Hot Rod Forum : Hotrodders Bulletin Board - View Single Post - Blow By on a fresh rebuild. Possible ?? PLEASE HELP. Pics inside
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Old 09-23-2008, 09:57 AM
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Frisco Frisco is offline
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Quote:
Originally Posted by Sin7
As stated in my first post, the engine was bought back in November 06' from a local reputable builder.

He immediately fired it up, and it ran for about 15 min....never once smoked and it sounded strong... I'm trying to think back on it and I don't recall if we ever discussed it being "broken in yet". All I know is that he had rebuilt it. To what extent I am not sure. Idle and oil pressure was great while on the run stand...

The motor sat on an covered engine stand in my garage for a little over a year.

Anyhow, shortly after installing the motor into my impala, i had timing issues. For a week straight I messed with it and I just couldn't get it to start. Finally a friend came by and we were able to find TDC and the car fired right up !...

A few days later is when I finally drove the car on its maiden voyage. I drove it to work for the first time. The trip itself is about 9 miles on city streets each direction. Total drive time about 35 minutes in traffic ranging from 30-40 mph. Car ran really well.

The smell had a very high gas concentration.

That same day I created a post entitled "light blue smoke".... I thought i was running too rich. So I fiddled with the mixture screws. It didn't make any improvements though....

JD Brown asked about the use of synthetic oil. And the honest answer to that is... I figured it was the right move. In my head I figured, well i might as well use the "best stuff". So i dropped in some 5w30 synthetic oil in it after the motor was installed...... There really was no logical reason behind the use of synthetic.....
I shortened up your post a little.

The 15 minute run by the original builder should have been enough to "break-in" the cam provided he had regular non-detergent oil and hopefully a good zinc additive.

The oil and the filter should have been changed immediately after that run.

You do not have enough miles on the engine for the rings to have fully seated. How long this takes is dependent on how the cylinders were honed and what type of rings were installed.

You should not switch to synthetic oil until after you have around 2000-3000 miles on the engine.

You should change the oil and filter on a new engine at 50 miles then again at 100 miles, 500 miles, 1000 miles and then every 3000 miles.

Having the engine sit for a year could possibly have enabled the valve seals to dry out and thus leak. They may need replacing.

Having the engine sit for a year could also have possibly allowed some of the rings to have gotten "stuck". This would allow excessive oil consumption in one or more cylinders and would also possibly be a contributing factor for lower than expected compression. Freeing "stuck" rings can sometimes be accomplished by putting a small amount (a tablespoon) of Marvel Mystery Oil in each cylinder. Let it soak overnight. Crank the engine over several times without the plugs in to blow the excess oil out. Replace the plugs and start the engine. It will smoke very heavy while burning off any residual Marvel Mystery Oil for a short time. If the ring(s) were not stuck too bad, they should free up.

The plug you show does not indicate any oil fouling and this surprises me due to the large amount of both burned on and wet oil shown in the other photos.

The high level of gas smell could have been due to incorrect carb adjustment as well as the timing being off. Was the choke fully open at the time? Excess gas could have "washed" the cylinders down.

Checking the compression is usually performed with the ignition disabled, the throttle held wide open, and all spark plugs removed.

What are your compression readings for each cylinder?

A simple baffle can be fabricated from a piece of 1/8" thick steel or aluminum plate. Tap the two cast bosses in the valve cover that are located close to the hole in the cover. Use short bolts there to attach the flat baffle.
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