390xp

[SawGarage]

This 4 jaw chuck, each jaw is independent of the others, so you must adjust each one individually, way better to use 4 jaw when machining already made parts like this.

I guess is so you can adjust x axis and y axis when setting up the equipment, and if you know the exact center of the bore.. (not hard by knowing the dia, and triangulating to find CL) it's fairly quick after getting all the 'mechanicals' in place??


The mind-set is there, the hands-on as much ,well isn't...

cool... I want one

 

[parrisw]

I guess is so you can adjust x axis and y axis when setting up the equipment, and if you know the exact center of the bore.. (not hard by knowing the dia, and triangulating to find CL) it's fairly quick after getting all the 'mechanicals' in place??


The mind-set is there, the hands-on as much ,well isn't...

cool... I want one

No, you just bolt it to the plate, chuck the plate in the jaw, then you must set it square, meaning the bore parallel with the lathe, then use a dial indicator inside the bore, then turn the piece until the indicator reads 1/2thou or less runout.

 

[Logger4Life]

when you machined the squish band did you have to angle the band toward the combustion chamber a few thousands and if so how much? I will be doing the same thing tomorrow. I know from measuring the stock band depth that it slowly increases in depth until the combustion chamber chamfer.

 

[parrisw]

when you machined the squish band did you have to angle the band toward the combustion chamber a few thousands and if so how much? I will be doing the same thing tomorrow. I know from measuring the stock band depth that it slowly increases in depth until the combustion chamber chamfer.

2° taper is what I did.

 

[parrisw]

Got the squish band all done. Finally, relieved now. Got in a little trouble for doing it on Christmas day though!! LOL

 

[jropo]

Got the squish band all done. Finally, relieved now. Got in a little trouble for doing it on Christmas day though!! LOL

Nice work!
I got in trouble just for checking up on this tread on Christmas.
Is there any gains from smoothing out the dome at the top of the cyl.?

 

[NORMZILLA44]

Xmas or not, some thing's just can't wait Will!

 

[parrisw]

Nice work!
I got in trouble just for checking up on this tread on Christmas.
Is there any gains from smoothing out the dome at the top of the cyl.?

Yes, its gets done in conjunction with machining the base of the cylinder as well, smaller combustion chamber, higher compression.

 

[tlandrum]

how much did you take out of it will? it doesnt look like you cut much out. id like to see how much you gain in compression per say 10 thou of material removed. how much time will you have in it doing it this way as opposed to just doing a pop up? im not trying to give you a hard time. just trying to see where the gains will out weigh the cost and extra time of it all

 

[parrisw]

how much did you take out of it will? it doesnt look like you cut much out. id like to see how much you gain in compression per say 10 thou of material removed. how much time will you have in it doing it this way as opposed to just doing a pop up? im not trying to give you a hard time. just trying to see where the gains will out weigh the cost and extra time of it all

Hey, no problem at all. Time is a non issue for me since I enjoy doing this. If I had to get paid to do it, then ya, would be harder due to setup time, but I'll get faster. According to Eric he see's a 5-10 psi increase over a popup with same amount of material removed. I started with just going to remove .020, then I had to clean it up so its more likely in the .025 range maybe slightly more. I like trying different things, so its all good.

Time, yes this takes longer. Its my first time and it took me about an hour to cut the squish band the second time.

 

[Outlaw5.0]

How much is everyone cutting from the chamber?. My new 390Xp is at 150psi, the squish is .038-.039 currently. I thought of just cutting the base .015 and running a few tanks thru it, but I doubt it gain 25 psi or more.

My first MS460 I cut the squish band .010 and tightened the squish to .020, it ended up at 200 psi. Compression started at 160psi out of the box new.

 

[parrisw]

How much is everyone cutting from the chamber?. My new 390Xp is at 150psi, the squish is .038-.039 currently. I thought of just cutting the base .015 and running a few tanks thru it, but I doubt it gain 25 psi or more.

My first MS460 I cut the squish band .010 and tightened the squish to .020, it ended up at 200 psi. Compression started at 160psi out of the box new.

Are you sure youre 390 is at 38-39thou squish???? I've never seen one that high, all the ones I've done were under 30thou, this one is .028

 

[Outlaw5.0]

Checked it 3 times.

 

[komatsuvarna]

Hey, no problem at all. Time is a non issue for me since I enjoy doing this. If I had to get paid to do it, then ya, would be harder due to setup time, but I'll get faster. According to Eric he see's a 5-10 psi increase over a popup with same amount of material removed. I started with just going to remove .020, then I had to clean it up so its more likely in the .025 range maybe slightly more. I like trying different things, so its all good.

Time, yes this takes longer. Its my first time and it took me about an hour to cut the squish band the second time.

JMO, I think its worth the time just for the fact that later on down the road anybody can put a new Piston in if needed. 2 of my saws have popups now, but I think in the future Ill be sending them off to be cut on. Probably not that big of a deal if ya have the stuff to do it, But when Im old and grey, I dunno that I want to trying to find someone to cut me a piston for a 372 I ported 25 years ago .....just saying....:msp_smile:

 

[parrisw]

JMO, I think its worth the time just for the fact that later on down the road anybody can put a new Piston in if needed. 2 of my saws have popups now, but I think in the future Ill be sending them off to be cut on. Probably not that big of a deal if ya have the stuff to do it, But when Im old and grey, I dunno that I want to trying to find someone to cut me a piston for a 372 I ported 25 years ago .....just saying....:msp_smile:

Yep. Plus I heard the saw likes it without a popup, so I'm going to find out. I'll be doing a 372 next, since I'm pretty familiar with those I'll have a better idea on how well it works, and I have a pretty good running 372 to compare it to.

 

[NORMZILLA44]

Looking good Will Carry on!

 

[parrisw]

Looking good Will Carry on!

Soon!!

 

[jropo]

Are you sure youre 390 is at 38-39thou squish???? I've never seen one that high, all the ones I've done were under 30thou, this one is .028

What's the lowest?

 

[NORMZILLA44]

Well anticipated, the thing I like about you Will you take your time, and don't get in a hurry. That's qaulity work my friend! I would not have a problem with you working on any one of my saw's!

 

[parrisw]

What's the lowest?

All the ones I've done have been real close around .028 give or take a thou or 2 range. I've done machine work on 4 or 5 other 390's.

Well anticipated, the thing I like about you Will you take your time, and don't get in a hurry. That's qaulity work my friend! I would not have a problem with you working on any one of my saw's!

Thanks Norm.

Ya, I don't get in a panic about most things. The only time I try to be faster is when working on someone else's saw.