SQ4 Crank Spline Repairs

[Syd.Kallechy]

Hello All,

I don't post on here often as I have quite a bit of hands on experience and a well set up garage I can access. However I have come across something I am not sure I want to tackle with regard to the Rear Crank Spline repair. Not sure if anyone has experience with these but I have several cranks with worn splines that I would like to have repaired. Does anyone have experience with a shop in the UK that does these? I've been looking into weld repair on various internet sites and I think it may be possible if you pre-heat them and use the correct welding procedure and then find someone who can re-machine the splines and then a heat treat after. I'm comfortable with the welding but not so much the machining aspect and in truth would prefer someone do the entire job if they have the experience and know how. I also wonder if hard chroming might be an option?

Does anyone on the forum have experience with this, or know of someone here in the UK that can repair these? If you have experience with any shops regrinding the crank journals I would also like to hear about that as well, as I have two sets of cranks I want to repair and both need the journals (Big ends) touched up and the splines on Rear Cranks needing the repair.
I would appreciate anyone's feedback as I am fairly new to the UK and not familiar with all the reputable shops here (I'm a displaced Canadian on a work transfer!)

Thanks very much for your assistance!

Syd K

[bob cottam]

Hi Syd, I had just such a repair done to a BSA A10 crank splines some time ago by SRM Engineering-BSA specialists in Aberystwyth, Wales.They did a very good job for me.It might be worth contacting them to see if they would do an Ariel crank? , Regards, Bob.

[Brian.Fosh]

Later shock absorbers have a splined intermediate sleeve to overcome wearing the splines directly on the crank. These can be used on earlier cranks.

[Syd.Kallechy]

Thanks you two ....I'll check with SRM and see what they say. If I have luck with them I'll post the results in case someone else has an worn crank they would like to resurrect!

[Simon.Gardiner]

Steve McFarlane in Cardiff has also rebult the splines on A10s, although he's currently booked up with electric start conversions for the next few months
Steve McFarlane Engineering
Tel: 029 2064 5045
99 Brunswick St, Canton, Cardiff, South Glamorgan, CF5 1LL

The BSA guys also give T&L Engineering in Bedford good references for restoring metalwork although I don't know if they can rebuild splines

HTH

SG

[keith wainwright]

HI All coming back to the worn splines re square fours. Going back into my engineering days. We reconditioned paper converting machinery, this involved repairing worn splines, shafts and bearing housings. We used a process called Thermal metal spraying that does not require a lot of heat on the "product to be built up with new metal. Ideal I would have thought for crankshaft spline repair. Then it's a question of grinding back to original diameter and
re-matchining splines. Hard chroming is not an option it would take many coatings to replace worn areas on splines. Unfortunately the company in question no longer exists. But doing a troll on the net should find many Company's that specialise in this process. Just another note to state how good this process was, it was used on reconditioning large jet landing gear, struts and trunions. Keith

[Syd.Kallechy]

Hi Keith i ended up sending mine to SEP. (before Paul reported their turntime issues). The cranks have been there about a month now and I know they haven't started them yet but I also told them I wasn't in a rush for September. I plan on calling them later this week to see what they have to say and will advise the group when they are done or if I decide to pull them out if SEP turns out to be a problem!

[Syd.Kallechy]

Hello All, I got my cranks back from SEP about 2weeks ago (so roughly 2-1/2 months). Not exactly fast but I did tell them I wasn’t in a rush. They welded up two cranks and remachined the splines and also Ground the Rod journals and the timing side bush journals. All the journal work looked great with a nice radius on the corners ...the splines fit fine in a new coupling but are not the prettiest cosmetically (I would have preferred they added a bit more weld and machined the OD for a nicer finish)...but I guess the will work.