Mr Steve Morris, thank you. I raced 2 valve 4cyl turbo dodge engines years ago. They had a 1.6 intake/1.4ex valve. The only way to make HP was massive intake pressure 30+ psi. Lots of chamber heat. Lots of "glow plugs" in the chamber causing broken pistons. Made an open chamber 1/4 inch to coolant. Unreasonable piston breakage went away, tuning window became huge. No one would believe me. Now, it is accepted. Thank You Sir.
I was waiting to hear mean effective torque and flame propagation and all that nerdiness lol. I remember hearing OEMs put a lot of effort into getting quench right as it has a huge impact on exhaust pollution emissions also. The Otto cycle engine never ceases to amaze.
Quench causes turbulence and reduces the possibility of more ignition or knock. The downside of a chamber having good quench is it can restrict the flow of a cylinder head. Hence difference between and ooenbchamber and closed chamber BBC head. Plus heads with more quench are typically dirtier in smog due to un burnt gases not igniting in the quench area.
Mr Morris says exactly what I found in highly boosted engines. If you can't make the quench work perfectly, or if the casting is too thick causing a hot-spot, grind it away
In the two stroke world we call it a squish band, it must be properly cut into the head for the engine to produce top power without detonation. Typical MX engines and Roadrace engines have different combustion chamber shapes and geometry. Yamaha developed a head combustion shape for roadrace engines so they wouldn’t blowup on long straights at 16,000 rpm.
It still has a pad area. It seems more like he converted a Heart shape chamber into a regular closed chamber. Idk how much this changes things, the heart shape is supposed to be good for preventing detonation as is.
Open chambers typically have higher octane requirements because of less quench. From my time owning a head shop company we looked to improve quench versus eliminate it and found higher horsepower when we had 2 sides of quench in a chamber.
Any loss of compression when modifying the chamber of a knock- prone combination will be made up when you can add ignition timing back into the program, making consistent power, and not hurting parts
We call that area "squish." Because it "squishes" the fuel charge into a the burn measurably. In my 2-stroke engines squish is everything. I cut the heads squish area 3*. at .028. from the outer wall, growing the further towards the center. The squish velocity was measured to be optimal this way with flat top pistons. I also tried custom dome pistons that were also 3* keeping it unchanged through the squish area. I ended up changing the .028 to .032. This motor set 12 set land speed records at El Mirage. These were all 2 strokes race engines though. I am sharing this with you in the hope you can find something you can use on your motors. I have been a subscriber of yours for many years ,since you were working out of your first shop. I just bought a 632 motor to run N/A. The heads are junk. Rock bottom AFR Enforcers. I am going through cancer treatment so money is a bit tight. I no longer have my shop. "Grand Prix Racing of Corona Ca.' Do you have a good used set to sell? I have a beautiful 67 El Camino, I 4-linked. We reduced the weight of the car significantly. The car dynoed 930hp. I want to run mid 8.0s but I don't the HP to carry it. Cheers, to you, an amazing innovator. Steve S.
I like too think about it this way. The quench is being squeezed out like a fan instead of a fine stream. The fan promotes particle burn more evenly. Then collecting all the 💦 droplets together for less atomization.
My current understanding is that quench is good, up until a certain point. There's advanced engineering calculations for estimating maximum quench velocity and when it gets too high it makes the rate of pressure rise too fast, which itself can induce detonation. (The 2 cycle motorcycle guys obsess over the "right amount of quench" -but they have WAY more quench area, so it makes sense that they worry about "too much quench velocity" more vs. 4 cycle wedge head engines.)
God Bless Steve Morris, his Family & friends. You are a true scholar and Christian. I have been the victim of many machine shop mistakes costing 10s of thousands of dollars dealing with Marine Engines.... Need i say more.... But boy has it taught me to check EVERYTHING !! Keep up the good work and congratulations on Tom Baileys Record setting runs.
@@lop8828 yes it drops the compression, no that's not the only reason it helps, not even the main reason. Same compression I'm at but with the squish pads still in place and there's det.
That configuration would rely on specifics, such as allowing for the growth of an aluminum rod if applicable. I dont know what Steve is doing specifically, but I would guess not likely with most of his combos.
He would have to gave the piston above the deck in order to touch the head with the head gasket on. Otherwise at zero deck height the head would still be the thickness of the head gasket off the top of the piston.....right?
Hot, running, dynamic, the deck height would have to be + to achieve that, yes. I'm just pointing out that cold, static, maybe not so much. If aluminum rods are used for example, you have to allow for a certain amount of "growth/expansion" and you would not start at the dimensions you suggested. Overall point being... As always- it varies.
I agree with that Mark. I wonder how much growth there is when heated up? The thinnest head gaskets, I know they can be made whatever you want, are around .015" most are in the .030-.040" range.
Great vids Steve. Can you do a short vid on the clutch setup on the dyno. I know you said it had a flex plate with a spring. Can we get a look at that setup?
Steve if you use a dished piston with that head is it still nessasary to lay over the chamber? In theory there is no quench area even though the head has it as the dish is open.
The more quench the better that's why the vortec heads run so much better I have a small block in my S10 with vortec heads getting ready to build some 062s this video will help me smokey yunick said.030 clearance between your piston and quench area is optimal but sometimes not possible squeezing that mixture helps the burn also a little radius around the valve pockets to help the flow
So blending the combustion chamber helps the flow of the air/fuel on the compression stroke into the cc instead of it trying to stay in the quench in ignition which prevents detonation? So do you go about measuring engines to determine thickness of head gasket needed for ideal quench?
What’s a really bad quench to have? I know you said your only happy if you have all of it and of course many factors come in to play to do so but at what point should someone be considered? .040, .050, 060, .070, .080? Is it linear? As the quench becomes less the detonation increase or are you fine til say .060 and then it starts to go bad?
.060 is max, beyond that you're losing most of the benefit. .040 or less is ideal. With .035 to .040 being generally safe. There's two different views on quench, some think no quench is fine (not i) majority believe you need quench to control combustion with decent compression depending on the fuel.
When it comes to "why" softened chambers / tapered quench areas help with detonation and lots of boost: is it because too much quench velocity itself can actually induce detonation via too quick of a pressure rise?
Doesn't a tight quench also help stave off detonation by inducing turbulence in the chamber as it "squeezes out" the air/fuel mix between the face of the piston and the head?
@@tahcogunworks Whether close chamber or open chamber heads are prone to knocking is very dependant on the shape of the piston crown. Putting the correct piston shape into a open chamber to prevent knock unfortunately results in the compression ratio being too low, damn if you do and damn if you don't.
Interesting concept I only recently came across: There's actually two quench events: the 1st pushing the air/fuel mix out of the quench area and into the combustion area before TDC, then the 2nd occuring after TDC that accelerates the burning fuel-air mixture from the area around the plug out to the furthest reaches of the chamber. -The first helps ensure a good mixture and mixture motion and the 2nd accelerates the burn speed / which reduces the ignition requirements and gives detonation less time to happen. (Automotive engineers will estimate the quench velocity at a particular RPM on a given engine and then use this in additional calculations to estimate the ignition timing requirements using a bunch of additional inputs. -They start with the laminar flame speed and then use quench velocity, IAT and a bunch of other factors to estimate the turbulent flame speed and the distance from the plug to the furthest reaches of the cylinder to estimate the timine requirements.) -Insane that such things can be modeled well enough to get a good ignition timing base tune.
It leads to the question of how much gap is too much. As stated an Ideal gap of almost touching is one extreme but how much gap becomes too much and things go bad. A lot of people run steel rods on the street with around 30 to 40 thou clearance with a 4.040 bore and forged pistons (I added that detail as it affects the amount of piston rock), does this sound right ??
You didn't say anything about the head gasket thickness and what deck height the pistons should be with steel rods ? Seems to me if the piston is just touching the head surface then the pistons may have a positive deck height ?
Wow thanks Steve. I'm trying to build a 460 in my garage. Looks like someone's been in it. All the bearings are wiped and put small groves on the crank. And the oil pump looks aftermarket so I'm thinking maybe the oil pump went out. Maybe I can get away this wet sanding the crank with 1500 grit and new oil pump. But the motor ran good at 75 psi. Cam bearings looked good. For the heads there's a lot of carbon. Original looking pistons 8:1 compression. I like to bump up the compression any suggestions with the pistons and heads. I was thinking some high dome pistons. There's only 1 machine shop j the area and he's over booked and works short hours and just don't wave my stuff sitting there.
Is the other term "softing" the chamber. Does it help on a NA engine? Also I remember guys putting a groove in the guench area pointed towards the spark plug. Have you seen anyone do that? I have a straight 8 buick combustion chambers that I would like to improve.
Yes, the most common term is "softening" the chamber. No, it doesn't help N/A engines. A "flame slot" does nothing, as it was just experimental. Hope this helps.
@@dondotterer24 Somender Singh was the guy making vee grooves in the deck. The results weren't conclusive or scienced out enough for me to crank up the cutoff wheel.
Just curious, would moving the spark plug closer to the quench area help? At least theoretically speaking. Or adding a second spark plug near or in the quench area, wouldn’t that help? Basing the off of flame front travel and shortening the distance of the flame front to the quench area seems like it would resolve that issue without laying back the quench area.
If the spark plug was positioned to close to the quench area, the high gas velocities ejected from the quench could blow out the initial burn at the spark plug. Yes, adding another spark plug will work, the two flame fronts from each spark plug will only merge not causing any problems. The result is the engine will need less timing advance and still get a slight increase in overall performance, but may not be worth the effort.
Getting enough compression without a piston dome getting in the way of combustion was always a problem with true hemi heads. That's why modern hemi's have a steeper included valve angle and sides filled in. In any case, a 4V pent-roof combustion chamber is best.
Up front I do not know much about the Old Hemi's other than they needed a lot of timing to make good torque. I do find it interesting that the New Design of the Hemi's do indeed have quench on both sides of the valves, and they do make really good horsepower and torque, with decent gas mileage now.
So in a n.a. motor tight quench isn't that important as a open chamber? Where you don't have as much quench ? You can still unshroud the valves in a closed chamber head. Just wondering.
Where were you twenty years ago when I was trying to figure this out on 17:1 engines, I did this purely by trial and error and even doubted my sanity for pursuing it, on a cast head deal no less i got a combustion chamber imprint on the piston at one stage as I went too far like you described but even with an MSD knock meter it did not show up nor could you here it, i realised then how destructive spark/preignition knock must be if you can hear it
How is softening the quench pad any different than reducing compression ratio? Aren't they ultimately the same thing? Can't you just drop the piston down into the bore a few thousandths just like the ford lightning engine? They dropped the piston .200 in the hole.
Interesting. In daily drivers, one read open chambers reduced CO. Where as closed, made more power. Also due to lack of budget , I made a compromise, that according to some may of cost 5%. Which is terrible, if true and in time will be sorted regardless. The apparent big no- no, was to reduce compression ratio, using a 80 thou head gasket, hence losing all the squish. Any thoughts would be welcome. Regards, ,Adam..
Yes open chambers reduce CO, instead they produce more CO2. When the fuel mixture produces more CO2, the mixture in the combustion chamber is hotter, thus higher pressures. Unfortunately, the higher gas temperatures can heat saturate the piston causing detonation. If you can design the engine to produce more CO2 and less CO without detonation, the vehicle will reduce emissions, gain power and fuel economy. You need the highest compression ratio with the lowest octane that will run with that C.R.
Quench is a very misunderstood word..Also Steve, have you ever had anybody work for you that attended SAMTECH in Houston? It was called the School of Automotive Machinists when I was there.
@@stevemorrisracing right on. Just wondering if you had. Do you know who judson massengill is? BTW I watch all your content. Thanks for sharing. I don't get to build engines like this anymore, or hear a dyno room with a 9k RPM engines roaring near daily. I miss those days. I still port alot of ls heads and build those but I'm talkin real engines! Cya on the next one.
Watching flame propagation videos through transparent heads, it seems to me that at high RPM the piston will be half way down the bore before the flame front traverses the quench area. Flame speed constant while piston speed increases disregarding spark advance.
Pro Stock, and most race heads are not "closed" chamber. They are just smaller, due to the shallow valve angles, yes. Big difference between smaller chambers and chambers considered to be a "closed" style.
What about sbc's they are a closed chamber and then in 1971 they went to an open chamber but all the hi-perf heads are the closed chamber design. Very rarely do you see anything bigger then a 68 to 70cc chamber.
I'm trying to do a build now its a 406 sbc with flat top 2 valve relief pistons I'm running a 6.125 rod with a custom roller 276int. 284ex. on a 105 with 710 int. and 660ex. Static is 11.6 with a .015 quench. Im trying to do it on 91 oct. Do you think its doable with that tight of a quench ?
