Hi
What sizes are the valves in L-16 or L-18 heads?? I am looking for suitable 32mm exhaustvalves for my A15 head but I still haven

Inlets are 42 or 44mm
Exhausts are 33 or 35mm

depending on the casting number. W53 head (1600/510) had the smaller valves (some others might also). casting mark is between #1 & 2 spark plugs.

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does any one know ahy A series had smaller Exhaust valves while L series has bigger exhaust valves! any technical reasons if u have any.
barpk

Thanx for the answer!! Maybe it

barpk i think you should re-read those values



and i still want to know whats involved in putting bigger valves in????????

Yep, bigger valves does not really mean better flow and more HP, I know about a couple of guys that tried that (I'm not sure but i think it was 3-4 sizes bigger than standard) and created less power than a standard A-14 and they had webers, a custom exhaust etc

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sorry for confusion!
what i meant is that in A series Exhaust valves r smaller then ITS intake Vlaves, but in L-seires Exhaust valves r larger then L-Series intake Vlaves, why is that?
barpk

L-series valves are (as re-stated from above):

Inlets: 42mm
Exhausts: 33mm

or

Inlets: 44mm
Exhausts: 35mm

I don't know of any modern engines where the exhausts are bigger than the intakes (except possibly in 3-valve engines). The reason is that exhaust gas is exiting under pressure, and so requires a smaller valve. This allows more space for bigger intake valves, and helps keep the flow balanced.

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Don't forget the "210" casting head (US L16 only) has even samller valves. They use 38mm intake valves, with 33mm exhaust. I think this head/valve combo came on L14's in other parts of the world.

>and i still want to know whats involved in putting bigger valves in????????

Hi Michael!!

I need bigger exhaust valves because I am turbocharging my engine, otherwise exhaustgases hasn