smoking 360

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SLTruman

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I have a 360 motor that I've had rebuilt and it's got blue smoke coming out of both exhaust pipes, more so on deceleration. The sleaves were not honed because they appeared to be in good shape. The motor only has two or three hours running time on it since the rebuild. What things could cause it to smoke? It runs good. It didn't seem to smoke until it got warm. It's in a 76 duster that I have put a lot of money into. I want to sell the car and little things seem to be in the way. I've also mentioned on the transmission post sight that I need a synchronizer for third gear and need to know how much of a job that will be. It's a nice car...

Dale
 
Dale, who built the motor? I had an issue of this sort and after tearing it down we found the valve guides were never replaced. They had been knerled. You could scrape the oil deposits off the top of the piston with a putty knife. Yes it did smoke.
Small Block
 
If the valve seals were replaced, it sounds like the rings haven't seated. It should have at least been honed to take any polish out of the cylinders and allow the new rings to bite. I bought a 67 Honda 350 Dream that the engine was just rebuilt and it was smoking from start up and was run about an hour or two and was still smoking so the guy sold it (cheap) cause he was frustrated. I rode the bike 18 miles home and I ran it pretty hard, by the time I got home the rings had seated and no more smoke. Might be what you have.
 
If it smokes when you first start it up that will be the valve seals...if it smokes after you start it up and continues then it's the piston rings....blue smoke is oil...don't ever assume that something is in great shape....rebuild means honning..
 
When you say the sleeves were not honed, I assume you mean the cylinders. If that is the case, and you installed new rings, they most likely have not seated (and may not). Any time the rings are replaced the bored must be honed lightly to "break the glaze" or provide a uniform new surface texture to help the piston rings seat. The rings actually need a slightly rough bore surface as they "wear in" so to speak. Also, the ridge at the top of the cylinder must be reamed away completely or the top ring may be broken.

Smoke during deceleration is commonly caused by excessive valve guide clearance. Were the guides replaced? New seals will not help if the guides are worn excessively.

If either one of these procedures was skipped I would certainly not say the engine had been "rebuilt".
 
Well, I appreciate the responses from all of you. At this point, from what I can see after reading your comments, I'm not very optimistic about getting out of this very easy, or very cheap to say the least. I spent about three hours or so today going around the intake manifold, tightening up lose manifold bolts. I noticed oil deposits close to most of them, due to leaking around the edge of the manifold. I thought it might have been leaking oil into the combustion chamber and went around and tightened all of them. I let it run for about an hour afterwords and it was blowing blue smoke out both pipes quite heavily. It seemed that the warmer it got, the more it smoked. Before my mechanic put the heads on, he showed me the inside of the cylinders and pointed out to me that there wasn't a ridge at the top of them and that they looked good. If I would have known that they needed honing I would have had him do it. He spot checked the heads by turning them upside down with some kind of fluid in them and the valves didn't leak out so no major work done on the heads other than replacing push rods because of needing different length do to new crankshaft and larger 3/4 cam shaft. The engine sounds very tight, no rattles, no knocking, just very smooth running. I'd like to run the motor more and see if there's any change. My wife and I don't have much more money to put into this and I somehow need to get this to stop smoking in order to sell it. We've only been able to spend money on it periodically due to fixed income. A relative of mine did most of the work. He's built several motors before and I thought he was up on all of this. Anyway, If there's any mopar mechanics in the Big Rapids, Morley area that could help me fix this without needing a high dollar it would be nice. Once again, thanks for the information all of you have given me.

Dale
 
I was in Big Rapids 20 years ago when I was at Ferris State, lol

I live near Detroit now, sorry. If I was in Grand Rapids I would stop on by. Your a 2 1/2 drive one way

It still could be the intake gasket, if its not steel the gasket can tear and it never seal no matter how tight. I would pull the intake and look, I thought removing and replacing the intake was a 3 hour job, lol How come it took you 3 hours to check the intake bolt torque--just woundering?
 
