Thread: New cylinder head question

Originally Posted by Themadmob

Hi All, I have a brand new cylinder head and new valves ... My question is apparently I must take the cylinder head to an engineering shop to have a bevel cut into the valve ports for a good seal ... Is this standard ?

that sort of depends.

are you talking about the seating cuts for the valve to seal against or the stem seal or the manifold end of the port?

if you're talking about the valve seat then yes/no/maybe.

if they are a raw head that isnt premachined then yes, you need to have the valve seats faced.

if they are a machined head then yes and no. if the seating matches your valves then no, if the seating does not match your valves then yes. Idealy though a machined up head will come prematched, if youve ordered some kind of odd setup then you should have ordered the valves to match.

if the head is pre machined then you can also have the valves cut to match your head in which case, no you dont need to machine the head.

If the head is setup to take inserts, then no it doesnt need machining you just need to get the inserts in.

If youre talking about the stem seals...

Maybe, it depends on the finish quality of the head and the seals, Confirm which bevel you're being advised about, where and why its being recommended as theres a few variations of seal design that need a different setupp.


if its the actual exhaust port thats being talked about, yes and no. doing it helps the flow and the gasket setup but its not really a performance engine that we're talking about here.



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Hi .. Thanks for info .. It's a brand new head .. Here is a photo

just do the bearing blue test on the valve seats and faces ,that will tell you what you need to do.

a thin blue line on the valve will give a good seat but poor heat transferance

a thick blue line doesnt seat so well but gives good heat transfer.

and in complete line means you need to do some work.

it doesnt mean you have to get it machined, you can get valve seating kits that will let you do it. you can also make your own jig to let you grind valves on a a bench grinder.

IVe also done them in lathes with a sharpening stone.

The photos appear to show an early Series 2 head. Note that the rocker gear and push rods from a later head may not be suitable and also that this head may not fit an engine with a later timing cover.
Check all your options before spending more money
Cookey