husqvarna 350/351 to 346xp conversion

[locofrog]

ok being a car guy and a chainsaw guy has finally crossed paths. loving the imports i've seen many motor swaps over the years and currently have a half dead in the water project of my own in a 2jz-gte 240sx. now i dont have alot of time for the car because of all the saw work ive took on. but i've been hankering to do a motorswap anyway.
that brings us to the 350/346xp conversion. cheap chasis with a more impressive powerplant. i just need to know what all goes into a swap like this as far as parts. do i need the big bore kit, or should i go with the more standard sized cylinder. what carb to run on it. i plan on porting but i doubt i'll do a popup or anything. or is there a better swap i can do that'll yield better results. maybe brad or some of the other guys that have done stuff like this can chime in. any help is appreciated.

loco

 

[moody]

In the grand scheme of things its fairly straight line conversion. Use a 340,345, or 350 case and crank there will be no difference between those, get a riser and 346 top end.

 

[rupedoggy]

Buy the 346 piston and put it in your 350. Reach under that flap in the muffler and hog it out with you dremel. Do the mods, porting if you still want more.

 

[procarbine2k1]

http://www.arboristsite.com/chainsaw/204481.htm

Some good reading, 345 to 346 conversion that Stumpy did a while back.

 

[sunfish]

The 350/351 in your title? Not the same saw.
351 has a metal case and is the predecessor to the 353.

 

[nmurph]

The 350/351 in your title? Not the same saw.
351 has a metal case and is the predecessor to the 353.

Yep, straight swap as is a 350.

If you can read this, thank a 346

 

[locofrog]

i had done a fair bit of reading on this before i posted but was evidently still unclear about things. i realize the 351 was a mag saw, but i thought the conversion would work on it as well. maybe i misunderstood... stuff runs together when researching sometimes. now i gotta go read that thread by stumpy. thanks guys for the advice.

loco

 

[UK Rich]

Stuff like this makes me wish I'd kept my old 350.

 

[nmurph]

Here are the basics-

340/345 -> 346 ----need piston/cylinder and riser. These saws are clamshell with the cylinder split at the crank. The riser serves as the base of the cylinder to cap the crank. (I believe the carb is different but the stock carb will work)
350 -> A 346 will bolt on. This saw comes with the riser capped by a pro-style cylinder and a plastic crankcase. The piston is dished.
351 -> It is a direct swap with a 346 cylinder. It is an older version of the 353 with a magnesium crankcase.
353 -> It is a direct swap with a 346 with a magnesium crankcase. The 353 is not as strong as an NE but is close to an OE.

Also, the early 350's and 351 were 44mm and used the same cylinder with different pistons. The 350 was upgraded to 45mm bore and used the same cylinder as the 353, with the difference being the piston (dished vs. flat-topped).

 

[SawTroll]

....

Also, the early 350/353 were 44mm and used the same cylinder with different pistons. The later versions of both were upgraded to 45mm bores and used the same cylinder with different pistons. The 351 was 44mm bore and used the same cylinder as the 350, with the difference being the piston (dished vs. flat-topped).

Very good post, but a slight mistake in the quoted part;

The 44mm (open port) ones were the original 350 (like you said) and the 351. The 353 always was 45mm. The newer EPA 350 use the 353 cylinder with a "dished" piston.

Another thing is that a lot of aftermarket top ends are sold as "346 kits" without actually being patterned after the 44.3mm top end of the NE346xp - stay clear of those. The best option is the OEM 44.3mm 346xp one.

 

[SawTroll]

Did anyone mention that you need the 346xp cylinder bolts (at least I think you do, but I may be mixing it up with something else)? :msp_confused:

 

[redunshee]

Here are the basics-

340/345 -> 346 ----need piston/cylinder and riser. These saws are clamshell with the cylinder split at the crank. The riser serves as the base of the cylinder to cap the crank. (I believe the carb is different but the stock carb will work)
350 -> A 346 will bolt on. This saw comes with the riser capped by a pro-style cylinder and a plastic crankcase. The piston is dished.
351 -> It is a direct swap with a 346 cylinder. It is an older version of the 353 with a magnesium crankcase.
353 -> It is a direct swap with a 346 with a magnesium crankcase. The 353 is not as strong as an NE but is close to an OE.

Also, the early 350/353 were 44mm and used the same cylinder with different pistons. The later versions of both were upgraded to 45mm bores and used the same cylinder with different pistons. The 351 was 44mm bore and used the same cylinder as the 350, with the difference being the piston (dished vs. flat-topped).

Great info, Neal. Concise and thorough.
Bob

 

[nmurph]

Did anyone mention that you need the 346xp cylinder bolts (at least I think you do, but I may be mixing it up with something else)? :msp_confused:

Yes, I believe you need longer cylinder bolts than those used on the 346/353/351 if you are bolting it onto the 340/345/350 crankcases. The threaded inserts on those cases are located at the bottom of the case and a longer bolt is required to reach the deeper threads.

 

[UK Rich]

And I thought I needed to get out more...

 

[nmurph]

Great info, Neal. Concise and thorough.
Bob

Bob, Niko pointed out an error in what I wrote (surprise). I edited my post to correct it. Could you edit and re-quote your's so the information is consistant and correct? I would hate for someone to read your quote of me and get inaccurate info.

 

[dsell]

I'd like to point out another difference on these saws. The crankshaft is the same on the 340, 345 and 350. The crankshaft is the same on the 346, 351, and 353. However, there is at least one difference between these two cranks. The diameter of the crankshaft where the oil pump pinion turns is larger on the 346, 351, and 353. Therefore, the oil pump pinion is 503892102 for the 346, 351, and 353. 503892202 for the 350, 503931801 for the non adjustable oil pumps.

 

[nmurph]

Yes, but those differences don't effect whether or not a 346 top end will bolt on and there are other minor differences like the muffler support. But the bottom line is that a 346/353 will bolt up to the lesser variants with the addition of a couple of parts.

David, do you have the orignal SB with the info about the 154 Walbro carb replacement?

Neal

 

[dsell]

Yes, but those differences don't effect whether or not a 346 top end will bolt on and there are other minor differences like the muffler support. But the bottom line is that a 346/353 will bolt up to the lesser variants with the addition of a couple of parts.

David, do you have the orignal SB with the info about the 154 Walbro carb replacement?

Neal

SB, 340, 345, 350, 346, 351, Carburetor, 2002-09
The carburetors for the above models have been replaced in order to improve starting, performance,
and for reasons of compatibility. Old and new versions are fully interchangeable.
C3-EL18 (EPA) introduced from serial number: 340 023902301
345 023900501
350 023801301
346 023700001
351 023700001
C3-EL17 introduced from serial number: 351 023200001

New part no. Description Excl. part no. Remark
503 28 32-08 Carburetor C3-EL18 (EPA) 503 28 16-14 HDA 159 A (EPA)
503 28 32-07 Carburetor C3-EL17 503 28 18-03 HDA 154 C

 

[nmurph]

I was looking for an original PDF SB.

 

[sunfish]

I never had any trouble with the original carb on my 1999 346, until last year. It started acting up and I put a 357 carb on it. Probably just needed a kit.