fishtailfred Posted August 30, 2008 Share Posted August 30, 2008 Cool Porting a steel head must be such fun Quote Link to comment Share on other sites More sharing options...
slipsittin Posted September 14, 2008 Share Posted September 14, 2008 With the 2L the best flow is taking the guide right out to the port contour, the pisser is that the 2L have a short valve guide to start with and doing this really shortens the life of the guides. My guess is that the big reason why I haven't got the high lift flow comparied to Vizard is that my head still has all the valve guides, I'm still deciding if I should whack them or not... Really? I have done and seen better results with leaving them in and going about the whole thing a more practical way. If you are going for the best performance/economy/torque why are you taking out all that atomises the fuel??? Flow benches are easy to get readings from but can throw you in the wrong direction just as easy with good readings. Good to see you having a go though. Corey Quote Link to comment Share on other sites More sharing options...
nismo.capri Posted September 24, 2008 Author Share Posted September 24, 2008 Sorry it's been a while work and my new esky van jhave got in the way! The good news is that I have more pics and 2 flow tests to post. I'll get them up hopefully tonight if not tomorrow Quote Link to comment Share on other sites More sharing options...
nismo.capri Posted September 24, 2008 Author Share Posted September 24, 2008 Cool Porting a steel head must be such fun Hi Fred! Yeah I'm a sucker for punishment The few alloy heads I've done feels like butter compaired to the cast iron I'm used to Quote Link to comment Share on other sites More sharing options...
nismo.capri Posted September 24, 2008 Author Share Posted September 24, 2008 Really? I have done and seen better results with leaving them in and going about the whole thing a more practical way. Can you quantify that? No offense but this thread is about showing proveable data that can be replicated and I've herd a lot of stories about 200 hp pintos. If you are going for the best performance/economy/torque why are you taking out all that atomises the fuel??? Are you talking about the factory cast finish on the walls of the port or the valve guides or both? Flow benches are easy to get readings from but can throw you in the wrong direction just as easy with good readings. For sure. Make the port huge and it will make massive numbers on the bench, it will be a piece of shit on the car however. This is why I'm using Dave Vizards graph as a guide. Good to see you having a go though. Corey That's what It's all about, I'm doing this for the fun of it Quote Link to comment Share on other sites More sharing options...
slipsittin Posted September 24, 2008 Share Posted September 24, 2008 Really? I have done and seen better results with leaving them in and going about the whole thing a more practical way. Can you quantify that? No offense but this thread is about showing proveable data that can be replicated and I've herd a lot of stories about 200 hp pintos. The best carb pinto I have built was 190hp@7800rpm, 145 ft/lbs of torque@5900rpm at the rear wheels of a MK3 cortina with a celica 5 speed and std diff with lsd. The rotating parts were all altered to give the high HP reading and the torque is amplified due to the gearbox, but it was a good set of figures all the same. The cam was useless and untill 3800rpm though but its what the guy wanted. It had 48mm webbers and I made the headers and the exhaust system. This engine also eat up 15k and the car was extremely fuel hungry for the feel of the performance. It would of been good to see it in an escort or something lighter. If you are going for the best performance/economy/torque why are you taking out all that atomises the fuel??? Are you talking about the factory cast finish on the walls of the port or the valve guides or both? The surrounding metal around the valve guide is there for more than just supporting the guide from breaking during valve wide open. It is the main piece of the swirl factor when the valve opens halfway. Swirl pattering the valves will give you a better attomisation in the port and the combustion chamber in the head takes over from there (which in the pintos is close but no cigar) Flow benches are easy to get readings from but can throw you in the wrong direction just as easy with good readings. For sure. Make the port huge and it will make massive numbers on the bench, it will be a piece of shit on the car however. This is why I'm using Dave Vizards graph as a guide. David Vizard has produced more books than we can shake a stick at but he never has to this day shown us a streaming video of his work. This is because he will show us charts and the way to do alot of things, but at the end of the day he doesn't use the head gaskets we use or the valves we can get or most importantly the fuel we get here. If I was to listen to a person who was doing it here and is a legend it would be Bob Homwood and he can back it up on the track and on video (unedited) Good to see you having a go though. Corey That's what It's all about, I'm doing this for the fun of it A never more true coment has been said my friend and was wasn't trying to spit at you I was mearly making a comment in passing. Keep it up and think out side just the ports being smooth cause that has no gain for atomisation what so ever Corey Quote Link to comment Share on other sites More sharing options...
cute wee gem Posted September 24, 2008 Share Posted September 24, 2008 A never more true coment has been said my friend and was wasn't trying to spit at you I was mearly making a comment in passing.Keep it up and think out side just the ports being smooth cause that has no gain for atomisation what so ever Corey Why not let us in on your thoughts about finish? Quote Link to comment Share on other sites More sharing options...
