sidevalve engine thread types

Post by **davidseymour** » Sun Sep 16, 2007 6:03 pm

can anyone tell me what sort of threads are on sidevalave engines,i am having problems with the following;
-gearbox to engine mountings
-bottom hose outlet mountings
-tappet cover bolts
many thanks
david seymour

Post by **bigginger** » Sun Sep 16, 2007 6:08 pm

Harry Mango is the guy who'll know, but he's busy organising/running a rally today. I'd guess Mike Shipman (think that's right) will be able to help too.

Post by **HarryMango** » Sun Sep 16, 2007 7:21 pm

Can't help I'm afraid with sidevalve threads - they had some very strange ones - metric threads with whitworth heads - I think Andrew was referring to Mike Perry who runs the MM Register - he should know.

Rog

Post by **bigginger** » Sun Sep 16, 2007 7:53 pm

Aha - I was

Post by **Matt** » Sun Sep 16, 2007 7:58 pm

The ones on Clem's engine and gearbox were a fine pitched metric with whit. heads...

Post by **RobThomas** » Mon Sep 17, 2007 10:31 am

Called "Hispano" threads by one clever chap I met. If reeeealy stuck for nuts and bolts, I found a pile of very dead SV engines at the Bovingdon Tank Museum some years ago. Curator was called Steve Latham (IIRC)

Post by **RobThomas** » Wed Sep 19, 2007 10:00 am

Oooops. Try "Hotchkiss" threads.

Post by **mike.perry** » Wed Sep 19, 2007 10:35 am

Most SV engine bolts seem to be M8 or M10 metric, originally with whitworth heads.
The pitch on these bolts is not really course enough for alloy threads, eg gearbox to sump or dynamo to water jacket so the alloy threads can be re threaded by running through with a 3/8 UNC tap, no need to drill the hole first. The matching holes in the in the gearbox can then be drilled to take the new bolts. This will reduce the risk of stripping the threads when tightening the gearbox. Not original but it works.