@@danatkins6751 2 things. First, i would advise AGAINST .015" quench. Go .040". Will live a lot longer and be much happier. It will also drop compression to a safer 93 octane friendly 11.1. No need for 11.5. Second, the valve events on that camshaft are way too long. I've made 700+ on pump fuel with over 10 degrees less on the intake 15 less on the exhaust. I also recommend a separation of 108. Intake center at 104 to 105. Your cam events are too long and will kill way too much cylinder pressure, AKA: Power. The cam you have is designed more for 13.1... Hope this helps.
One Picture is worth a thousand words. ( Sharpy Squiggles don't count ). Some Chambers easily lend themselves to your cryptic "description", and some don't. The "~10-thousandths Clearance per Inch of Bore Rule" is not new to knowledgeable folks. The relatively new trend of completely eliminating Quench on some Engines is interesting. What circumstances this technique works for seems to still be some kind of a SECRET !!! Turbulence normally makes Power all by its self, AND reduces Detonation as a bonus. I'd be interested in finding-out if Port-Induced Tumble and Swirl can completely replace the "Turbulence-function" of "Tight-Quench- Clearances" , and also reduce timing requirements at the same time . Or, is this concept only useful under extremely high Cylinder-Pressures, and/or, high-RPM conditions. . . .
I'd like to see Steve do some HHO R&D. It would be interesting to see HHO in performance applications and if it lends to performance increases and cleaner output gasses.
![Felix "Unfair" | [Stray Kids : SKZ-PLAYER]](http://i.ytimg.com/vi/Oswujxm2Ag0/mqdefault.jpg)
Mr Steve Morris, thank you. I raced 2 valve 4cyl turbo dodge engines years ago. They had a 1.6 intake/1.4ex valve. The only way to make HP was massive intake pressure 30+ psi. Lots of chamber heat. Lots of "glow plugs" in the chamber causing broken pistons. Made an open chamber 1/4 inch to coolant. Unreasonable piston breakage went away, tuning window became huge. No one would believe me. Now, it is accepted. Thank You Sir.
I was waiting to hear mean effective torque and flame propagation and all that nerdiness lol. I remember hearing OEMs put a lot of effort into getting quench right as it has a huge impact on exhaust pollution emissions also. The Otto cycle engine never ceases to amaze.
Never heard of quench, freaking cool!! Thank you for making me a little smarter
Quench causes turbulence and reduces the possibility of more ignition or knock.
The downside of a chamber having good quench is it can restrict the flow of a cylinder head. Hence difference between and ooenbchamber and closed chamber BBC head. Plus heads with more quench are typically dirtier in smog due to un burnt gases not igniting in the quench area.
Guy grabs a head probably worth more than my short block to draw a picture on 😂. Steve’s a G
I'm soo glad I found your channel! Your info you are passing on is invaluable! Especially for a at home engine guy! Keep the tech coming!
man I learned so much more than i thought i knew and i really understand now, thanks for this
All these years of internet experts focusing on quench like it adds 500hp, and Steve shoots them all down in 5 seconds. I love it.
I wish I had aluminum heads to write my notes on
Cool videos Steve!!
I’ve also heard it called softening the chambers .
Mr Morris says exactly what I found in highly boosted engines. If you can't make the quench work perfectly, or if the casting is too thick causing a hot-spot, grind it away
In the two stroke world we call it a squish band, it must be properly cut into the head for the engine to produce top power without detonation. Typical MX engines and Roadrace engines have different combustion chamber shapes and geometry. Yamaha developed a head combustion shape for roadrace engines so they wouldn’t blowup on long straights at 16,000 rpm.
Thanks for all the great Steve Tech videos
So basically you are making a closed chamber head open chamber to eliminate the hot spots that cause detonation.
You are everywhere, arent you......
Has nothing to do with open or closed chambers.
It still has a pad area. It seems more like he converted a Heart shape chamber into a regular closed chamber. Idk how much this changes things, the heart shape is supposed to be good for preventing detonation as is.
Open chambers typically have higher octane requirements because of less quench. From my time owning a head shop company we looked to improve quench versus eliminate it and found higher horsepower when we had 2 sides of quench in a chamber.
