@@DavidVizard yes sir, you're where I learned it! That and getting some help from Charles Servedio via videos / comments along the way. I believe I first saw it in a video where one of your students is showing some 289 chamber work. Your shared knowledge has been invaluable and I thank you for your education! Thanks for stopping by my conversion van channel.
I just watched a video from Charles Servedio concerning a Jeep 2.5L cylinder head. He mentioned in the video that one of your students ported the head. A comment that he made but then quickly retracted was concerning this very thing. The comment that he made (not quoting) was (if I understood his comment) he would have rounded the edge on the quench pad near the exhaust valve. He then said...oh wait, on this head, the exhaust goes out the same side as the intake came in....I take it to mean that he was referring to the fact that the Jeep 2.5/4.0 heads are not cross flow. Please comment on this technique specifically with respect to the cylinder heads found on Jeep 2.5L and 4.0L engines. My thinking was that regardless of which side the exhaust flows out of the cylinder head on, there would still be exhaust gas above the quench pad that would need to be scavenged....whether the gas was exiting 'stage left' or 'stage right', would it matter? I was thinking that it would not matter. Your thoughts Mr. Vizard please. Also, Charles Servedio mentioned that some "superstock bronze' was used on the floor of the exhaust runner (to help increase velocity and reduce reversion...I would presume). Where can I get some of that stuff and can you please point me the way to learn how to apply it? Thank you for your time and for the consideration.
Right, that's why I said I wasn't certain where it was originally credited.. probably a land before time lol but that's who I learned it from .. well also Charles Servedio. But what are your thoughts on it out of curiosity?
@@DS-mo6md I've done videos on it myself and this gets done on every pair of heads I do and my E7s have been 9s in the quarter mile with a 150 shot of nitrous and 10s on motor on a stock 302 short block and that's with a duel plane intake, Anderson cam you are welcome to check it out thank you for your response good luck with your build
I knew an old man that ran 10’s in 1965 with a 289 in a ‘62 Ranchero! His name was James Butler and he set world records and won world championships with his little truck! Then he unhooked his trailer from his tow vehicle, old Ford station wagon, then set world records with it. His wife Inez helped him tune the car....in the driveway....no aftermarket existed for SBF....Now that’s impressive! 59 year old technology! Then he built a 1940 Willys coupe with a supercharged Lincoln engine and outrun everybody with it.....Rowdy Willy! He was from Morton, Tx and everybody in drag racing in the 1960’s knows exactly who he was and didn’t want to line up next to him. He had a better win rate than Bob Glidden!
This is another area that benefits from exhaust valve de shrouding and increases low lift exhaust flow. I've had great success with this shape on F.E. Fords. Yes, it's a quench trade off, but by increasing evacuation of the exhaust, EGR effect is reduced.
Yeah I also intend to run the factory EGR in the van because I'm running cats so need the smog pump etc. As much as I'd love to make it simpler I don't want to choke on muffler fumes. If I can remember how to hook it all back up. I'm at that stage now. I haven't posted updates because my video camera broke but probably have to slideshow the engine going in... But yeah as far as de-shrouding it has been cleaned up in target areas... Full de-shroud on E7 I believe saw some losses, but it probably also depends on the valve job etc. It may have been Charlie Servedio who found that. So basically de-shrouding on the paths of the valves so like... center of cylinder toward exhaust and around this spot of quench area.. and intake entry toward spark plug boss
I would like to learn Pontiac specific cylinder heads particularly my #13 heads and they have a really thick distance between the exhaust valve seat and the quench pad and would require a lot of grinding down to get a transition. I wonder if I would hit water
Wanna buy an ultrasonic gauge? lol the probe was too big for what I got it for in the intake ports but it would easily work on a deck.. it will tell you though.
@@axlegrind4212no not really, this is before they were all blended. It's also a bit awkward of an angle and cut. All you're doing is relieving the edge. That's all that matters so even if something is mm back or something (ramp angle is slightly different degrees although all of these checked out) it doesn't matter. Doesn't have to be cloned perfectly. If one cylinder has more material gone than the other it's too insignificant of an amount to be detrimental on compression also. What do you think would happen? If you're even a porter you would know it's not a 100 percent precision task to clone no matter how many times you mic it. Yet all of my bowls and work measures out. My end result of these heads is above average for a diy person and they will perform. considering my under 200 hours of experience porting I got the hang of carving iron pretty well. Matches up to pro work in a side by side comparison.
@@DS-mo6md i rather see a small trough in that location rather than one opposite, to the spark plug side of the combustion chamber. i like the exhaust valve pretty much shrouded by the quench of the combustion chamber because imo, 90%+ of the exhaust flow travels over the intake valve into the exhaust port. that trough only works in a small percentage of the exhaust stroke but seems to be beneficial in the realm of tdc.
I don’t think that works the way you think it works. What you ground off is called a return and it wasn’t put there by accident. The original designers of the combustion chamber could have done the same as you yet they created a return instead. This return is a feature found in millions of engines. You have unknowingly created additional ‘crevice volume’, dead space where combustion cannot happen as well as perturbed flame tumbling. Where did you come up with that 3% figure?
@@PCMenten lol you clearly don't know what you're talking about about. It helps exhaust scavenging exactly as I say.. and 3 percent relative to the power output. And you think a truck head had performance in mind? These heads also suffer from low swirl. The gains are worth more than any CC loss or else it wouldn't be done. People like David Vizard (see gentleman below who has literally published books on engine modification and performance) and Charles Servedio would disagree with you.
lol You're one of those "if it would've worked better, the factory would've done it" guys. Hilarious. A pro porter can get huge HP gains over stock heads, regardless of what the factory did, or did not do.
Been doing this since about 1980, It had no official name until I named it 'Scavenge Plateau'
@@DavidVizard yes sir, you're where I learned it! That and getting some help from Charles Servedio via videos / comments along the way. I believe I first saw it in a video where one of your students is showing some 289 chamber work. Your shared knowledge has been invaluable and I thank you for your education! Thanks for stopping by my conversion van channel.
I just watched a video from Charles Servedio concerning a Jeep 2.5L cylinder head. He mentioned in the video that one of your students ported the head. A comment that he made but then quickly retracted was concerning this very thing. The comment that he made (not quoting) was (if I understood his comment) he would have rounded the edge on the quench pad near the exhaust valve. He then said...oh wait, on this head, the exhaust goes out the same side as the intake came in....I take it to mean that he was referring to the fact that the Jeep 2.5/4.0 heads are not cross flow. Please comment on this technique specifically with respect to the cylinder heads found on Jeep 2.5L and 4.0L engines. My thinking was that regardless of which side the exhaust flows out of the cylinder head on, there would still be exhaust gas above the quench pad that would need to be scavenged....whether the gas was exiting 'stage left' or 'stage right', would it matter? I was thinking that it would not matter. Your thoughts Mr. Vizard please. Also, Charles Servedio mentioned that some "superstock bronze' was used on the floor of the exhaust runner (to help increase velocity and reduce reversion...I would presume). Where can I get some of that stuff and can you please point me the way to learn how to apply it? Thank you for your time and for the consideration.
Been doing that since 1972. Common sense to any porter.
Thats a mod I've been doing forever that's not a david vizard thing
Right, that's why I said I wasn't certain where it was originally credited.. probably a land before time lol but that's who I learned it from .. well also Charles Servedio. But what are your thoughts on it out of curiosity?
@@DS-mo6md I've done videos on it myself and this gets done on every pair of heads I do and my E7s have been 9s in the quarter mile with a 150 shot of nitrous and 10s on motor on a stock 302 short block and that's with a duel plane intake, Anderson cam you are welcome to check it out thank you for your response good luck with your build
I knew an old man that ran 10’s in 1965 with a 289 in a ‘62 Ranchero! His name was James Butler and he set world records and won world championships with his little truck! Then he unhooked his trailer from his tow vehicle, old Ford station wagon, then set world records with it. His wife Inez helped him tune the car....in the driveway....no aftermarket existed for SBF....Now that’s impressive! 59 year old technology! Then he built a 1940 Willys coupe with a supercharged Lincoln engine and outrun everybody with it.....Rowdy Willy! He was from Morton, Tx and everybody in drag racing in the 1960’s knows exactly who he was and didn’t want to line up next to him. He had a better win rate than Bob Glidden!
This is another area that benefits from exhaust valve de shrouding and increases low lift exhaust flow. I've had great success with this shape on F.E. Fords. Yes, it's a quench trade off, but by increasing evacuation of the exhaust, EGR effect is reduced.
Yeah I also intend to run the factory EGR in the van because I'm running cats so need the smog pump etc. As much as I'd love to make it simpler I don't want to choke on muffler fumes. If I can remember how to hook it all back up. I'm at that stage now. I haven't posted updates because my video camera broke but probably have to slideshow the engine going in... But yeah as far as de-shrouding it has been cleaned up in target areas... Full de-shroud on E7 I believe saw some losses, but it probably also depends on the valve job etc. It may have been Charlie Servedio who found that. So basically de-shrouding on the paths of the valves so like... center of cylinder toward exhaust and around this spot of quench area.. and intake entry toward spark plug boss
I would like to learn Pontiac specific cylinder heads particularly my #13 heads and they have a really thick distance between the exhaust valve seat and the quench pad and would require a lot of grinding down to get a transition. I wonder if I would hit water
Wanna buy an ultrasonic gauge? lol the probe was too big for what I got it for in the intake ports but it would easily work on a deck.. it will tell you though.
I used to just deck the head till it was about touching the exhaust seat bumped the compression and helped the low lift on the exhaust
Does this only apply to SBF?
@@m97429 pretty much chambers with a hard edge in from of the quench area on the way out. It's basically like a major deshroud
hope that works out for you. those cuts are so uneven.
@@axlegrind4212no not really, this is before they were all blended. It's also a bit awkward of an angle and cut. All you're doing is relieving the edge. That's all that matters so even if something is mm back or something (ramp angle is slightly different degrees although all of these checked out) it doesn't matter. Doesn't have to be cloned perfectly. If one cylinder has more material gone than the other it's too insignificant of an amount to be detrimental on compression also. What do you think would happen? If you're even a porter you would know it's not a 100 percent precision task to clone no matter how many times you mic it. Yet all of my bowls and work measures out. My end result of these heads is above average for a diy person and they will perform. considering my under 200 hours of experience porting I got the hang of carving iron pretty well. Matches up to pro work in a side by side comparison.
@@axlegrind4212 now if you want to see something should see the bolt holes alignment on these chinese headers.
@@DS-mo6md i rather see a small trough in that location rather than one opposite, to the spark plug side of the combustion chamber. i like the exhaust valve pretty much shrouded by the quench of the combustion chamber because imo, 90%+ of the exhaust flow travels over the intake valve into the exhaust port. that trough only works in a small percentage of the exhaust stroke but seems to be beneficial in the realm of tdc.
I don’t think that works the way you think it works. What you ground off is called a return and it wasn’t put there by accident. The original designers of the combustion chamber could have done the same as you yet they created a return instead. This return is a feature found in millions of engines. You have unknowingly created additional ‘crevice volume’, dead space where combustion cannot happen as well as perturbed flame tumbling. Where did you come up with that 3% figure?
@@PCMenten lol you clearly don't know what you're talking about about. It helps exhaust scavenging exactly as I say.. and 3 percent relative to the power output. And you think a truck head had performance in mind? These heads also suffer from low swirl. The gains are worth more than any CC loss or else it wouldn't be done. People like David Vizard (see gentleman below who has literally published books on engine modification and performance) and Charles Servedio would disagree with you.
lol You're one of those "if it would've worked better, the factory would've done it" guys. Hilarious. A pro porter can get huge HP gains over stock heads, regardless of what the factory did, or did not do.
What about if there's just a small section of the plateau carved out to create a swirl on the exhaust gas? Interesting thought aye😅@@DS-mo6md