Stihl 661's

[Rich Fife]

I have 2 older 661s to build... one will be a 90% parts gather and vuild while the other saw is complete and will be a ground up build.

 

[Rich Fife]

I think that’s a good example of how the manufacturers aren’t just leaving less on the table. They’re also doing a lot of things that are a challenge to correct. Add that to increasingly proprietary components that don’t cross between models and designed obsolescence. EPA restrictions and ultra-light designs further muddy the water.
For me, the new stuff is irritating. It costs a fortune and isn’t very durable.
But there is power in there. Sometimes with different strategies, but it’s in therecan agree with that!

Ok, I can agree with that!

 

[huskihl]

I don't disagree for the most part... but, they still have to comply with emissions etc... an already low intake with a large squish matched to port width limitations due to port/piston design kinda sucks IMO. Had they raised the Intake floor 5* on the 661 man those saws would be crazy strong and optimal for porting and heavy machine work. Again, just my opinion. So, it seems less is more on these newer saws.

The gains are still there, but they’re achieved differently. There’s still room to widen the exhaust, after lathe work you raise the exhaust a little you end up with more ex port area, little transfer work, little intake work….

The first kick at the cat nets maybe 10% gains. Make a few changes and you’re at 25-30% or more. Gotta think outside the traditional box on the front fed saws

I guess it’s all opinion anyway as to how they run, feel, etc

 

[huskihl]

I had a stock 661 for a whole. I also have a non decomp 066. The 661 is gone now. Maybe something was wrong with it. I don't know but it wouldn't stay with the 066 in the wood

The 661’s all run more similarly. You had a good early 066 that would blow the doors off a late 66, particularly a 660

 

[Ketchup]

I have 2 older 661s to build... one will be a 90% parts gather and vuild while the other saw is complete and will be a ground up build.

You should stroke one.

 

[Rich Fife]

You should stroke one.

I have a 462 case in a box waiting to be stroked/put together... just don't have the ambition at the moment... I have a bitter taste in the mouth from those 462s... lmao

 

[Rich Fife]

The gains are still there, but they’re achieved differently. There’s still room to widen the exhaust, after lathe work you raise the exhaust a little you end up with more ex port area, little transfer work, little intake work….

The first kick at the cat nets maybe 10% gains. Make a few changes and you’re at 25-30% or more. Gotta think outside the traditional box on the front fed saws

Can you elaborate with some insight on these things? I feel as if I'm struggling with th a elaborate types of saws... perhaps my way of thinking is backwards with them...

I guess it’s all opinion anyway as to how they run, feel, etc

Hmmmmm, maybe not Opinion but how one operates the saws... I run/test the saws a bit on the aggressive side... so I try to make them take a little abuse before they fall flat... I guess its a matter of finding how the saw likes to be used... I have yet to feel out a saw... if it doesn't meet my way Iof cutting, I don't like it. Lol

 

[huskihl]

Can you elaborate with some insight on these things? I feel as if I'm struggling with th a elaborate types of saws... perhaps my way of thinking is backwards with them...

Hmmmmm, maybe not Opinion but how one operates the saws... I run/test the saws a bit on the aggressive side... so I try to make them take a little abuse before they fall flat... I guess its a matter of finding how the saw likes to be used... I have yet to feel out a saw... if it doesn't meet my way Iof cutting, I don't like it. Lol

Any pics of what you did? Timing numbers, etc?

 

[Redfin]

Had they raised the Intake floor 5*

Here is piece to your puzzle.

 

[Rich Fife]

Any pics of what you did? Timing numbers, etc?

Id have to check to see if i have pics or a video... but, the stock numbers were 100/120/81 .035" squish
I ended up with 101/121/84 .025" squish...
It runs good... just not to my liking... I'm gonna bump the timing a little.

 

[Redfin]

You need lots more duration and less at the same time.

 

[Rich Fife]

 

[Rich Fife]

Got a pointer from a buddy... gonna try messing with the secondaries.

 

[Rich Fife]

Figured I'd finish this 661... as I'm too sore to lift weights. Lol.
Cut the squish and base, raised the transfers added fingers...
103*
125*/127*
85*
The video is the first fire/heat cycle...

 

[Ketchup]

What are your thoughts on the intake duration?

 

[Rich Fife]

What are your thoughts on the intake duration?

With the fingers and larger uppers, it seems fine. No stumble off idle, it's actually crisp... the guy has another 661, I'm thinking the next one I'll try 83* and do a comparison

 

[rpmtim]

Read this thread over the last day or two,.
It's talked me into, out of, and back in to having my 661 ported at least twice.

 

[Long Bar]

Read this thread over the last day or two,.
It's talked me into, out of, and back in to having my 661 ported at least twice.

My first post here, get it done you won't regret it...

 

[Moparmyway]

My first post here, get it done you won't regret it...

Welcome to OPE !!

Scott builds one heck of a 661 !!!

Would you mind if I asked you to please take a few different pictures of the muffler up close for us ?

 

[markds2]

My first post here, get it done you won't regret it...

Great to see you here Winston!