My motor is smoking!

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mullinax95

mullinax95

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OK I had some bad heads on my 273 in which the valves were not sealing properly and the valve guides would allow the valve to wobble back and forth. This is a motor that supposed to have been rebuilt in July of 06. So I had some casting 302 heads redone with a Comp.valve job and installed them. The cranking compression with the old heads was 115 (highest) and now with the new heads it is 149(highest).

Now the motor is smoking!

I realize with the heads working correctly that the rings are working harder than they ever have.

I also realize that the headers probably has oil and gunk built up and needs to be burned off but how long does that take? I have been driving around town with no smoke issues (that I'm aware of) but yesterday I got it out on the interstate and drove about 20 miles one way and then 20 miles back. I would look in the rear view as I went along and really couldn't tell if it was smoking going down the interstate or not. But when I pulled off the interstate and came to a stop to turn it was smoking bad! I got to the house and reved it up a little and blue smoke came out of the exhaust.

Anyone ever had this experience?
Does the exhaust need to burned out some more?
Or is it just the rings gone bad?
I have over 100 miles since I installed the new heads.
 
Are you sure it is blue smoke and not gray? Checked your oil to make sure it does not smell like it has gas in it.
 
KSP said:
Are you sure it is blue smoke and not gray? Checked your oil to make sure it does not smell like it has gas in it.
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Ok I just checked it and the dipstick oil does not smell like gas. The PVC is new and the opposite valve cover has a breather oil cap.
 
Sounds like you are on the right track with the rings. I had a valve job done on a 318 that was burning oil. After I got it back together it still smoked because of the better sealing valves on the worn rings.
 
Does it smoke when you accelerate or deaccelerate? If it smokes on acceleration, it's most likely rings. If it smokes on deacceleration it's valve guides or a leaky intake manifold gasket.
 
ramcharger said:
Does it smoke when you accelerate or deaccelerate? If it smokes on acceleration, it's most likely rings. If it smokes on deacceleration it's valve guides or a leaky intake manifold gasket.
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I have looked in both cases and I can't see any smoke. If it is smoking in either case it is not enough for me to see as being the driver. But yesterday as I came off the interstate I could see it smoking then for sure while I was at a dead stop idling. I dropped by my moms house which wasn't that far away and I reved it up and it smoked then but was not as bad.
 
bobscuda67 said:
Sounds like you are on the right track with the rings. I had a valve job done on a 318 that was burning oil. After I got it back together it still smoked because of the better sealing valves on the worn rings.
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I never noticed any smoke before I added the new heads is what is so funny but like I said the rings might not be good enough to with stand the higher cylinder compression that the fresh heads are causing.
 
mullinax95 said:
I have looked in both cases and I can't see any smoke. If it is smoking in either case it is not enough for me to see as being the driver. But yesterday as I came off the interstate I could see it smoking then for sure while I was at a dead stop idling. I dropped by my moms house which wasn't that far away and I reved it up and it smoked then but was not as bad.
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I think you may have gotten the exhaust hot enough, far back enough, on the interstate to burn out the remaining oil.
 
Back when I was a kid I had a 70 Chevelle and it burned oil bad. I ran it that way for a month before I bought a good used 350 from a buddy and put it in. The exhaust system was so full of oil build up that at first I thought there was something wrong with the new 350 because it smoked as bad as the old engine. Took several days of driving to burn out all the oil residue. Finally went away after about a week.

Hope this is your case too but like you said doing a valve job on worn rings can cause this also. I'd say give it a week to 10 days to burn out any residue and if it's still smoking you know it's the rings.
 
If your rings were being overwhelmed by compression you would have blow-by. Are you using the same intake? Did you use rubber gaskets or RTV at the end rails? You could be pulling oil in through the intake ports. Remove the breather with the engine running and plug the hole in the valve cover. You should feel vacuum build. Does the smoke stop?
 
C130 Chief said:
If your rings were being overwhelmed by compression you would have blow-by. Are you using the same intake? Did you use rubber gaskets or RTV at the end rails? You could be pulling oil in through the intake ports. Remove the breather with the engine running and plug the hole in the valve cover. You should feel vacuum build. Does the smoke stop?
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Are you using the same intake?
Yes but it was machined down to fit the heads that were milled down to clean them up.

Did you use rubber gaskets or RTV at the end rails?

I used a large 1/4 bead of RTV at the end rails. I got a Felpro cam change gasket kit from Summit racing and it comes with steel intake gaskets. Could this be the problem instead of using the nicer intake gaskets that Felpro makes?

I removed the oil cap/breather and put my hand over it with the motor running about 3 days ago and did not fell vacuum pulling on my hand. The PVC was still hooked up over on the other valve cover if that makes a difference.

Heads 006.jpg


Heads 008.jpg
 
Did you seal the intake ports of those steel shim gaskets with something? I allways use the stuff from Loctite that comes in a can with a brush. Blueish/purple looking stuff. I forget the name of it.
 
fishy68 said:
Did you seal the intake ports of those steel shim gaskets with something? I allways use the stuff from Loctite that comes in a can with a brush. Blueish/purple looking stuff. I forget the name of it.
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No.

