Aluminum block questions

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jrcentllc
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Aluminum block questions

Post by jrcentllc »

Let me see, where to start?

I' ve assembled a big sbc (450 cid), using all top notch parts 6 years ago.

The block is a dart aluminum tall deck block.

Crank, rods, pistons, all have never had a problem.

Heads are All Pro high port 227's that have been worked over real good with good flow numbers.

Roller valvetrain, T&D shaft sys.

A Super Victor that has been modified to a port fuel injection F.A.S.T. system. (We had to cut the dividers back to get enough plenum area)


Problem # 1 - getting the intake gaskets to seal have been a little of a challenge. 1209 fel pro gaskets seam to be to hard, the Mr gaskets seam to seel better. The block was checked for squareness and is good, the intake was cut to proper angles after the welding of the injector bungs. All angles look and measure good. AND there has to be a spacer for the tall deck block, so there are 2 gaskets per side. Question 1 is has anyone got a better sealing method or gasket, has anyone tried o-ringing the intake port?

Problem#2 Bear with me this sounds goofy but true. We had had this engine apart on a bi yearly basis for oil leaks and upgrading parts, but every time it has a oil leak, from the lower outside head bolts (these are blind holes). We used oil dye to pinpoint the leak. This gets better, recently we leak tested the engine due to very slight oil smoke from the exhaust and it has a slight miss. During the test we could hear a hiss from #2 during the leak, soapy water reveild a compression leak up the outside head bolts, there is no external or internal coolant leaks. Question#2 what do I try as to get the upper half of this engine to seal?
I've been using 1004 or 1014 head gaskets, I've heard that MLS gaskets seap coolant? O-ringing? copper? do I need to do something different with the aluminum block, is this inherant with aluminum blocks? I have built hundreds of cast iron blocked small blocks with never a problem/problems like this. Does it have something to do with the sleeves?

thanks in advance, jon
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BRENT FAY
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Post by BRENT FAY »

From what you describe it would seem the sleeves have dropped some. Brent
jrcentllc
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Post by jrcentllc »

Am I correct in saying sleeve protrusion should be .003-.005?, because this is what I have.

When I got this block new I torqued a deck plates and head gasket on it, thin put it in my spray wash cabinet for a half to one hour approx ( 180 degrees), this was to seat the sleeves, is this correct?

thanks again
jon
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The only dumb question is one that wasn't asked and now you have a bigger problem.
BRENT FAY
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Post by BRENT FAY »

jr, I have done it several ways.

Are the sleeves below the deck now?

Similiar what you have done in the the hot tank..but did you have Both Banks torqued down with deck plates and then let cool down?

I bought an oven at a used appliance place for $25 and then made a cover/box (insulated the outside)when the door is open so I could put a block inside and heat it to 250° for a couple hours with plates bolted on and then let it set overnight the sleeves would move a couple thou down.

Or i have done the run it on the dyno or the weekend (when sleeves are standing .004 proud) and disassemble and then deck the block to the proper deck height. The newer blocks/machining/sleeves dont seem so sensitive to this though. Brent
jrcentllc
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Post by jrcentllc »

BRENT
AM I TO INTERPET WHAT YOUR SAYING AS, YOU RUN THE SLEEVE AT ZERO DECK?

THE SLEEVES ARE CURRENTLY( A LAST TIME APART) AT .003-.OO5 PROTRUSION.

HEAD GASKETS YOU USE ARE?
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jdperform
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Post by jdperform »

For sealing water with cometics use spray Hylomar. I remove the outside rivet and spread the gasket slightly spraying the Hylomar between the sections of the gasket and spraying the outside as well. It will help seal slight imperfections as well as too rough a RMS finish. I can give a part #.

Some heads come with an o-ring option. You could do that on a mill if done carefully. Or find a steel reinforced intake gasket fel-pro makes them for 18 deg stuff they are hard to trim to fit but with a little dilligence it can be done.
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