Valve spring height on *dot*head

[HWB]

Hello everyone I'm in the process of finding me a manual for the 748 but in the mean time I'm taking the head to the machine shop for a valve job and i need to know valve spring height for this head (*dot*head) to know how to go about this job. Cheers

[Gixer1460]

That's a question I don't think i've ever seen asked on OSS before! Probably because most people don't find it critical.  I assume you are talking fitted height? which would be influenced by seat cutting / valve recession? My manual isn't exactly forthcoming in valve spring info other than free lengths, no tolerance, wear limit, poundage etc! So would assume if they are about the correct length 'free', whatever they are fitted, is mint! Just don't recess the valves too much as that affects seat spring pressure but also compression ratio!

[no class]

.....if you are changing the seats for larger valves , the reputable machine shop will measure beforehand and set all dimensions accordingly ..... perhaps you could specify what your plans are ?  

[HWB]

I just finished porting the head, it will go into 1127 block to replace my N head (shim type), for the moment i wont go with bigger valves but i do feel a 5 angle valve job would benefit the flow. The head also has a very very slight dimple on its face me the ring of fire on combustion chamber #2 which im going to remove by skimming 0.3mm at the shop. Im afraid that attacking the job without backup numbers might ruin things. Hence the question

Edited April 28, 2021 by HWB

[Joseph]

I have the following :

Intake min. 35mm

Exhaust min. 37.8mm

Free length when off the engine

Edited April 28, 2021 by Joseph