Any loss of compression when modifying the chamber of a knock- prone combination will be made up when you can add ignition timing back into the program, making consistent power, and not hurting parts
We call that area "squish." Because it "squishes" the fuel charge into a the burn measurably. In my 2-stroke engines squish is everything. I cut the heads squish area 3*. at .028. from the outer wall, growing the further towards the center. The squish velocity was measured to be optimal this way with flat top pistons. I also tried custom dome pistons that were also 3* keeping it unchanged through the squish area. I ended up changing the .028 to .032. This motor set 12 set land speed records at El Mirage. These were all 2 strokes race engines though. I am sharing this with you in the hope you can find something you can use on your motors. I have been a subscriber of yours for many years ,since you were working out of your first shop. I just bought a 632 motor to run N/A. The heads are junk. Rock bottom AFR Enforcers. I am going through cancer treatment so money is a bit tight. I no longer have my shop. "Grand Prix Racing of Corona Ca.' Do you have a good used set to sell? I have a beautiful 67 El Camino, I 4-linked. We reduced the weight of the car significantly. The car dynoed 930hp. I want to run mid 8.0s but I don't the HP to carry it. Cheers, to you, an amazing innovator. Steve S.
I like too think about it this way. The quench is being squeezed out like a fan instead of a fine stream. The fan promotes particle burn more evenly. Then collecting all the 💦 droplets together for less atomization.
I always thought quench reduced octane requirements. And reduced knock.
My current understanding is that quench is good, up until a certain point. There's advanced engineering calculations for estimating maximum quench velocity and when it gets too high it makes the rate of pressure rise too fast, which itself can induce detonation. (The 2 cycle motorcycle guys obsess over the "right amount of quench" -but they have WAY more quench area, so it makes sense that they worry about "too much quench velocity" more vs. 4 cycle wedge head engines.)
That’s the way It was explained to me in mid 90’s stage 2 boosted v6 Buick engine head porter David Wink rip . Thanks Steve
I've got a stage 9 small block in my truck.
@@causeimbatmaaanu so fony !
@@MrBlackbutang thanks, I am funny. But so are you stage this and that people.
The term that you were looking for at the end of the video that describes chambers with the angle tapered quench area, was it "Softened" chambers?
Wonderfully explained as always.
Thanks for taking the time to share 👍
God Bless Steve Morris, his Family & friends. You are a true scholar and Christian. I have been the victim of many machine shop mistakes costing 10s of thousands of dollars dealing with Marine Engines.... Need i say more.... But boy has it taught me to check EVERYTHING !!
Keep up the good work and congratulations on Tom Baileys Record setting runs.
Why bring superstition into the issue?
*Where the hell did the Cleetus video go???*
This is what I do to all my Volvo Turbo cylinder heads I modify, and it makes the world of difference when it comes to running big boost with no det.
In term creating lower compression
@@lop8828 yes it drops the compression, no that's not the only reason it helps, not even the main reason. Same compression I'm at but with the squish pads still in place and there's det.
You the man....dig all videos
Appreciate the cool tips. I may not be putting engines together all the time but good knowledge any how.
Awesome info as usual
So you are running the piston out of the hole the thickness of your head gasket?
That configuration would rely on specifics, such as allowing for the growth of an aluminum rod if applicable.
I dont know what Steve is doing specifically, but I would guess not likely with most of his combos.
He would have to gave the piston above the deck in order to touch the head with the head gasket on. Otherwise at zero deck height the head would still be the thickness of the head gasket off the top of the piston.....right?
Hot, running, dynamic, the deck height would have to be + to achieve that, yes.
I'm just pointing out that cold, static, maybe not so much. If aluminum rods are used for example, you have to allow for a certain amount of "growth/expansion" and you would not start at the dimensions you suggested.
Overall point being... As always- it varies.
I agree with that Mark. I wonder how much growth there is when heated up? The thinnest head gaskets, I know they can be made whatever you want, are around .015" most are in the .030-.040" range.
Thats interesting. This doesn't effect compression at all?
Great vids Steve. Can you do a short vid on the clutch setup on the dyno. I know you said it had a flex plate with a spring. Can we get a look at that setup?
Steve if you use a dished piston with that head is it still nessasary to lay over the chamber? In theory there is no quench area even though the head has it as the dish is open.
