ELIMINATE your head gasket!

Stole this from Russ2251 @ DIYgokarts.com

Very straight forward.

Three things are needed:

1.) A large workable surface such as safety glass and must be absolutely flat. The surface I use (accurate to a few millionths inch) is from a discarded wafer prober and is not readily available unless you have connections in the analog/digital IC manufacturing industry.

2.) LOCTITE 320 grit grease grinding compound

3.) Permatex Super "300"

Apply compound to flat surface and begin lapping by applying pressure on head and move in random figure 8 and circular patterns-clockwise and counter clockwise.
Check every few minutes for a grayish color to begin to appear. After a while you will begin to understand why gaskets are used in the first place. I have yet to find any cylinder head that was not warped to some degree.

Head lapping is complete when entire surface is a uniform gray color.

Block is done the same way but is somewhat more difficult because of it's bulk/mass.

Clean up with mineral spirits, paint thinner, or kerosene.
I highly recommend that block be completely stripped of moving parts before lapping.
Thorough cleaning after lapping cannot be over stated.
If any compound is left behind, engine damage is a real possibility.
Assembly is done using Permatex Super "300".
Apply thinly to one or both surfaces and torque to maximum factory spec and done in the correct order. You'll know if you've done it correctly when a very small amount of sealant oozes out between head and block. Remember that what ever excess oozes out is also oozing into combustion chamber. Keep it to a minimum.
Clearances must be checked before final re-assembly.
Typical Briggs head gasket thickness is about .060" which is equivalent to milling off a pretty big chunk of metal.
My 1969 5hp Briggs and all four of my Lawn-Boy DuraForces had no clearance issues, but remember that no two engines are identical. Check and re-check clearances.

Addendum 4/30/10:
Would be a good idea to re-torque head bolts after a couple of cycles...that is...warm engine up to operating temperature and then let cool (couple hours) to ambient temperature, one or two times, then re-torque to max factory spec.

i think i'll keep my head gasket. seems like alot to go wrong there

Same. Id rather run stock than eff up my engine. Too many specifics to mess up.

Why? worst comes to worst, you have to run a gasket still if you screw it up.

That's just stupid, why?

Cause a gasket also insulates, a gasket also compress and decompress with the heat. Gaskets are cheap.

If by all means you dont wanna use one, then skip the 3 steps and just use the Permatex fluid gasket, but its still a gasket  

For the time and resources to gain just a bit more power, i think id rather just keep my gasket.

Hmm. I wouldn't be TOO quick to dismiss this. I know the author. He very likely knows more about engines than all of us here put together, plus a few more guys.

Why do it? Why do anything to improve performance? If you want to increase your compression ratio (and thus, power) without dishing out $ for pricey speed parts, or having a machine shop mill it, then you would do this.

Either way, I have just finished getting what I need to try this, so I'll have to update after I've done it. And no- you can't JUST put gasket maker on the factory surfaces- too imperfect, will never hold up to the pressures...

[quote="Doc Sprocket"]Hmm. I wouldn't be TOO quick to dismiss this. I know the author. He very likely knows more about engines than all of us here put together, plus a few more guys.

Either way, I'd stick to the gasket. Tho fluid gasket is also a gasket, so nothing gained with the above.

Or just get a copper gasket, lasts forever. We make those for Tractor pullin Racing over here, also make the gaskets for Caterpillar exhaust manifolds, and Rolls royce. (through work).

Thunderdivine wrote:

Tho fluid gasket is also a gasket, so nothing gained with the above.

Well- yes and no. The purpose of the exercise is to put a VERY fine finish on mating surfaces that are normally quite imperfect from the factory. I would lay down a bet that if you just put the gasket cement on the stock surfaces, it wouldn't work. The whole point of this is not to try to eliminate ANY gasket at all, it's to cheaply and easily create the same compression effect as having that very same amount decked off (and for cheaper than machining, and sometimes if you cannot get a copper gasket).

