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Old 10-19-2015, 05:29 PM   #1
Hampshire
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Leak at bottom of spacer on 350 - not valve cover

I know, tons of posts here & elsewhere about getting rid of leaks on VCs on SBCs... so please bear with me. I am looking at where a 1/2" spacer meets the head - not the VC to head.

It's a 350 Gen 1 crate motor. Cast Edelbrock VCs were not high enough for roller rockers so we added 1/2" aluminum spacers. My guy installed the spacers with black silicon - no gasket. He put the VCs on, gently screwed them down and let it sit for several days. It was started up about a month later - ever since that day it's leaked at the bottom of the spacers. (Not that it effects anything, but I put Fel-pro 1604s on the Valve covers - no problem there).

I'm going to have my guy re-do the spacer/head joint. We're thinking of using a high quality gasket - like the Felpro 1604 or the Felpro PermaDry Plus. We're also going to do it dry - with perhaps just a light coat of blue silicon attaching the gasket to the underside of the spacer (as I did the VCs).

Opinions? experience?
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Old 10-20-2015, 05:24 AM   #2
tmoble
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Re: Leak at bottom of spacer on 350 - not valve cover

the guy probably just had an air bubble in the RTV, happens from time to time. Also, this can happen if the surfaces in question aren't perfectly clean. Use spray brake cleaner and white papertowels.

If they are cast iron heads with cast v/c gasket surfaces don't use any hi-tech or big bux gaskets. They work best when both surfaces are machined, not cast.

since you know where the leak is pull the cover and spacer off carefully if you can, you might be able to see the air bubble or whatever in the RTV.

scrape a lot, clean with the little wire brushes that resemble toothbrushes. Don;y use the Scotchbrite rotary pads on a die grinder. That stuff will kill the bearings in your engine. You can use those off the engine, then clean the parts before re-installing.
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Old 10-20-2015, 09:53 AM   #3
Hampshire
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Re: Leak at bottom of spacer on 350 - not valve cover

My guy did all those things, cleaning, prep & so on.

I'm having another garage we both know do it this time (neither of us has time or available space right now)...anyway, they already tried getting the spacers off and it's going to be a job - they are really stuck fast.

Seeing as they are leaking in the classic SBC spots (lower rear - both sides), I think a solution other than cleaning & gluing them up again may be needed. Not keen about the labor (whether it's mine or I'm paying for it) to remove glued on spacers again.

The thick fel-pros (1604 & 1608 with steel core) with little or no sealant do work (I've used them on other VCs) and they have a good rep inn general for use on SBCs. Check other forums & Summit reviews.
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