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SBC 383. Blow by

General engine tech -- Drag Racing to Circle Track

Moderator: Team

smeg
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Joined: Fri Feb 09, 2007 12:43 am
Location: melbourne, Australia

Re: SBC 383. Blow by

Post by smeg »

Looks like some water has been sitting there?
F-BIRD'88
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Location: Ontario, Canada

Re: SBC 383. Blow by

Post by F-BIRD'88 »

May be a small crack in that cylinder wall . Water/coolant or something has rusted the cylinder surface.
steve cowan
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Re: SBC 383. Blow by

Post by steve cowan »

Check for cracked headbolts,I have 2 x 010 blocks cracked headbolts on #6 cylinder
steve c
73c34me
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Joined: Tue Feb 19, 2008 3:58 pm
Location: michigan

Re: SBC 383. Blow by

Post by 73c34me »

will do. any suggestions to check for cracks? the motor is still in the car. If no cracks, I may pull the rods and pistons from below, hone the cylinders and re-ring. I don't want to spend money on this block; which is .040" over. If I am going to spend money I would rather start with a new Dart SHP and build at least 400+ inches. However, pandemic and other factors would have me rather not spend that kind of money at this time.

Also, I removed all the intake valves and gave a "bench" test. I don't believe that there is any noticable guide wear that would need to be addressed. I mic'd the valve stems and there is no measurable taper. When I removed the valve seals, a couple had the inner metal "spring" slightly irregular... This may have happened upon removal, or, been contributing to the oil seepage problem.

I appreciate all feedback- I am by no means an expert, but am rather handy and have decades of experience with engines. Also a few expensive education moments as well!
73c34me
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Posts: 192
Joined: Tue Feb 19, 2008 3:58 pm
Location: michigan

Re: SBC 383. Blow by

Post by 73c34me »

Just got my blackstone oil analysis back. 0% water/ coolant in oil. Rules out a cracked cylinder i would think. Also, shows less than the average amount of fuel percent in the oil. Caveat, the preferred sample method is to run the engine for 15 minutes before collecting the sample. I couldn’t do this, there is a selection to indicate this scenario and the note said they would factor the no run collection and still proved a useful data for this portion of analysis.
I will enlarge/ blendthe oil drain back holes while the heads are off. Then clean the heads install new valve seals and run it.
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