How to clean a Head Gasket Surface

[BogusSVO]

How to Clean a Head Gasket Surface

There are many ways to clean a head gasket surface.
This is just one way, and it is the method I prefer.

I do not like the use of "rol-locs" for cleaning a head gasket surface, for block or head.
Cast iron or aluminum.

This is for COMPOSITE Head gaskets, Not MLS

MLS Head gasket surfaces need more prep.

A rol-loc can an will "wave" a gasket surface when used improperly. In most cases it is.

So do not use this!!

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What I prefer to use is a hard back body board with 80-100 grit sand paper.

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The reason to do it this way is....
1) more coverage area
2) will not "wave" the gasket surface
3) will show low spots in the gasket surface

Use moderate pressure when going over the gasket surface.

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and go at different angles, using long steady strokes

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and

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You want to go over it enough to just "shine" the surface and remove all the old traces of the head gasket but not remove the metal of the block or head.


You should end up with something like this.

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Now the surface is prepped so the head can be checked for warp and other imperfections.


Notice the dark marks above the exhaust valves and around the water ports, this shows the low areas and fire rings.

This head needs to be surfaced so to hold a head gasket properly.

 

[turboglenn]

Good info, i think a lot of people need to be educated about how damaging a roloc disc can be to a gasket surface. I see so many people clean gaskets off of good components with them and i just cringe and close my eyes thinking "well, that parts gonna leak from now on" . Hell, i try and warn most of them but few people seem to believe me that the little scotch brite material can turn their engine into a great paper weight in no time. Used lightly to get some things off certain gasket surfaces is ok, but rather than risking the chance if some one willl know how to use one correctly and gently i just advise against it all together


How ever i didn't really know about the body block being safe, but i know from your posts you know what you're tlaking about. so i'll keep that in mind, but to be honest i usually will take the slow route and spray gasket remover on, then use plastic scrapers for most of it and then the little tough parts i'll turn a normal razor straight up and scrape side to side (agian really lightly)

 

[BogusSVO]

Turboglenn..... if that is the method you use and are comfortable with, by all means stay with it!

I wish I have taken pics of head gasket surfaces that were ruined by rol-locks, I will say a rol-loc dose have its place, I have no issues with them being used for cleaning exhaust manifolds and intakes. But those have much thicker gaskets that can take up the "wave" a rol-loc leaves.

 

[turboglenn]

Yea, it may not be very fast but it gives me a little re-asssurance that i'm not harming anything in the process.

I am curious about using the block with 100 grit though. I think i'm gonna have to give that a try next time i have a stubborn gasket to clean off a similar surface.

Aside from the body-block what would you suggest for cleaning the engine block in the areas between the cylinders there the material is thin? Also do you recomend any difference in cleaning media or technique on the cast iron block. or any difference between cast iron and aluminum

 

[BogusSVO]

turboglenn.... I use this method on both blocks and heads, cast iron and aluminum.

I have not had any issue any way with this.

as far as the thin spots between cylinders, This way has worked for me.
I had to replace the HG on a 2.3 ford in the chasis, and this is how I cleaned the block.

 

[turbo_rookie]

what all would be needed to do to a block and head if one were to run a MLS gasket? i bought a MLS gasket and am curious as to what i will need to do to get a good "seat". is this something a person can do or is it machine shop specific work?

 

[BogusSVO]

turbo_rookie.... it should be prepped by a machineshop for best results, at least the first time,

read this....
http://www.dsmtuners.com/forums/new...face-4g63t-cylinder-head-mls-head-gasket.html

the reason I say a machine shop, is that the surface finish is so important. Not knowing what condition or how many head gaskets have been replaced on your block and head, get them both surfaced to the proper finish.

Now if you do not have the time to have the block milled, I would go to composite head gasket w/ARP head studs, if you look you will find many running 30 PSI + on a composite HG with a good tune.

 

[turbo_rookie]

thats what i thought, this is the first head gasket change the car has ever seen, i have a composite that came with my rebuild kit, and i have arp head studs but i heard MLS was better so i figured i would put it on while i was in there and be done with it. if it wasnt for building my head i wouldnt worry about it just yet, but im doing a rebuild and building the head at the same time. so i figured may as well just do it all at once and do it with the best while im at it. thanks for the info and the super fast response.

