Husqvarna 350 to 346 conversion.

[cranman1951]

Greetings friends...I just decided to rebuild a 350 Husky I picked up for zip, and thought it would be a hoot to make it into a 346xp (almost). I watched most of Mattyo's video's ( very informative and interesting BTW Matt!) and ordered what I thought was a true 346 closed post 45mm piston and cylinder from Reisman Platt on e-bay. It showed up today and quality looked great, but although it didn't look like an open port cylinder, it didn't look like a true closed port either....at least like the 44.3 mm 346 cylinders I've seen pics of. I've read that the 353 had a 45mm closed port cylinder and was wondering if that is what showed up today....and if so, how will it's performance rate with the 45mm 346xp piston and cylinder???

 

[jltrent]

What you have looks like a 353 cylinder as the side ports for airflow like a 346xp cylinder has that one does not have. It will perform well, but as far as RPMs go it will not 4-stock as fast. You are looking at maybe 13500rpms compared to 14500 rpms on the 346xp and trigger response want be as fast.

 

[huskihl]

The oem cylinder will never be called 45mm on eBay. They call it either 44 or 44.3. Usually there is a husky logo in the pics and the ad will say it’s oem. Here’s a link

https://www.ebay.com/itm/114570154585

 

[cranman1951]

I just tore the 350 down, and its the same cylinder as the one I bought....dished piston though.....I guess what I have is a 353 like jltrent mentioned. I should have gone with the OEM,,,,drat. The piston, ring and cylinder in the 350 look perfect, and the crankcase held 10 lbs no sweat. Question for the Husky boys, What performance difference will there be if I just replace the dished piston with a 353 flattop, compared with the 346 piston and cylinder? basically it will be a plastic 353. Is the difference between the 353 noticeably more then the 45mm 350 with the dished piston? I don't know how accurate my compression gauge is, but it only read 100 lbs with the old piston and cylinder. Is the 44.3 mm cylinder on the 346 the only one made for the 346xp? If so, which is the most desirable piston and cylinder combination to get ( this time from Husky LOL) I've been favorable impressed with the 350's I've run ,but even though I've rebuilt some 353's I've never put them or the 346 into wood.

 

[Wood Doctor]

I installed one of those 45 cylinders on one of my 350 saws and it was a remarkable improvement. It's not a 346xp, but it made a huge difference and runs side-by-side with my 353. I have a gut feeling you will like your saw when you are finished with that installation. Just MHO.

 

[old guy]

Also get the Hyway popup piston put in there. The squish with the stock pistons will be .040 - .043 (also the hyway), measure the actual squish with solder thru the sparkplug hole, then have the riser machined to bring squish to .020, this will get you 180+ lbs of comp.
That's just for starters, their's also porting & piston work.
Those things can be made to fly.

 

[cuinrearview]

A 45mm 350 cylinder and a 353 cylinder are one and the same. The only difference performance-wise is the piston. Dished vs flat. My compression=more power so you will notice it. It will perform exactly like a 353. A 346xp though, it is not. The performance of that top end, plastic or mag bottom end, is another level.

 

[cranman1951]

Thanks guys....I'm thinking of either using my new 353 top end or using the old cylinder and getting the pop up piston. I didn't start with a complete saw, and I just priced out the aftermarket parts I'll need to make it a runner, so I'll save the 346 project for another saw.....

 

[Huskitoter]

Look at the hp ratings. Going from a dished pistons to a flat increases it from 3.2 to 3.3. The 44.3 xp cylinder is 3.7 in stock form. There are inexpensive AM xp kits out there. You just purchased the wrong one.

 

[cranman1951]

Huskitoter....I'll be doing a 346 conversion on my next build, the 45mm cylinder with a popup intrigues me. I'm just doing the build for experience, and the fact I really like the 350 platform. I've had three stock 350's I've gotten some hours on, now if I can put together a high compression 353 top and then the 346 swap, I'll be able to compare them and make informed decisions about the improvement in performance. What AM 346 kits do you recommend? If I can't save a bundle I'd rather go OEM. Thanks for the info

 

[Huskitoter]

I haven't used one. My plan was similar to yours. I got a flat piston, ported the cylinder, mm, bgd. It runs too good to mess with now. Then I kind of lost interest when I started a 357 build. But I'm left wondering what it could have been if I had gone with the closed port cylinder.

Others have mentioned the Warhawk. It's easy to see the difference in the pics if you look at the big curved transfers on the outside of the cylinders.

 

[old guy]

Go with the oem cyl., & you have to groove the riser for the different impulse on the 346.

 

[huskihl]

Look at the hp ratings. Going from a dished pistons to a flat increases it from 3.2 to 3.3. The 44.3 xp cylinder is 3.7 in stock form. There are inexpensive AM xp kits out there. You just purchased the wrong one.

They don’t run like the OEM kit though. I’d bet most aftermarket kits are closer to 3 hp, rather than 3.7

 

[cuinrearview]

If you knock .010 off of the bearing cup you'll be north of 175psi with no gasket and that popup.

 

[old guy]

If you knock .010 off of the bearing cup you'll be north of 175psi with no gasket and that popup.

Yeah, but why not take off .020 & use the gasket?

 

[cuinrearview]

Yeah, but why not take off .020 use the gasket?

Sure

 

[RED-85-Z51]

Im at 145psi on my Hyway 53cc top end with no gasket and im very happy with how it runs, starts...idles. Yeah it could go tighter...

Sent from my LM-G820 using Tapatalk

 

[old guy]

Not trying to be arguementitive, I have done a few huskys without base gaskets cus I don't have equipment to machine cylinders, but I use 80 grit emory cloth on a flat surface to cut down 350 risers.
I can keep flatness to .001, which is .0005 better than some factory I have measured.