Pre swap cleaning of the head intake port gasket surfaces

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CopperNick

Royal Smart Person
Supporting Member
Feb 20, 2018
2,382
113
Canada
So before my unscheduled trip to the EMERG and then the OR, I had managed to dismantle the stock 5.3 intake and get it removed from my 5.3 project. Doing this left me with a nasty mess of accumulated crud and corruption on the valley cover that finally yielded to a lot of scrubbing with varsol and brake cleaner. For the intake ports on the heads, I went with CFC free brake cleaner exclusively and it did a good job of dissolving and removing most of the carbon deposits. Think this engine either mush have idled a lot or, started and driven without any warmup, or was used for short distance comings and goings.

All of which brings me to the intake gasket faces on the heads. Once I had cleaned away all the schmutz what I found was that the gasket surfaces where the original gaskets had set had undergone some kind of "electrolysis" activity as the gaskets had marked the aluminum and left tracking or a light pattern in the metal. The fingernail across the surface trick does not catch so these marks are not particularly deep or wide.

I would like to try and buff them out but I am not sure what to use, or even if it is necessary. I am thinking that a buffing ball mounted to a dremel tool might work, but I also thinking that 600 gr wet/dry paper soaked in either cutting oil or even brake cleaner and wrapped on a flat sanding block might work as well. My main concern here is to avoid damaging the surfaces further in the process. These are not cast iron units like the old SBC's that you can wail on with a hammer and a chisel, they are aluminum and, for values of the term, "delicate" in that it is easy to get too enthusiastic and end up removing too much material; = junk.

Any suggestions or recommendation here??



Nick
 

mwjoyce78

Not-quite-so-new-guy
Aug 10, 2018
26
3
New Hampshire
So before my unscheduled trip to the EMERG and then the OR, I had managed to dismantle the stock 5.3 intake and get it removed from my 5.3 project. Doing this left me with a nasty mess of accumulated crud and corruption on the valley cover that finally yielded to a lot of scrubbing with varsol and brake cleaner. For the intake ports on the heads, I went with CFC free brake cleaner exclusively and it did a good job of dissolving and removing most of the carbon deposits. Think this engine either mush have idled a lot or, started and driven without any warmup, or was used for short distance comings and goings.

All of which brings me to the intake gasket faces on the heads. Once I had cleaned away all the schmutz what I found was that the gasket surfaces where the original gaskets had set had undergone some kind of "electrolysis" activity as the gaskets had marked the aluminum and left tracking or a light pattern in the metal. The fingernail across the surface trick does not catch so these marks are not particularly deep or wide.

I would like to try and buff them out but I am not sure what to use, or even if it is necessary. I am thinking that a buffing ball mounted to a dremel tool might work, but I also thinking that 600 gr wet/dry paper soaked in either cutting oil or even brake cleaner and wrapped on a flat sanding block might work as well. My main concern here is to avoid damaging the surfaces further in the process. These are not cast iron units like the old SBC's that you can wail on with a hammer and a chisel, they are aluminum and, for values of the term, "delicate" in that it is easy to get too enthusiastic and end up removing too much material; = junk.

Any suggestions or recommendation here??



Nick
I did an intake job on a Buick with iron block and Aluminum intake. The pitting was fairly severe… enough to cause the gasket to leak coolant into the cylinder heads. Cleaned it up with solvent, repaired the pitting with JB weld by filling it and sanding down in the method you described with a flat block. Worked mint for me.

Good luck.

Matt
 

-dw-

Greasemonkey
Mar 15, 2021
149
63
Central MN
I have watched guys that have to shine up gasket surfaces on everything they touch. Drives me batty. Not necessary. Surface staining is not going to affect gasket sealing. I mainly use a sharp gasket scraper or a new razor blade to prep metal surfaces. I use the disks when the gasket stuff is tough.
 
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abbey castro

G-Body Guru
Oct 31, 2015
805
93
Harker Hts TX
Staining vs pitting are two different things. Staining is not detrimental to the surface. Pitting is the eating away of the surface. I wouldn't worry about staining, use a scratch pad to clean it away.
 

64nailhead

Goat Herder
Supporting Member
Dec 1, 2014
5,111
113
Upstate NY
What gasket are you using. The aftermarket FelPro is very forgiving as compared to the factory style.

These are what I'm using with a factory style intake - no leaks at 25psi

 

CopperNick

Royal Smart Person
Supporting Member
Thread starter
Feb 20, 2018
2,382
113
Canada
Ah, uh, yeah, well, you are right about the Fel-Pro gaskets and those would be just fine: If I were going back to the truck intake. Ah, NO, uh-uh, not happening. Scored a beautiful, well in my eyes anyway, LS6 manifold from Corey that is a rectangular port and which fits my LS2 5.3 And yes I have Fel-pro gaskets for it. First thing I went out and acquired.

My greatest concern here is that, even with the tolerance built into those gaskets, that scritching on the heads where the old gaskets sat will allow air "seepage" and lead to lean out. I can always cheat and use Permatex spray a gasket on the gasket surfaces to "fill" the scritches and seal them.

Just looking for a consensus of opinion here.



Nick
 
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