First port and question about timing for 346xp cylinder

[Headhunter1111]

Trying my hand at bringing a dead 350 to life. I’ve read about everything I can get my hands on about porting these 350,346,353’s.
I fell for the slick marketing of the Hyway titanikel cylinder (this one was advertised as a 353 kit) and the “pop up” piston.

I have read quite a few threads by MATTYO, MasterMind and TreeMonkey and all seem to run similar numbers for the 346xp, or 350 to 346.
my question is in regards to setting up port timing and the transfers on this saw. I worked the bearing cup to get .023 squish and my timing numbers currently are Exhaust 108, Intake 78, and transfers open at 136°
I’m a bit confused by the transfer timing as all of the gentlemen I named above have listed around 123-124° for the transfers (and at least one specifically states he doesn’t really mess with the upper transfers)
This 10° difference seems pretty substantial. Am I reading the numbers wrong or do I have a weird p&c?

How would this affect the saws performance compared to the 124°?
Most of what I’ve learned so far has been in regards to intake and exhaust so I’m curious to learn about upper transfers and how lower transfer height affects saw performance as well as why it might be better to raise these?

Just trying to learn something. Thanks in advance.

 

[davidwyby]

@huskihl

 

[huskihl]

@huskihl

Present.

Not sure about the transfer height. Recheck using a ring in the bore and feel for the height with a pick. Or remove the transfer covers if it has them. 122-125 would be where I’d open them with the exhaust at 108 if it’s a 346 style bottom fed cylinder. I’d probably open them a little bit lower if it was the 353 type cylinder with the removable covers. I’ve only ported a couple 353’s and don’t really have a solid recipe for them yet

 

[andyshine77]

I've made up a few wicked strong 346's

107 on the exhaust
122 - 121 on the transfers. I angle them up.
Intake 78

That's with the squish bad cut and Squish set to .016" blend the transfers to match the case and gasket, and I open them up a little, but nothing crazy.

357 intake boot, carb and filter, tight fit but it does fit.

 

[Headhunter1111]

@huskihl I will recheck the transfers. It is in fact the 45mm “big bore” cylinder 346xp style. I’ll try to load some pics of what I’ve done so far. Opened up the bearing cup/riser to match the cylinder and then beveled the lower transfers, took off some of the sharp edges and set the squish.
@andyshine77 I’m considering the 357/359 filter and holder. Have you run the stock 350 carbs with that set up or do you think it needs more fuel as well?

Could either of you gentlemen, or anyone else for that matter, tell me how the tranfer height affects performance in these saws? I’m really having trouble comprehending how transfer height affect the power band.

 

[Ketchup]

At 136 your transfer uppers have too short of duration. They don’t provide enough fuel for max performance. Maybe you read them off the top of the popup?

 

[huskihl]

@huskihl I will recheck the transfers. It is in fact the 45mm “big bore” cylinder 346xp style. I’ll try to load some pics of what I’ve done so far. Opened up the bearing cup/riser to match the cylinder and then beveled the lower transfers, took off some of the sharp edges and set the squish.
@andyshine77 I’m considering the 357/359 filter and holder. Have you run the stock 350 carbs with that set up or do you think it needs more fuel as well?

Could either of you gentlemen, or anyone else for that matter, tell me how the tranfer height affects performance in these saws? I’m really having trouble comprehending how transfer height affect the power band.

Raising the uppers will move the power band up

 

[Headhunter1111]

At 136 your transfer uppers have too short of duration. They don’t provide enough fuel for max performance. Maybe you read them off the top of the popup?

I measured them looking through the spark plug hole just as I saw the top of the transfer at the edge of the piston, not the pop up. I checked it several times to be sure I was reading the degree wheel right. I also noticed the top of the piston never dropped below the bottom of the transfer but kept a portion of it covered. I will put the thing back together and attempt some pictures. Thank you for explaining the problem with the low transfers that clarifies it for me a lot.

 

[Wonkydonkey]

It’s common to get these errors looking through the exhaust to try and get the transfer #.

although it’s a pain setting it up 0* tdc then popping of the cylinder and inserting a ring then carfully putting it back with out moving the ring. It’s the way to get an accurate # of the transfers.

