Maney stage 3 head

Chaps,

I recently stripped a Maney stage 3 head and was surprised to find heat insulators under all four spring seats.

Is this correct ?

And, can anyone advise what the installed valve spring height should be ?

Nigel, did it come from Steve that way, or could they have been added later? All the heads I've bought from Steve (one Stage 2 and three Stage 3s, I think) have come with just the head and valves, no springs, rockers, etc. His web site listed the heads that way, and he sold the spring kits separately.

Ken

Almost certainly added later I think Ken.

I know I didn’t fit them on my 920 build, hence I’m questioning if they should be in this head.

So I need to establish if these have been added ‘correctly’ ie maintaining the correct valve spring height, or not.

I have a witness mark, a line running directly across the centre of the cam follower, to me that ‘could’ indicate excess spring pressure.

Do you know what the valve spring installed height should be with Steve’s springs Ken ?

have the valves been sunk into the head?

acadian said:

have the valves been sunk into the head?

Click to expand...

Depends what you mean?

They are as they left Steves workshop. It’s was unused.

Do your own set-up for the springs. Use a pressure gauge and set the seat pressure you want to use.

Most likely those heat washers should not be there.

I’m not clever enough to reinvent stuff Steves already done mate!

I just wanna ensure it’s put together as he intended.

Steve used different springs, for different builds, at different times. For several years he mostly used, and sold, springs that I supplied to him from R/D springs. The ones he sold were their VSK-901N kit.

For this kit, R/D recommends 1.330” – 1.360”installed height, for up to .450” valve lift. This kit uses their #1005 springs. At 1.350” installed height, pressure is 85# on seat and 225# at .450” lift. Free length is1.700” Spring rate 311lb/in. Coil bind is at .775" height. (From R/D web site).

If the springs you have are 1.700" free length and 1.250" diameter, with titanium retainers, they are likely this kit.

FWIW, I mostly set the installed spring height for this kit at 1.350".

For some of his builds with more radical cams (N480) and higher rpm (ultra short strokes) he used 1034IRL springs from R/D, at their recommendation, that used a higher spec spring material and a little higher spring rate (and cost a bit more).

I've attached the R/D instruction sheets for their standard Norton kit below.





I've also attached the table below, for anyone that might find it useful, with some tabulated spring data I collected a while back. I haven't updated it for a while, though.



Ken

Wow, thanks Ken!

This is for a 1007 head BTW.

I’m measuring the free length at 1.82”. Diameter at 1.250”. Black steel spring cups and titanium spring retainers.

Installed lengths look to be between 1.36” and 1.37”.

This is WITH the mysterious heat insulating washers fitted, which are 0.068” thick.

I‘m getting a coil bound length of 0.788”.

So… my conclusion at the moment is the heat insulators are supposed to be there as without them I’m looking at installed lengths of 1.428-1.438”.

I’ll check spring length at full lift next time I’m in the shed.

I recently rebuilt my stage 1 Maney head for use in the Atlas Domiracer, & used the heat insulation washers which gave an installed spring height roughly to Combat spec. which I judged to be suitable for the PW3 cam I'm using. Without spacers the Maney bottom cups would not sit against the head, as the outer radius is smaller than the original Norton ones.

Fast Eddie said:

Wow, thanks Ken!

This is for a 1007 head BTW.

I’m measuring the free length at 1.82”. Diameter at 1.250”. Black steel spring cups and titanium spring retainers.

Installed lengths look to be between 1.36” and 1.37”.

This is WITH the mysterious heat insulating washers fitted, which are 0.068” thick.

I‘m getting a coil bound length of 0.788”.

So… my conclusion at the moment is the heat insulators are supposed to be there as without them I’m looking at installed lengths of 1.428-1.438”.

I’ll check spring length at full lift next time I’m in the shed.

Click to expand...

Yeah, definitely not the R/D spring kit.

Ken

lcrken said:

Yeah, definitely not the R/D spring kit.