Dodge Freak,

Ya, I spent about 3 hours, not just tightening, but cleaning the manifold as good as I could get it. It had a dark discoloration here and there mixed in with oil on silver paint. It looks like the gasket is some kind of pressed cardboard. I ran it in the garage last night again and it went about 45 minutes without smoking, so I shut it off. Today, I let it run for about 2 hours. There was no smoke when I first started it, but within a minute or so it started smoking again and never stopped for about two hours. When I gave it gas, it really came out heavy blue smoke. What I don't understand, is why didn't it smoke last night for about 45 minutes at all. There is no leakage around intake now that I got all the bolts tight. It would be nice if you were on to something about the intake gasket. I'll have to find someone to help me pull the intake off. What kind of a setup have you got down there? Do you do much engine work? I went too many years to Ferris. The degree didn't do me a bit of good as far as employment. Appreciate your input!!

Dale
 
Nice car, yeah Ferris wasn't so kind to me either. Had a great time at school thou!

What happens is the intake ports suck the oil in the ports and the hot engine burns the oil. I use a valley tray over the camshaft to limit the oil getting throw up to the intake along with Fel-Pro print-o-seal intake gasket with a steel core. It is made only for big 340-360 ports. Still with care the normal Fel-Pro's work good but they will split if torque too much.

Its only a guess but it happens, sometimes the intake doesn't seal to the head, the top does but there is a slight gap on the bottom, in those cases the intake needs to be milled. Intakes can even crack but that is rare. You need to lay the intake loose no bolts and look/check with a feeler gauge at the front of the intake ports. Sometimes the intake ends hits the block and won't go down far enough. Why RTV should be used and not those cork seals that come with the intake gaskets.

Here is my 340 before rebuilt, it runs great but I been getting 8 mpg, LOL. My 3.91 gears would not enjoy a 200+ mile freeway ride/ make that my gas card, the motor loves 4,000 rpm's on the freeways.



You know as soon as the intake is off, the ports will have oil inside and the gasket might be ripped. Edit, oh you do have the big port 360, well here is my favorite gasket but its not cheap--can be re-used at last for many years.

http://www.summitracing.com/parts/FPP-1213S-3/
 
I would do a leak down test both cold then warmed up. Then pull the heads and look at the pistons. My the way, what do the spark-pluds look like?
KP
 
Oh, you are using a pcv valve, check that for oil! If there is no shield under in the valve cover hole the pcv valve will suck the oil right up big time, pull the pcv and see if the oil burning stops!
 
Dale, that is a great looking car indeed. I wish you werent 2+ hours away. I'd help ya for free. But in all honesty, there's a good possibility the smoke is the piston rings from not honing the cylinders. If it's run longer under load (driven) it MAY improve, but I wouldnt put money on it. That is if the rings are indeed the problem.

So you plan on selling this car? If you still have it this coming spring, I would be willing to buy it even if the rings are the problem.
 
OK look at the full thread, got confused with the 273 motor burning oil.

Are you just running the motor while parked? The rings need a heavy load to help seal them. Yes the cylinders should have been hone.

On speedtalk I seen old school guys talk about using boni-am or comet to seal rings, ha ha. You use a table spoon down the carb while the engine is running! Does it work, most times nope but the theory is the girt hones the cylinders and seats the rings.

Pull that pcv valve valve off first!
 
dodge freak said:
OK look at the full thread, got confused with the 273 motor burning oil.

Are you just running the motor while parked? The rings need a heavy load to help seal them. Yes the cylinders should have been hone.

On speedtalk I seen old school guys talk about using boni-am or comet to seal rings, ha ha. You use a table spoon down the carb while the engine is running! Does it work, most times nope but the theory is the girt hones the cylinders and seats the rings.

Pull that pcv valve valve off first!
Click to expand...

I wouldnt doubt it...seems a little extreme though. hehe. But there's a powder made by total seal that does the same thing. Lots of good information on speedtalk. There are a couple clowns, but lot of people who know some serious stuff.
 
Hmmmm what type of ring did you put in? Cast iron or chrome moly? I have had a hard time myself getting the Chrome ones to seal without a rebore and cross section hone.
 
