The Stovebolt Site Forums The Shop Area Engine Shop 235 Rebuilt Engine Smoke

Hi all,
I had my stock 235 engine rebuilt. I am also restoring the truck. It has yet to be outside and driven. I noticed yesterday while working on an engine heating problem the engine is starting to blow blue smoke. I checked the dip stick and the oil level is at "add oil."

How can the engine now need more oil? I have no leaks, and the truck has not even been on the road yet.
Do I need to worry about the smoke?

Thank you!

Jon

Your rings are not seated yet and the smoke should go away after following this procedure:

http://www.hastingsmfg.com/ServiceTips/breakin_procedure.htm

Excessive idling after rebuild is not good for cam break in either which has it's own procedure for wear in of mating parts.

what Curt said, plus the apparent oil use may be - if you have a filter - the extra oil it holds wasn't taken into account when the engine was first filled

Bill

I don't think a rebuilt motor should be burning enough oil to notice. It will smoke when first started because of the oil used in assembly.

I just think it is strange the engine is at "add oil" when I have hardly run it. I put the required amount of oil in. There are no leaks and truck has been in garage for 9 months.

but remember Jon, the engine was dry when you put in the proper amount, nothing in the lines and up top yet - and do you have a filter? add the extra quart for that? if it had burned the quart you'd have been smoked out

Bill

The difference between wet (already running, new oil change) and dry (new engine) is about 1 pint.
How do you know you put in the required amount of oil? Are the pan or stick from another engine? Did you take a stick reading when you did this?
Smoke while idling may also be intake guides, especially if the drains aren't clear or the rockers are getting too much oil.
New pump? Oil pressure? What weight oil?

Sorry to get so weird about this. I guess its like having your first child. Over protective of all the work I have put into it.

Panic:
The shop that rebuilt the engine gave me new engine oil or break in oil. I will have to call them to find out again. The stick and pan are from the original engine...at least it better be.
I let the engine sit over night to drain the oil to the pan. Checked the stick and thats where it was at add oil. I think I either put 5 or 6 quarts in..and enough to comp for the oil filter.
I will add more oil and see what happens...I hope it is just that the rings have not set...

Thanks guys for the help...

Jon

Love Living in San Francisco! Got a notice in the mail about my smoking truck. I will have to drive the truck at night to break in the engine. Only have 70 miles on engine now.

A rebuilt engine that smokes bad enough you got a letter???? Something is wrong.

It might smoke for a few minutes after the first start up, but should clear up pretty quick unless maybe the exhaust system is burning out old oil.

Sounds to me like whoever built it may have broken a ring or two.

Would a compression check tell me if I have a broken ring?

I am unable to get out to the HWY to let er go until I drive through the city...

Compression test can't hurt and while you have the plugs out, look at them and see if they are oily. If you see any that are oily, black oily, make note what hole they came out of.

Shouldn't be on a fresh rebuild. If you find one or two oily plugs, then yhou have found the bad cylinders.

If it used lots of oil before tghe rebuild there may be some residual oil in the exhaust system and it may be burning it out.

If chrome rings were used there can be a longer break-in time.

Still shouldn't smoke bad enough to get a letter even if chrome rings were used.

I have used chrome rings many times and while they are harder to seat, they usually don't smoke like crazy.

Was this engine bored over size or just re-ringed?

Let me find that out on the rings. It smokes only at an idle and it is blue.
While on the highway it does fine.

Only at idle, not running down the road?

What all was done to the cylinder head? New guides, knurl them, new stem seals?

How bad is the smoke?

Hi Roy,
Yes, as far as I know everything (I trust) was gone through. I called the rebuild shop and the owner used regular rings not chrome. When I get some time I will pull the plugs and take a look at them to see hwo they look. Plus, When it stops raining, I will take a video of the smoke and post it on You Tube.
Give everyone an idea what I am dealing with.

Hi Roy and all,
Here are some pics of the plugs. 1-6 left to right.
Looks like 3 and 4 have oil on them the rest look dry.

Let me know!

Thank you

Jon

Did they bore the block and install oversize pistons and rings, or just clean the block and put new rings on old pistons?

Looks like 3 and 4 are your culprit cylinders. Those plugs should be tanned like the others.

Hi Roy,
The shop just cleaned the block honed and installed new pistons and rings. I will now be contacting him to see what he wants to do to fix the issue...

Thanks!

Jon

Good luck.

But cylinders 3 and 4 are too oily. Hard to tell about number 5. But they all should look like 1, 2, and 6.

Driving it more won't fix that problem.

