SNAKESNAKE
ArboristSite Lurker
HELLO I AM WORKING ON A STIHL 046 BIG BORE WITH A 54MM PISTON DOES ANYONE KNOW THE RING GAP THE PISTON HAS RUBBER RING STOPS IN SO I THINK RING GAP SHOULD BE BIG I AM NOT SURE PLEASE HELP THANKS!
ring gap
- Thread starter SNAKESNAKE
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How far do you have the ring into the bore? That seems excessive to me but for the life of me I cannot remember how much clearance per 10mm of bore there should be. It's probably been written in a post before, just need to search maybe.
Got it!
troutfisher
Addicted to ArboristSite
.010 will be good. remember, that's a little piston compared to a tractor or truck motor.
SNAKESNAKE
ArboristSite Lurker
SNAKESNAKE
ArboristSite Lurker
thanks for the info I have 8 thousands
I have this picture saved on my PC, no idea where I got it from ( 0.2 - 0.4 mm = .008 - .016" ):
This one is saved right next to it:
This one is saved right next to it:
About three years ago I installed an 046 BBK top end in a friend's non-running o46 Mag that had no compression. Word got out when I finished that this saw was a marvelous performing piece of equipment--lighter than a 660 but with about the same power. Within two months after I worked on it, some crook stole the saw right out of my friend's garage. It was never found.
Little Al
Addicted to ArboristSite
In the good old imperial measurement days it was 4/6 thou per inch of bore can't be ar**ed to work out the metric.
1mm = about 0.040
That's all you really have to remember for quick ref or to be exact, 1"=25.4 mm
SO 4 thou is about 0.1mm
0.2 - 0.4 mm = .008 - .016" - for the ring gap , I edited the post to make more clearly.
0.05 mm = .002" , or rather .001" per 1" of bore - for piston to cylinder clearance , says it clearly on the feeler gauge/picture.
Little Al
Addicted to ArboristSite
Thanks for that, Living in France all dimensions are metric but being originally from the UK & old school ( 80 years old) I tend to revert to Imperial measurements It's me age you know
well that's my excuse & I'm sticking to it
I just rebuilt the top end on a vintage Husky 61. Ring gap on the old top end was 0.12". Piston-to-cylinder clearance was .007". Hard to believe that it even started and ran like that, but it did. Compression was an amazing 125 psi. The piston side walls were black from the blow by and the top was covered with a thick layer of carbon. Rings were not seized, but not much was left of them.
New top end ring gap is .01" and the clearance is .002". This engine now runs like the day it was sold new.
New top end ring gap is .01" and the clearance is .002". This engine now runs like the day it was sold new.
