Snellerized Saws Conquers the 75cc 372XPW

[blsnelling]

Have you put an X-Torque carb on a 71cc cylinder, I put one on my 2171 that Jason ported, made a noticeable difference


Sent from my iPhone using Tapatalk

Several. I put them on 390XPs and 395XPs as well.

 

[Chainsaw Jim]

Port timing numbers are different, you have to use a degree wheel, as .020" .040" is a bit hard to eye up lol.

BTW them saws run well enough, I guess.[emoji6]

Sent from my HTC One_M8 using Tapatalk

That's a low blow man.
I measured them. You don't need a degree wheel to compare two jugs side be side with a micro ruler. The two I have are identical. That's not to say they don't vary when comparing molds at the factory like many of the Stihl jugs.

 

[Mike Gott]

Several. I put them on 390XPs and 395XPs as well.

Does it take much to put on a 390? I want to put one on my 2186


Sent from my iPhone using Tapatalk

 

[blsnelling]

I'm holding an oe 372 and a 75cc cylinder in my hands side by side and the only difference between the two cylinders is the restricted transfer tunnels and bore size. The ports are all identical shape and location. Exact same timing.

Port timing numbers are different, you have to use a degree wheel, as .020" .040" is a bit hard to eye up lol.

BTW them saws run well enough, I guess.[emoji6]

Sent from my HTC One_M8 using Tapatalk

That's a low blow man.
I measured them. You don't need a degree wheel to compare two jugs side be side with a micro ruler. The two I have are identical. That's not to say they don't vary when comparing molds at the factory like many of the Stihl jugs.

As @Andyshine77 already pointed out, both the exhaust and transfers are higher on the 71cc cylinder. You will never find the transfers at 130° on a 71cc 372XP cylinder.

 

[blsnelling]

Does it take much to put on a 390? I want to put one on my 2186


Sent from my iPhone using Tapatalk

Should be a direct bolt on. I forget if you need the dropped choke rod.

 

[Mike Gott]

Should be a direct bolt on. I forget if you need the dropped choke rod.

I was wondering about that, takes less than it does to put one on the non-xtorque 372's then


Sent from my iPhone using Tapatalk

 

[blsnelling]

I was wondering about that, takes less than it does to put one on the non-xtorque 372's then


Sent from my iPhone using Tapatalk

Correct. The intake boot on the 372 has to be either trimmed and rotated or replaced with one from a 385/390. You also have to use the XTorq throttle cable holder and filter adapter. This is because the bolts are straight across on the standard 372 and different heights on the others.

 

[weimedog]

Correct. The intake boot on the 372 has to be either trimmed and rotated or replaced with one from a 385/390. You also have to use the XTorq throttle cable holder and filter adapter. This is because the bolts are straight across on the standard 372 and different heights on the others.

If you use a 385/390 boot then it has to either have the intake casting shimmed up or squeeze down the boot to a smaller diameter as the intake is smaller on a 372 conventional than either the x-torque or 385/390...then you have to decide what to do with that "step" from the larger diameter boot to the smaller diameter intake...

You have a pic on which approach you use?

 

[Mike Gott]

Correct. The intake boot on the 372 has to be either trimmed and rotated or replaced with one from a 385/390. You also have to use the XTorq throttle cable holder and filter adapter. This is because the bolts are straight across on the standard 372 and different heights on the others.

Yup that's what I did on my 2171, I trimmed the ears on the 71 intake boot and used everything else from the x-torque carb/air filter assembly


Sent from my iPhone using Tapatalk

 

[Mike Gott]

If you use a 385/390 boot then it has to either have the intake casting shimmed up or squeeze down the boot to a smaller diameter as the intake is smaller on a 372 conventional than either the x-torque or 385/390...then you have to decide what to do with that "step" from the larger diameter boot to the smaller diameter intake...

You have a pic on which approach you use?

All you need to do is trim the ears of the flange and rotate it, I cut the impulse grommet part off too, when you rotate it, it interferes with the top cover


Sent from my iPhone using Tapatalk

 

[Andyshine77]

That's a low blow man.
I measured them. You don't need a degree wheel to compare two jugs side be side with a micro ruler. The two I have are identical. That's not to say they don't vary when comparing molds at the factory like many of the Stihl jugs.

Low blow?? That was not my intention. With that said, yes you have to degree the cylinder that's the only real accurate way to get port timing.

Sent from my HTC One_M8 using Tapatalk

 

[jmssaws]

Low blow?? That was not my intention. With that said, yes you have to degree the cylinder that's the only real accurate way to get port timing.

Sent from my HTC One_M8 using Tapatalk

Wrong.
Shawn carr measures port timing and it's much more accurate.

 

[Andyshine77]

Wrong.
Shawn carr measures port timing and it's much more accurate.

I have no doubt their other methods. Eyeballing is not one of them, and that was my point and you know that. You seem quite moody.

Unfortunately Brad's threads seem to bring out the worst in people. Some things just never change.



Sent from my HTC One_M8 using Tapatalk

 

[Chainsaw Jim]

This degree wheel hocus pocus crap is getting old. I think it's all about deterring folks from ever trying by making it look too complicated. Yes it's necessary to use one when the cylinder is bolted on the case or when the only thing you have to go by is degree numbers, but not when you are comparing jugs sharing the same stroke with a micro ruler.

So I pulled another 372 50mm jug off the shelf to compare and it has the same exhaust timing but the transfers are a couple degrees higher. So that makes all three that I have with the same exhaust and intake timing, but only two of three sharing the same transfer timing.
So apparently it would be like five people arguing over 046 stock numbers.

 

[Andyshine77]

This degree wheel hocus pocus crap is getting old. I think it's all about deterring folks from ever trying by making it look too complicated. Yes it's necessary to use one when the cylinder is bolted on the case or when the only thing you have to go by is degree numbers, but not when you are comparing jugs sharing the same stroke with a micro ruler.

So I pulled another 372 50mm jug off the shelf to compare and it has the same exhaust timing but the transfers are a couple degrees higher. So that makes all three that I have with the same exhaust and intake timing, but only two of three sharing the same transfer timing.
So apparently it would be like five people arguing over 046 stock numbers.

It's not complicated in any way. The why you word your responses is very defensive, no need to huff and puff.

Take care and take it easy, fellow chainsaw enthusiast.

 

[Big_Wood]

I did. All I replaced was the P&C, and intake boot.

so your still running the heavier XT flywheel?

Should be a direct bolt on. I forget if you need the dropped choke rod.

no choke needed. bolt and go. i find they run better with the devider still in there.

 

[jmssaws]

I measure the exhaust and transfers height with a caliper when I'm digging through my 066 cylinders looking for a good one.
Now that I've done it a bunch I can take a cylinder and measure from the base and know almost exactly where the exhaust and transfers are,between a good cylinder and a bad one can be 030 to 060 or more difference. I don't port this way but I can get really close by measuring.

 

[blsnelling]

This degree wheel hocus pocus crap is getting old. I think it's all about deterring folks from ever trying by making it look too complicated.

Getting old? Trying to make it look too complicated? Where in the world did you get that?

 

[Mike Gott]

so your still running the heavier XT flywheel?



no choke needed. bolt and go. i find they run better with the devider still in there.

Oh really, I pulled the divider out when it on my 71


Sent from my iPhone using Tapatalk

 

[jmssaws]

Oh really, I pulled the divider out when it on my 71


Sent from my iPhone using Tapatalk

Sup mike?
I always pull the divider.