bore size, and then compared to the size of the pistons. It may be that the cylinders are too large(bore size) for the pistons. Cheap rings will cause it too, but normally won't live 5 years before having a problem.
I'd say pull it and start over...just my .02.....

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Can I do this?? (4/14)
5/25/10 1:00pm

BlueX2

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Well, five years doesn't really explain it. It was in storage for a few years, then it took over a year to paint, etc. So I figure that I have less than 200 miles on the car since the rebuild.

From what I'm reading, it appears that this is more than I can do.

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Can I do this?? (5/14)
5/25/10 1:10pm

Adams' Apple

Well now...that changes things a bit.
It could be that the rings have never even seated from the rebuild. Depending on what type they were, it may take even more steady driving to get them seated properly, if they even will at this point. Fresh engine re-builds will usually burn/use a little oil until the rings get seated...
Some quality moly/chrome moly rings take a long time(relatively) to seat properly, and even that depends on the quality of the surface in the bores, as in how they were finish-honed.
I might suggest at this point having a leak-down test done, and compare the leakage across the board on all cylinders. If one or two leak considerably more than the others, then it would be best to pull and start over. If they all leak about the same, then it may just need some driving miles to seat the rings better.
Does the engine run ok, other than the smoke?

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Can I do this?? (6/14)
5/25/10 1:49pm

BlueX2

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Thanks for the info Joel!

Yeah, the car runs great, very strong. I'm totally happy with it, lots of power - it just smokes and loses oil.

Again, no oil shows up under the car. It puts out a cloud when it first starts, and doesn't smoke as much after that. In tooking at it from the rear, the driver's side is noticable while the car is parked and driving down the road, and the passenger's side is just about nonexistant. It's more noticable during downshifting, but there is a steady small amount coming from the driver's side at all times.

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Can I do this?? (7/14)
5/25/10 10:19pm

Adams' Apple

Slim possibility that it has some damaged, or even missing valve seals...

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Can I do this?? (8/14)
5/25/10 10:35pm

ranger3

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North Charleston, SC - USA

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1975 L48 AT AC T-top

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I think Joel is correct suggesting valve seals. One of the telltales signs is smooke when you let off the gas. If you are running around 2000rpm, let off the accelerator and see smoke from the exhaust, that is usually a good sign of bad seals. hth.

Scott

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Can I do this?? (9/14)
5/26/10 9:46am

fp_vetter72

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COPPERAS COVE, TX - USA

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1972 corvette stingray convertible 2007 coupe

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I would have to say it's the valves leaking down, if it was the rings it would smoke all the time. The valve guides are probably bad or harder than woodpecker lips, this allows oil to drain down through the valve into the cylinder this gives you the blue smoke on start up, when you let up off the gas to shift the engine will suck through the guides and this causes the puff of smoke when shifting. You can change the seals in the car. My two cent's.

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Can I do this?? (10/14)
5/28/10 12:36pm

nosal1
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Dunedin, FL - USA

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1980 Corvette Torch Red with Gold metallic 370HP/350 CU.IN.Turbo 350 w/shift kit.Originally CA.Car with 305 CU.IN.

Joined: 3/21/2006
Posts: 262

I concur with both Joel and Scott on the valve seals and possibly the valve guides gone south. Compression test wet and dry should tell you which,Valves or rings..

I assume the cam and lifters were seasoned properly with a run up to 2200 rpm or better for a minimum of 15-20 minutes...and a ZDDP oil or additive used for flat tappet cams.
There has been a rash of cam and lifter failures of late due to lack of Zinc Phosphate in the present day oil. Roller cam engines do not need the ZDDP.Cam manufactures are now sending out with their cams and lifters a disclaimer about using off the self oil without ZDDP....

Good luck and have a great day........

Sal C

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Can I do this?? (11/14)
5/28/10 12:50pm

VetteSpecialties
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Mounds View, MN - USA

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70 LT1 coupe, 69 350 HP coupe, 69 390HP 427 coupe, 71 LS5 convert, 85 coupe, 93 coupe

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I have never actually looked at a woodpecker's lips, but I agree that the first thing I thought when I read your first post was poor or incorrectly installed valve seals. And the wet/dry compression test is the way to tell. Warm up the engine, pull the coil wire and remove the spark plugs. Check and record every cylinder's compression. Then spray oil in each cylinder and check again. If the compression goes up significantly after the oil, the rings are leaking, so plan on a complete rebuild. If it stays about the same, just pull the heads and take them to a competent rebuilder.

And yes you can do this.

Larry

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Can I do this?? (12/14)
5/28/10 3:15pm

Larry, You the man for adding the instructions to do the wet/dry test.I always assume Vette drivers know how to take apart and put together Vettes,which is not the case.I have been doing it since I was 13 years old and a few years with Chevrolet Corvette Plant in St.Louis and still building engines today,54 yrs. later.....

Have a great day all....... Sal C

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Can I do this?? (13/14)
5/28/10 6:06pm

BlueX2

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Thanks guys, I really appreciate the info.

Another thing I was told is that the car might not have the correct oil in it that it needs in order to go through the break in period. To be honest, I don't know what it had in it, and I was just told this past week to try something like a 10w40 for the first 500 miles or so. Like I told Joel, I think the car only had about 150 miles put on it in the last five years since the rebuild, so it never went though a break in period. At this point is it too late for that?

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Can I do this?? (14/14)
5/29/10 12:42pm

That is not true. While a proper break-in helps seal everything quickly, remember that new cars have a couple of miles on them when you get them, and you just drive them. There are oils that speed the wear in of the rings, they are not necessary. I use diesel oil for 500 miles to ease the cam beak-in, but that is probably over kill unless you have high valve spring pressures. I still lean toward poor quality or improperly installed valve seals.

Larry

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