mk1-forum.net

Hi,

I have stripped 2 Cooper heads...one std valves 1.218" Intake, 1.0" Exhaust, the other 1.31" Intake, 1.151 Exhaust.

Both heads could use hardened exhaust seats, almost certainly new guides...and new valves.

There appear to be limited valve offerings on the major supplier sites.

What ideas do others have?

Rick/Hunter2

The big valve head before disassembly with a std intake and exhaust valve on the right for basic comparison.
https://www.facebook.com/photo/?fbid=10 ... 4941191039

The std valve head after clean up and before crack test. NO cracks.
https://www.facebook.com/photo.php?fbid ... 345&type=3

My small bore head uses REC valves in 1.25” inlet and 1.07” exhaust. They’ve got a good range

http://www.gsvalves.co.uk/assets/race-e ... alogue.pdf

Rick , the head with the larger valves may have 1275 intake and exhaust valves installed .
Check the length of all the valves. The 1275 valves are longer I believe.

Craig

Right you are Craig...

The big valves are +3.575" with single narrow groove and the stock valves are +3.42" with wide single groove.

Question...did you do this?? (answer not required)

So maybe REC/G&S valves??

Problem I had with the REC valves is you can’t get the fitted spring heights anything like tall enough using aftermarket retainers collets and springs.

I have recently rebuilt several 295 heads. I have the machine shop install new cast valve guides, followed by hard valve seats intake and exhaust, I have been using the late triple groove unleaded O/S intake and exhaust valves. Followed by CC and surface to desired C/R. I have seen 1275 valves installed but it sure screws up valve train geometry, spring pressures and I think they are a little big for most. It will require retainers and keepers to match. That's been my solution since 1275 cores have become so hard to find. Steve (CTR)

Can you not turn down the stems? Mine runs 1275 valves. Not sure if they’ve been shortened or not

A little off topic, may I ask what double springs will you choose to fit in your 295 head? C-AEA 525 or C-AEA 526 from Minispares?
Since the original 295 double innner springs are hard to find new now, for fast road engine, any other made recommended?
Thanks.

Al

I used a set of standard sized rimflow valves, not sure of their availability now though (was about 15 years ago). I have also had an 1100 head with turned down 1275 valves - had to put spacers under the springs I think and it could have done with spacers under the rocker pillars as well as it really screwed with the rocker angle and ate valve guides - went like a 2 stroke .

Al, I used a SW5 kit that came with the springs. Made a lovely torquey engine that you could thrash as well - valve bounce kicked in about 6500rpm

My 12g295 has 1275 valves, I did put spacers under springs and also under rocker pillars, seems to work really well and no issues with clearance to rocker cover,
My head came modified with these valves already installed,

All excellent info/experience...

Have been in touch with G&S, overnight response to questions of availability etc.

Following up with on their REC 101 with 1.338" Inlet size and REC 102 with 1.141" Exhaust size, given that the head had been cut for the 1.31" 1275 intakes. The 'big valve' head will need new hardened exhaust seats...not yet sure about the need or not for new intake seats.

The 'standard' head can readily use the SV-300-4 Inlet valve at 1.25" and the SV300/51 Exhaust valve at 1.060".

They collets for both valve sets.

BOTH Heads have been crack tested and are good!