 

[sschambers]

I realize this is almost 2 months old but I wanted to add my 2 cents...with the proper tools and proper know-how, a rol-loc, a straight edge and a good feeler gauge set will get you by on most head gasket jobs. I've done many, many heads like this. Many 4 cylinder cars including my old GST, a buddy's 420a, a few Cavaliers and my own 300Z's heads and block decks just to name a few. (have a higher fail chance on the Z - 2 heads, 2 decks). Also, I use the rol-locs that attach to a drill, not a die grinder. You must take into consideration the roughness of the disc (or 'cookie' as most call them), how fast its spinning and how its cutting. I've always used the maroon colored discs (medium) and a cordless drill. I do this after scraping most of the old gasket off. When I feel somewhat satisfied, I'll go through with the straight edge and feeler gauge. I'll repeat these steps until I feel fully confident in the surfaces. Then I'll clean everything with clean rags and brake cleaner. If anyone ever does this method, you have to take into account the RA (roughness average) so don't use something too coarse/heavy. Let the tools you have do the work, don't force anything and have patience. As an enthusiast I absolutely love doing work like this and seeing the outcome. My Z has two MLS head gaskets along with new(er) gaskets throughout the engine (everything done within the last 10,000 miles. Its a summer car, hardly driven). Most people on the Z forums warned me, swore up and down that I NEEDED the heads to be resurfaced. Well neither one was professionally done and the car runs like new, no problems whatsoever. So as long as over-heating wasn't present and there's no warapge, there's really not a point in getting your heads machined.

 

[BogusSVO]

SSchambers... To me, the method I have laid out is simple and safe.
Rol-locs get alot of use in alot of shops, most people do not use the care you do when ckeaning block/head.
If the rol-loc is used on an edge, it will "wave" the surface, and will roll the edges
For most "common" guys or new guys wrenching or learning to wrench, I would perfer to see them use this method, than a rol loc.

There are many more ways to clean gasket surfaces, This is just the one I was taught over 20 years ago and still use.

 

[jrohner]

Razor blade has always worked good for me.

 

[rlacasse1]

So 80-100 grit sandpaper won't remove too much material from the head or block?

I have always used a rol-loc carefully and have never had a problem, but I'm open to new ways. I would just be worried that I would screw something up with the sandpaper.

 

[BogusSVO]

You are only doing a few strokes with the longboard/sandpaper.

Plus a rol loc will not show low spots in the deck.

You run less of a chance of screwing something up with the longboard/sandpaper when compaired to a rol-loc

 

[sschambers]

This is all true and great information. When I did my Z, I even went as far as 'lapping' the head/deck areas with sand paper after using the rol-locs, using a very similar method mentioned above. Lapping is starting with a heavier grit sand paper and finishing with a finer grit. The idea here is to make the surface smoother (and shinier at the same time). I started with 100grit and finished with 400. So I didn't 'lap' to a mirror finish (there's really no point to). What you're doing is removing the deeper sanding marks/imperfections each time you move to a finer grit. This isn't absolutely necessary but I'm more of a perfectionist . Now I'm not saying to anyone that beginners/inexperienced people should use these methods but to anyone who has an eye for perfection and the right touch, different methods can be used and are proven to work well. If you are unsure, get at least the head resurfaced professionally (usually about $50). But keep in mind, you can't keep getting the same head resurfaced time and time again...

 

[Bud92gsx]

Mods should make this a tech article..Your experience makes it really worth while to read and follow the same way you do it..

 

[rlacasse1]

OK, question. Since I don't have my roloc handy I am using your method.

Is it ok to use a sanding block that has foam on the bottom of it. I'm kind of iffy on that. I feel that if I use one with foam it will roll edges since the foam will bend around edges.

So should I use one that is just metal on the bottom, or is foam ok?

Guess I should add, the one I have has foam on the bottom but it is really stiff. I have to push really hard to get the foam to give. I think it'll be ok, but I want opinions.

 

[bryanwheat]

OK, question. Since I don't have my roloc handy I am using your method.

Is it ok to use a sanding block that has foam on the bottom of it. I'm kind of iffy on that. I feel that if I use one with foam it will roll edges since the foam will bend around edges.

So should I use one that is just metal on the bottom, or is foam ok?

You can just use a good scraper. IF you hold it at the right angle you will never scratch the head or deck surface.

 

[95AWD6Bolt]

Someone should link Jafromobile's youtube video on this topic. He uses the sander mentioned in the op's post and a razor blade. It provides step by step details on how to do it.

I would link it but youtube is blocked here at work.

 

[rlacasse1]

Well, I typically use a rol-loc, I just don't have my compressor here so I'm screwed.

But I'll youtube that name.

 

[BoostedBen]

Unless you have an expieranced hand rolocs are a terrible idea. Using a long board is the best quick way.

If your patient, the best slow way is a plastic scrapper, and a few razor blades, as well as some shop towels and some kind of non residue forming solvent. Cheaper brake cleaner will leave residue. I prefer paint thinner (acetone).

 

[bryanwheat]

Some of you guys really over complicate this. Go buy one of these for 2 bucks, scrape the old gasket off, clean the surface with acetone and install.

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