HELP husky 335 xpt rebuilt, piston hitting cylinder head

[Alanmurphy6912]

So I bought a husquvarna 335 xpt in running order,poorly running but at any rate it's never been rebuilt as far as I was told so I tore it down and put a new little red barn piston and ring in it and sealed the cylinder with motoseal as instructed and put back together. When I torqued down the cylinder the piston seems to be catching or hitting on the cylinder head area. I checked squish with the smallest solder I had and it about pinched it off. It's coming out to like .0014. So I thought maybe this piston is wrong. Measured and is identical size to the oem I pulled out of the saw. So I then ordered an entire new old stock piston and cylinder kit from husqvarna and to my surprise the piston and cylinder bore are larger than my original. So I assume it's for a 338. At any rate all seemed same so I put it back together with the now the new oem piston and cylinder kit and this time put a thicker bead of moto seal on it and let it just about dry over night as to make a thicker gasket. Still hits the cylinder head I think (you cant really see inside the cylinder) so I'm now at a loss and sorta baffled on what is happening or what to do. Any suggestions or anyone who has been through this I'd be super grateful for.your advice! And yes the piston is faced correctly and the crank put in the right direction etc. Thanks in advance

 

[Gord404]

The only trouble with thick sealant is it might not allow you to set bearings and seals in tight

 

[quicksilver-ms]

some years had a metal cylinder gasket 537 10 04 01

 

[Alanmurphy6912]

some years had a metal cylinder gasket 537 10 04 01

It didnt have any gasket when I tore it apart but seems like it is missing something gasket wise. I'm not sure if the bearings aren't seating in the bottom case half or something? I'm having the same issue with what I presume is the 338xpt oem p/c kit I bought on ebay because the piston and bore measure 43mm instead of 38mm like the piston and cylinder I took off. I'm still just stumped on why this is happening. And what to do. I can make my own gasket but as stated above I'm leery to wether the seals that are on the bearings will seal or not. I'd probably have to moto seal it also

 

[Franny K]

My 338xpt is 31mm stroke 40mm bore there was a California model 338 with more displacement. Probably should pull up that illustrated parts diagram for that California version and see if your cylinder/piston kit # is for that and what sort of gasket is involved. This doesn't help with why the aftermarket piston same dimensions did not work.

 

[Woodslasher]

Check the squish again, if it's still under .020 add a gasket. If it's not, pull the coil off and see if the stickiness goes away.

 

[Gord404]

imo clamshells dont use gaskets just sealent around casts to clamp the bearigs and seals tight.

 

[farmguywithasaw]

I wouldn’t use a lil red barn piston unless there is no other option. I bought one for my brush saw and after two and a half tanks of fuel the pin snap ring **** out and toasted the cylinder. Some aluminum around the grove went with it