Rocker Shaft

[Darren Groves]

I stripped down my spare rocker shaft today as I was going to refurb to replace the one on the car. The shaft has signs of wear so I was going to replace that as they're fairly cheap. If the shaft is worn, does this mean the actual rockers will be too or does the majority of the wear happen on the shaft? Is it a bad idea to fit old rockers on a new shaft or doesn't matter?

 

[Clive]

Most wear always seems to be on the shaft. A friend has just done a shaft replacement and commented that the used rockers felt pretty tight on the new shaft. Plus it will help keep them all oiled up as less loses. 

Well worth doing....

[Pete Lewis]

Needs a metalagist answer as to why buts , its common that the hard shaft takes the wear and the bronze bush or alloy piston are fine but the pins and shafts are worn

 

pete

[Ben Caswell]

Just a theory!! ..... The main load is one point at the bottom of the rocker shaft but the load point on the rocker is moving and spread over a larger area.

 

You should be able to assess the rocker wear by sliding it along to another none worn part of the shaft.  

[Darren Groves]

You should be able to assess the rocker wear by sliding it along to another none worn part of the shaft.  

 

I did do that, there was some play, but not a huge amount though it could be felt. What is considered acceptable?

[Clive]

I reckon if you can easily catch a nail on it best to replace. Especially ias it is already apart. 

[Darren Groves]

Definitely a new shaft, but if you move the rockers onto an unused part of the shaft there is still some play, not huge, but there. Is a small amount of play normal or does that indicate worn rockers also?

[Pete Lewis]

This is the old favourite of compromise or utopia

 

shafts are 0.5607 -0.5612"

 

Rocker bores 0.562 -0.563"

 

so clearance ranges 0.0023" to 0.0008"

 

Well something like that

 

pete

[Clive]

Rockers a bit worn. But worth the cost of replacing? Very very doubtful, most of the wear will have been sorted with the new shaft, and will function way better than previously. Don't fret, all will be fine for another 50k....

[DerekS]

For what it's worth, I spent a lot of money on a new complete assembly after noticing slight play on the rocker arms and slight wear on the rocker arm pads...

The new one arrived with more or less the same amount of play as the old one, I fitted it anyway but after giving it some thought I dressed the pads up on the old one with an oilstone and refitted it; it's been fine. Don't be too keen on splashing the cash. I could kick myself for wasting so much money.

[Darren Groves]

 Don't be too keen on splashing the cash. I could kick myself for wasting so much money.

 

I was hoping just to do it for the cost of a new shaft, so I think I'll just do that and polish the slight indents of of the tips, it's going to be better than what I have.

 

Thanks to all.