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350 scorred piston
Posted: Thu Dec 20, 2012 3:12 pm
by Dean
Remember me - the guy with the head removal issues. Got the head off and the exhaust valve looks a bit burned - figured that was was my compression issue. Not even! Took the barrel off this morning and the piston is in pretty bad shape - alot of horizontal scorring and ridges. The rings hovever appear intact. The barrel doesn't look to bad either. Seem to have quite a bit of side to side play when moving the rod side to side - seems OK and snug with vertical motion. Am I looking at a bottom end rebuild? Will get my son to download video when he returns from college this weekend. Seems my winter project may indeed take all winter. Well, thats what hobbies are for.
Thanks, Dean
350 scorred piston
Posted: Thu Dec 20, 2012 3:38 pm
by PeteF
Side to side play is OK within limits ( a few mm) as long as you're sure there's no up and down play. Check for a lip at the top of the barrel where the rings stop on their upward stroke. If there is a significant lip it denotes wear on the bore. If that's OK and the bore isn't scored, you could just try a new piston and hone the bore, but a rebore might be safer.
350 scorred piston
Posted: Thu Dec 20, 2012 3:39 pm
by Dennis C
Side play is quite normal and nothing to worry about, as long as there is no vertical plat all is well.
350 scorred piston
Posted: Thu Dec 20, 2012 4:29 pm
by Alan R
Hello DEAN--------- don't forget to check the fit of the WRIST PIN into its' hole in the con-rod... NO float or play allowed...looking forward to those photos--------
350 scorred piston
Posted: Thu Dec 20, 2012 5:08 pm
by Dean
How do you think the piston got so beat up? The rings look intact and the bore looks smooth. Any ideas?
Thanks, Dean
350 scorred piston
Posted: Thu Dec 20, 2012 5:34 pm
by Alan R
Hi again--- my No2 Bullet has, in the past, had a bronze bush fitted in the small-end eye by a previous owner.. BUT, that does leave the wall thickness of the small end very thin....The bush has now become loose so I will require a new con-rod ie an engine out job... If your small-end is damaged or compromised you MIGHT get away with it being bushed BUT I would seek the first-hand advice of a professional engineer initially.... Are there any Enfield owners clubs near you with someone who can come and asses the situation for you ??? Sounds to me like you could do with some Experienced help, now ??
350 scorred piston
Posted: Thu Dec 20, 2012 10:46 pm
by Dean
There is a few millimeters of side play on the rod - but no laxity on vertical. No good machine shop for miles. Considering having Hitchcocks send me an alloy cylinder and a matching new piston/ring set up. Will do the valves as well. Got the bike several years ago and it has never been a good runner - hope this will be my remedy.
Dean