Block head gasket preparation?

jwilliams81

jwilliams81

Senior Member
I have the head off and milled. Now I need to focus some attention on the block so that the head gasket seals well.
I have read a lot of threads here and watched some Youtube videos.

I wanted to ask how you guys clean the carbon buildup off the pistons? Just use a putty knife? What type of cleaners should I use?

Does the mating surface on the block need to be bare metal shiny, or just remove the old gunk and that is good enough? Suggestions on tools or cleaners for that as well?

Here is a picture of the block after I pulled the head.
 

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It might be overkill on my part but I make it as clean as I possibly can. I don't want to do it twice because of lack of effort the first time, and then buy the best head gasket available, don't cheap out. Wayne
 
Get is clean as a whisle - doesnt need to be polished but does need every spec of dirt and old oil/grease off it. Then wipe with acetone till it comes out dry. I have used razor blades to scrape carbon off stuff before - just dont go anywhere near the cyl walls and try to keep the gunk from going into the water jacket. Also dont scrape the tops of the valves with much force - rather soft and can bend very easily.

Clean up your head studs too so the head slides easier and doesnt scrape a bunch of crap off them to land on your cleaned gasket surface...

Then use the plain ol copper headgasket with some copper coat spray stuff and it will seal nicely.
 
I hold a vacuum cleaner hose in front of the single edge razor and start scraping all the junk off. Be careful on the aluminum pistons, as the razor will trim the aluminum quite easily.
 
Rotate each piston to the top,then work on it. Old credit card, cut a new edge when it gets worn down. Some WD-40 would help loosen the carbon, then wipe it clean.
 
Yup i have done the vacuum cleaner thing (careful about sucking up WD 40 fumes...) and yes the razor can dig into the aluminum. Just go slow and take your time - razors are well razors and will cut to the bone before you even know it.
 
J,
Remember, when replacing a head gasket, "CLEANLINESS IS NEXT TO GODLINESS"!
I even run a drill bit through the head bores, so some crud is NOT scraped down on the gasket & I clean the studs with an EMERY cloth strip.
Bill Clean
 
U don't have to go anal crazy,,, your putty knife will work on the Pistons and most likely on the block... U can use brake kleen or carb clean along with that..then take some 80 grit sand paper and hand rub it around the block surface some. You want all foreign material removed. Then do a final wipe with brake kleen to remove any oils etc and put her together
Your A had a copper gasket a lot easier than the composite ones that don't come off in one piece
 
Thanks Mitch. I didn't think it had to be "machined" looking... but I figured I had to get all the dirt and old gunk off of it.
I also like the emery cloth idea on the head studs.
 
Ok, let me know what you guys think.

The picture is from the other side, but the tops of all 4 pistons look like this. The razor blade took the carbon right off the pistons.
 

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Looks fine from here. Use a copper gasket with Copper Coat on both sides and if the head isn't warped, you should be fine. Remember to retorqued several times.
 
I will be removing the head of my A this winter so these are good suggestions for me. My question is - should I replace the studs and nuts also?
 
Yea your threatening to open a whole cargo container of worms trying to remove head studs...Check past posts about how to remove broken off studs - if you dont have a welder i would not change them.
 
I tried removing one, and it snapped off leaving the piece in the block. I had to call a mobile bolt extractor to come get it out. You can drill it out also, but I didn't trust myself.

I agree with what is said above, if they are in decent shape and aren't rust pitted don't try and replace them.

I liked the emery cloth on the stud idea. I did that last night and they look much better.

I have the copper coat and copper gasket ready to go on.
 
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