 

[Ketchup]

I measured them looking through the spark plug hole just as I saw the top of the transfer at the edge of the piston, not the pop up. I checked it several times to be sure I was reading the degree wheel right. I also noticed the top of the piston never dropped below the bottom of the transfer but kept a portion of it covered. I will put the thing back together and attempt some pictures. Thank you for explaining the problem with the low transfers that clarifies it for me a lot.

That sounds right. You probably just have a goofy jug. I would definitely raise them.

10 degrees is kind of a lot to raise. Be careful you don’t grind through the tunnel wall.

 

[ZukiRyder400]

Present.

Not sure about the transfer height. Recheck using a ring in the bore and feel for the height with a pick. Or remove the transfer covers if it has them. 122-125 would be where I’d open them with the exhaust at 108 if it’s a 346 style bottom fed cylinder. I’d probably open them a little bit lower if it was the 353 type cylinder with the removable covers. I’ve only ported a couple of those and don’t really have a solid recipe for them yet

^^Some solid stuff Kev.

 

[Mastermind]

I've made up a few wicked strong 346's

107 on the exhaust
122 - 121 on the transfers. I angle them up.
Intake 78

That's with the squish bad cut and Squish set to .016" blend the transfers to match the case and gasket, and I open them up a little, but nothing crazy.

357 intake boot, carb and filter, tight fit but it dies fit.

This guy's 346 beat us all.....badly.

Pay attention to what he's saying.

 

[ZukiRyder400]

I've made up a few wicked strong 346's

107 on the exhaust
122 - 121 on the transfers. I angle them up.
Intake 78

That's with the squish bad cut and Squish set to .016" blend the transfers to match the case and gasket, and I open them up a little, but nothing crazy.

357 intake boot, carb and filter, tight fit but it does fit.

I might try .017" and .040" out of the band on a 353 cylinder I am getting. Might try a 110* EX and super short BD on the primaries, like 12-14* (122-124* timing) , secondary uppers at about 127-128. Intake isn't gonna be widened at all, as I like snappiness . Gonna leave the lowers stock, I am not going to case match them.

 

[huskihl]

I might try .017" and .040" out of the band on a 353 cylinder I am getting. Might try a 110* EX and super short BD on the primaries, like 12-14* (122-124* timing) , secondary uppers at about 127-128. Intake isn't gonna be widened at all, as I like snappiness . Gonna leave the lowers stock, I am not going to case match them.

14° isn’t super short bd if the ex is low and wide with a good hole in the muffler. That’s my normal work saw stuff. But you knew that

 

[ZukiRyder400]

An

14° isn’t super short bd if the ex is low and wide with a good hole in the muffler. That’s my normal work saw stuff. But you knew that

Its just shorter than what I am used to seeing/hearing/grinding etc. if ya get what I'm a sayin. And

I deed. lol

 

[ZukiRyder400]

@Headhunter1111 All in all, I would listen to both Huskihl and Andyshine. Personally I have not ran one of Andys 346s but they look great. And Kevin builds a freakin torque monster 346.

 

[Mastermind]

Its just shorter than what I am used to seeing/hearing/grinding etc.

I use a little longer blowdown on quad ports.....but 14 on a two port motor is about right on in my mind too.

 

[Headhunter1111]

This guy's 346 beat us all.....badly.

Pay attention to what he's saying.

@Headhunter1111 All in all, I would listen to both Huskihl and Andyshine. Personally I have not ran one of Andys 346s but they look great. And Kevin builds a freakin torque monster 346.

Duly noted gents. I appreciate the wealth of knowledge available at your finger tips on this forum. Pretty cool stuff. I did not get pics today but am hoping that Sunday I can measure the transfers again.
Anyone have a suggestion on a good right angle tool that’s not going to put me in the poor house?

 

[Mastermind]

Duly noted gents. I appreciate the wealth of knowledge available at your finger tips on this forum. Pretty cool stuff. I did not get pics today but am hoping that Sunday I can measure the transfers again.
Anyone have a suggestion on a good right angle tool that’s not going to put me in the poor house?

I've got the MC182 from CC Specialty. It's a good tool.....but yeah, pretty pricey.

A few guys have found a cheaper alternative, maybe they can weigh in with details.

 

[Ronie]

I got one of these off Aliexpress, it seems to work ok but I can't say how long it will last.
https://www.aliexpress.com/item/1005002982012255.html?spm=a2g0s.9042311.0.0.dcd44c4dSC7oYz