Rings not seating on 63 SB

I now have approx. 1500 mi on total re-build (block was bored, new rings, seals, etc.) and still blowing smoke out exhaust when accelerating from stop. The machine shop that did the boring and supplied the parts for the job are not being very helpful or forthcoming in identifying this as a problem or what could be done to mitigate this smoke. The car has used approx. 1.5 quarts of 30 wt. oil in the 900 mi. since last changed. The machine shop had us change the oil and filter, after running for an hour after starting for the first time, then again at about 500 mi. before getting out on the road for a long run. I am not sure if this is a condition that needs more miles to settle in or if I should be doing something to try to assist the rings in seating. I remember Dad mentioned SAE30 ND (for 500 miles?). The machine shop assured me that the parts they supplied for the re-build are the ones that they've been using for quite a while and they've not experienced any problems in similar circumstances. The man who did the re-build for me has been doing this for many years, and he can't remember a Chevy SB taking this long to seat. Any knowledge to share, regarding this condition, will be appreciated- lib

Reply to
lib
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It looks like it could be cylinders not honed properly or wrong oil rings. Have you checked the compression? Did the guy who put it together check the ring gap in the cylinders when installing?

Have you pulled the plugs to see if it's all cylinders or just one that's oil fouled?

What work did you have done on the block?

Unless some> I now have approx. 1500 mi on total re-build (block was bored, new rings,

Reply to
Eugene Blanchard

If a shop did the work I would make them fix it...

Reply to
ZÿRiX

In my experience smoke on acceleration are valve guides leaking, smoke on deceleration (high vacuum) are rings. Perhaps the valve seals are the culprit. I'd check the spark plugs maybe you can figure out which cylinder(s) are the problem. I'd take it back to the shop and say "FIX IT"! You seem to have broken it in correctly...

Butcher '96 LT-4 CE

Reply to
Butcher

I agree, a puff of blue smoke on acceleration is valve guide seals leaking, constant blue smoke at idle is rings. 1.5 qt over 900 mi sounds more like rings. Hopefully its valve seals as they are a lot easier to change. Maybe someone forgot them?

Someone screwed up and now its a blame game between the machine shop and the guy who rebuilt it.

Reply to
Eugene Blanchard

Eliminate the little things first, check the PCV valve in the back of the carb and it's vacuum path. Run a vacuum test and pay close attention to how the gage reacts, cheap gage and instructions should come with it. With the oil fill cap off do you feel a pulse of air when it is idling? If nothing shows up there it's time to quit guessing and pull the plugs and take a good look at their condition. While they are out, run a compression check. If you don't get a noticeable blue puff of smoke at startup after it has sat for awhile it's not the valve seals. If you find one plug that looks like the culprit you could change those seals and see if it makes a difference, my guess is it may not.

By the way I did not say 30 weight non-detergent oil and I wouldn't be running that weight in it in the first place for break in after a rebuild, maybe even 20. Please note that this is no longer recommended for today's hotter running engines but worked on the engines of the early '70s and older. Information came from an old sprint car engine builder and it actually requires the rings to break the lubricating film between them and the cylinder wall. Your engine builder may not be relating to the age of your engine as well, he must be working on more modern engines that require a heavier weight detergent oil at startup.

Interesting read -

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Good luck.....

Reply to
Dad

You have a problem.... Could be valve seals, on DECELERATION you will see smoke from the vacuum created in the cylinder sucking oil past the seals. But it doesn't sound like it from your description.

My first suspicions are that the machine shop not getting a good pattern on the cylinder walls during the honing process. Too smooth of stones or bad crosshatch pattern or the combo of the two. And possibly boring to wrong specs. (oversize). But you should hear some piston slap when it's cold if the cylinders are too big for the piston/ring package.

Or the builder broke some rings, or didn't stagger the ring gaps. Or left off one or both of the thin oil ring support rings. Or hand filed the ring gaps OUTRAGEOUSLY too large. With today's metallurgy you shouldn't be having any ring seating issues at all.

Reply to
Ric Seyler

A long time ago, I honed a Ford V6 with one of those drill hone attachments and did an absolutely horrid job. When I got it all together, it didn't burn oil but it did take 1000 miles to seat the compression rings. It ran with little power for the first 500 miles and then you could feel the rings start to seat and the power come in - all 105 hp! Ran that car for another

50,000 miles without any engine problems.
Reply to
Eugene Blanchard

I pulled and checked all the plugs- all clean and not oily. I isolated the PVC valve and it appears to be working properly. I don't feel any pulse at the oil filler cap at idle. It appears the next step will be to have the timing adjusted to 8 deg. and see if it improves. If not, will have to test all holes. Fortunately, it runs strong, I can drive it when I want to, and the motor shouldn't be eating itself up until I get this resolved-lib

Reply to
lib

Finger pointing time with no resolution.

Reply to
tww1491

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