Need help with Squish - Dolmar 5105s and Redmax GZ4350 (Husky 543xp)

[MobyDooDuckDong]

Question: working on my saws this week, need to ask.......Squish, not sure what the minimum (or normal acceptable) Squish is on either of these machines? Measured the 5105 tonight, measured .031 (with oem gasket installed) have few different sized gasket materiel to work with but wanted to ask folks here for advice - help. Already gutted the mufflers and did the port job both saws so, that's already done. Asking; what is the recommended squish ? what is good safe tolerance for either model machine. Much thanks in advance!

 

[J D]

Aim for 0.020".
No less than 0.018"

 

[MobyDooDuckDong]

Aim for 0.020".
No less than 0.018"

Much thanks! Researching i found most specs seemed to be in this range - after a few tries, finally got it to .021 - hope to get the rest of it back together tonight. Dolmar 5105.

 

[MobyDooDuckDong]

Much thanks! Researching i found most specs seemed to be in this range - after a few tries, finally got it to .021 - hope to get the rest of it back together tonight. Dolmar 5105.

Follow up question - now working on my RedMax 4350 - option, pop-up piston w/ oem gasket or pop-up piston with DIY gasket adjusted squish to .020 or, just the oem piston with adjusted squish ? Pop Up Piston is from Little Red Barn, Also have a Maikita 3500 that I'm also messing with, if for no other reason that I'm boarded....already muffler modded, ported etc. Squish ? why not, right.

Got the Dolmar 5105 back together tonight, runs like a banshee.....much thanks for your advice, really appreciate it.

 

[RedneckChainsawRepair]

@huskihl is from your state and very knowledgeable on such stuff.

 

[huskihl]

Be careful with LRB pistons. Quite well known to be junk. And be careful on tapered bands and domed pistons while setting squish. The outside of the band can get tight if you’re not measuring out far enough.
Use .040” rosin core solder so it squishes easily. Bigger stuff won’t flatten out

 

[J D]

pop-up piston w/ oem gasket or pop-up piston with DIY gasket adjusted squish to .020 or, just the oem piston with adjusted squish?

For me (assuming the pop-up wasn't junk) it would depend on compression & what the squish ended up at. If compression was sub 160PSI &/or squish ended up closer to 0.030" with no gasket I'd be running the pop-up.
Deciding if that pop-up is likely to try & imitate a grenade at some point comes down to a lot of factors... the main one being experience (& most with suitable experience just avoid the cheap stuff).
I'd be interested to know what factors others consider when making a judgement on piston quality & serviceability

 

[MobyDooDuckDong]

Much thanks to everyone, after some additional research and a very close look of the LRB pop-up piston - i returned it and decided to stayed with the OEM piston - setting the squish to .020 - .021 - with mild porting, a DIY muffler, and re-tuning carb - saw run great.