036 pro question(s)

[goatchin]

036 pro squish question(s)

I just finished my first saw project-rebuilding a burned up 036 pro. Decided i would check the squish, which is .037" on 4 sides. I did a couple searches and found that most like to run around a .02 minimun squish.

I am using a Woodland Pro piston from Bailey's, a OEM base gasket, OEM cylinder-I was able to clean off the alumnium.

Will the squish reduce a little bit after the saw has a couple tanks run through it? meaning will the gasket compress down a little? piston change in some way

Right now when the piston is at BDC, there is approx. 1/8" of piston showing in the exaust port (rings are below the exaust port). If the base gasket were to be removed, resulting in the cylinder sitting lower on the piston (vice versa, tomato tomato), will this cause a timing problem?

Thanks for any advice yall may be able to offer

 

[rickyrooster]

removing the base gasket should get you in the ballpark on the squish, but I would recheck it to be sure. I would shoot for .020-.024 for it. I would raise the exhaust back to stock. Your piston sticking up at the bottom .020 more should'nt be a problem.

 

[excess650]

Squish will not change after buttoning the saw up and running it. Compression will increase slightly as carbon forms on the top of the piston, and inside the combustion chamber.

Did you measure the thickness of your base gasket?

When I was doing my 660 I found that Stihl offered 1mm and .5mm base gaskets. Even with the .5mm I had .035" squish, so I cut a gasket from .005" brass sheet. Later, when I did my 272xp, I found the factory fiber base gasket compressed to about .5mm, and opted to cut another from .010" brass sheet. I didn't mess with the ports in either saw, and both run great.

 

[blsnelling]

Stihl base gaskets are typically about .018. You'll be perfectly fine with a .018-.019 squish. And I would not do anything to the exhaust port. Your after compression here. Besides, we're talking about maybe 1* port timing anyway. It's not enough to worry about on a worksaw. Make sure you use a fuel proof sealant like Threebond 1104 or 1194 and recheck your squish afterwards. I'd expect to see perhaps a 10 PSI compression jump. Just a guess there.

 

[goatchin]

Thanks guys-good info.

No I never measured the new gasket-still have the old one, so if neccisarry to measure it, i can.

My concern when removing the base gasket was, is it going to shorten the exaust port enough to where not all the exaust is being "expelled" from the cylinder...I'm prolly just thinking to much on this one.

If ol' Brad says dont worry bout the port, guess that'll be 'nuff convincing for me not to worry about it haha

 

[blsnelling]

You don't need to be worried about the piston sticking up in the exhaust port .018 at BDC. Your exhaust flow is mainly at the roof of the port when it first opens.

 

[goatchin]

sounds good

The Threebond 1104 or 1194 sealant you were talking about, where can ya get it, any other brands work just as good if i cant find the Threebond? Just a thin layer is all i need when puttin it on the base?

Thanks

 

[excess650]

I think that you'll find it at most any motorcycle shop. At the Yamaha shops its called Yamabond, and I thought that I had seen something at the Honda dealers. Its a semi-drying sealant, and generally impervious to gasoline. Unlike silicone, it doesn't make the little balls that end up in the bearings or in the pressurized oil systems of 4-strokes. Its used for metal-on-metal and can be used with gaskets.

Yeah, just a thin layer. I used it on both sides of my brass gaskets, but may not have needed it at all. Some of the Stihl base gaskets are rubber coated on both sides, and some are bare, blued steel.

 

[goatchin]

okay thanks

 

[goatchin]

I just pulled out the base gasket and put the jug back on temporarily-havent got the sealent yet.

Question-befor when i measured the squish, the soder measured out the same all the way through the "squished" area. When i did the squish this time the soder is thinner on the very end and gets alot thicker going away from the squish band area. Goes from .019"-.024". which one do i go by or do i take an average? Alot closer to were it should be now...anyone need a 036 pro base gasket haha?

 

[Brian VT]

I just pulled out the base gasket and put the jug back on temporarily...Alot closer to were it should be now...anyone need a 036 pro base gasket haha?

Great. lol