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Allan G, Cyborg, mondtster
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Original Post (Thread Starter)
#821517 08/28/2020 6:17 PM
by reverb
Hello; I have this doubt about oil passing rings and the rings. I mean; if the engine starts always first kick, included the first time; that indicates that you have compression (among good spark et all) there; means the rings are actuating right so how the oil rings are actuating wrong? (with the same gap as the first ring)
Hastings oil rings do not have a top side.
-other points are:
-fine oil pressure
-honed with 150 grit emery cloth.
-"dry" assembled

Liked Replies
#821598 Aug 29th a 05:24 AM
by mondtster
Originally Posted by reverb
...pistons and rings new. Cylinders brushed with 150 grit as mentioned.
What do you mean with finish problems? Bad honing? Possible; yes.

When you hone a cylinder with such coarse stones what do you expect the outcome to be?

Honing a cylinder, particularly with coarse stones, leaves peaks and valleys on the cylinder wall. The piston rings ride on the peaks, although the break in process knocks those peaks down to a point. The oil control ring scrapes the majority of the oil off the cylinder walls but it cannot scrape the oil out of the valleys. This is fine because the rings still need some lube. The oil in those valleys is ultimately burned, and when enough oil is in those valleys and burned it will manifest itself as smoke and oil smell. You could replace the oil control ring repeatedly and still have the same results if the cylinder wall finish never changes.

One of the other things I deal with on a daily basis are aircraft engines. It used to be common to repair cylinders by chrome plating them, which would leave a hard, crackled looking finish. Soft iron rings are used in these cylinders so there aren’t break in concerns yet they are notorious for burning a lot of oil. The answer is the same as what I wrote above, the oil consumption will never stop until the cylinders are thrown away and replaced with something that has a different bore preparation.

I’m aware that many recommend using iron rings and coarse stones on Triumph cylinders. That said, I don’t think I’ve seen anyone recommend something as coarse as 150 grit. The installation instructions that came with my MAP pistons and rings is more in line with what I would expect, which from what I remember is 240 grit and a 600 grit finish.

All this assumes that you have proper clearances on all the components and that you have straight bores as well.
1 member likes this
#821627 Aug 29th a 01:30 PM
by kommando
I am not sure that using 150 grit Emery cloth will give the same finish as using a proper 150 grit honing stones. Even if the grit is equivalent the finish would not be the same and I suspect with the cloth and using hand pressure the peaks would be flat and not a full V.
1 member likes this
#821650 Aug 29th a 04:06 PM
by henryanthony
The link below includes comments by JH about rings and honing and, in my opinion, is worth reading.
1 member likes this
#821678 Aug 29th a 07:12 PM
by John Healy
John Healy
The link below includes comments by JH about rings and honing and, in my opinion, is worth reading.

In that thread I asked why didn't you see aftermarket pistons in .010" oversize.

The basic answer is when you bore the cylinder from the base using equipment that is square the cylinder will rarely clean up at .010". You end having to go to .020" to get the bore square to the base and cleaned up.
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#821790 Aug 30th a 01:09 PM
by Hillbilly bike
Hillbilly bike
220 stone is commonly used for auto engines using cast iron or chrome rings. I'm no pro engine builder and can be a bit indifferent ..In the past 25 years I had about 4 Triumph cylinders bored at machines shops. These were auto orientated machinists so they likely used a 220 stone.I also reringed a few more myself ,honing the less than perfect cylinders with a brush and or three leg hone and holding the cylinder between my boots using brake fluid for lube...None of these engines made visuable smoke after running for a few minutes. My two race bikes used coated gas nitrided modular iron or steel rings with a 280 or maybe a 320 grit finish. Instant break in. I use break in oil but sometimes just Jaso rated oil..The only engine that smoked was a 55 A10...upon disassembly I found several bent second position oil scraper rings were out of round. Maybe my fault, maybe bent in the box....I now always shine a bright light light from below when checking ring gap to make sure the rings fit the bore..
And just because you don't see smoke it still might use more oil than normal...It's my opinion that visuable smoke after a few minutes running and typical short road test loading the engine....Well you got a
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