5 replies to this topic

[gazza82]

Recently I've heard of two different owners who have had the cylinder heads re-conned only to find that some of the valves are shorter that the other .. meaning that it is almost impossible to set the rocker spacing.

 

So the question is, are all A-Series valves the same length?

 

 

[LouisHek]

Hi. I am from Germany. I need to participe with this forum. Thanks for all.

[Turbo Phil]

No they're not all the same length. 1275 valves come in two lengths and the smallbore ones are shorter again.

Phil.

 

[gazza82]

Thanks Phil

[ACDodd]

Valve heights different after reconditioning is usually due to seat cutting. Some seats need more cutting than others to restore an effective seal. If you want valve seated height all the same you must take your head to a specialist and tell them what you require. The cost will be higher as more work is needed to achieve this.

Ac

Edited by ACDodd, 16 August 2018 - 07:29 AM.

[carbon]

As well as different valve lengths, I have seen 'large bore' single groove valves of same length but with the collet groove distance from the valve tip machined at up to 1mm difference in height between inlet and exhausts. So the valve spring retainers end up at different heights.

 

This complicates setting the spring heights, need to use shims. But at least the valve tip heights are all the same (as long as valve seats are at correct heights).