I did a cam change about a year ago and used the above steel gaskets and had no trouble with them. But this time knowing that the heads and intake have had work done to them I was :scratch: about the steel gaskets this time.
 
Yep, composition gaskets are generally better. Or at least I've had better luck with them anyhow. Give your intake a re-torque, and try to determine just how much oil you are burning.

If you got no crankcase vacuum, then either you are on the right track with the worn ring theory, or your PCV system has issues. I know you put on a new PCV valve, but I've had bad ones (esp FRAM) new.
 
this is a clasic problem when you do a value job with out replacing the rings on decelation the carb is closed and you get a vacuum in the hole intake system and the oil is pulled past the weak oil ring in the old days this was a very common problem with people that did not want to spend the extra money to do it right and at my shop we would not do just a value on high milige engines but that just my $.002 worth
 
340demon said:
this is a clasic problem when you do a value job with out replacing the rings on decelation the carb is closed and you get a vacuum in the hole intake system and the oil is pulled past the weak oil ring in the old days this was a very common problem with people that did not want to spend the extra money to do it right and at my shop we would not do just a value on high milige engines but that just my $.002 worth
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I was told when I bought the car that the motor was rebuilt and a year later dropped in and fired up in July of 06. I bought the car in October of 06. Sure enough when I bought the car the motor was very clean and looked new. I would say that the motor does not have over 30,000 miles on it max. Its just hard for me to understand that it would be the rings but if the motor was built anything like the old heads...no wonder it is smoking.


I retorqued the intake to 45 ft/lbs instead of the stock 35 ft/lbs ( I have ARP intake bolts) and fired it up. It's smoking now while idling with the motor warmed up. It more than likely would have smoked retorqued intake bolts or not. If I goose it a bit a cloud forms at the rear of the car.

I guess it's time for me to find a 318 or 360.
 
408 stroker!!!! I think this is the way I'm going. sounds like you can get a lot of power out of those engines.
 
71DartGuy said:
408 stroker!!!! I think this is the way I'm going. sounds like you can get a lot of power out of those engines.
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Yeah that would be nice!

They do produce some mind blowing power. The 3.79 crank is the way to go form reading on here. Less stress on the block.

But I got a price to have one built not to long ago and it blew me back in the chair!

They want a small fortune for the crate storkers also.

I'll more than likely try to find a straight up 360. I got a friend of mine that might be able to round me up one.
 
Tell him to find 2!! I'm just about done with all my suspension work so finding a good donor will be next for me. On a sidenote, I called a guy up here in G'ville a couple days ago and he has 2 a-body 4 speeds for sale. he wants 200 a piece. Didnt know if you'd be interested since your local. Oh, he also has a 360 roller motor, I think its a 95 model.

Mike
 
71DartGuy said:
Tell him to find 2!! I'm just about done with all my suspension work so finding a good donor will be next for me. On a sidenote, I called a guy up here in G'ville a couple days ago and he has 2 a-body 4 speeds for sale. he wants 200 a piece. Didnt know if you'd be interested since your local. Oh, he also has a 360 roller motor, I think its a 95 model.

Mike
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Will do.

No I don't need a transmission but I'll keep that in mind.

Roller motor huh?

I think I might need to stick to the old school motors since I have new heads that I can take off the motor I have and put them on another motor.
 
Yeah thats the way I'm going, 85 or later cause they just seem easier to find parts for. I would definitely use those heads considering the work and money you have in them
 
Sorry to hear about your problems after you just went through all the trouble to put some good heads on there. When you had the heads off how did the cylinders look? With 30,000 miles those cylinder walls should have looked like new. You should have still seen the cross hatch pattern with no lip at the top. We know the heads you used to have on there were not rebuilt but maybe the bottom end was? I'd pull that intake and see if oil is in the intake ports of the heads. If so then you are sucking oil in from the intake to head gasket. Worth a look. Could be intake gasket and now oil is laying around in the exhaust causing lots of smoke.
 
340sFastback said:
Sorry to hear about your problems after you just went through all the trouble to put some good heads on there. When you had the heads off how did the cylinders look? With 30,000 miles those cylinder walls should have looked like new. You should have still seen the cross hatch pattern with no lip at the top. We know the heads you used to have on there were not rebuilt but maybe the bottom end was? I'd pull that intake and see if oil is in the intake ports of the heads. If so then you are sucking oil in from the intake to head gasket. Worth a look. Could be intake gasket and now oil is laying around in the exhaust causing lots of smoke.
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I could still see the cross hatch pattern very slightly and there is a very thin lip at the top of the cylinders. I have my doubts about this engine ever been rebuilt in 06 now but I talked to the engine builder and asked a few questions. He was rude and acted like he didn't have enough time answer a few questions. The only questions I had at the time was what was the lift range of the valve springs. But he told me that the motor was rebuilt and fired up in July of 06 so I really don't know for sure.

I might take the intake off and see. I know that it is getting worse fast whatever is happening.
 
I think if you take the intake off and its dry the next step is to pull the heads and see if its a head gasket issue. If its neither of those then it has to be rings. Again sorry about your engine.
 
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