OK Guys,
I disconnected the pcv valve, no change. I don't know leak down test, or how to do them. I'm pretty sure the rings are not chrome. Once again, I'm not an engine mechanic so, anything major I'm gonna half to get someone else to help me through it. There are so many different kinds of intakes with plates or pellans? on the bottom and different fits to heads and such, I need to know which one is right before I try to do it myself. The majority of the oil does come out on acceleration once it gets warmed up. It smokes more now than it did before we put rings in it. It doesn't seem to me that it would smoke worse instead of better. Anyway, common sense isn't gonna get me through this one... The guy who did most of the work is a cousin of mine who's built some gm motors for mud runners, but he looked a little confused when doing my 360. In order to find him I'd half to borrow a coon dog and smell him out of the bushes in the woods somewhere...
 
This is a big if/maybe but if the rings are put on upside down they leak very bad. Doesn't seem likely. Then again most builders know to hone the cylinders to break the glaze on the walls.

Its either bad rings or that intake gasket or crack intake--very unlikely its crack.

Wounder how Ferris auto school is today, if its even there anymore, lol. Back when I was there the local people would drop their cars off to get worked on by the students. The owners just paid for parts, no labor. Took forever thou
 
Havn't found anyone I can trust around here to advise me except you guys in A-body. I still wonder why part of the time it didn't smoke since rebuild. I'm gonna take the intake off tomorrow and see what things look like underneath. One thing to mention that I've been thinking about today is that when we were getting rid of rocker clatter and changing push rods for correct length, the oil was flying freely to the inside of fender wells and next to intake gaskets. That was before I tightened intake bolts down and before I saw that they were lose. You say over torqueing intake bolts will crack the gasket. I may have over tightened them, but don't think so. I havn't checked spark plugs yet. Anyway, I'll see what it all looks like tomorrow...
 
Yeah its unlikely you over torque them.

Intakes can be hard to seal. I make a big job of it, I use that almost $40 gasket, clean the surfaces with brake cleaner--others like carb clean have oil base like. I hi-tack the intake gasket to the head only and keep the intake side dry--those gaskets are re-usable if done right. The gaskets stick to the heads and stay put forever until you throw them away.

Tightening the intake is a biggie, no room for torque wenches either. Its a feel you get, start in the middle and first snug them all up and work in small steps. Very surprising how long it takes. You think its tight and when you get back to the center you see its loose again. I aim for around 25-30 lbs only by feel.

Taking the intake off will tell you alot, be sure to drain the rad first.
 
dodge freak said:
Yeah its unlikely you over torque them.

Intakes can be hard to seal. I make a big job of it, I use that almost $40 gasket, clean the surfaces with brake cleaner--others like carb clean have oil base like. I hi-tack the intake gasket to the head only and keep the intake side dry--those gaskets are re-usable if done right. The gaskets stick to the heads and stay put forever until you throw them away.

Tightening the intake is a biggie, no room for torque wenches either. Its a feel you get, start in the middle and first snug them all up and work in small steps. Very surprising how long it takes. You think its tight and when you get back to the center you see its loose again. I aim for around 25-30 lbs only by feel.

Taking the intake off will tell you alot, be sure to drain the rad first.
Click to expand...

I thought I was the only one who doesnt use a torque wrench for an intake...LOL After doing a lot of them you definitely DO get a feel for it.
 
Well, I'm picking up where I left off Aug. 26th,

I had my mopar mechanic help me put the intake gasket on correctly with sealer where it's supposed to be. We fired it up and it doesn't smoke nearly as much as before, but still has some smoke coming out. One person asked me if the valve guides, and seals had been replaced. I don't think they were. I'm sure the new rings are cast iron. I was shown the cylinders and could see that there were no ridges on them so I don't think a new ring is probably cracked or broken. We bought a lot of parts at Advance Auto in Big Rapids and can probably come up with receipts on new crank shaft and bearings etc.
I've had my mopar friend work on electrical, changing over to electronic ignition. It's running good, but need to make sure that the wires are connected right in order for the alternator to charge the battery correctly. It needs a third gear synchronizer and a little brake work. One person mentioned that to seat the rings good it needs to be run down the road under a load. It's only been run on jack stands for a period of a few hours.
I am going to try to find a Michigan mopar forum and see if anyone in Michigan might be interested in buying it the way it is. We've got too much sweat and blood into this and need to see what we can get for it. POS Dakota, if you are interested, get in touch with me. My wife says we have at least 15,000. into the Duster including the 900. we paid for it. We don't expect to get anywhere near that, but want to get what we can.
 
Here are some of the pictures of the car!
 

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