The more quench the better that's why the vortec heads run so much better I have a small block in my S10 with vortec heads getting ready to build some 062s this video will help me smokey yunick said.030 clearance between your piston and quench area is optimal but sometimes not possible squeezing that mixture helps the burn also a little radius around the valve pockets to help the flow
So blending the combustion chamber helps the flow of the air/fuel on the compression stroke into the cc instead of it trying to stay in the quench in ignition which prevents detonation? So do you go about measuring engines to determine thickness of head gasket needed for ideal quench?
What’s a really bad quench to have? I know you said your only happy if you have all of it and of course many factors come in to play to do so but at what point should someone be considered? .040, .050, 060, .070, .080? Is it linear? As the quench becomes less the detonation increase or are you fine til say .060 and then it starts to go bad?
.060 is max, beyond that you're losing most of the benefit. .040 or less is ideal. With .035 to .040 being generally safe. There's two different views on quench, some think no quench is fine (not i) majority believe you need quench to control combustion with decent compression depending on the fuel.
Hey Steve, I am trying to learn more about head work. Do you have any reading or viewing educational recommendations?
When it comes to "why" softened chambers / tapered quench areas help with detonation and lots of boost: is it because too much quench velocity itself can actually induce detonation via too quick of a pressure rise?
Did Cleetus request that y'all make his fastest pass ever video private? I thought it was pretty bad ass!!
Doesn't a tight quench also help stave off detonation by inducing turbulence in the chamber as it "squeezes out" the air/fuel mix between the face of the piston and the head?
That's what all head companies told our shop that quench reduces knock and detonation. And larger open chambers are more prone for knocking.
@@tahcogunworks Whether close chamber or open chamber heads are prone to knocking is very dependant on the shape of the piston crown. Putting the correct piston shape into a open chamber to prevent knock unfortunately results in the compression ratio being too low, damn if you do and damn if you don't.
Interesting concept I only recently came across: There's actually two quench events: the 1st pushing the air/fuel mix out of the quench area and into the combustion area before TDC, then the 2nd occuring after TDC that accelerates the burning fuel-air mixture from the area around the plug out to the furthest reaches of the chamber. -The first helps ensure a good mixture and mixture motion and the 2nd accelerates the burn speed / which reduces the ignition requirements and gives detonation less time to happen. (Automotive engineers will estimate the quench velocity at a particular RPM on a given engine and then use this in additional calculations to estimate the ignition timing requirements using a bunch of additional inputs. -They start with the laminar flame speed and then use quench velocity, IAT and a bunch of other factors to estimate the turbulent flame speed and the distance from the plug to the furthest reaches of the cylinder to estimate the timine requirements.) -Insane that such things can be modeled well enough to get a good ignition timing base tune.
It leads to the question of how much gap is too much. As stated an Ideal gap of almost touching is one extreme but how much gap becomes too much and things go bad.
A lot of people run steel rods on the street with around 30 to 40 thou clearance with a 4.040 bore and forged pistons (I added that detail as it affects the amount of piston rock), does this sound right ??
You didn't say anything about the head gasket thickness and what deck height the pistons should be with steel rods ? Seems to me if the piston is just touching the head surface then the pistons may have a positive deck height ?
Thats why he said its a lot of trial and error
Wow thanks Steve. I'm trying to build a 460 in my garage. Looks like someone's been in it. All the bearings are wiped and put small groves on the crank. And the oil pump looks aftermarket so I'm thinking maybe the oil pump went out. Maybe I can get away this wet sanding the crank with 1500 grit and new oil pump. But the motor ran good at 75 psi.
Cam bearings looked good.
For the heads there's a lot of carbon. Original looking pistons 8:1 compression.
I like to bump up the compression any suggestions with the pistons and heads. I was thinking some high dome pistons.
There's only 1 machine shop j the area and he's over booked and works short hours and just don't wave my stuff sitting there.
Is the other term "softing" the chamber. Does it help on a NA engine? Also I remember guys putting a groove in the guench area pointed towards the spark plug. Have you seen anyone do that? I have a straight 8 buick combustion chambers that I would like to improve.
Yes, the most common term is "softening" the chamber.
No, it doesn't help N/A engines.
A "flame slot" does nothing, as it was just experimental. Hope this helps.
@@vengeanceizmine9878 Thank you.
@@dondotterer24 👍
@@dondotterer24 Somender Singh was the guy making vee grooves in the deck. The results weren't conclusive or scienced out enough for me to crank up the cutoff wheel.
