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Post by olyman on Feb 4, 2024 19:41:49 GMT
I remember Bones teaching us a while back about the different types of cylinders and rings they used hough 75/76/77. I know there was jugs that has no steel inside but were just coated. I have a set that I want to use, buy can't recall the rules you have to go by. For example I think you can use Chrome inside cast iron, but can't use chrome inside chrome...
Also I assume that if a ring surface is still very shiny that it must be chrome.
Thanks in advance
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Post by bones on Feb 7, 2024 15:51:18 GMT
gasp !!!! olyman, that was eons ago ha ha.
For 74, 75 & 76 all type 440 cylinders were chrome lined, not a steel sleeve with chrome lining just chrome directly onto aluminum. for 77 there is a mix of chrome, i think nikasil and steel. There seems to be some doubt about any with nikasil, ( I have a old dealer counter price book and it seems to indicate the existance of nikasil). For 78 & 79 they were all steel.
You can not use chrome faced rings in chrome lined cylinders. I doo not think ski doo / rotax ever used any chrome faced rings in these engines, not 100% sure.
The after market rings are same for all years, I dont know what the face on them is. For a few years a had a lot of them engines in/out of shop, but I never used aftermarket rings as I was kinda unsure of material. Maybe them rings are OK ??
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Post by olyman on Feb 8, 2024 16:37:05 GMT
Oh it has been a long time! I remember lots from the old site... and defintely forget more!!
Thank you yet again for offering the info. It makes good sense as to what is allowed vs not.
I have a handfull of used type 440 pistons, and at least two different kinds of jugs (all are Elko). The 'lined' or 'coated' jugs have lots of different markings on them - but you have to work at the factory to know what they mean. I've noticed some of the pistons have a different color to them and have a clearly stamped "A" ontop. Im guessing that it might belong to a 'lined' jug? The rings on that piston appeared to not be chromed. I say that because I have other 440 slugs that are definitly coated rings - the Top L-ring is still very shiny on the cylinder surface.
On this engine I have assembled the best parts I have, which are both kinds of cylinder (mag is lined, and pto is steel. Mag piston is stamped A & has the typical gray L-ring. PTO piston is not stamped A and has same kind of rings.
Everything is just assembled loose.. wanted to make sure its ok before trying to run it
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