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Discussion Starter · #1 ·
Hello Guys & Ladies

Here is my problem in 1996 i bought a 350 Cubic Inch 300 Hp Crate from GM, I have had it rebuilt 3 times. Last time 2 month's ago i took it to a machine shop and had them stroke it to a 383.
From the second rebuild 2 years ago i have had blue smoke out the tail pipes, This only happens when i am letting off after having the engine under heavy load, The heads and all other components in this block are new, File fit rings kieth black piston's Comp Cam. 750 Holley.

It seems to me that the engine is not breathing properly, It looks to me that the pcv valve is pulling to much oil into the carb. On decelaration. Can this be possible.. This is beginning to frustrate me to the bone. Any help would be appreciated..


Cheer's Jim
 

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yup, happens all the time. Do you have a baffled valve cover?

IF not make one, if the problem persists, stuff some steel-woll in the baffle (make damned sure it won't fall into the motor). This will let the fumes through, and the oil will stay out!

K
 

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Discussion Starter · #3 ·
Thanx Killerformula

Besides the steel wool, Is their any other option like different valve covers? Aftermarket of some type that would be better than the stock ones i have tried 2 different sets of covers all with baffles.



Cheer's Jim
 

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yup, you definately want the ones with the baffles-

You can run two PCV's as well, if you want to even out the suction. Hook them on either side of your filter element. Fabrication required, each sold seperately.

K:thumbup:
 

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Hey Jimbo,
'You see the problem is that you are treating your car unfairly...it is blowing blue smoke because it is sad...the car wasnt used for over a year. The Camaro just feels depressed, show her some love and the problem will go away.'
But i promise you i wont go away

28 DAYS
 

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78Z said:
Hello Guys & Ladies

Here is my problem in 1996 i bought a 350 Cubic Inch 300 Hp Crate from GM, I have had it rebuilt 3 times. Last time 2 month's ago i took it to a machine shop and had them stroke it to a 383.
From the second rebuild 2 years ago i have had blue smoke out the tail pipes, This only happens when i am letting off after having the engine under heavy load, The heads and all other components in this block are new, File fit rings kieth black piston's Comp Cam. 750 Holley.

It seems to me that the engine is not breathing properly, It looks to me that the pcv valve is pulling to much oil into the carb. On decelaration. Can this be possible.. This is beginning to frustrate me to the bone. Any help would be appreciated..


Cheer's Jim
PCV shouldn't pull any oil into the carb.

Do you have baffles on your valve covers?

What is your maintenance record?

Are you beating this engine to death?

3 rebuilds in 8 years tells me either your machine shop has issues, or you are killing it.
 

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Discussion Starter · #9 · (Edited)
Brat Brat

Hello Brat

Is this your mechanical side talking..LOL Or you speaking from the heart..Sure hope your not Blowing blueee...


See Ya in 28 days

Hello Lonestar

I have had to have it rebuilt 3 times because the the front main bearing went after 800 miles,then after that rebuild it was doing the same thing it is now Blueeee Smoke.. So i had it stroked. And yet again Blueee..


PCV shouldn't pull any oil into the carb. Really i'm being told different, By alot of people.

Do you have baffles on your valve covers? Yes factory GM covers

What is your maintenance record? Oil & filter is changed every 500 miles

Are you beating this engine to death? Not at all.

3 rebuilds in 8 years tells me either your machine shop has issues, or you are killing it.

I drive it when it need to be driven, No abuse though.


Cheer's Jim
 

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Did you redo the heads the last time you redid the block?

Sounds like bad or defective valve guide seals.

You didn't say, but you do have a crankcase breather of some kind don't you?

Troy
 

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Discussion Starter · #12 ·
Hello Troy

On the first rebuild the heads where not tuched. So i assumed the heads where the problem and sent them to a machine show and had them redone this never halped at all. On the third rebuild i had them do everything again valve seals valve guides the works. No differance

I do have a breather on the valve cover PCV on one side and the breather on the other..Nothing seem to help.

I was told by a friend that these block where made in Mexico and the where tin cylinder walls then plated with{ nicasel } Have you ever heard of this. He is trying to tell me in other words the rings are scoring the cylinders due to soft walls.. And hard rings.

Cheer's Jim
 

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Yes, I have heard of that, but i've never run into it.

Sounds like you have every thing else in order.

If thats the case, after three trys, I would get another block.

Good Luck

Troy
 

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How bad is the smoke? Is it only on deceleration? How much oil does the engine use/burn?

If you do not have a baffleon your PCV you can stuck oil into your intake. You can buy rubber grommets that have a baffle built in. Mr. Gasket makes them (and some others) do a search on the Mr. Gasket site and you should be able to get a part number.

I wouldn't panic just yet, there could be a simple solution. What kind of transmission are you running? If automatic do you have the modulator hooked up? If so you might want to try to disconnect it and see if that eliminates the smoke if so you have a bad modulator. This would make sense if all three engine were doing the same thing.

How many miles are on this rebuild? Are the rings seated yet? If all the above advice from others dosn't help, I would pour a quart of tranny fluid in my crankcase and see if that will cure it (has been know to help seat the rings).

Royce
 

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Discussion Starter · #15 ·
Hey Royce

First nice ride you have their, I have a baffle under the pcv and also the pipe to the carb, the only one that is open is the oil filler.
I have a Muncie 4 speed transmission. And its only on deceleration

I only have 800 miles on the rebuild, And it has used about 2.3 liters. {Quarts} I have bumped the oil 3 time in this 800 miles and cut open the filters to see if i could notice any filings or anything out of the ordinary but nothing has shown up so far..
:thumbup:

Cheer's Jim
 

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Do you know what kind of seals they used on the heads/valves? Sounds like more of a seal/guide problem with the heads than anything else. Are these the same heads that hve been on the engine all along?

Don't rule out the intake manifol not sealing correctly either. Typically it will dun a little rough if that's the case (like a vacuum leak).

I would start with the manifold and then move to the heads. It doesn't act/sound like a ring/cylinder problem to me.

Thanks for the compliment on the car.

Royce
 

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Due to the fact that it is only happening on deceleration, I would say it is a problem with pressure buildup in the crankcase.

Bad valve guides would not cause this as the pressure in the cylinder would be greater than that in the valve cover...oil would go up instead of down.

This is why I asked about the machining methods used as it sounds more to me like a ring problem.

Check your PCV system for blockage and run a leak down test on the cylinders.
 

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pumping blueeeeeeeeeee

On decelleration, your carb is closed so that creates a partial vacuum in the intake runners, causing the cylinder to suck oil down the intake valve guide, if the guide is worn or the seal is shot. Particularly if you are shutting down from high rpm. As for the pcv valve, if its worn out or frozen up, that could cause sucking of oil all the time. One way to eliminate that problem is to just replace the pcv valve, which probably should be done about every 30K or so miles anyway. Dont just rattle it to see if the disc is free. It could have carbon built up on the seat and be preventing it from closing off as it should. And they arent that expensive. I replace them on my vehicles every 30k miles, just to be safe.
 

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Could be excessive crankcase pressure, but bad guides or seals act up on deceleration, vacuum in the cylinder sucks oil in around the stem.

TRoy
 
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