Absolute Largest Valves

[Peredur]

What are the largest inlet valves that can be fitted to a smallblock head? (14SE or 16Se)
I'm planning a short stroke 1300 and I'm wondering if a 40mm inlet valve will fit if I leave the exhaust at 31mm or if I could getaway with a 40/32 combination even?

*mowgli or C612DNM if you've any experience with this then please chip in.

Thanks

[garyc]

Look here. http://www.gsvalves.co.uk/tablet/race-engine-components.html

[Peredur]

Thanks for that, the largest that REC specify for these are 39mm, I'm wondering if they'll accommodate more.

[mowgli]

i'm hoping to stick some 20seh inlet valves into my head...
they are 41.8mm. the std ones are about 38mm, so i would need to find 1.9mm each side..

federal mogul online parts list with dimensions [click] (http://www.fmecat.eu/selProd2.asp?make=117&model=%20&engine=17574~20%20SEH&litre=%20&prdgrp=4&langID=1&TsVer=&engseal=0)

[Peredur]

I've found that the inlets from a BMW M20B50 are 40*7*102 ish so would be ideal for a 16se head
As I'm hoping to build a short stroke lump I want to help it with cylinder filling as much as possible

Thanks Mike

[mowgli]

the bmw ones were on my list, but the collets are different to gm ones.. a bit of machining would probably sort that out ok.

[Peredur]

Worth a punt I'd have thought, what size exhausts are you hoping to use? I'm sortof thinking of just cleaning up the standard ones tbh.

[mowgli]

i was planning to keep the std 1.6 exhaust valves. the blydenstein b+ heads only had bigger inlets iirc

[mk1nova_rich]

I was going to say even most full blown race heads don't have much bigger exhaust valves than standard. Keep the stock ones for more inlet valve clearance

[Peredur]

Thanks Rich, that was exactly my train of thought, rather than go +1 on both, keep the ex as it is just clean the valve up and go +2mm on the inlet, even if it needs new seats cut and let in.

Thanks

[Peredur]

Just found out on corsa-a.de that a certain Mr Schiermeister was running 41mm inlets :thumb: