MK1 - Possible Rear Crank Gear Play

Singles, twins and fours.
camstevens
Holder of a Nylon Anorak
Holder of a Nylon Anorak
Posts: 241
Joined: Mon Nov 21, 2016 5:01 pm
Location: Kew, London
Contact:

Re: MK1 - Possible Rear Crank Gear Play

Post by camstevens »

Newly fitted key
Newly fitted key
Just fitted the new key.....its as "snug as a bug in a rug" compared to the old. I would say about .0005" clearance as opposed to considerbale play in the old...probably in excess of 0.002". It also definitely showed signs of fretting on the shaft portion of the key. I'm hoping, as per Mark's experience, goes a long way to tightening things up.

Cam
camstevens
Holder of a Nylon Anorak
Holder of a Nylon Anorak
Posts: 241
Joined: Mon Nov 21, 2016 5:01 pm
Location: Kew, London
Contact:

Re: MK1 - Possible Rear Crank Gear Play

Post by camstevens »

Hi All
The Henkel site runs a comparison engine between different Loctite products.....I have more confidence in this than some of the chat rooms that pop up! Looks like 648 is the appropriate option, given the interference fit.

Link below;

https://www.henkel-adhesives.com/br/en/ ... e_648.html

Cam
allan.walker
Holder of a Waxed Cotton Anorak
Holder of a Waxed Cotton Anorak
Posts: 338
Joined: Fri Sep 28, 2018 8:35 am
Contact:

Re: MK1 - Possible Rear Crank Gear Play

Post by allan.walker »

Should there be any discernible clearance between a Woodruff key and the crankshaft? I've not removed the connecting gears on mine yet, but every other engine I have worked on has had very tight Woodruff keys. They have needed to be driven out of place and on rebuilding with new ones, they needed to be tapped in.
camstevens
Holder of a Nylon Anorak
Holder of a Nylon Anorak
Posts: 241
Joined: Mon Nov 21, 2016 5:01 pm
Location: Kew, London
Contact:

Re: MK1 - Possible Rear Crank Gear Play

Post by camstevens »

Hi Allan
It's not an interference, but pretty snug. Roger Gwynn advised the tolerance is between 0 and .002", so on that basis I would appear to be in a good place. As above, the original key had about 0.002 to 0.003" , and had signs of fretting on the shaft portion.

Cam
allan.walker
Holder of a Waxed Cotton Anorak
Holder of a Waxed Cotton Anorak
Posts: 338
Joined: Fri Sep 28, 2018 8:35 am
Contact:

Re: MK1 - Possible Rear Crank Gear Play

Post by allan.walker »

Ahh, I see. It sounds like yours is fine now.
Simon.Gardiner
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 1670
Joined: Tue Aug 02, 2011 11:37 pm
Location: South West (Bristol-ish)
Contact:

Re: MK1 - Possible Rear Crank Gear Play

Post by Simon.Gardiner »

camstevens wrote:Hi All
The Henkel site runs a comparison engine between different Loctite products.....I have more confidence in this than some of the chat rooms that pop up! Looks like 648 is the appropriate option, given the interference fit.
648 is what I settled on for the VH
I made a call to Loctite tech support about the various specs - albeit 4 years ago, and I've not checked the specs since.
At June 2017:
Loctite 648 - should be OK, new formulation is slightly better performer, but at 200C performance goes off a cliff
Loctite 6300 - thinner than 648 but not as strong (648 is 30%-50% stronger), but less heat degradation (NB no toleration of oil on surfaces)
Loctite 620 - higher temp but thicker to apply so likely to get pushed out of the surfaces

SG
Web admin (webmaster@arielownersmcc.com)

'55 Huntmaster, '56 VH, ' 51 VH, '62 Arrow, '80 R100RT, '00 Sprint ST (now with a new Arrow project, and just now those 4-stroke Ariel parts can't even make one running bike...)
User avatar
paul.jameson
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 2934
Joined: Wed Oct 12, 2011 3:04 pm
Location: Herefordshire
Contact:

Re: MK1 - Possible Rear Crank Gear Play

Post by paul.jameson »

When this problem appeared on my 4G, shortly after the rebuild, I put the gears back on with Loctite 620. Getting on for 3000 miles later, the problem is still solved - but I don't tow a double adult sidecar around with the bike!
Paul Jameson
35 LG (project), 37 RH500, 52 ex ISDT KHA, 54 KH(A), 75 Healey 1000/4.
Former Machine Registrar & Archivist, General Secretary and Single Spares Organiser (over a 25 year period).
Now Archivist (but not Machine Registrar), Gauges and Clocks Spares Organiser.
MARK.WALSH
Holder of a Nylon Anorak
Holder of a Nylon Anorak
Posts: 299
Joined: Tue Dec 27, 2011 10:46 pm
Location: Kent England
Contact:

Re: MK1 - Possible Rear Crank Gear Play

Post by MARK.WALSH »

Hi Simes
I think I used 620 loctite .

Cam,
As for the new woodruff key - I had to press it into the shaft as there was no discernible play . ( Also using a press helped ensure it was straight and unlikely to shift / ride up as the coupling was pressed on.)
- Another check - engage the woodruff key separately on the coupling before reassembly in case there is play there instead.

Good luck
Mark
camstevens
Holder of a Nylon Anorak
Holder of a Nylon Anorak
Posts: 241
Joined: Mon Nov 21, 2016 5:01 pm
Location: Kew, London
Contact:

Re: MK1 - Possible Rear Crank Gear Play

Post by camstevens »

Hi Mark
Actually, my woodruff key is a tighter fit than I thought (interference) as I hadn't pressed it all the way to the base of the shaft slot. However, there is about 0.002" play in the gear slot. The loctite is really designed for curved mating surfaces, so not sure if it would help to "pack out" the gear slot.
Apparently 0.002" play is within alowable tolerance, but I do have 0.002" shim, but I'm not sure if it would be practical to use.

Cam
allan.walker
Holder of a Waxed Cotton Anorak
Holder of a Waxed Cotton Anorak
Posts: 338
Joined: Fri Sep 28, 2018 8:35 am
Contact:

Re: MK1 - Possible Rear Crank Gear Play

Post by allan.walker »

camstevens wrote:
Apparently 0.002" play is within allowable tolerance, but I do have 0.002" shim, but I'm not sure if it would be practical to use.

Cam
Hello Cam,
Do you mean it is not a practical proposition to try and fit the shim, or that you feel it would be of no practical benefit?

Allan.
Post Reply

Who is online

Users browsing this forum: No registered users and 3 guests