Have you put bigger valves on 3.2 heads? How big ?

[BReyes]

Have you put bigger valves on 3.2 heads? How big ?

Thank you.

Regards,

[MBruns]

Bernard, you can do 52mm intakes no problem, we have done the 43.5 ex on some race heads but the valve to valve is real close and cam selection is tricky so we usually go with the 41.5mm ex.
Mike Bruns JBRacing

[m42racer]

Bernard,

The above post has some good info. Maybe to add to it when fitting bigger Valves, I think the Valve Seats have to be replaced when fitting the RSR sizes.
52.50mm Intakes and 43.50mm Exhaust are standard RSR sizes. Larger Intakes and Exhaust have been fitted, but when you start to get up into these even bigger sizes, the Intake and Exhaust systems needs to support the bigger flow.
If you email me, I will send you some photos of my Heads with the bigger Valves.

[89turbocabmike]

m42racer, welcome. Always enjoy your input on the Rennlist turbo board

[Wayne 962]

What engine are you building, and for what purpose. Bigger isn't always better. For most street engines, the 3.2 valve sizes are good, and sometimes almost too big...

-Wayne

[BReyes]

Mike. I read about bigger valves on a 3.6/3.8, and that 3.2 heads limit hp to the 300's, so just trying to learn.

I'm thinking about the cam first and then max flow in/out, and am wondering if what we talked as regards to porting the heads will be enough. When I'm ready I'll bring them to you for twin plug at least.

M42racer. pm sent. Thanks for posting bothe here and on other sites. The turbo info is coming together for me.

Wayne. 3.2 twin turbo (in planning stage).

[MBruns]

Bernard, the 3.2 heads are pretty good stock, they are better than some race heads that we have tested, we use the big valves/seats on our race engines that produce 110-125 hp per liter normaly asperated and have a rev range 5500-8500 as far as a hot street engine I would spend the money somewhere else. and you will make plenty of power
Mike Bruns

[asphaltgambler]

My belief for a street engine normally aspirated that the valves are large enough. In my 3,4 build the ports were smoothed but the valves are stock size.