I want to stick with 1/4 diameter for clearance reasons
I have two choices to make longer pushrods .Use two sets and mig weld together .I have them.
Option two is use 1/4 chrome moly tube and turn down pushrod ends to fit.Have also.
Smith pushrods and others do 5/16 for mini in chrome moly.Not 1/4.
Problem is me and my mate grab a 300mm length of 1/4 chrome moly tube and we think we can flex it with our hands.
It is -049 wall thickness.
Help please from engineering peeps

Why don't you set up an actual test some how and see for sure if it bends, as oppose to you think it bends?
The $$$ in the rest of your engine I would not stuff around with any if but and maybes!

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1963 Morris 850 Smoke Grey
1963 Morris 850 Shadow Blue
1965 Morris Mini Smooth Van
1966 Morris Mini Van
1969 Morris Mini Deluxe Resto
5/72 Clubman Gt

Welding the buggers together lol.Compressive forces only
Spoke to a respected mate today Knows his stuff from experience.
Same school of thought as manufacturer
Will be TIG but im sure MIG would be fine
Weighed up clearance and strength and good advise

I dunno.... they do have side loading on them - like if one bends (for whatever reason) they don't like being used after they're straightened again

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did I tell you that I won a trophy?

Thanks guys I think lots of failures are from rubbing pushrods and coil bind
The rocker makes an arc over the valvetip and that rocker is on a shaft so there must be other forces on the rod.How much I dont know.
The holes in my block have been drilled to half inch so should be no issue there
I think also Simon once bent and restraightened fatigue has prolly started

I'm curious as to how you will weld them DEAD straight. The head will want to warp and just either side of the weld will be a weak point I would think?

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1963 Morris 850 Smoke Grey
1963 Morris 850 Shadow Blue
1965 Morris Mini Smooth Van
1966 Morris Mini Van
1969 Morris Mini Deluxe Resto
5/72 Clubman Gt

Yes I agree on weld pulls .My mate suggests they are mass manufactured and arent dead straight anyway
Elder pushrods were welded .Scumbag that has my original head will have them too.Getting it going is all that matters now.
Dont believe welding was or is an issue .A stepped joint with loctite 601 is a thought i have

How much longer do they need to be? Would it be easier to get some custom depth cam followers or insert some spacers inside them if its only a small amount? Just throwing ideas about!

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1963 Morris 850 Smoke Grey
1963 Morris 850 Shadow Blue
1965 Morris Mini Smooth Van
1966 Morris Mini Van
1969 Morris Mini Deluxe Resto
5/72 Clubman Gt

Thats a brilliant idea and could have been done except the 1100s bottom end is complete and on gearbox with transfer case flywheel etc on.

In a lathe...one end in the Headstock, tuther in the Tailstock

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"Show me the Mini!"

Yep just ran that by Rob He is machinist Welder multiskilled.
Another good call .Ken has done it (welded)and offered to do it years back .I dont think there was ever an issue with the welded rods
MED appear to be CNC making them for their Arden heads .
Previously they appeared to do what looked like an Elder head without the Elder logo.

Filing holes for standard pushrod Hoping 5/16 works

Sometimes ya gotta put the hard yards in for the end result.

bore the cam follower tunnels out a bit and use grey motor holden ones, they come in 2 different base thicknesses - use the thicker ones. I'd assume the block is off the gearbox atm as you are putting fillings down the pushrod holes .....

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120bhp with 450kg just fun waiting to happen

We were prob. drunk when we set it up last and thought this will be a good idea

No this is the head needed a little relieving.The holes in the block have been drilled to half inch.
Thanks for the info on grey motor followers.I think thats how racers are able to use more radical cam profiles