Stihl 066 timing numbers

[subhunter]

Does anyone have the numbers handy for the 066 stock? And numbers to shoot for when porting?
I am going to try to mod my 064 to an 066. I got a good buy on flea bay for one. Thanks in advance.......

 

[mdavlee]

It will depend on what cylinder you're using. The newer cylinders have exhaust duration close to 170° stock and intake was over 160° if I remember right. The older mahle cylinders with no decomp I haven't personally used one so I don't have any numbers. I think mtngun has timing numbers for a lot of 066 cylinders.

 

[subhunter]

It is an older one with out the decomp. I hope it gets here tomorrow. I already have the piston. What would be some good timing numbers to shoot for or jsut leave it as is and widen? I know I am getting ahead of myself :big_smile:

 

[mdavlee]

I guess you'll have to wait and see what you have to work with. I want to try one of those older cylinders out and see if it does make any more power than a newer stihl brand cylinder.

 

[mtngun]

BrMorgan and I posted #'s for the old jugs a year or two ago, but the search function still doesn't seem to work for older threads.

From memory, some, but not all, of the old jugs were about 150 intake & 160 exhaust. Compared to the newer ones which are about 160 intake and 170 exhaust.

 

[AUSSIE1]

If you want no's for porting with a degree wheel, use it to determine the current stock no's.
The first thing, before knowing in which direction you will go is to know your stock no's, post them here, then the experienced can direct you.

 

[subhunter]

Alright I got the jug and it looks to be in decent shape. I washed it up and slapped it on and the damn piston hits the crank case:msp_mad: So now i am going to have to shave a bit of metal off the intake side of the case. Yesterday I went ahead and drilled and tapped the bolt holes to m6x25. Now on to trimming the case a tad.....Then I will try to get some numbers with the degree wheel. Thanks for the replies

 

[subhunter]

WOW! what a tedious task trying to grind a small lip off the crank case. Some shavings ended up falling down but I believe I got them out rinsing with wd40 and either. I put the degree wheel on and came up with ex- 174 intake-160 bd-26 and the squish without a gasket was .013. I am going to run to the dealer later and get a stock gasket. Do these numbers seem close? I checked the 4 times and came up same all but one and that time TDC was out. So with the current numbers for a work saw would it be best to leave it as is and just widen? I drew the porrts on the piston and it seemed to definitely have some room for widening. This is the second saw I have used a degree wheel on and compared a 372xp's numbers this one seems to be about where it needs,but that is the purpose of this thread...???

 

[mtngun]

ex- 174 intake-160 bd-26 and the squish without a gasket was .013. So with the current numbers for a work saw would it be best to leave it as is and just widen?

Set squish and widen. :msp_wink:

Thanks for the numbers. No surprise on the port timing, as it does seem to vary from one jug to the next with no clear trend.

 

[AUSSIE1]

Set squish and widen. :msp_wink:

Thanks for the numbers. No surprise on the port timing, as it does seem to vary from one jug to the next with no clear trend.

Mtngun, does that seem a little high to you on the Ex without base gasket?

 

[mtngun]

Mtngun, does that seem a little high to you on the Ex without base gasket?

Maybe a bit, but if you had 10 people measure the same jug, you'd get 10 different results, so I don't sweat a few degrees.

 

[subhunter]

I may be taking the reading a little early or late even. It sometimes confuses me when to take the reading. I have read as soon as you see the light but I like to take the reading when I can just barely see over the crown and into the jug. The numbers did read the smae on the up and down stroke so I called it good. I got a little more work done on the piston windows and measured the squish band for a very small pop up.

 

[mdavlee]

That sounds pretty close to what I got when I checked mine. I can check it again when I get home for reference.

 

[AUSSIE1]

I may be taking the reading a little early or late even. It sometimes confuses me when to take the reading. I have read as soon as you see the light but I like to take the reading when I can just barely see over the crown and into the jug. The numbers did read the smae on the up and down stroke so I called it good. I got a little more work done on the piston windows and measured the squish band for a very small pop up.

Personally I don't go by light as it can be deceiving and go by spotting when the port opens.

 

[subhunter]

I got a bit more done on the 064. I had a .014 pop up cut into the piston and did some widening. I think it turned out pretty good. I still have not got it all the way back together but will tomorrow. Here is a few pics.

Where i had to trim the case for the piston to clear

Pop up

I did get the jug back on and gave it a pull and it has quite a bit of compression. Just hopefully it will run

 

[blsnelling]

It looks like you only clearanced the case on the intake side. It should be even on both sides. Perhaps it's just the picture.

 

[subhunter]

No you are correct. When the piston would not clear BDC I bolted it down with all four bolts but left just enough in each loose so I could view inside. It seemed to to me it was only hitting on the intake side? I cut it out as you see and then it rotated freely. Maybe I missed something? It doesnt not hit at bdc now.

 

[subhunter]

I got to really put this saw into some wood today. last week I ran it a little and it started acting up after it got hot. The symptoms were that it would bog trying to go WOT. I thought maybe tank vent or fuel line/filter. I replaced the vents line and it seemed to run well,in the shop and stayed running for well over 15 minutes idleing and blipping the throttle. So I thought problem solved.well wrong today after three semi-long noodling cuts same problem. Not sure whats up. I am not sure if the tank vent can keep up or if its another issue. I did go through the carb and it looked very clean and the kit was put in it last fall, so that points me away from carb. I am going to get a new fuel line and filter in a little bit but just wanted to put this out to see what the incredible minds here had to say.....

 

[subhunter]

update

Alright as to the last posted problem. Turns out it was the air filter. Saw would run strong with out it but with filter on after a few cuts just would bog down, almost like the brake was engaged. I went and bought a new HD filter today and it runs really well now. I could not believe that it was wanting to pull that much more air through. Before that filter had been in use for a while with a stock 064 and worked well. After installing the new one the saw was super rich from the previous setting. I hope to get it into some more wood soon.

 

[mtngun]

What was wrong with the old air filter ? Was the old filter also an HD1, or one of the previous versions ?