Yotehunter66
ArboristSite Member
Getting ready to install a new piston in my 372xp. Which way do the markings on the piston face, should the ring gap be in a certain position and what do you guys use to lubricate the piston?
Piston install
- Thread starter Yotehunter66
- Start date
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Arrow pointing toward the exhaust port, ring pin located on the intake side and two stroke oil to lube the piston upon install.
big.griff
ArboristSite Member
Arrow on top of piston faces exhaust. Gap in rings go where alignment pins are. Make sure to measure ring gap
What should the ring gap be?
Husky1982
ArboristSite Lurker
Not sure what the end gap should be but the previous replys are correct, arrow should point towards the exhaust port, and align the rings up with the alignment pins inside the grooves. Lube the piston with the same 2-cycle oil you mix your gas with. There is a thread on here titled "Piston Ring End Gap" that might be able to help you as well.
Adirondackstihl
Flyz, Fuel & Fotos
Check piston clearance too. Should be about 0.0025-0.003 for a new piston
Like they said.
Seriously, double check to make sure that you have installed any gaskets, bearings, or other things that need to go on first, before you mount the piston, cylinder, etc.. Also, cover the case opening with a clean rag, so that if a cir-clip pops out, you don't have to tear things down again to retrieve it!
Philbert
beelsr
ArboristSite Guru
oke:In another thread an A.S. member noted that he called those 'Jesus clips'.
Not that you need to pray that they are correctly installed. He suggested that half the time that someone is attempting to remove or install one, it will suddenly pop out and fly by your face, causing the person to exclaim . . . .
I found that instructive as well as humorous.
Philbert
cat-face timber
Knot Bumper
I was taking off one of those ####ING clips for a part I was trading a member here and wow they sure can fly fast!!!
beelsr
ArboristSite Guru
good pliers help. i have a few pair with little divots at the tip for springs. work well.
a gunsmithing trick is to use a ziploc baggie when doing stuff with springs (e.g., slide disassembly) so they can't fly very far.
Their called Jesus clips, because when they go flying only God knows where they are.
Yotehunter66
ArboristSite Member
What do you guys use to compress the rings while installing?
I use a filed down toothbrush handle and my fingers.
A piston stop makes things much easier
I wonder if the Jesus Clip is a offshoot of what helicopter mechanics affectionately call the single nut (Jesus Nut) that held the rotors on the 'copter. Its easy to imagine what someone would say if that came off! In like manner, if this clip fails or comes out while running, it's quite likely that nasty things are going to happen.
Yotehunter66
ArboristSite Member
New piston is installed. Ring clearance was around .008. New compression check was above 150 psi. My last question is what is a good starting point for the high flow setting on the carb during break in? This is a new carb too so it hasn't been adjusted yet.
Yotehunter66
ArboristSite Member
I got the low idle adjusted so it's not stumbling when revving. The high speed I adjusted so I'm running at about 12,700 and I'm pretty sure she's four stroking. Putting out a little smoke but I would rather have it running a little rich while it's breaking in. How long should I wait before leaning it out a little? I also set the idle at about 2500 rpm.
