Combustion chamber size

[defrag010]

since we are applying pressure to the top of the piston to turn the crank,
wouldn't you want to use the entire piston top since that pressure is expressed as psi?

The burn lasts long enough that it will act on the full diameter.

With this in mind, would the increase in surface area of the reverse dome piston mean anything? in terms of pressure/area?

[pdq67]

I figure Joe know's one heck of a lot more about heads than he's letting on.

Anyway, Ed's heads probably did have that much money spent on them, but the fact is that a closed chambered head that flow's the SAME as an open chambered head will make more power because you can consider that it is a very crude form of a modern "fast-burn" head so that it will need less timimg to get the job done.

Closed chamber suckers are smog dirtier tho is why GM back off from them...

I figure that if we could put big enough valves and ports in Mr Feuling's aluminum 454 Torque P/U heads, that they would be very GOOD heads for race applications.

Mr. Feulings heads have a peanut shaped, centrally located sparkplug chamber for max burn eff. is why I mention this..

We would need to peanut dish the pistons to hold the CR proper, but what the hey!

I would dearly love to see a couple of heads modernized nowadays and they are the old Jag "May" head and the old MOPAR 318 "poli" head.

And if I had a fully equipped welding and machine shop, I would install a set of LS- heads on an old 350 block as well as a set of 409 "W" heads on a BB and then a set of BB heads on the old 409 just for the fun of it!

Please carry-on and Joe keep commenting..

Thx,

pdq67

[TORQUE INC]

I am going with the smaller chamber and the dish

Not exactly sure how the SBC gets a smaller or larger dish and I am sure the 1500 companies that make them all do it a bit different.

Would not think that whatever the difference is in how you get 65cc or 80cc for a combustion chamber would shroud the valves or do something to hinder airflow or the ability to make power ,does anyone have flow numbers for the AFR heads joe uses and have tested both ?

[defrag010]

And if I had a fully equipped welding and machine shop, I would install a set of LS- heads on an old 350 block

World's motown LS block takes care of that one for ya.. no need to fabricate!

I'll tell you, though, what I have always wanted to do is put some LS heads on a smallblock ford. Bore spacing is really close, and the headbolt holes and coolant passages are also real close. Next time you are tinkering around, get a LS headgasket and set it on top of a SBF, you'll see what I mean! I think it could be done with some drilling and some timeserts and some sort of makeshift coolant crossover with fittings drilled in the front of the heads like those guys do when they put LT1 heads on a SBC.

[Dick Gazan]

Joe ...I could never make the dished piston deal work as well as the flat top. Everything being the same the dished struggled in the middle of the dyno pull due to detonation with several motors. More fuel helped but he burn pattern was so different both on the pistons and the head that I just never used them except for standard beaters.

Dick Gazan

[new engine builder]

I have always "scribed" the gasket to the head and then "rolled the head" over as far as I possibly can when the rules would allow.
In other words a larger dia. chamber would " un-shroud" the valves as much as possible.
Big dia. chamber but less depth.

[JBV-HEADS]

PDQ,

I’m not sure if you are refering to Joe Sherman or me. Since you also refer to Jim and I am definitely a follower of many of his chamber shapes, I’ll try to answer. Yes I have over 10 years of working on chamber designs from late 90’s to my semi retirement. I know most movers, their theories, and seen many of their test or performed them myself. I had a nice Poly 318 in a 63 fury but the bean counters went a different way. Lot of potential lost, but bean counters always win in business.

Torque,

The answer is no on using the whole top of the piston. Any pressure on any part of the piston will move it. We are dealing with a finite amount of BTUs or energy and if we place it in a smaller area, then we increase the psi on top of the piston. A simple parable is the smaller compact chambers that produce more power than the larger smog chambers. If we need to take it more then look at the space shuttle. The explosion is centered and small relative to the energy. It is focused. It does not try to fill the whole world to move itself. Just a small area and a way it goes. There are many that need to continue to educate themselves to what is happening here. Some even make the components to measure this. They have something to sell but don’t know what it means. I’ve noticed some of them are finally catching on, so maybe there will be more advancements. The whole piston top does not need to have pressure on it to move the piston. Any part will do. Many mistakenly think it is pressure like a balloon that pushes the piston down. It’s not. Its pressure applied to any part of the piston top that starts the movement. The Horan chamber just magnifies the explosion forces available into a smaller more compact area. It also directs these forces into each other, again magnifying those same forces. Center these forces over the pin and rod if possible to reduce frictional losses and you now are approaching the best we can do at this time.

