NH 350 big end condition check (video)

Singles, twins and fours.
cmattina
Holder of a Nylon Anorak
Holder of a Nylon Anorak
Posts: 110
Joined: Mon Apr 06, 2020 11:59 pm
Contact:

NH 350 big end condition check (video)

Postby cmattina » Wed Jan 20, 2021 8:55 pm

Hey guys just looking for an opinion on the big end "wobble" I have. I can confirm there is no up/down movement, and normal side to side movement, but what I am trying to show in the video is a "wobble"


https://youtu.be/HDq1xzZlQiQ
Charlie Mattina
1950(ish) NH350
Ontario, Canada

User avatar
paul.jameson
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 2203
Joined: Wed Oct 12, 2011 3:04 pm
Location: Herefordshire
Contact:

Re: NH 350 big end condition check (video)

Postby paul.jameson » Wed Jan 20, 2021 9:12 pm

If the sludge trap isn't / wasn't full, I wouldn't worry but run it and see how it goes. If the sludge trap is / was full, I would worry but run it and see how it goes.
Paul Jameson
36 4G, 37 VH, 54 KH(A), 75 Healey 1000/4, 52/53 ex ISDT KHA (project).
Former Machine Registrar & Archivist, General Secretary and Single Spares Organiser (over a 25 year period).
Now Archivist once more - but not Machine Registrar.

cmattina
Holder of a Nylon Anorak
Holder of a Nylon Anorak
Posts: 110
Joined: Mon Apr 06, 2020 11:59 pm
Contact:

Re: NH 350 big end condition check (video)

Postby cmattina » Wed Jan 20, 2021 9:28 pm

The sludge trap was clean as a whistle, so hard to know exactly what it was like. Appreciate your opinion though, just didn't want someone to say "it's toast".
Charlie Mattina
1950(ish) NH350
Ontario, Canada

john.whiting
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 1738
Joined: Sun May 22, 2011 2:10 pm
Location: Brisbane QLD
Contact:

Re: NH 350 big end condition check (video)

Postby john.whiting » Thu Jan 21, 2021 1:59 am

For a 1/2" wide roller track,3/16" side to side at the small end is good,and 3/8" is OK....But if you wash the oil from the bigend ,the up and down on a dial gauge is the best check.....most roller bigends need around .0015" clearance new .

nevhunter
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 4219
Joined: Tue May 10, 2011 9:42 am
Location: Victoria.. Australia.
Contact:

Re: NH 350 big end condition check (video)

Postby nevhunter » Thu Jan 21, 2021 6:59 am

A big end fails by the hardened surface flaking from the highly finished surface where the roller s run on the crankpin. Usually the piston and bore get scratched and sometimes the scavenge oil pump by the very hard fragments of steel. This happens over a relatively short time, once it starts and then you will pick up a knock . By then it's cactus, well and truly. . An inspection is required and any pitting means she's on the way out. The sleeve usually lasts longer than the pin and often you can reinstall it 180 degrees out and hone or lap it to fit a new pin with slightly oversize rollers. Nev


Return to “Four stroke”

Who is online

Users browsing this forum: d.mulcahy and 14 guests