Matchless 500cc single.

[john.k]

Can I put coil valve springs in a  ally head 1950s Matchless single motor?......Is there enough space for the  hairpins be replaced with coils?.......Reason I ask is I want to put a Matchless top end on a JAP 600 sidevalve motor ,of the pseudo industrial variety.......weightsaving should be considerable.

[iansoady]

Why do you want to ditch the hairpins?

[john.k]

Mainly because I dont have any ......no springs ,top collars or lower holders.....and they seem the be more pricey than the head........I think I recall in one of the old magazines a tip to replace the hairpins with coil springs.

[iansoady]

Steve Surbey should be able to fix you up with used ones. http://www.amcclassicspares.com/

[john.k]

This is a project with a $50 budget.....any new parts will be ex Perkins diesel spares price list .....I do have some hairpin springs,but they are all badly grooved .

[beng]

Just look at the space available and grab some springs and keepers out of any old scrap engine laying around and see if they fit. Maybe some biking friend has an old set of valve springs and keepers laying around they will let you try. A side-valve engine, the head is basically a slab of metal with holes in it for the plug and bolts. Get some old beverage cans of aluminum and melt them down and pour them into an impression you made in a pile of sand using the old head. You can have someone mill the cylinder side of the head, and with a home drill press and hand tools you should be able to spot-face the bolt-holes, plug hole and tap it for the plug threads.

[Rex]

You make it all sound so easy. One problem is the engine is OHV....

[john.k]

Yes,major problem with that plan is since the 10c return ,I never see any kind of cans around............in fact to get enough beer cans to cast a JAP head,I would need to become an alcoholic...........or be like my old boss and hand out free beer ----tomorrow.

[john.k]

Anyhoo,the plan is coming together ....bits that fit together include a HD 74 rod,Ducati 860 piston assy,(same pin dia),sleeved the JAP crankpin to suit HD dimensions,made a new barrel to suit rod /piston ,and completed the head using mostly what I had,including grooved springs........now need to make up pushrods ,tubes ,and some kind of mod to the SV JAP lifters...............things on hold a bit while I get my old crawler crane back from across town (sold the land ,had a year to clear out...long past)......with the covid ,half of truck drivers are off at any given time ,causing major problems......then the floods complicated things further,as the towies are moving flooded trucks around to repairers or auctions on contract to the insurers,so no time for me.