Pushrod Material

[tony.barnett]

I've been looking for some tubing to make a VH pushrod. The original tube was 7/16" OD and 20 thou wall thickness.

I can get:-

1. mild steel seamless tube 7/16" OD, 2mm wall (80 thou) - so likely heavier than the original, but does that really matter in a road engine?
or
2. Stainless tube 7/16" OD 28thou wall. - close to the original dimensions but is stainless Ok to use in this application?

I can't find suitable chromoly tubing.

What would you choose?

[nevhunter]

I'd give the stainless a go but use a bit more tappet clearance.Nev

[Pete.Silson]

What valve springs have you got? The heavier springs (VS20?) on the iron VH put quite a load on the pushrod so I wouldn't use mild steel.

I would probably go for stainless tubing, however 316 stainless has a thermal expansion 30% greater than mild steel so I would add a couple of thou to the tappets.

The original chromoly tubing in my VH was 1/32" (.031") wall thickness which is about 21g. The nearest I found to this was 4130 with 20g (.036") wall which I eventually got from Germany (at a price). In the US 4130 is as cheap as mild steel but the postage costs seem prohibitive.

Pete

[tony.barnett]

I would probably go for stainless tubing, however 316 stainless has a thermal expansion 30% greater than mild steel so I would add a couple of thou to the tappets.

The original chromoly tubing in my VH was 1/32" (.031") wall thickness which is about 21g. The nearest I found to this was 4130 with 20g (.036") wall which I eventually got from Germany (at a price). In the US 4130 is as cheap as mild steel but the postage costs seem prohibitive.

Pete

Is that cos it overheats on the rear pushrod?...Its a joke....honest

I'll go for stainless. Can't find chromoly anywhere.

Thanks for the replies.

[Pete.Silson]

Is that cos it overheats on the rear pushrod?...

You're only allowed to make comments like that if you've got a four-potter in your garage.

I can sell you one if you want.

[tony.barnett]

Is that cos it overheats on the rear pushrod?...

You're only allowed to make comments like that if you've got a four-potter in your garage.

I can sell you one if you want.

Sadly my garage is somewhat full Pete...far better it stays in yours

[dave.owen]

If you really wanted a sq4 you would make room

[tony.barnett]

If you really wanted a sq4 you would make room

I don't have a boat big enough for such a large anchor...

[dave.owen]

Ha ha

[TimM]

You should be able to find T45 tube in a suitable size. I wouldn't use stainless for 2 reasons, it's more flexible than a good steel and it's thermal expansion is akin to aluminium.