Valves and valve trains issues
Discussion
There's a very good reason why I don't do phone or answer emails from people who only want free advice. However, I answer what I have time for on here. It strikes me that for all the money you intend to spend you could answer most of your own questions with the right tools (burette etc) and proper measurement.
If you start with a 2 litre injection head with 50cc chambers, deck the block so that flat top pistons are flush with the top it only takes about 2mm off the head to get 12:1 which is not a problem at all. No need to use a 1600 head for that CR and it would only create more problems with valve length.
I have no idea if current aftermarket followers are any good or still crap. I haven't seen any for years. However I've never seen a cam that needed to use anything other than stock followers and I've used some pretty serious cams in race and stock car engines.
I don't have any 46mm valves left so that's another problem solved
I do have 44.5mm ones.
I would say it's far more important that the head modifier knows how to do Pinto heads properly than what size valves you use. No point having the biggest possible valves but crap porting that loses 20bhp from what would otherwise be possible. I've done 200 bhp easily enough on 44.5mm inlets as has Dave Vizard and very few people get much more. 46mm is probably worth another 8-10 bhp if ported really well but it's hardly a deal breaker.
I believe everything else is answered in detail on my website in the Pinto article itself or elsewhere.
If you start with a 2 litre injection head with 50cc chambers, deck the block so that flat top pistons are flush with the top it only takes about 2mm off the head to get 12:1 which is not a problem at all. No need to use a 1600 head for that CR and it would only create more problems with valve length.
I have no idea if current aftermarket followers are any good or still crap. I haven't seen any for years. However I've never seen a cam that needed to use anything other than stock followers and I've used some pretty serious cams in race and stock car engines.
I don't have any 46mm valves left so that's another problem solved
I do have 44.5mm ones.I would say it's far more important that the head modifier knows how to do Pinto heads properly than what size valves you use. No point having the biggest possible valves but crap porting that loses 20bhp from what would otherwise be possible. I've done 200 bhp easily enough on 44.5mm inlets as has Dave Vizard and very few people get much more. 46mm is probably worth another 8-10 bhp if ported really well but it's hardly a deal breaker.
I believe everything else is answered in detail on my website in the Pinto article itself or elsewhere.
I discuss the ideal exhaust valve sizes in great detail on my website.
http://www.pumaracing.co.uk/Exvalve.htm
Why do you think I would give different advice to you than to anyone else? If you want to fit 38mm exhaust valves then go ahead, it's your engine. If you had a 2 litre engine with 34mm exhaust valves you'd fit 36mm ones and think you'd done the ideal thing. If the engine has 36mm exhaust valves to start with why would you change them? Because you think everything must be made bigger to make it better?
I can sell you 44.5mm inlet valves if you email me. My email doesn't block anyone so if you can't reach me it's a problem at your end not mine. Maybe AOL is blocking some email senders so try and get a friend with a different email address to reach me. I can post to anywhere in Europe so that isn't a problem.
http://www.pumaracing.co.uk/Exvalve.htm
Why do you think I would give different advice to you than to anyone else? If you want to fit 38mm exhaust valves then go ahead, it's your engine. If you had a 2 litre engine with 34mm exhaust valves you'd fit 36mm ones and think you'd done the ideal thing. If the engine has 36mm exhaust valves to start with why would you change them? Because you think everything must be made bigger to make it better?
I can sell you 44.5mm inlet valves if you email me. My email doesn't block anyone so if you can't reach me it's a problem at your end not mine. Maybe AOL is blocking some email senders so try and get a friend with a different email address to reach me. I can post to anywhere in Europe so that isn't a problem.
Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff