head gasket material

timbuc24u · #1 11-01-2009, 01:25 AM

Hi norm,i was wondering if you can possibly tell me what would be a good head gasket material to use on my engine from kings motors with slant style plug.also i did a compression check before it blew and it had 190lbs +,is this a normal amount of pressure for these type of engines?and what could be reasons for a HG to blow,as this is the third time it has gone on me.and i have tried copper with no sealant,also tried aluminum with hi-temp alum. paint as a sealer installed with paint wet.

**Bikeguy Joe** · #2 11-01-2009, 08:43 AM

190 lbs of compression?!?

Not normal, for these or any small two stroke. You may get away with doubling up the base gasket, and/or head gasket to lower the compression a bit.

**Bikeguy Joe** · #3 11-01-2009, 08:43 AM

Sorry Norm, I just hadta.

no problem Joe.
As for the head gasket and the numbers on the compression? I've never seen any s

for what the compression should be. If you engine has the. larger dia studs for the head/cylinder you might try a couple of inch lbs more torque. Also lap the head and cylinder to get a dull finish all the way around on the sealing surfaces.
If you want to lower the compression either a thicker head gasket or base gasket. Plus a different size base gasket will change the port timing a little some thing you can play with to see what would work the best
One thing I intend to try is machining an o-ring groove on either the head or the cylinder and use an o-ring for a gasket.
I have played with head gaskets made out of very high temp fibers they seem to work ok but a metal gasket seems to work best.
You might need to heat cycle your engine and re torque your head a couple of times to get the head to seal re torque after the head is at room temp should help.

Ghost0 · #4 11-01-2009, 12:14 PM

Another tip, those slant heads are notorious for not being flat. I would shave the head and cylinder flat using some sand paper on a piece of glass or other guaranteed flat material.

timbuc24u · #5 11-02-2009, 01:11 AM

hello everyone and thanks for the info,i just finished the head gasket,and this time i went back to the copper, coated with aluminum spray paint.also i did as suggested on lapping the head on a piece of glass and i'm glad i did cause it did seem to be a bit warped.and did the top of cyl.with a flat file.just took it for test ride and ran great so far,but seemed to idle a bit higher than normal with screw out all the way,if it continues i guess ill try moving c-clip up 1 notch and checking for leaks.will let u know what happens.

**Norman** · #6 11-02-2009, 11:27 AM

I've removed the studs on the intake and using a mill file smoothed the intake surface on the cylinder and intake manifold you can coat the surfaces with machinist dye or dry marker and see the areas that are low as you file them. You can also do this to the exhaust on the pipe and the cylinder.
Be careful and watch closely to see how your doing.

if you've got the idle screw almost out check for leaks and make sure that the throttle slide is able to go all the way closed. Sounds to me like something ain't quite right.
If you have had the head off did you replace the base gasket?
the stock ones(cylinder base gasket) will tear and leak when you just pull the head off even if you didn't mess with the cylinder.

bobsyouruncle · #7 11-03-2009, 06:42 AM

where would one find machinist dye?

**Norman** · #8 11-03-2009, 10:03 PM

auto parts store or a store that sells quality hand tools might even try a welding supply store.

K.i.p · #9 11-13-2009, 06:39 AM

Regarding machinist dye. Machinist here, a sharpy marker (color of your choice) will also do a nice job on the cheap. I use them daily.