066 with 84psi... sad day! Porters?

[singletrack100]

So while tearing my 066 down for a decent well-deserved cleaning now that the wood's cut and fire season's wound down and I am home, I thought I was able to turn it over by the flywheel by hand far too easy. I did a compression test with my old Matco tester, cold, several pulls, twice and both times came up with 84psi. I know this is far less than it should be from what I've read here in the past. She still runs great, at least last week anyway.

I know the saw is not stock as the cylinder is a Mahle, so it's been replaced somewhere in the past prior to my ownership. Since being on this forum over the last couple years I've always planned to send this saw to one of the guys here for woods-porting; this is a working saw, not a racer.

My question is: who on here does that? I know of Brad Snelling and Mastermind, aka "The Chimp (Randy, right?) Also, from the past I knew this was around $250-300 plus parts but don't know about now-a-days. So you guys that do this, I would like to know how this works... do I get a topend and send both it and the powerhead to you or do you get it,,, what about seals while it's there, turn-around, other suggested stuff, etc.? I have a mounts kit I was going to do until I discovered this... should I do it first or just throw them in the box? I think I'm set up for PM but not sure... Thanks guys, any direction is appreciated!

Duane

 

[cutforfun]

Mahle is a OEM cylinder so that's good, I would pull the muffler and look at the piston. 84 is low compression, low enough that it probably won't run. I would not trust your compression findings if the piston looks good and the saw will start.

 

[SquareFile]

Mahle is OEM. At 84psi it would not run. Use your gauge on another saw to verify its accurate.

 

[Guido Salvage]

No way that saw would have run on 84 PSI. Does your tester have a Schrader valve?

 

[singletrack100]

I will test my 029 to verify... it's been awhile since I used it on a vehicle but it showed in specs then. Yes, it has a schrader valve and did not leak down after test either time... I've replaced the schrader a time or two because of that... stand by for 029 results...

 

[Guido Salvage]

Make sure your decomp valve is not pushed in...

 

[singletrack100]

OK,,, the gauge, laying on the bench a minute ago still showed the 84 from the 066 test. It had not leaked down. HOWEVER, i yanked on the 029 and it showed 80... I need to run to a buddy's shop in a minute to pick up a replaced tire for the truck and will put his gauge on both and yank on 'em... btw, I espected to see "Stihl" on the cylinder; did not know Mahle was stock for those!

Maybe things aren't so bad but I would have surely thought it would have taken quite a bit more turning the flywheel by hand? I still would like the porter's info, but will post results here in a bit when I get back!

Thanks so far

 

[singletrack100]

No decomp on this one BTW and I would plug it if there was, but thank you!

 

[Chris_In_VT]

Alright, let's take bets, his gauge is bad and the 066 is actually blowing 180psi?
Or both the 066 and the 029 are toast.

I'm banking on bad gauge.

 

[Guido Salvage]

Neither one will run if his gauge is accurate. I wonder how many times he pulled?

 

[Ron660]

Same thing happened to me several months ago....bad gauge. Valve stem on compression hose may need replacing also.

 

[Hinerman]

I vote for bad gauge.

 

[blsnelling]

The Schrader valve must be at the very tip of the hose.

 

[pioneerguy600]

I vote that he didn`t keep pulling the engine over til he hit max pressure on his gauge.

 

[singletrack100]

Ok gang, I'm back... and no, I didnt pull slowly or once... I pulled mightily on both over and over, passed the point of max pressure being built just to be sure. The Schrader is not in the end of the hose, it is an expensive gauge, not a HF. The schrader is right below the gauge on the side. The gauge does not bleed down until I release the pressure; it's still showing the 80 from the last time I posted.

I was actually schooled back in the day (mid '80's) as a mechanic and spent many years as such for trade so I know when testing compression it needs to be cranked until max pressure is reached. I know from this forum that when doing saws, they are tested cold, not warm like cars. In fact this was just addressed in another forum in the passed week. I also know you rip the cord for all you're worth, as if trying to start. So,,, about 8-9 pulls of cord each test, on each saw, with max pressure being reached at 4-6 pulls.

Went to shop. That gauge blew 92 on the 029. Would not screw into 066 as 066 has had a "kingsert" repair, or at least that's what Max called it. I would know it as a heli-coil, but anyway, that part is still on the plug and has been for I don't know how long. So, no definite reading on that one yet.

BOTH saws DO run, and quite well actually. Both are MM'd and tuned to fourstroke out of cut and be clean in cut, provided "the cut" isn't some rose bush or two inch thick branch but an actual "cut", like bar depth cut or something. Both saws start well when cold and always one (even half-hearted) pull when hot. Neither run any different when upright, upside down, sideways, pointed up or down or any other angle. The muffler was off the 066 a month ago and no scoring on it's piston. The 029's was off last week. Clean.

I didn't test due to failure to run or any performance related issues, only that I felt the flywheel should have offered more resistance than it did when I turned it, like I should have had to really grab it to turn it over, leastwise so I thought anyway. So, while the gauge(s) may be off, I'm still wondering about the porting info? Yes, the spark plug thread will be addressed, either through another repair if deemed salvageable or through another top-end, but woods-porting is still in this saw's future, and hopefully during this winter (off-season here). She is getting some age and I would like to go into next season with her fresh and lively!

Thanks a bunch so far!

Duane

 

[singletrack100]

FWIW, the saw was in the solvent tank 2 1/2 hours ago and blown dry. I just screwed the same plug, with it's "kingsert" or heli-coil or whatever, back into it. It hasn't been run since Sunday a week ago. Fired on the second pull with choke, flipped choke off, pulled and off to the races she went! No performance problems. An still interested in the porting info regarding porter's, how much, how to, what's done and included, what do I provide, etc..

 

[cutforfun]

You must have the valve at the end of the hose to get an actual reading on small two stroke motors

 

[sld961]

Like cutforfun said, you need a Schrader valve in the end of the hose. The combustion chamber is small enough on these engines that the extra volume of air in the hose essentially ads to the volume of the combustion chamber and gives low readings.

 

[singletrack100]

Copy, now that's something that makes sense. Unfortunately the only gauges I know of around here are the automotive type such as mine. I know there are still some old guys around here from not too long ago (15+ years ago) that did all this when logging was big here. I'm not to worried right now about either saw as I said they run great.

Who else besides Brad and Randy (Chimp, Mastermind) does the woods-porting? I'm not opposed to working with either of these gentlemen in case I've mistakenly alluded to that. i'm quite for it actually. I just know there are others as well and most of them all get along quite well and do good work. I just need to know details please... in the meantime, if I can find someone with one of those gauges we'll see what I can come up with.

Thanks gang,

Duane

 

[blsnelling]

I don't offer repairs and am turning down most port work. I do appreciate your consideration though!