WD 3GL questions push rods/rocker boxes

[Mikedearing]

Hi other than removing the push rods to measure their length from a perfectly running engine which as you might imagine I am reluctant to do, can anyone tell me what length they might be ? I cannot find length( and diameter ) anywhere - I can get a vernier into the other one.... but..

Also I note that there are a few variations of g3l rocker boxes as they developed from the very basic early one, does anyone know if the cylinder heads are particularly picky about which one to use - yes I've got an engine without pushrods pushrod tubes valve springs and rocker box (and a few other notable bits), I have a variety of bits that might work but I'm unbeknownst.

There was a chap In the Pyrenees who a few years back had many bits and was charming and fount of knowledge, I got an email back from his wife saying he was gone -( I didn't like to pry) and she has lots of bits but genuinely doesn't seem to know the specs to them.. a conundrum indeed.. thank you if anyone can help - I suspect many plumstead bits are interchangeable but I'd like to know what I'm doing first Thank you Mike

NB

Also I cannot find a really good technical narrative about the development of the g3l - I have all the books and have the resources here too - odd considering it must have been the biggest single seller ever .. though I suppose the other bikes were produced for longer periods..

[clive]

Mike I ran a later WD G3L motor for a while on my rigid 350 ( it has a 50 AJS engine now). In my experience the wd motors had iron push rods whereas later pushrods were aluminium (with the same steel end caps.) I did try a set in a later engine with an aluminium head and if I remember correctly there were issues to do with expansion rates when hot. I did have a pair of NOS WD pushrods but I think I may have sold them. Off to the garage today so I will check. I suggest you place a wanted ad as they are not allowed in the main forum. If I can I will let you have details of the dimensions.

[clive]

Not sure how helpful I am going to be. Turns out I have 5 pushrods all steel . Two are 9 1/8 long (measured from bottom to top without the adjustable cup.)and 0.333 inch diameter. These I think came from that wd motor. The other 3 are 9 1/2 inches long and the rod part is 0.375 inch diameter. Perhaps someone with more certain parts can confirm the correct size.

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[Mikedearing]

Blimey the plot thickens well I'd love the rods if they are right obviously I have a model 12 engine in pieces so I'll measure those rods which might be shorter though off the top of my head I can't remember the bore and stroke difference

[Duncan]

Hi Mike, I had always thought like Clive that the iron head engine pushrods were steel, following this thread I thought I would look at a couple of parts books to see if the part numbers followed through and noticed that in 1937 the 500's had a Duralumin pushrod, the part number changes in 1939 but the material is not stated, this may mean they went to steel hence the change in part number. No help for your original question I know but interesting.

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[Mikedearing]

I bet they used steel because it was more resistant to army mechanics

[Mikedearing]

Clive I can't remember the etiquette of the forum , but if the pushrods are available I'd be very interested in them

[clive]

Mike you need to move to PM to make any offers or I will be forced to tell myself off!

[Mikedearing]

I will do just that then Thank you

Mike