Russ is very careful how he writes stuff, and goes into very good detail, covering the bases. This ain't half as scary, risky, or bizzarre as it sounds.

Since I for one, love low-budget, effectinve performance mods, I will be trying this. I recently picked up a slab of dead-flat granite to do it on. I have already used it to resurface a carb. Brilliant.

People have done this since the model T days. Apparantly, some high end foreign car manufacurers had engines without head gaskets from the factory back then. I was reading in a book about how to hop up model t engines and they mentioned this. Although the way they did it, they ground the head right on top of the block instead of grinding both head and block seprately on a flat surface. I always wanted to try this, but never heard of anyone trying it on a mower engine. Pretty neat idea.

I JUST did it today. It'll be awhile before the engine is finished, but the process went well. I'll toss a pic or two up here.

It seams like my engine has had this done before to the extreme because you can see the "teeth" all the way around the bored

Are you going to sand the head doc?

Sorry- I realized I goofed the pics. Fixed... Yup- head done, too.

I might have to try this sometime.

See. I'm a good thread "borrower" haha lol

i took the gasket off a pushmower i had, it ran perfect and didnt bog down as much , tried it with another 'mower and it wouldnt seal.
but like you said, no two engines are the same.

I lapped the head on my 5 hp on a picse of glass and it has wayyyy more power.

Thunderdivine wrote:

In these rough casts that the blocks are made from, there will always be small imperfections that appear on surfaces like this. Tho I know it's possible, I still would recommend a gasket.  But nice job so far.

I won't argue that, for sure. However, I will add that in addition so minor surface defects, warpage is a real possibility too. It is astounding how good the head looked when I laid a straightedge across it in several locations- yet when I performed this task, it took a fair bit of work to get it completely level. With a used head, you never know what you're going to get, especially if the bolts were not previously torqued correctly or the engine hot too hot at some point.

Speaking of casting defects- I got into porting it yesterday too- wow... Just wow. Amazing it flowed at all.

I know, but they claim it's better to be rough on the intake, and maybe 3-400 grit on the exhaust side.

It's the reversed golf ball dots principle with the intake side, where a smooth mirror wall will create drag and low velocity, a rough wall won't. But ofcourse there's limits. It's huge time savings for the manufactures so they say it's ment to be that way  

Oh, woah! Don't get me wrong- I'm porting, not chroming... LOL- I was referring to seriously restrictive casting flash and defects, not very minor surface imperfections. No- I'm not going to go crazy polishing the intake ports, just rounding the corners, smoothing sharp edges, etc.

Doc Sprocket wrote:

Oh, woah! Don't get me wrong- I'm porting, not chroming... LOL- I was referring to seriously restrictive casting flash and defects, not very minor surface imperfections. No- I'm not going to go crazy polishing the intake ports, just rounding the corners, smoothing sharp edges, etc.

lol yeah there is alot of crap left over from the cast, my opposed one's was the same.

Thunderdivine wrote:

I know, but they claim it's better to be rough on the intake, and maybe 3-400 grit on the exhaust side.

It's the reversed golf ball dots principle with the intake side, where a smooth mirror wall will create drag and low velocity, a rough wall won't. But ofcourse there's limits. It's huge time savings for the manufactures so they say it's ment to be that way  

Ive heard of something similar to that, but instead of ruff intake runner/port it is just a smaller opening on the intake port were the manifold mates with it, then gets bigger toward the combustion chamber side, creates a Venturi effect in witch air is at a higher velocity than if it was just the same size port the whole way through, never heard of leaving the ports ruff tho, lol

Yeah- the accepted school of thought is that you want the intake tract "rough" on a near-microscopic level. A slight bit of turbulence in the charge helps mix it better, and the flow will "drag" on a super-polished surface.

Having the port too large will cost you velocity too- so I was careful not to enlarge it, just smooth out the restrictions.