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Tue Oct 22, 2019 12:22 pm

I'm preparing to do a quick valve job on a set of heads for a friend, they're Brazil 041's with 39X32 valves. I'm wanting to do stainless valves all around, but can't seem to find a source for 39mm stainless valves for the intake.

I'm sure this has been done before, so what stainless valves can be used for the intake?

Thanks!

Tue Oct 22, 2019 12:38 pm

I haven't seen standard stainless 39mm valves. You could just take a standard 40mm and turn .040" off the outside edge, or measure and see if the 40mm valve will fit the seat. I bet it will. Move the sealing surface out a bit, and you will also get a little more flow.

Brian

Tue Oct 22, 2019 1:31 pm

As I recall the 39x32 combo was know to run hot due to the intake/exhaust ratio. I believe these heads were originally intended for Brazilian market VWs that ran on Ethanol.

Tue Oct 22, 2019 2:55 pm

Lo Cash John wrote: As I recall the 39x32 combo was know to run hot due to the intake/exhaust ratio. I believe these heads were originally intended for Brazilian market VWs that ran on Ethanol.
Yes they had a tendency to run warmer. Most of it was due to insufficient exhaust systems and some of it was intentional.
Streamline the snot out of the exhaust without hogging it out, keep the intake just about stock apart from the obvius small improvement. Do a competition valve seat job on both seats and you´ll be fine. Going 1½" exhaust all the way through helps well too.

Wrt. the intake, you can do as Brian says, or you can the 40 mm intake in the 39 seat. If you do, you can pull the contact surface on the valve inward by ½ mm and then make a deeper 70 degree undercut. If you have the tools for it you can break the lower edge with a 85 degree cut. If not, just let it be.

Tue Oct 22, 2019 4:35 pm

Yep, just trim the valves to fit.

the brazil steel 39mm valves are just fine too, if the stems aren't worn out, no real reason to replace them. Or, save them for later to make into 37mm valves ect.

Tue Oct 22, 2019 11:26 pm

Awesome! Thanks for all the replies. I'm thinking I'll just go with stainless exhaust valves and some new standard 39mm intake valves from ACN since I know they have them in stock.

And yes, these heads will be getting a bit of port work done, similar to the 041 heads on my engine. Should turn out pretty alright 8)