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Puff of blue smoke at shifting of gears
My 427 FE S/O has 7500 miles, I noticed that if I gun the car in from 1st to 2nd gear I will see a puff of blue smoke at gear shift 1st to 2nd and also 2nd to 3rd. While I have not tested the compression of this engine it does not show any evidence of burning any oil or diminishing compression. Any thoughts? I hope this does not mean I will need rings any time soon...:confused: I use CAstrol 10-W-40 non synthetic oil and Fram filters.
tks Basque1 |
My bet is on the valve seals....
What kind are you using and how old are they? |
Don't know I have the car since feb.
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Doesn't have anything to do with it, but I'd ditch those Fram filters while your at it. They are generally considered inferior. (Do some searches for oil filters on this site and Fram is really one of the only filters most people consider to be crap).
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Brent, what would be some other signs that would lead to a bad seal. I might have a similar problem. Should there be oil on top of the valve? With Weber's I can see the valve if I take the carb off.
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The typical signs of bad valve stem seals are a puff of blue smoke on a restart or a wisp of blue smoke during prolonged deceleration (max vacuum).
Run it up to reasonably high rpm in 3rd gear and lift off the throttle and let it coast down in gear. You might need someone to follow you since the view in our mirrors is neither steady nor panoramic. |
Sounds like a valve seal, but could be intake gasket leak. R U sure its not using any oil? How do the valve stems look?
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Quote:
Usually new engines don't have valve seal issues because we've gotten away from running the old o-rings and umbrella seals. However I've seen a lot of old cars puff on an upshift. |
good rule of thumb, if you're smoking on acceleration look to the rings, if smoking on lift/upshift/downshift look to the valve seals.
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From a basic view of the whole shootin match, you are going to do either a top end or all in.
So, do the tests. Leak down and compression. Speculation is fine if there is some sort of contest, but you are going to do the work, get the data so you have a target. :D :D |
One thing I would do before I went to too much trouble.....
Yank a valve cover off and see how much oil is going to the top end when you give her a little gas... I like to run about a .065" oil restrictor to the cylinder heads on the FE's....otherwise you could get a whole lot of oil up there. You could possibly have a flood under a full throttle condition and it would make it easier for a valve seal to suck a little oil down. |
It's puffing under vacuum. My bet is on stem seals if its on both pipes. Probably filling the valve covers up or the seals are getting marginal. Usually intake gaskets are more gruesome when they fail - heavy oil consumption and poor idle. If you are seeing oil or heavy residue on top of the valve it's a sure sign of guide and/or seal issues.
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Do you have the oil deflector/drainback plates under the rocker assys?
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Have you over revved the motor or hit the rev limiter?
BAsque 1 If the smoking is only on shifts and not startups also, it could be mechanical. This also depends on which valve stem seals are in the heads.
Some guys still use the old umbrella style and they weep down the valve stem and into the cylinder. They are cheap and easy to buy. When vacuum is applied to them, the oil is sucked through faster and you get a smoke trail alot of the time. Pos seal ones have a circle clip on the top of the seal to stop oil from going down the stem, even under vacuum. Alot better seal. Leak down test and compression test are not much help in this case. As far as an oil oriface in the heads,DEPENDING on the rockers, .085" is for street motors. .065" is for race motors on the track. I tryed .065" with an hvhp oil pump and found that a blueing was happening on the adjusters and tips of the pushrods. The other thing is the spring produce alot of heat. They need to be cooled off also. My heads are flooded to the holes of the intake manifold. I also have a 12 quart system. I have Erson rocker setup and don't run tins for return flow of the oil in the heads. This was on cast FE heads and my Shebly ones now. Run your motor 1-1.5 quarts over full any way. Over 30 years I have never seen a motor destroyed from too much oil, just not enough oil to the correct places. Have to also remember this is an FE Ford motor not a SBC one. The reading you see at the guage IS NOT what the pressure reading is at #4 and #8 rods or the heads, unless the motor is a sideoiler. JMO Rick L. |
I also have a new 427 windsor (1000 miles) i am getting a little blue smoke at idle and using a quart every 200 miles using vavoline 10-30 VR1 race oil. once the motor is hot and sits for a while it smokes alot at start up. this is a new motor all the valve seat seale could not be bad.Could it be a bad intake gasket sucking oil up into the combustion chambers then leaking into chambers when the motor is off? Mike
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Very possible...
But oil consumption of a quart of every 200 miles makes me think it's a ring seal issue. Was it dyno'd? |
I second the vote on rings. The 427 Windsor will punch the piston pin through the oil ring land. It usually seems to work OK, but I personally do not like that and avoid it whenever possible. It just makes any marginal ring issues into big ones. You might have some second rings upside down, or the oil expander is getting pinched in the groove, or???.
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I got the car back in February and I was told by the previous owner that he did not drive the car a lot and it shows. It was suggested to me by an FE authority that i might have dried out seals which now that are been used more often are leaking a bit. I was recommended to use Viton seals. I ordered them and soon to be installed. Stay tuned.
Tks guys for your insight. I wish I can get a more definitive answer to the hard to start after a spirited run----has been diagnosed as vapor lock. Cheers Basque1 |
Maybe you should lift your foot of the gas pedal when you shift and the tyres wont smoke so much !!!!!
Jokes aside...... for a new motor to use a little oil is quite normal especially since you are not really aware af how much attention was paid to detail when assembling the engine.Rememeber that a lot of guys replace the bolt on gaskets etc and think that they have rebuilt the entire engine.Sometimes its easier to just pull it out and rebuild the motor.John Also I would use nothing less than a 20W 50, these are not modern close tolerance engines. |
my new 427 windsor used oil and smoked i sent it right back to ford and they went through the motor (rings & bearings) honed the cylinders and ran it on the dyno 555 h.p. 548 lbs. torque does not use any oil and does not smoke and NO CHARGE FOR ANYTHING THEY ALSO PAID THE SHIPPING
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