064 Cylinder base gasket

[drsamm]

OK, this is going to sound like a really stupid question to the more seasoned people here...but I have a question about the cylinder base gasket for an 064 I'm fixing, with a new piston. When removing the cylinder, the base gasket that was on it came apart and was rendered useless. It appears to have been non metallic, so I'm not sure if it had been replaced at one time with something other than standard OEM. I have an OEM gasket kit 1122 007 1051 that has 2 metal gaskets in it with each being slightly different. My question is - does the ridged side go up or down? Probably an elementary question but I just want to get it correct the first time. The two of them may also be different in thickness and one has sides that protrude in toward the connecting rod - not sure what that's all about. Anyway, I'm sure many of you know these answers, so please educate me on the correct side up and why these would be a bit different...any help is greatly appreciated!

 

[BuckthornBonnie]

I have seen the gasket paper version of 064 gaskets, yes. That’s not directly answering your question since it still may have been worked on.

The two base gaskets- 1122 series have the 064/early 066 and the 660 (with the 650 in there just for fun). Hold the gaskets up to your cylinder base and/or case and you’ll see a slight difference in the bolt layout. I can’t blow up your pics right now to differentiate, but one is probably 064, the other is later 066/660.
Bump up...convex?

 

[drsamm]

Thank you. Yes, I think that particular gasket set covers the early 064 and the later 066, so I'm thinking you are right. So you say the bump (yes convex) surface does face upward toward the cylinder base? That kind of made sense to me, so it would crush downward when pressed by the cylinder but I wanted somebody to make me sure of it. Seems like every time I have a 50/50 flip of the coin situation, whatever makes sense to me is always wrong...by what you are saying, I actually was thinking right this time! My wife will be amazed...

 

[BuckthornBonnie]

I recall one build where I tried the wrong gasket without lining everything up first... things aren’t off by much, but they’re off.

 

[RED-85-Z51]

064 cylinder bolts are M5 and 066/660 is m6 as i recall. I drill the 064 and tap it for the larger m6 bolts when i 660 big bore kit one. One gasket probably has smaller holes

Sent from my LM-G820 using Tapatalk

 

[L34]

Convex (dip) faces down towards crank.

 

[drf255]

As above. The OEM kit has 2 base gaskets.

The 064 is M5 holes and the 066 has the M6. There is also 3 seals in there IIRC, gotta use what fits.

The case gasket is different for the 660, that one won’t work.

Convex up is what I have read to be correct. Probably doesn’t matter, I have done both ways with no issue.

 

[L34]

I always put dip down but drf has more experience than me.
I should of said concave (dip) down not convex.

 

[BuckthornBonnie]

Yes to the m5 bolts on the 064. Did any early 066s use m5, too?

 

[L34]

I have a very early red eye and that is m6.

 

[L34]

It is the thin base cylinder so m6x20
Then they went to thick base so m6x25

 

[Mad Professor]

Not 064 kit handy here , but many stihl gasket sets come with two base gaskets, one is thick the other thin. Thick one is for places with only low octane fuels.

 

[drsamm]

Thank you all for the good information! Didn't know the bolt hole sizes would be different from the 064 to the 066, so it wouldn't have occurred to me to compare the two for that - nice to learn something new. With all of this, I think I can get it sorted out now. Does anybody have a handy trick for getting those aggravating-assed little circlips for the wrist pin in place? I've done a lot of them by now but have grown a bit tired of the struggle. Surely there is a good way to get these in without it taking 30 minutes and countless pauses for cussing sessions. And of course, occassionaly, the little "tink" sound and it launches into parts unknown never to be seen again...

 

[Yukon Stihl]

The right tool for the job...
But they circlip tools aren't cheap.
Check your squish and use the appropriate gasket acording to the squish clearance.

 

[BuckthornBonnie]

Bolt holes, alignment, and piston skirt clearance are the keys for your gasket question. While Stihl does have different gasket thicknesses for some series, they’re usually not both provided in a gasket kit. Looking at your pics now- m5 bolts, match it up with your case and cylinder in a dry fit, post pic here. I built a 660 last summer and an 064 two weeks ago... one would think I could ID the gasket on site but... nope; too many saws in my head.
You can notch a small screwdriver with a file and use it CAREFULLY to work the clip in. One slip and you can stab your off hand. I do a lot of top ends and don’t have the tool yet. I work on everything so Id need all sizes.

 

[BuckthornBonnie]

Bigger holes, right?

 

[Totembear]

@Definitive Dave sells the circlip tools. If you use them alot, a lifesaver beleive me!

 

[drsamm]

Yes, the holes were slightly bigger on the set with the wider sides. These are obviously for the 066. Thank you for the advice. It would have taken me a while to figure that one out...