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sidevalve engine thread types
Posted: Sun Sep 16, 2007 6:03 pm
by davidseymour
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
Posted: Sun Sep 16, 2007 6:08 pm
by bigginger
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.
Posted: Sun Sep 16, 2007 7:21 pm
by HarryMango
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
Posted: Sun Sep 16, 2007 7:53 pm
by bigginger
Aha - I was
Posted: Sun Sep 16, 2007 7:58 pm
by Matt
The ones on Clem's engine and gearbox were a fine pitched metric with whit. heads...
Posted: Mon Sep 17, 2007 10:31 am
by RobThomas
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)
Posted: Wed Sep 19, 2007 10:00 am
by RobThomas
Oooops. Try "Hotchkiss" threads.
Posted: Wed Sep 19, 2007 10:35 am
by mike.perry
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.