372XP free bee

[TRI955]

I raised this one more than the last and bigger on the windows on the piston, there is a noticeable difference in my opinion.

 

[ronT2]

Cheater!!!

Really I’m just jealous. I get to do all that with my foredom. I like the windowed piston to.

Nice job, looks like it’s running great!

 

[parrisw]

I raised this one more than the last and bigger on the windows on the piston, there is a noticeable difference in my opinion.

Cool, thanks. I just doing a 372 now. Maybe I'll go higher on this one. I just cut windows in it, by hand BTW, you cheater!!! Its the first time I've tried that.

 

[RiverRat2]

I raised this one more than the last and bigger on the windows on the piston, there is a noticeable difference in my opinion.

Check your PM's

 

[blsnelling]

Hey, do you guys feel that it helps to raise that part above the base? I've always gone flush with the base.

I raised this one more than the last and bigger on the windows on the piston, there is a noticeable difference in my opinion.

I only take mine up to even with the base. LINK

 

[Andyshine77]

Even with the base sounds about right to me, you don't want to lose too much base pressure, if you do the charge will just sit in the transfers IMHO.

BTW Mike the saw is running great, and 175psi is good for a 372.

 

[Chesterewers]

Even with the base sounds about right to me, you don't want to lose too much base pressure, if you do the charge will just sit in the transfers IMHO.

BTW Mike the saw is running great, and 175psi is good for a 372.

I am still waiting for my piston to get back from having the skirts ceramic coated for friction reduction, when I do I am going to use a degree wheel to check timing, my concern is I may have opened up the intake on the lower side the timing a little too far, not yet sure, I tried to keep my grinding minimal by eye but should I be concerned about that sort of change? I am thinking if I did take too much out just use jb weld as I read someone did on the exhaust. What do you all advise if it is open a little too far? On the exhaust timing I used a hand file to prevent removing too much material at once and believe it should be okay.

 

[AUSSIE1]

Hey, do you guys feel that it helps to raise that part above the base? I've always gone flush with the base.

You can go up to 5mm Will.

 

[komatsuvarna]

Subscribing,,, and have a few questions.

Does it do any good to window the piston on a 372xp unless your gonna mill the cylinder skirt at or above the base?

What kinda 90* tools do you guys use to widen the transfers?

 

[AUSSIE1]

Subscribing,,, and have a few questions.

Does it do any good to window the piston on a 372xp unless your gonna mill the cylinder skirt at or above the base?

What kinda 90* tools do you guys use to widen the transfers?

Personally I haven't determined whether a windowed piston makes any difference.

Since raising that portion of the cyl a couple of years ago, I've been using the 064 piston which has windows. The reason for this piston being used wasn't for the windows but a means to create a popup and benefit from wider skirts. This in the BB kit of course.

I use a contra angle (90°) for changing the duration etc of the upper transfers.

Widening isn't really the purpose, more like redirecting the flow toward the back of the cyl.

 

[komatsuvarna]

Widening isn't really the purpose, more like redirecting the flow toward the back of the cyl.

Thanks Al, Thats what I meant. I havent really got these porting terms down pat yet.

 

[AUSSIE1]

Thanks Al, Thats what I meant. I havent really got these porting terms down pat yet.

Yeah sure mate, I thought that's what you meant, but thought I better throw that in just in case.

 

[blsnelling]

Subscribing,,, and have a few questions.

Does it do any good to window the piston on a 372xp unless your gonna mill the cylinder skirt at or above the base?

What kinda 90* tools do you guys use to widen the transfers?

I would not window the piston unless raising the cylinder sides. There would be no flow through the windows otherwise.

 

[komatsuvarna]

I would not window the piston unless raising the cylinder sides. There would be no flow through the windows otherwise.

Kind of what I thought, but just making sure.

One more question, Any reason I cant raise the cylinder sides without milling the cylinder to get the squish tighter? I checked my 372 once, but cant remember what the squish was,,,,but seems like it was close to .037/.040,,, somewhere in that area. I dont have anyway to mill the cylinder base and was just gonna remove the base gasket as long as the squish wasnt too tight, which I dont think it will be.

 

[blsnelling]

You'll be almost perfect with removing the gasket. Go for it.

 

[parrisw]

You can go up to 5mm Will.

Thanks AL! I may just do that.

 

[Chesterewers]

Yeah sure mate, I thought that's what you meant, but thought I better throw that in just in case.

hello on a 372 timing for the intake floor I took it down .60-.65 open more on timing, on the exhaust side I raised it towards the top close to .60 does that sound like it will work? I have widened intake and exhaust a little also and can go a little bit more on each. Let me know thanks.

 

[parrisw]

hello on a 372 timing for the intake floor I took it down .60-.65 open more on timing, on the exhaust side I raised it towards the top close to .60 does that sound like it will work? I have widened intake and exhaust a little also and can go a little bit more on each. Let me know thanks.

How did you come up with those numbers? You really need a starting and finishing point, check with accuracy with a degree wheel.

 

[Chesterewers]

How did you come up with those numbers? You really need a starting and finishing point, check with accuracy with a degree wheel.

I have a micrometer and 2 cylinders to measure off from. the one I ported and the one that is stock. I havn't put it on the saw yet to put a degree wheel on it.

 

[parrisw]

I have a micrometer and 2 cylinders to measure off from. the one I ported and the one that is stock. I havn't put it on the saw yet to put a degree wheel on it.

Sorry, I'm not really getting what your doing? Measuring a cylinder that has already been ported? Then transferring that to a cylinder to be ported? How are you getting your measurements?