Dick,

I don’t have pictures of your chamber and piston cutout but I’ll make an observation. We know that squish areas between .060-.100 have a tendency to detonate. There is enough a/f there to ignite but not enough quench to stop it. Over .100 and it acts like a normal chamber. Under .060 and the quench is too cool and it won’t ignite. It only takes a very small area in that .060-.100 range to start an extra ignition source. Because of heat the beak between the intake and exhaust with a non conforming piston cutout to it, would create one of these danger spots for detonation to start. Blower motor would even be worse. Make sure that your piston cutout matches the chamber cutout and I suspect that this would give you the best of both worlds. We know it does not take much on a cutting edge motor to run into problems. They are double edged swords. They cut through the field, but off just a little and they cut off your leg. Try to match these two surfaces, even if you must cut the beak on a mill. The bath tub chamber has worked for years. Good luck,

Joe

[new engine builder]

PDQ,

I’m not sure if you are refering to Joe Sherman or me. Since you also refer to Jim and I am definitely a follower of many of his chamber shapes, I’ll try to answer. Yes I have over 10 years of working on chamber designs from late 90’s to my semi retirement. I know most movers, their theories, and seen many of their test or performed them myself. I had a nice Poly 318 in a 63 fury but the bean counters went a different way. Lot of potential lost, but bean counters always win in business.

Torque,

The answer is no on using the whole top of the piston. Any pressure on any part of the piston will move it. We are dealing with a finite amount of BTUs or energy and if we place it in a smaller area, then we increase the psi on top of the piston. A simple parable is the smaller compact chambers that produce more power than the larger smog chambers. If we need to take it more then look at the space shuttle. The explosion is centered and small relative to the energy. It is focused. It does not try to fill the whole world to move itself. Just a small area and a way it goes. There are many that need to continue to educate themselves to what is happening here. Some even make the components to measure this. They have something to sell but don’t know what it means. I’ve noticed some of them are finally catching on, so maybe there will be more advancements. The whole piston top does not need to have pressure on it to move the piston. Any part will do. Many mistakenly think it is pressure like a balloon that pushes the piston down. It’s not. Its pressure applied to any part of the piston top that starts the movement. The Horan chamber just magnifies the explosion forces available into a smaller more compact area. It also directs these forces into each other, again magnifying those same forces. Center these forces over the pin and rod if possible to reduce frictional losses and you now are approaching the best we can do at this time.

Dick,

I don’t have pictures of your chamber and piston cutout but I’ll make an observation. We know that squish areas between .060-.100 have a tendency to detonate. There is enough a/f there to ignite but not enough quench to stop it. Over .100 and it acts like a normal chamber. Under .060 and the quench is too cool and it won’t ignite. It only takes a very small area in that .060-.100 range to start an extra ignition source. Because of heat the beak between the intake and exhaust with a non conforming piston cutout to it, would create one of these danger spots for detonation to start. Blower motor would even be worse. Make sure that your piston cutout matches the chamber cutout and I suspect that this would give you the best of both worlds. We know it does not take much on a cutting edge motor to run into problems. They are double edged swords. They cut through the field, but off just a little and they cut off your leg. Try to match these two surfaces, even if you must cut the beak on a mill. The bath tub chamber has worked for years. Good luck,

Joe

This is great info.
If you get time could you dive into spark plug location/depth?
Tunning with spark plug heat ranges?

I would like to hear your thoughts on this.Thanks.

[racer1320x]

the $3500+ Ed had into those heads are why they worked well.

Sorry to inform you but I did not have anywhere near $3,500 in my #215 closed chamber oval ports!!

Now for the TRUTH and the FACTS!

I paid Larry Woodward aka Brandywine Cylinder Head Service $2,000 in 2006 to fully port these heads(NO welding or epoxy in the port) including new tulip exhaust valves and angle milling AND porting two manifolds, my dual place Air Gap and a Weiand Xcelerator that he also extended the runners into the plenum. You can call him to confirm the cost and the work

Further and more importantly, the fully ported heads were worth NOTHING on the time slip over their previous state which was gasket matched and bowl blended, done by my friend and engine builder Rich Biebel aka scdiv1 over at Bracket Talk. You can contact him as well to confirm.

My car/combo "worked well" because unlike most, I know bigger ain't better, I know it's all about rate of acceleration, I know it's all about shift recovery, I know all your ET running n/a is made in the 1st 330 feet and 60 foot is everything and to this end, oval shaped intake ports will produce quicker ET's!!!

What quicker than average ET's for a given combo ain't about is meaningless flow bench and dyno numbers that those trying to sell you something tout and those that are misinformed either seek or brag about.

It's easy for me to outrun the competition in a similar with more of everything when they like most run too big a head, cam, manifold, carb, etc.!!

Here's 3880 lbs. of all steel Chevelle with a full factory interior being launched off the footbrake at 2500 RPM and running through a full exhaust...



Ed Bigley 1968 Chevelle

Ed Bigley 1968 Chevelle

and here's the engine that accelerated it to those ET's



and here's the spec's of this 11:1 468 engine with cast iron oval port heads having 101cc chambers under the hood of my nearly 3900 lb. Chevelle that ran quicker and faster than EVERY 454, 496, 502, GM's 720HP 572 and most 540's in a similar Chevelle here in Division 1 brackets, up to 2008 when I sold it.



4.310 bore x 4.00 stroke
internally balanced.
GM 4 bolt main block, windage tray, oval port heads, lifter valley tray and steel chrome valve covers.
Clevite bearings
Crower crank, rods and roller lifters
Wiesco pistons
Speed Pro file-fit rings
RollMaster timing chain/billet gears
Cloyes 2 piece aluminum timing cover
ATI balancer
Moroso 6 quart kick out pan
Melling HV oil pump
Manley Severe Duty 2.25/1.88 valves
Manley Nextek polished dual valve springs
LSM roller cam 254/260 @ .050, .740 lift 107 LSA, "C" firing order
Manley Titanium retainers
Comp keepers
Comp one piece moly pushrods
Crane 1.7 TR aka "wide body" Gold roller rockers
Fel-Pro gaskets throughout
ARP bolts throughout
Holley Strip Dominator single plane manifold

Makes at least 725HP@ 6300 and 600+ ft./lbs. torque @ 5100 RPM! Some say at least 750HP!!

NO chinese junk here!

BTW, I'll take a smaller combustion chamber along with the minimum dome need to achieve the desire compression ratio over a larger chamber everytime!

[miniv8]

We know that squish areas between .060-.100 have a tendency to detonate. There is enough a/f there to ignite but not enough quench to stop it. Over .100 and it acts like a normal chamber. Under .060 and the quench is too cool and it won’t ignite. It only takes a very small area in that .060-.100 range to start an extra ignition source. Because of heat the beak between the intake and exhaust with a non conforming piston cutout to it, would create one of these danger spots for detonation to start. Blower motor would even be worse.
Joe

Sorry to hijack the thread but, Why are nitrous engines so different?

I keep hearing of increasing quench distances from the nitrous crowd.

[SS402]

It's a fine line... I've always thought that propagation of the flame front was paramount, reverse dome has similar effect of raised dome piston in the sense that it has negative impact on propagation. Using flat tops as the foundation then building compression by minimizing chamber size offers great quench action to combat detonation, enabling the flame front to propagate as smoothly as possible also ensures maximum combustion fo the given combination. Wasted heat is wasted energy, poor combusion chamber design and interfering with the flame front leads to excessive timing which leads to excessive heat and wasted energy.

[SS402]

We know that squish areas between .060-.100 have a tendency to detonate. There is enough a/f there to ignite but not enough quench to stop it. Over .100 and it acts like a normal chamber. Under .060 and the quench is too cool and it won’t ignite. It only takes a very small area in that .060-.100 range to start an extra ignition source. Because of heat the beak between the intake and exhaust with a non conforming piston cutout to it, would create one of these danger spots for detonation to start. Blower motor would even be worse.
Joe

Sorry to hijack the thread but, Why are nitrous engines so different?

