[54 Chevy]

I have a 468bbc that blows smoke out the tail pipe when it is started afer sitting for a while. It will also do this after cruising around normally for a while and then rapping the throttle good and hard. After that it takes a while before it will blow the smoke again. Its almost like it needs time for the oil to build up somewhere before it becomes an issue.

The motor was reportedly a crate motor and I was given receipts for it. So it doesn't have many miles on it. I have all of the specs if any of them come into question.

1. Why the time delay between smokey episodes. Where is the oil pooling up? Could it be pooling up in exhaust system?

2. Where is the oil most likely coming from? Rings not seated in yet? Ring failure? Valve guides in heads?

3. Can I check valve guide condition (slop) while leaving the heads mounted on the engine? How do I do this?

I plan to tear into it soon. I haven't done a leak down or compression test yet but it is one of the first things I plan to do.

Before I tear into it I would like to put together a game plan.

By the way... this engine is in a 66' Malibu Chevelle and makes over 500hp. It runs great except for the occational smoke.

Thanks for all of your suggestions.

[RegaMaro]

what colour is the smoke? how much?

How many miles are on it now and what type of rings does it have? Could be blowby if rings arn't seated or it could be runnign rich as well. Give it a little run down a safe vacant road and then shut it off and come to a stop and check your plugs. Compare your readings to here....

[wildman926]

I am interested in knowing the outcome, because my new motor is doing the same. It has less than 500 miles. I do notice that when it needs an oil change (change it when I can not see clearly on the dipstick until fully broken in), it almost stops completely. But after I change it, starts smoking again.

Like mine, it is probably not broken in yet.

[54 Chevy]

The smoke is white and it puffs out a 3foot diameter cloud when it happens. Then like I said, it doesn't do it agin until it either sits for a while or I drive normally and then quickly rev the motor.

The reason I ask about where the oil could be pooling up is it seems to me that if it were rings it would happen all of the time. Because of the pistons going up and down all of the time wouldn't it continue to blow smoke? Mine doesn't seem to do that.

I suppose it could pool up in the head some where and the quick rev of the motor somehow let it dump int to cylinders.

Could it be coming from the rings all of the time and pooling up in the exhaust and the the quick rev of the motor blows it out?

I'm only guessing here but I'm looking for pointers from someone who has been through this before. I'm not worried about having to dig into the motor I just dont want to do a lot of unecessary work. If someone comes abck and says "hey bonehead, let those rings seat in" then I'll know I'm just being paranoid.

Here is some information the the pistons, rings, and heads.

Pistons: Speed-Pro Hypereutectic Dome H581P
Rings: Speed-Pro file fit Plasma Moly # R-959065, Gap .022”
Cylinder Heads: Chevy 336781 Cast Iron 119cc
Valves: Speed-Pro Stainless Steel Severe Duty
Intake 2.19” #V-2059R
Exhaust 1.88” #V-2053R
Springs: Speed-Pro Heavy Duty #VS1581
Retainers: Speed-Pro Heavy Duty #VSR7015
Locks: Speed-Pro Heavy Duty #VK338R

By-the-way, thanks for the great spark plug reading link. Thats a keeper for the reference archives.

[MI2600]

White smoke usually indicates water.

[stuartc]

check the coolant level before and after driving. sounds like head gasket on its way out?put antifreeze init as well because that is good for finding leaks
cheers stuart
you can do the valve gudies leaving the heads on you can get a spring compressing tool for the valve springs just make sure you get the piston on top of its travel before you remove the sring
take the spark plug out and put a small rod in there so you can feel the piston coming up
or you can get a tool that fits in the spark plug hole and you put an air line on it and that holds the valves up
cheers stuart

[wildman926]

54 chevy - "hey bonehead, let those rings seat in" since you said "So it doesn't have many miles on it"

Seriously, I went through the same thing, freaking out about the same issue, and one of the knowledgeable board members here told me to relax. But is still gets me to wonder when it iwll stop, however, I need to drive it more. No problem with with power/performance though.

[scholman]

I would replace the valve guide seals.
When the engine sits the oil runs down the guide of the intake valve and then sits on the valve head until you start the engine. There is still oil in the guide area for a while and when you step on the gass hard or make the engine rev up fast this extra oil will be "sucked" doen the stem of the valve when it opens and again cause the engine to smoke. Once you have the oil burned out of there the engine runs fine. Then it all starts over again when you shut her off and then restart.

Scholman

[4onthefloor 2]

Originally posted by scholman
I would replace the valve guide seals.
When the engine sits the oil runs down the guide of the intake valve and then sits on the valve head until you start the engine. There is still oil in the guide area for a while and when you step on the gass hard or make the engine rev up fast this extra oil will be "sucked" doen the stem of the valve when it opens and again cause the engine to smoke. Once you have the oil burned out of there the engine runs fine. Then it all starts over again when you shut her off and then restart.

Scholman

I agree with you Scholman sounds like seals to me.

[54 Chevy]

I don't think its a head gasket problem because my coolant looks great and the level never seems to change. However, I do have an oil consumption problem that would seem to fit well with the valve guide suggestions.

The valve guide seals seem to be the prevailing theory. (on this site and from my bench racing buds)

Can the valve guide seals be replaced without removing the heads? Any tips on how to go about doing this? Any special tools required?

Any recommendations on which type and brand of seals to use?

Thanks a ton!!!

[wildman926]

I replaced my valve seals from the teflon positive type to the viton in hopes of curing the problem, and it helped a little.

HERE is what they look like.

Just get a air fitting adaptor for you plug holes, and us about 65 psi to keep the valve up. Use a hand spring compressor, and remove the valve lock, then retainer, and spring. Remove/replace the seals being careful of the valve tip being so sharp (found my original seals torn from this). Reverse same, then adjust valvetrain, and you are good to go.

[54 Chevy]

What would be considered to be an OK tolerance for valve stem slop with in the guides? Can I check this by using an indicator and pushing the valve stem back and forth? The collet, spring, and seal would be removed while doing this.

[poncho62]

Valve seals........................

[4onthefloor 2]

Valve seals........................not your rings use umberla seals. sorry fore the bad spelling my wife's not here to help me

[85 vette]

Does it puff smoke between gears? If you don't know have some one stand behind and watch as you drive away. If it puffs between gears it's valve guides. And by the way, white smoke doesn't only mean water. Try getting some oil in your exhaust manifold and you'll see some white smoke. Also, i've only seen this in diesel engines, if there is an air bubble in the fuel system they will run rough as crap and blow clouds of white smoke like crazy. I never saw a gas engine do that but anythings possible. If you changed your valve seals and it still does it then it's your guides. You might want to try knurling them.