i'm going to get a head ported and some bigger valves fitted for an a series turbo buildup. is it pretty much a case of fit the biggest valves i can?

also pretty sure i'm going to have a standard bottom end but for o-ringing. any thoughts or comments...

when jeff taylor built but turbo a15 he said its harder to it bigger exhaust valves on a heads than the inlets, or maybe its easier to get them dunno but thats one thing to think about. also when he did the head he left the exhaust ports almost stock something about keeping the velocity of the gasses high before the turbo. one more thing if youre going to use stock bottom end u can get just as good reseults from a stainless steel headgasket compared to the oringed block, speedway cars use this idea. may also save some hassles coz if u are using stock bottom end u might get away with not rebuilding it by simply changing to stainless head gasket if u get it ringed youll have to rebuild it.

i've been trying to research what different people have used. feral in his tomei A13 had 40mm inlet and 35mm exhaust, dman1000 used 38 in 33 ex. i spoke to the guy who is doing the head and he said he'd rather trim a valve down in its diameter (say from 42 - 38) to make it fit rather than cutting down the length of them as done in the 1600 valve use. he was worried about them snapping where the new groove had to be machined...

stainless head gasket hey. I am rebuilding the bottom end anyway and o-ringing cost $180 - whats a stainless gasket worth?

Toyota 2R inlet valves and L16 exhaust. 2R are 40mm and L16 are 35mm from memory, [im sure someone can confirm] the stems are too long and need to be shortened. dont forget lashcaps. Thats whats in my JTS head.

cool, i'll look into that. is there any worries with shortening valves? are they hardened or heat treated or can you just shorten them and cut the new groove in no worries?

Lash caps...?

Sounds like you are planning on doing it properly, if so should not be considering shortening valves, instead you would be finding out who can supply stainless items IMO.
JTS do these at a reasonable price and at pretty much any size you require.

I have used shortened valves without problems in high reving street engines for years.

We used camira valves cut and spun down. Bonus is a 7mm stem.

Used to rev the engine to 9k RPM regularly. When I sold the engine to my cousin, he turned up regularly with it running on 3 cylinders due to bent pushrods that had jumped out from under the rockers!

Engine is still going strong in a track car.

The guy who did my machine work has been doing this for years.

Lash Caps

while you are at it, i would also go for "K-Liners" in the valve guides aswell. extra bit of security. they are not expensive either.

K-liners

Glad someone posted this subject.
Always interesting.