Ken

Click to expand...

Do you think so Ken?

The springs have not been fitted long so have spent very little time under compression.

Is the 1.7” figure you quote for new springs?

This is another reason I got to looking at spring lengths etc.

Note the line running through the centre of the followers.

We’re talking around 3 hours track use, max 6,000 rpm.

Any thoughts ?

Fast Eddie said:

I’m measuring the free length at 1.82”. Diameter at 1.250”. Black steel spring cups and titanium spring retainers.

Installed lengths look to be between 1.36” and 1.37”.

This is WITH the mysterious heat insulating washers fitted, which are 0.068” thick.

Click to expand...

Heat insulating washers were standard and should always be used.
The metal alloys used in engines all lose strength at raised temperatures. The higher the temperature, the greater the loss. As the temperature increases, less of this strength loss is recovered when the temperature returns to ambient. The amount of permanent loss in strength is also dependent on the length of time spent at temperature - the longer the time, the greater the permanent loss. Once the yield strength of the valve spring reduces to a level below the stress generated at full valve lift, the spring is past it's best. This is the reason for fitting heat insulating washers, especially on the exhaust side. Valve springs are never going to last forever, but don't reduce that life unnecessarily by leaving the insulating washers out.
This permanent loss of strength also occurs when heads and crankcases are heated in order to aid removal of bearings, valve seats & guides, so be careful.

You don't find heat insulating washers in other similar motors. Their value in reducing actual spring temps is debatable but their use as as spacer is important. Note that the exhaust valves usually dont' have a valve float problem - just the intakes. Ron Wood told me that at 8000 RPM the early style race springs can experience valve float and coil bind. If this happens and continues to happen then the springs can heat up to extreme temps from the coil binding, lose their tension and need replacement.

Stevez in the country Nige

Do the Commando race cams which are in common use have inlet and exhaust lobes which are of different shapes from each other ? I only ever use methanol fuel, so heat is not so much of a problem. Also I do not use radical cams. All the theories do not necessarily work together to give the best result. When using petrol as fuel, compression ratio, jetting and ignition timing are much more critical. Even when using methanol, the heat build-up is high.
If you need to impose a 6000 RPM rev limit - ? I often see 7500 RPM on up-changes.

Fast Eddie said:

Do you think so Ken?

The springs have not been fitted long so have spent very little time under compression.

Is the 1.7” figure you quote for new springs?

Click to expand...

Yes., that's for new springs. But I'm not quite so sure today about yours not being R/D springs. 1.700" is the number R/D listed for free length, but I just found some old data where I had measured the pressures of various brand Norton valve springs, starting at uncompressed, and measuring in increments to coil bind. And the free length I measured for the R/D spring from the Norton kit was 1.802". Unfortunately, I don't have any new R/D springs left to measure except some of the IRL items.

Ken

lcrken said:

Yes., that's for new springs. But I'm not quite so sure today about yours not being R/D springs. 1.700" is the number R/D listed for free length, but I just found some old data where I had measured the pressures of various brand Norton valve springs, starting at uncompressed, and measuring in increments to coil bind. And the free length I measured for the R/D spring from the Norton kit was 1.802". Unfortunately, I don't have any new R/D springs left to measure except some of the IRL items.

Ken

Click to expand...

Thanks Ken.

And… any thoughts on my pics in post #13 ?

acotrel said:

Do the Commando race cams which are in common use have inlet and exhaust lobes which are of different shapes from each other ?

Click to expand...

Some do, and some don't. The 2S, 3S, and 4s cams from Norton have higher lift profiles for the intake valve than for the exhaust, as do some of the aftermarket cams (Sifton, Norris, Megacycle, WEB-CAM, Dunstall). The standard Commando cam has the same lift profile for both intake and exhaust, as do some of the aftermarket cams (PW3, Axtell, some Megacycle, Sifton, and Norris). Several of the aftermarket manufacturers have both types of designs available.

Ken