I keep hearing of increasing quench distances from the nitrous crowd.

there not increasing the quench intentionally, running the juice just allows them to run more quench than a N/A motor

[DrillDawg]

IMO, it is space to pack more N2O/gas in the cyl, N2O likes a little more room to react and release the O and mix with the gas, you might be able to run a little more timing, the reaction provides it's own turbulence, the cyl pressures are to high for higher compression. It all depends on how much N2O your trying to use. Some drag type bikes run a turbo type of piston and a .080 to .100 spacer plate under the cyl.


DD

[af2]

the $3500+ Ed had into those heads are why they worked well.

Sorry to inform you but I did not have anywhere near $3,500 in my #215 closed chamber oval ports!!

Now for the TRUTH and the FACTS!

I paid Larry Woodward aka Brandywine Cylinder Head Service $2,000 in 2006 to fully port these heads(NO welding or epoxy in the port) including new tulip exhaust valves and angle milling AND porting two manifolds, my dual place Air Gap and a Weiand Xcelerator that he also extended the runners into the plenum. You can call him to confirm the cost and the work

Further and more importantly, the fully ported heads were worth NOTHING on the time slip over their previous state which was gasket matched and bowl blended, done by my friend and engine builder Rich Biebel aka scdiv1 over at Bracket Talk. You can contact him as well to confirm.

My car/combo "worked well" because unlike most, I know bigger ain't better, I know it's all about rate of acceleration, I know it's all about shift recovery, I know all your ET running n/a is made in the 1st 330 feet and 60 foot is everything and to this end, oval shaped intake ports will produce quicker ET's!!!

What quicker than average ET's for a given combo ain't about is meaningless flow bench and dyno numbers that those trying to sell you something tout and those that are misinformed either seek or brag about.

It's easy for me to outrun the competition in a similar with more of everything when they like most run too big a head, cam, manifold, carb, etc.!!

Here's 3880 lbs. of all steel Chevelle with a full factory interior being launched off the footbrake at 2500 RPM and running through a full exhaust...



Ed Bigley 1968 Chevelle

Ed Bigley 1968 Chevelle

and here's the engine that accelerated it to those ET's



and here's the spec's of this 11:1 468 engine with cast iron oval port heads having 101cc chambers under the hood of my nearly 3900 lb. Chevelle that ran quicker and faster than EVERY 454, 496, 502, GM's 720HP 572 and most 540's in a similar Chevelle here in Division 1 brackets, up to 2008 when I sold it.



4.310 bore x 4.00 stroke
internally balanced.
GM 4 bolt main block, windage tray, oval port heads, lifter valley tray and steel chrome valve covers.
Clevite bearings
Crower crank, rods and roller lifters
Wiesco pistons
Speed Pro file-fit rings
RollMaster timing chain/billet gears
Cloyes 2 piece aluminum timing cover
ATI balancer
Moroso 6 quart kick out pan
Melling HV oil pump
Manley Severe Duty 2.25/1.88 valves
Manley Nextek polished dual valve springs
LSM roller cam 254/260 @ .050, .740 lift 107 LSA, "C" firing order
Manley Titanium retainers
Comp keepers
Comp one piece moly pushrods
Crane 1.7 TR aka "wide body" Gold roller rockers
Fel-Pro gaskets throughout
ARP bolts throughout
Holley Strip Dominator single plane manifold

Makes at least 725HP@ 6300 and 600+ ft./lbs. torque @ 5100 RPM! Some say at least 750HP!!

NO chinese junk here!

BTW, I'll take a smaller combustion chamber along with the minimum dome need to achieve the desire compression ratio over a larger chamber everytime!

You know Butch??

[pdq67]

Sure he know's Butch and so do I except I've never met him in person.

Hey Ed, you ever sneak back to both t/c's?? I bet I can count on one hand the number of time's I've been back to them!! Don't miss them at all....

Now, BTTT... Let me throw this at you.

The Brits have built their small bore engines with round quench flats and round dishs as well as no quench and true smooth flat-tops in the past by standing up the intake and exhaust ports and both valves at 90 degrees with no chamber in the head like a "W" engine so they could get a good suck and blow. (I think they had to build small-bore engines because of taxes or some such BS??

Not ideal for intake and exhaust systems but I think that it worked quite well for them way back then. But it made for a tall head and long ports..

pdq67