Rocker tubes V springs

sidecar · Post by **sidecar** » Sun Oct 28, 2012 10:42 am

Hi guys, I've acquired a Myford 7 lathe and need to use it for something! I was thinking about making some tubes to replace the rocker shaft springs and was wondering what are the actual benefits of going for tubes over springs. Any thoughts?

spend · Post by **spend** » Sun Oct 28, 2012 11:43 am

Some spring is still needed even with solid spacer tubes IMHO, all you are doing is to try & remove the gross lateral movement that the original springs require, but I think you still need to consider:

- Thermal expansion
- Trying to keep rocker arm sideways movement limited
- Friction on the sides of the rocker arm
- Oiling - ie how much is allowed to escape out of the bush.

My solution was to make spacers and then assemble like rocker - shim - spring washer - shim - spacer. I used ally tube but have seen some done with copper plumbing pipe (eek).

ETA Note: I found that using this method there was no need to restrict the oil flow up into the rocker shafts (with roller rockers) as the shims & springs helped retain oil pressure in the rocker bushings, even when using additional oiling up the pushrods into the rocker arms.

sidecar · Post by **sidecar** » Sun Oct 28, 2012 7:16 pm

Hi Dave,

Thanks for your reply, I'll bear in mind your comments.

I guess tubes will allow less oil to bleed out of the rockers than what the springs do although the clearance gap and wavy washers must give a pretty
easy escape route for the oil.

I'm still wondering what the advantage of going to tubes is, if indeed there is any advantage. maybe there is just a bit less friction in the rocker gear with tubes.

Cheers,

Pete

Flying Phil · Post by **Flying Phil** » Thu Nov 01, 2012 7:29 am

Hi Pete
I've used tubes on my Rover V8's and "A" series engines. There is a minute! reduction in friction. There are no expansion problems as the heads expand more than the rocker shaft assemblies because the heads run at a higher temp.

sidecar · Post by **sidecar** » Thu Nov 01, 2012 1:12 pm

Cheers Phil,

I might make a set of tube just so I can boast about them down the pub!

(Even though they probably make F all difference!)

Denis247 · Post by **Denis247** » Thu Nov 01, 2012 5:01 pm

Flying Phil wrote:Hi Pete
I've used tubes on my Rover V8's and "A" series engines. There is a minute! reduction in friction. There are no expansion problems as the heads expand more than the rocker shaft assemblies because the heads run at a higher temp.

I used them in a 1293S engine but I thought it was because of the high revs.
A GOOD additive would provide better friction reduction imho (I use ZX1),