Can old 346xp be fitted with NE346xp P&C?

[bjorn773]

I already went through everything and blew mine up.

I got the kit, widened the exhaust and intake port, lowered the intake slightly, and cleaned up the transfers (didn't feel comfortable widening the transfers). Threw it on a husky 350 and did a quick muff mod. It was cutting great and had very nice power. Running safety chain, it beat my buddies ported 026 (which is 15-20% faster than when it was stock). So I was pretty happy. Then one of the wrist pin clips let go. Didn't even have a tank through it yet. Lucas replaced the kit, so I now I'm starting over.

I got the kit already, but this time I ordered a OEM ring and clips. Plus I'm switching over to a 3/8" 16" bar. A pop-up might be in order too.

Yikes, now I'm nervous. This is not the prettiest looking aftermarket p&c. Well, no guts no glory. I'll try it. I can always put my oe cylinder and meteor piston back in if it blows up.

 

[bjorn773]

Once again, I should have searched prior to asking questions. I am gonna attempt to get some timing numbers on this p&c. I'll post whatever numbers I can come up with and see if they make any sense to the pro's here. I'll do the stock p&c first, since they're on the saw currently.

 

[bjorn773]

Ok, I took some timing readings. Be kind, I'm a virgin at this stuff.

Exh begins opening @85*ATDC
Exh fully open @18*BBDC or 162*ATDC
Int begins opening @82*BTDC
Int fully open @28*BTDC
Transfer opens @68*BBDC or 112 ATDC

Do these sound like logical numbers?
Am I interested in the opening numbers primarily or the duration?

 

[roncoinc]

Wheres the link ???

i just got an almost like new 350 that was gassed..would like to try the aftermarket 346ne kit on it..

wheres the link ?
tnx..

 

[poulson01]

I run a 50cc cyl/pis on my oe346xpg

Me too. My favorite saw.

Actually all 50cc saws are better off with .325 chain, at least in hardwood, providing you coose the right chain models (.325 chain vary a lot more in design and cutting ability than 3/8" chain does).

I run 16" RSC and an 8 pin.....in hard wood. Like butter!

 

[SawTroll]

Me too. My favorite saw.



I run 16" RSC and an 8 pin.....in hard wood. Like butter!

Sounds good, but change to Oregon LP if you want to save a few tenths of a second in each cut....

 

[poulson01]

I file!

Edit: LP .325 or 3/8?

 

[bjorn773]

I'll have to dig around for the source for my p&c. I know I got it off ebay.

 

[bjorn773]

Here's the link.

http://cgi.ebay.com/Cylinder-piston...emQQptZLH_DefaultDomain_0?hash=item5ad7b9d6fa

 

[nanuk]

can these A/M cylinders really increase performance on an H350?

would be a worthy upgrade if so... also, with the "riser" of the 350, one could probably hide one under a 340, and win beer!

 

[bjorn773]

The biggest difference I saw between the 350 cylinder and this one is the shape and size of the transfers. The 346 has kinda fat rounded transfer ports with a nice bulging out type arc to them(looking at the casting from the outside). It seems like it would breathe better. I just sold my 350, so I can't take pics of the cylinder for comparison. Seems to me the 350 had screw on transfer covers that could be removed from the outside... would make modding the transfer ports easier. The 346 has no such access covers. You see a fair amount of conversation around here about putting the 346 topend on 350's, so they must provide an improvement in performance.

 

[bjorn773]

Ok, I have my new numbers on the timing. Anyone know how these sound... this is the oe cylinder. If these look correct, I'll measure my aftermarket cylinder for a comparison.


Intake 69* BTDC
Exhaust 105* ATDC
Transfer 121* ATDC

 

[Tzed250]

Ok, I have my new numbers on the timing. Anyone know how these sound... this is the oe cylinder. If these look correct, I'll measure my aftermarket cylinder for a comparison.


Intake 69* BTDC
Exhaust 105* ATDC
Transfer 121* ATDC

You should limit the questions to one thread. makes thing much easier.


.

 

[SawTroll]

I file!

Edit: LP .325 or 3/8?

Oregon LP in .325.

 

[roncoinc]

The biggest difference I saw between the 350 cylinder and this one is the shape and size of the transfers. The 346 has kinda fat rounded transfer ports with a nice bulging out type arc to them(looking at the casting from the outside). It seems like it would breathe better. I just sold my 350, so I can't take pics of the cylinder for comparison. Seems to me the 350 had screw on transfer covers that could be removed from the outside... would make modding the transfer ports easier. The 346 has no such access covers. You see a fair amount of conversation around here about putting the 346 topend on 350's, so they must provide an improvement in performance.

Heres a pic of a 350 cyl i worked on today,wont clean up well enough so am thinking to replace with an aftermarket 346 p&C if there are no problems with intake and exhaust..

 

[bjorn773]

You should limit the questions to one thread. makes thing much easier.


.

You're right, but at the time of posting I wasn't having much luck getting the port timing question answered. I figured not everyone reads every post, so I would try to get the attention of more avid porters by starting a timing post. Perhaps not the best approach. Anyway, I still have not heard whether my new numbers make any more sense than the previous numbers did. ????

 

[bjorn773]

I finally got my new cylinder bolted on and took some measurements.

Intake 77 deg
Exhaust 107 deg
Transfer 130 deg

My OE had:
Int 70
Exh 107
Tra 123

I know I posted different numbers a while ago, but I've since improved my degree wheel mount. These should be more accurate numbers.

So, my intake has 14 degrees more duration than stock
Exhaust is identical
Transfers have 14 degrees less duration than stock

Should I raise my transfers by 7 degrees to at least match stock? What about the exhaust? I will appreciate any input, thanks.

 

[bjorn773]

These were measured without a base gasket. The gasket miked out at .021"
I milled the cylinder for .016" squish. Thanks.

 

[nmurph]

bjorn,

any news on this project? i have three 346's arriving today. cylinders may need replacing and i am thinking about using an aftermarket P/C.

 

[bjorn773]

The aftermarket p&c will fit, though the castings are pretty rough. I got mine off ebay for $100. I was planning to port it anyway, so the castings were not as much of a concern. I had some minor clearance issues, had to grind a little of the crankcase out to accomodate the larger piston. Otherwise, it screams. Truth be told though, I've only used it to do post port test cuts. I hope to run it soon, too many other things to do in the summer months.