Head/Base Gasket Thickness : AF16/AF18/SC10

[ThaiGyro]

Does anyone have OEM gasket thicknesses for base and head gaskets? (We have no manuals, so we measure the old ones and guesstimate)

[gsx600racer]

I got .0175" from my 2001 Honda Elite stock cylinder.

[gsx600racer]

I have a couple aftermarket gasket kits, but they are not going to help you.

I do have this head gasket from my stock ZX50 engine(SC10). It's squished out pretty good if you look at the picture.

I measured the "very" outside of the gasket and got .0194"

My guess is it could of been .020" I measured all around its the .0194" was pretty consistent.



Hope this helps ThaiGyro

[ThaiGyro]

Thank you much! Especially the head gasket thickness. The copper we ordered was supposed to be .20 and .15...but we received .25 only, though it was marked .20! That is how China does business. We sent it back. Chinalco Luong Copper. I guess we should have bought Thai brands.

[gsx600racer]

Dec 5, 2017 22:33:38 GMT -5 ThaiGyro said:

Thank you much! Especially the head gasket thickness. The copper we ordered was supposed to be .20 and .15...but we received .25 only, though it was marked .20! That is how China does business. We sent it back. Chinalco Luong Copper. I guess we should have bought Thai brands.

The Honda head gasket thickness could be different. I have Mellow Yellow torn down on the bench. I can pull the head and check the gasket in the next couple days.(dealing with a nasty sinus infection) 

[pitobread]

Pay a machinist to cut an o-ring groove in the head. o-ring the head, ditch the gasket altogether. I ran that last summer and it  tightened up the squish a bit.  Worked Great!

[ThaiGyro]

Thanks pito! You are a mind reader...We have done so on many 4T, 4 cylinder engines...and a few Austin Healey's and others. My dilemma is how deep to cut the groove and how thick to machine the gasket...I now have good enough numbers. The machine work is quite simple. My experience is that you can easily over torque the ring, but if it is harder than the head and cylinder, less of an issue.

My last Suzuki GSXR-1000 made 202 hp with an aluminum O-ringed head. Fun engine is a 940 pound race car!

We are making replacement gaskets for many older Honda engines, plus always upgrading race bikes here...Mostly two-strokes, but some 4 bangers.  Our personal scooters and big bikes get the real poop!

[pitobread]

It entirely depends on the O-ring you use. The depth of the groove is supposed to be "X" percentage of the cross section of the o-ring. I think for mine I did 80% But I actually used a rubber o-ring . I was on a stock cylinder and bore so I just wanted to play around with what I had. I am a machinist by trade, and have a copy of The Machinery Handbook. It has the formulas for correctly cutting the depth of a rubber o-ring groove.

For other materials it would depend on how well it displaces. For a metal one I would guess it only needs to be a few thou proud to seal well, but some amount of trial and error would probably have to be done. On high HP/Turbo/High cylinder pressure stuff it's super common to do soft aluminum/annealed copper rings for maximum sealing.

And yeah with those soft copper/aluminum rings once they are displaced they don't really spring back, so they would be very prone to over tightening.

[gsx600racer]

Dec 5, 2017 22:33:38 GMT -5 ThaiGyro said:

Thank you much! Especially the head gasket thickness. The copper we ordered was supposed to be .20 and .15...but we received .25 only, though it was marked .20! That is how China does business. We sent it back. Chinalco Luong Copper. I guess we should have bought Thai brands.

Here is the AF16 head gasket(used). Safe to say it's .020".