Thread: 066 piston options / muffler question

With a case of CAD I got what I hope is going to turn out to be a reasonable deal on an 066 mag powerhead. It came with a dual port muffler, the factory 3/4 wrap handle, large felling dogs and cover. $350. I put some gas in, cleaned the air filter and gave it a quick cleaning and look over. I ran it for a bit and it runs good, starts fast and has no love for wood. My compression gauge has alwayse been pretty honest in the past and this saw will blow 162 psi. We've cut with it for a few days now, it'll outrun my 064 by a good margin and it'll eat my new 660 with dp cover for lunch.

I pulled the muffler off to blast it, and open up the side port a bit more, and some new paint. The piston has no scoreing but the crown is showing some erosion above the top ring on the exhaust side. It's not bad but I am probably to replace it when I get time to take the saw apart. In need of another project I've been gathering parts at the Stihl dealer for a rebuild/restore, berrings, gasket kit, starter rope, and msc small and worn parts.

Does the baffle in the muffler limit the power? There's 18 holes in it @ .200 diameter. That doesn't add up to enough. Remove the whole thing, just the front or drill holes in the front of it?

What are the thoughts on a Meteor piston vs a OEM piston? I'd prefer to not to spend the extra on an OEM, but don't want something that's likely to fail. I'd hope the Meteor is better quality than the cheaper aftermarket ones. What rings come on the Meteor? No love for the cheap groved ez-break rings. Northwoods saw should have the Metors in stock by now or verry shortly and t would be about $50 after shipping.

Would I see any significant power increase going to a BB kit, vs mild porting the OEM cylinder that I already have and the new piston? My thinking is that I'm better off touching up the OEM cylinder and running it with a new piston.

Keep your OEM cylinder as the saw is making very decent comp as is, the Meteor piston is very good quality and I have used many of them. I reuse the OEM pin and circlips as the OEM pin is lighter in weight.I run 2 BBkits and they are OK but prefer the OEM cylinder and piston but in your case I would go this way. The Meteor piston uses good quality rings , not those cheap thin grooved ones that come with BB kits. I have found that if the OEM cylinder is woods ported that it makes as much or even a bit more power than a BB kit does in stock form ans is of a much better quality.Also the piston can be opened up around the windows to give a better breathing effect and lighten it up a bit. If you just leave the OEM cylinder stock and put a Meteor piston in it it will run and last very well. On the muffler I just cut out the front of the inside baffle and make the muffler a dual port with 2 5/8" holes and that seems to give the 066 all the grunt I and speed it should have. I have tried most of the setups myself and these are just my findings and opinions and I am sure others will have different advice and opinions.
Pioneerguy600

Originally Posted by wi50

Does the baffle in the muffler limit the power? There's 18 holes in it @ .200 diameter. That doesn't add up to enough. Remove the whole thing, just the front or drill holes in the front of it?

What are the thoughts on a Meteor piston vs a OEM piston? I'd prefer to not to spend the extra on an OEM, but don't want something that's likely to fail. I'd hope the Meteor is better quality than the cheaper aftermarket ones. What rings come on the Meteor? No love for the cheap groved ez-break rings. Northwoods saw should have the Metors in stock by now or verry shortly and t would be about $50 after shipping.

Would I see any significant power increase going to a BB kit, vs mild porting the OEM cylinder that I already have and the new piston? My thinking is that I'm better off touching up the OEM cylinder and running it with a new piston.

Meteor makes a very nice piston. The rings on them are not grooved I'd have no issues using one.

You can remove the entire baffle in the muffler or just drill out the end of it. It just depends on how ambitious you're feeling.

Are you going to port the BB? If so, you should be fine. The roof of the exhaust port needs more radius. If you don't like the grooved rings, you can buy Husy 395 rings for about $30.

thank's so far guys.

I would port the BB if I get one, but in my case I'll run with the OEM cylinder and the Meteor, unless for some reason when I take it off it's bad. But makeing the comp. it is now and how it runs, and looks from eht exhaust port I'd say it's just fine, and I'm $100 ahead going that route by the time I get a BB and good rings VS the Meteor.

My only issue with takeing the whole baffle out is noise, but it probably won't matter. The stock hole in the muffler needs to be opened up and this one has the DP cover, I can probably mill the slot in the cover a bit larger also.

Sometime I'd like to make a billet cylinder, removable head and removable transfer covers for one as a race saw, I have equipment to do so or access and friends with equipment to do so depending on how fancy one would get. I wonder what kind of power it would make if it was running a much larger cylinder yet, a completly different carb and a pipe. But that's a project for an old saw carcas as I don't feel like wrecking one of my good saws quite yet.