circle crank ms660

[Deets066]

Wonder if one of these fancy full circle cranks would work on my pipe and head saw

 

[Deets066]

 

[Moparmyway]

Wonder if one of these fancy full circle cranks would work on my pipe and head saw

Yup !!

 

[jmssaws]

I'm gonna try 98 123 78 and go wide.

 

[jmssaws]

Someone give me some more ideas,I'm shooting in the dark here.

Bounce some ideas around, let's learn something.

 

[Moparmyway]

So you're going to raise intake and exhaust, but leave transferr timing alone........will you be widening the transferrs ?

 

[jmssaws]

So you're going to raise intake and exhaust, but leave transferr timing alone........will you be widening the transferrs ?

Yes, I usually don't widen them. Probably just open them towards the exhaust a little.

 

[jmssaws]

I'm gonna flatten the uppers but no change in height

 

[Moparmyway]

So, opening the transferrs where they flow the most and making them flat at the top, while raising the exhaust to increase blowdown and raising the intake to trap even more ..........

Do you think the circle crank or the 288 piston is making this one run so well ?

 

[GoBigBlue1984]

Watching and waiting patiently. This is getting very good.

 

[Moparmyway]

View attachment 16444
Watching and waiting patiently. This is getting very good.

Yup

 

[jmssaws]

So, opening the transferrs where they flow the most and making them flat at the top, while raising the exhaust to increase blowdown and raising the intake to trap even more ..........

Do you think the circle crank or the 288 piston is making this one run so well ?

I haven't taken advantage of the 288 piston yet so I'm thinking it's all velocity.
It's as strong if not stronger than a ported saw completely stock. It does have compression but that's all. The carb still has the limiter caps. Lol

 

[awol]

If you get good gains just from working the transfers over, go ahead and add a pair of nice, deep, wide fingers over the intake!

 

[Redfin]

I'm gonna try 98 123 78 and go wide.

I think thats a dang good start. You will know right out of the gate if you need more intake.

 

[Redfin]

If you get good gains just from working the transfers over, go ahead and add a pair of nice, deep, wide fingers over the intake!

I missed this one typing mine. Adding fingers with this piston will hinder being able to use all the skirt witdh.

 

[awol]

The main advantage of the extra skirt width, is the ability to go wider with the intake and exhaust port. Adding fingers will not hinder that, plus the single ring, gapped over the intake port allows both a very wide exhaust, and nice deep, wide fingers.

 

[Red97]

Very interesting...

Not much help from me, (never been in a stihl)

But subscribed....

 

[Redfin]

The main advantage of the extra skirt width, is the ability to go wider with the intake and exhaust port. Adding fingers will not hinder that, plus the single ring, gapped over the intake port allows both a very wide exhaust, and nice deep, wide fingers.

This is 80 and as wide as I was willing to go for ring support with a 288 piston. I suppose I could have gone further at the bottom. I could have gone further without the fingers and Im now wondering if fingers was a good idea with this piston.

 

[jmssaws]

I'm gonna put a few tanks through it tomorrow to limber things up then do some grinding.

How wide of a exhaust have you guys gotten away with?

 

[jmssaws]

I'm going as wide as the intake can go,epoxy the lowers?