# Sticky  DIY head surfacing after gasket failure



## Kiss4aFrog

I came across this article by Matt Gonitzke on how to surface a head using a square of glass and sandpaper. Maybe it's old news to a lot of you but I thought it worth sharing and seeing if maybe it should be a "sticky".

It seems like a no brainier as I always surfaced automotive heads when doing a head gasket job but never thought about doing it on a small engine.
I'm sure sending it out to have it surfaced at a shop is a more perfect way to get it flat but this seemed like a great way to get very close and sure beats just tossing in a new gasket and hoping for the best.
I like that it's easy and fairly cheap too :wavetowel2:

http://www.mgonitzke.net/cubcadet/tools/headgasket.pdf


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## YSHSfan

It is common to do that on carburetor mating surfaces. At work we have a block of glass of about 8x8 inches, double glass and a double sided adhesive film in between that we use with sandpaper for that purpose.


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## SlowRider22

That's a fantastic write-up, Frog. Thanks for passing it along.
It's quite coincidental timing of you posting it, too, because I'm actually doing that same repair on my pop's lawn tractor...replacing the head gasket.
Such a simple method for effective results


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## Motor City

I've used pieces of granite tile I have left over from my bathroom floor.


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## coastie56

Great write up Froggy. This procedure also applies for the Kids 2 stroke Mopeds and small dirt bikes!


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## Zedhead

I've used this method for block decks on Subaru's with great success. Over 350K miles on one of the engines


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## firedudetl1

think I saw the same technique in an old kohler repair manual - caution was to use the right grit paper so you don't take too much off - high number wet/dry paper


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## firedudetl1

posted before I read the article - use caution with oven cleaner - most cleaner cans recommend not using on aluminum as it can dissolve Al - usually contains lye


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## bandito

I have seen some similar in a motorcycle forum but instead of sandpaper lapping compound was used.


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## toroused

For those who have done something like this before, about how much time did it take to wet sand the head in the article - 20 minutes, 30 minutes, an hour? Even more?

Also, as far as the directions stating to turn this thing periodically during the process, what is the best method - turning from say 6:00 to 9:00 then to 12:00 etc. in some type of specific, circular sequence?


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## nwcove

toroused said:


> For those who have done something like this before, about how much time did it take to wet sand the head in the article - 20 minutes, 30 minutes, an hour? Even more?
> 
> Also, as far as the directions stating to turn this thing periodically during the process, what is the best method - turning from say 6:00 to 9:00 then to 12:00 etc. in some type of specific, circular sequence?


ive done this to numerous ob motor heads, and there is no " how much time". a slightly warped head can be done in less than a half hour. a really twisted one may take close to 2 hrs. i do figure 8's and rotate the head 180 now and then...all depends on what you see on the mating surface.


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## Kiss4aFrog

The amount of time it takes would depend on how badly it's warped. You can always take a magic marker and color the surface before you start sanding to make sure you have it flat. Usually the sanding itself will make the metal look bright so it's pretty easy to see. I'd rotate it 90 degrees each time.


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## 10953

Kiss4aFrog said:


> The amount of time it takes would depend on how badly it's warped. You can always take a magic marker and color the surface before you start sanding to make sure you have it flat. Usually the sanding itself will make the metal look bright so it's pretty easy to see. I'd rotate it 90 degrees each time.


that's how i mark mine. blue or black magic marker unless your lucky and have some machinist blue laying around to mark the surface
i also use lapping compound in place of sand paper using 3 grades course med fine to get a better surface,


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## aveteam

nwcove said:


> ive done this to numerous ob motor heads, and there is no " how much time". a slightly warped head can be done in less than a half hour. a really twisted one may take close to 2 hrs. i do figure 8's and rotate the head 180 now and then...all depends on what you see on the mating surface.


I'll second the figure 8 pattern. I do mechanical assembly and whenever we have to lap a part that is the recommended way.

Sent from my LG-M322 using Tapatalk


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## Russell Stephan

Iffin' one does a lot of small engine work it would make sense to obtain a full emery cloth sheet size granite surface plate. They pop up on Craigslist every so often. I got my two from Grizzly Industrial. One is small for checking the shock valving shims on dirt bike suspension stacks. The sheet-sized one gets combined with spray adhesive, a full sheet of emery cloth, and time for perfectly lapped mating surfaces.

And per a previous recommendation, use permanent magic marker as a layout ink to indicate progress.

Actually, the last two lapping sessions I did were for the two halves of two snow blower auger transmissions. Also, keep in mind not to go nuts on parts like the auger transmission case halves -- there's stuff in the middle they squeeze. One can also burn through aluminum on small parts quickly. Clean up the surfaces just enough to get a good seal and by all means use the magic marker (Sharpie's are perfect) trick as an indicator.


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## JoBlack

Great suggestions above, use very thick glass if you can find it, or granite. You are basically building a lapping table (without the grooves). The movement is figure 8’s, and you can quickly see the progress on the part in how it ‘flashes’ when you rotate it and it reflects the light. You will notice the visual change in the surface appearance.


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## shallowwatersailor

When I went to Engineman "A" School in the USCG back in 1969, we learned how to lap diesel injectors. The method was to use the Figure 8 pattern that _nwcove_ and _aveteam _mention. We were using a metal lapping block for the steel piece parts. But a 600-800 grit wet dry sandpaper should give good results. You might want to use a marker to coat the surface and then watch the progress as it shines up evenly.


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## CarbineMan

On an Ariens 824 after replacing the carb used a Dremel to match the intake port. Not sure if there was more power but it made he feel better.


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## CarlB

Kiss4aFrog said:


> The amount of time it takes would depend on how badly it's warped. You can always take a magic marker and color the surface before you start sanding to make sure you have it flat. Usually the sanding itself will make the metal look bright so it's pretty easy to see. I'd rotate it 90 degrees each time.


i usually give it a light dusting of black primer so i can see how im coming along


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