Valve sizes on an RV8...........

[simonb9]

If an RV8 engine has 1.63" inlets and 1.40" exhausts, what sort of size are these compared to a standard head ?? Stage 2/3 , etc ??

[Boosted Ls1]

I've used 43/37's which is a common thing to do. Combined they add up to 80 and you can't get much bigger without moving the guides further apart.

Boosted.

[simonb9]

Boosted Ls1 said:

I've used 43/37's which is a common thing to do. Combined they add up to 80 and you can't get much bigger without moving the guides further apart.

Boosted.

So 63/40 sounds wrong then ?? As it way over 80 ?? Sorry to sound a bit vague, just seen an advert which states a certain engine spec.........

[HarryW]

simonb9 said:

Boosted Ls1 said:

I've used 43/37's which is a common thing to do. Combined they add up to 80 and you can't get much bigger without moving the guides further apart.

Boosted.

So 63/40 sounds wrong then ?? As it way over 80 ?? Sorry to sound a bit vague, just seen an advert which states a certain engine spec.........

1.63" is not 63 it is ~41.4mm likewise 1.4" ~ 35.5mm which equates to 77 on 'boosted's' max scale of 80 above, so there is some scope for bigger valves.

[simonb9]

Yes sorry, quite right !!. So its about right then for a 'bigger valve' head.

[number 7]

TVR's own version of a BV head is 42.8mm inlet, 36.8mm exhaust. Des Hamill's book say that the largest valves JE uses are 43.2mm inlet and 37.0mm exhaust. I'll let you do the conversion
7.