Took truck out again and now it is at 100 miles. Pulled the plugs out and 3 and 4 are starting to look more like the rest of the other plugs.
Still get a puff of blue smoke right as I start up from coming to a stop at a stop sign. But after that there is no smoke.

I noticed also the oil level was down at half between full and add on the dip stick at 80 miles.

Jon

Keep your fingers crossed, but I would not worry until you have 1000 miles on it. Best of luck.

Thank you. We will see. Sucks having to take it out at night though

Shouldn't be smoking bad enough after a rebuild to have to take it out at night. Shouldn't smoke at all, even if chrome rings were installed.

Shouldn't use 1/2 qt of oil in only 80 miles.

Be more realistic to expect it to use a quart of oil in the first 500 to 1,000 miles until the rings seat.

My bet is broken rings on those two cylinders.

Have you run a compression test yet?

Hi Roy.
Was thinking about that but was told it would not tell me if there was a problem.

But what the heck?? I will do a check tomorrow. Give the wife something to do....she can push the starter

Thank you Roy for watching my questions!

Jon

It can't hurt, and if there are a couple of rings broken, it should tell you.

Good luck.

Another question. When it is running, if you take the oil filler cap off do you get a lot of "blowby"? Does it have the road draft tube and if so do you see smoke or vapor going out of it?

If rings are your problem you will have quite a bit of "blowby" or compression leaking by.

Another good test would be a leak down test on each cylinder. Apllying air pressure into each cylinder to see if ny are letting more air by the rings than the ones next to it.

Okay,
I will check. "Hotrod Lincoln" gave me some good thoughts on what to check as well.

Hotrod Lincoln is a good one to listen to. I ask him questions too from time to time. He's always good enough to listen and answer.

Give you all an update:
Took truck out last night and ran down the hwy for a total of about 64 miles.
I have yet to do a comp check.
When it first starts up there is no smoke. It runs great and no smoke on the highway. However, while waiting for a stop light to change, as I start back up, thats when it will send a small cloud of blue smoke. There is a total of 180 miles now on the engine.

That sounds a little like the oil being sucked by the valve guides. But it would also do the same thing after coasting down a long hill and then stepping on the accelerator to hold your speed.

Is it still going through lots of oil in a short time? (Ex 1 qt in 100 miles is too much on a fresh rebuild.)

I had an old vehicle once that I put another engine in and it smoked like the devil for a while. But it wasn't loosing any oil. Finally figured out that the exhaust system was oily from the old engine and it took a while for it to burn all that old oil out.

Roy,
Thank you for help.
I will keep checking on things.

Jon

Well not sure if you installed the rings, But if you did make sure the gap on all your rings is not in a line. They all need to be off set or they will not seal. I have rebuild a countless amount of Diesel engines witch have way higher compression and not one has smoked. Good luck.

I should have just had the guy paint the engine. It never smoked before I tore it down and it ran great....Oh well, I will get it right.
Thank you GrandpasTruck

The "lined-up rings" thing is an "old mechanic's tale", sort of like an old wives' tale. Rings move around the piston all the time, and the gaps do line up occasionally. In a matter of a few seconds, they'll be in a different position. I've watched that happen on a glass-cylindered research engine many times by freezing the piston motion with a delay-flash timing light.
Jerry

What you are describing sure sounds like oil getting past the valve guides, to me.

Took truck out last night again. There was alot less smoke at stops.
When the oil gets past the guildes or rings..can you explain why it seems to only do it at low speeds or an idle?
When I remove the head what should I be looking for? Will there be burn marks or grooves?

Thank you guys!

Unkl, At idle and low speeds the pressure (vacuum higher) is lower on the manifold side of the valve guide so the tendency for leakage is greater.When pressure difference is greater across an oriface(valve guide/valve clearance)the flow is increased.
But don't panic yet valve guide sealing can be improved without removing the head and you havn't given it a very long break in chance yet.
Make sure the operating temp is getting up to min 180 deg F,and work it hard as you can, high gear acceleration uphill, very little idling,etc.
Although the lower ring is the major oil control ring, the 2nd and top rings play a part in oil control and they are expanded by the higher gas pressures in the comb chamber when higher loading as in open throttle operation.
don't panic yet.
Maybe I'll have a war story later.

There should be a small O-ring on the top end of the valve as part of the retainer etc. I have no idea if you can see this when they are together. If they are missing you could have the problem. If the valve guides are really worn and the head is being flodded with a lot of oil, this would also cause the problem. I don't know all the details of your year of engine but some required a restriction on the feed to the rockers to prevent an oversupply of oil to them.