slipsittin Posted September 24, 2008 Share Posted September 24, 2008 If the port face is smooth it causes stiction and the fuel molecules stick to it rather than mixing with the air. The extent of how rough it is can help way more than many would think. I normally use a stone that is medium grit to finish an inlet. The exhaust side is different while needing to make sure the vortex is spinning the correct way (ie direction) as the gases leave the valve (this is where the swirled valves come in to it again), it also needs to keep spinning as it travels through the port to the exhaust manifold. If the port is to smooth it will cause the vortex to stop spinning symetrically and create an incorrect pulse in the port momentarily stalling the gases and there for not fully emptying the cylinder. This causes the next compression stroke to be uneficiant and can also cause mis firing and fouling spark plugs. I have seen some head porting guys have paid over 15k for and knew before the engine was assembled it was crap, and to prove it to one guy (who was a big name in the 80's) I bolted a standard head for the main race day and he cleaned up insted of being 5th. Nissan RB engines for example don't need to be ported to show big numbers on the dyno and TRUST/GREEDY use a stocker on their 900hp engines. Other manufacturers also have the same results then put a crap exhaust system on them to stop them blowing up to save face. I hope that is what you were after Corey Quote Link to comment Share on other sites More sharing options...
Testament Posted September 25, 2008 Share Posted September 25, 2008 the exhaust is coated in a carbon more or less straight away as well, whether its a mirror finish or as rough as guts. Quote Link to comment Share on other sites More sharing options...
nismo.capri Posted September 25, 2008 Author Share Posted September 25, 2008 Ok, so first the update. So I decided to see if I could shape the valve guide to increase the flow but leave the valve guide the full length. I went for a knife edge to split the flow around the valve guide boss Here's the flow compaired to stage 1. The difference for an hour and a half of narrowing the valve boss and putting a knife edge was pretty much nothing, see how the 2 runs are on top of each other on the graph. I was a bit surprised as I thought that It would at least show a loss as I had opened up the port some by removing material from the boss and a tiny bit from the wall, I'd have thought that this increase in area would have dropped the bottom end and picked tup the top more. Quote Link to comment Share on other sites More sharing options...
nismo.capri Posted September 25, 2008 Author Share Posted September 25, 2008 Since the shaping of the valve guide boss didn't achieve fuk all I decide to take the top off it. Dave Vizard said that the valve guide needed to go and if you believe the flow numbers it's correct at the top end of the lift Here's my stage 3 vs the stock head Here it is against Vizard Its so close that you could argue that the difference is the flow bench Next up is filling the bottom of the port.... Quote Link to comment Share on other sites More sharing options...
nismo.capri Posted September 25, 2008 Author Share Posted September 25, 2008 The best carb pinto I have built was 190hp@7800rpm, 145 ft/lbs of torque@5900rpm at the rear wheels of a MK3 cortina with a celica 5 speed and std diff with lsd. Nice! Do you still have the run I'd love to see the shape of the torque curve. The rotating parts were all altered to give the high HP reading and the torque is amplified due to the gearbox, but it was a good set of figures all the same. That torque reading sounds like a flywheel reading, the dyno should have taken the gearing in to account? The cam was useless and untill 3800rpm though but its what the guy wanted. This is what worries me... I want to get some good numbers on the dyno to show that my porting is doing the bizz but to do that I need a cam that isn't going to be too road frendly. Do you remember the duration of the cam was it in the 300 degree range? It had 48mm webbers and I made the headers and the exhaust system. This engine also eat up 15k and the car was extremely fuel hungry for the feel of the performance. Would I be right in thinking that you did a lot of work on the bottom end lightning and balancing? The surrounding metal around the valve guide is there for more than just supporting the guide from breaking during valve wide open. It is the main piece of the swirl factor when the valve opens halfway. Swirl pattering the valves will give you a better attomisation in the port and the combustion chamber in the head takes over from there (which in the pintos is close but no cigar) I'm going for quench and some grooves to keep turblence up in the combustion chamber David Vizard has produced more books than we can shake a stick at but he never has to this day shown us a streaming video of his work. This is because he will show us charts and the way to do alot of things, but at the end of the day he doesn't use the head gaskets we use or the valves we can get or most importantly the fuel we get here. I couldn't agree more but he's the only published data I can get. You know what engine builders are like for keeping secrets If I was to listen to a person who was doing it here and is a legend it would be Bob Homwood and he can back it up on the track and on video (unedited) Any chance you can get flow data or pics from him? A never more true coment has been said my friend and was wasn't trying to spit at you I was mearly making a comment in passing. I love talking to people with first hand experiance aboiut the 2L. I've had a few disagreements with people who have a friend/bro/work mate with a "200 hp" pinto. Most proven HP I've seen is from a guy in Aus who has a 2L that spins to 9000 rpms that make 150 rwhp. Have a look at this article http://autospeed.com/cms/A_107746/article.html this guy has done over 120 dyno runs and he's only making 100 rwkW (~137 HP) Keep it up and think out side just the ports being smooth cause that has no gain for atomisation what so ever Corey I do the same as you and finish them with a ruff stone Quote Link to comment Share on other sites More sharing options...
nismo.capri Posted September 26, 2008 Author Share Posted September 26, 2008 The exhaust side is different while needing to make sure the vortex is spinning the correct way (ie direction) as the gases leave the valve (this is where the swirled valves come in to it again), it also needs to keep spinning as it travels through the port to the exhaust manifold. If the port is to smooth it will cause the vortex to stop spinning symetrically and create an incorrect pulse in the port momentarily stalling the gases and there for not fully emptying the cylinder. This causes the next compression stroke to be uneficiant and can also cause mis firing and fouling spark plugs. How do you know there's a vortex, what's generating it? Doesn't that would go against what current gas/fluid dynamicms models show? I can't see a texture on the back of a valve effecting the entire flow or even much of the flow with a 2L head as the flow is going around the valve which is why radiusing the exhaust valve is a benifit with the 2L. I have seen some head porting guys have paid over 15k for and knew before the engine was assembled it was crap, and to prove it to one guy (who was a big name in the 80's) I bolted a standard head for the main race day and he cleaned up insted of being 5th. Seen that my self, porting jobs that result in huge flow numbers right at the last 100 tho of lift but kill low and mid lift reducing the total area under the graph to less than the factory head. Nissan RB engines for example don't need to be ported to show big numbers on the dyno and TRUST/GREEDY use a stocker on their 900hp engines. They don't need to be ported but I've seen a port job add 50 rwhp to a drift car running an RB25. Quote Link to comment Share on other sites More sharing options...
Testament Posted September 26, 2008 Share Posted September 26, 2008 sorry I can't help myself any longer - what you really need for an 8 valve head: although admittedly at the end of the day its pretty hard to break 200hp with these too Quote Link to comment Share on other sites More sharing options...
treggo Posted September 26, 2008 Share Posted September 26, 2008 Pintos are 8 valve, just single cam Quote Link to comment Share on other sites More sharing options...
treggo Posted September 26, 2008 Share Posted September 26, 2008 How many hrs are in that head atm? Quote Link to comment Share on other sites More sharing options...
nismo.capri Posted September 26, 2008 Author Share Posted September 26, 2008 sorry I can't help myself any longer - what you really need for an 8 valve head: although admittedly at the end of the day its pretty hard to break 200hp with these too Why? All that would offer is being able to phase cams a bit it's still 8 valve .....Is it a Fiat head? I've had a few Fiats, rebuilt some too. I was swearing at my 128 trying to get the cam box off and the next door neighbour who was an old guy at the time said "now you know why they lost the war" Quote Link to comment Share on other sites More sharing options...
nismo.capri Posted September 26, 2008 Author Share Posted September 26, 2008 How many hrs are in that head atm? Far too many, but it's the first time I've been able to do some changes then a flow tests to see so I couldn't pass up the oppotunity Quote Link to comment Share on other sites More sharing options...
slipsittin Posted September 26, 2008 Share Posted September 26, 2008 How do you know there's a vortex, what's generating it? Doesn't that would go against what current gas/fluid dynamicms models show? I can't see a texture on the back of a valve effecting the entire flow or even much of the flow with a 2L head as the flow is going around the valve which is why radiusing the exhaust valve is a benifit with the 2L. How do I know there is a vortex?????? Honestly if you are wanting to get the best results you need to be able to know how the gases go in and out. It is generated by the turbulance of the valve opening and the sucking of the exhaust port but it all starts with the combustion chamber. Its not texture on the back of the valve dude, its a tracked set of lines to ensure the gases are spinning into the cylinder in the right direction for the combustion chamber. Not being rude but Do you do this for a living???? And for your info The guy I mentioned has broken the 200hp barrier with cast crossflow and non crossflow heads. He also is getting massive 300hp plus from BDA engines. These are real figures not I think by the feel in the seat. I spent over 300 hours working flow benches and milling combustion chambers on jet sprint boat heads to get that last drop of power out of a small block chev only to have a rod stud snap and smash the whole thing to bits. After 20 years in this trade you come to realise "Thats the way it goes sometimes". Quote Link to comment Share on other sites More sharing options...
cute wee gem Posted September 26, 2008 Share Posted September 26, 2008 After 20 years in this trade you come to realise "Why the fuck didn't we just use a Toyota V8?". So are you saying theres no gain over using a twincam head other than cam timing? Most I've seen have a lot better "looking" heads with a wide valve angle and better runner shape. I don't know all the fancy maths behind it so I just have to go off common sence (with whatever works in my head atleast), but I'd like to hear your reasoning. Cheers. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.