@@ewetoobz3840 Thank you
Just curious, would moving the spark plug closer to the quench area help? At least theoretically speaking. Or adding a second spark plug near or in the quench area, wouldn’t that help? Basing the off of flame front travel and shortening the distance of the flame front to the quench area seems like it would resolve that issue without laying back the quench area.
They did that years ago, hemi.
If the spark plug was positioned to close to the quench area, the high gas velocities ejected from the quench could blow out the initial burn at the spark plug.
Yes, adding another spark plug will work, the two flame fronts from each spark plug will only merge not causing any problems. The result is the engine will need less timing advance and still get a slight increase in overall performance, but may not be worth the effort.
Can you do a video on NO Quench
Great content thanks for sharing, very informative
So does this mean hemis are much better design? More timing less detonation?
Getting enough compression without a piston dome getting in the way of combustion was always a problem with true hemi heads.
That's why modern hemi's have a steeper included valve angle and sides filled in.
In any case, a 4V pent-roof combustion chamber is best.
Up front I do not know much about the Old Hemi's other than they needed a lot of timing to make good torque. I do find it interesting that the New Design of the Hemi's do indeed have quench on both sides of the valves, and they do make really good horsepower and torque, with decent gas mileage now.
So in a n.a. motor tight quench isn't that important as a open chamber? Where you don't have as much quench ? You can still unshroud the valves in a closed chamber head. Just wondering.
On na he wants to get the quench as tight as possible in a race application
Where were you twenty years ago when I was trying to figure this out on 17:1 engines, I did this purely by trial and error and even doubted my sanity for pursuing it, on a cast head deal no less i got a combustion chamber imprint on the piston at one stage as I went too far like you described but even with an MSD knock meter it did not show up nor could you here it, i realised then how destructive spark/preignition knock must be if you can hear it
Is quench the same as squish?
Yes .
@@flappingflight8537 Thanks.
How is softening the quench pad any different than reducing compression ratio? Aren't they ultimately the same thing? Can't you just drop the piston down into the bore a few thousandths just like the ford lightning engine? They dropped the piston .200 in the hole.
Knock city.
Interesting. In daily drivers, one read open chambers reduced CO. Where as closed, made more power. Also due to lack of budget , I made a compromise, that according to some may of cost 5%. Which is terrible, if true and in time will be sorted regardless. The apparent big no- no, was to reduce compression ratio, using a 80 thou head gasket, hence losing all the squish. Any thoughts would be welcome.
Regards,
,Adam..
Yes open chambers reduce CO, instead they produce more CO2. When the fuel mixture produces more CO2, the mixture in the combustion chamber is hotter, thus higher pressures. Unfortunately, the higher gas temperatures can heat saturate the piston causing detonation.
If you can design the engine to produce more CO2 and less CO without detonation, the vehicle will reduce emissions, gain power and fuel economy.
You need the highest compression ratio with the lowest octane that will run with that C.R.
THAT IS DEEP.
Quench is a very misunderstood word..Also Steve, have you ever had anybody work for you that attended SAMTECH in Houston? It was called the School of Automotive Machinists when I was there.
nope
@@stevemorrisracing right on. Just wondering if you had. Do you know who judson massengill is? BTW I watch all your content. Thanks for sharing. I don't get to build engines like this anymore, or hear a dyno room with a 9k RPM engines roaring near daily. I miss those days. I still port alot of ls heads and build those but I'm talkin real engines! Cya on the next one.
There are two distinct processes going on here. Quench and Squish. You need to consider both.
Watching flame propagation videos through transparent heads, it seems to me that at high RPM the piston will be half way down the bore before the flame front traverses the quench area. Flame speed constant while piston speed increases disregarding spark advance.
Reason why it helps is because it squeezes the mixture back into the combustion chamber
When the Piston is just giving the head a little rub.
And i thought on all sharp edges, including the edge where the milled out conical area begins, will be predetonation aka knock.
Why do most bbc race motors run open chamber heads but pro stock run a relatively closed chamber head ? Is it cuz of valve angles ?
Pro Stock, and most race heads are not "closed" chamber. They are just smaller, due to the shallow valve angles, yes. Big difference between smaller chambers and chambers considered to be a "closed" style.
What about sbc's they are a closed chamber and then in 1971 they went to an open chamber but all the hi-perf heads are the closed chamber design. Very rarely do you see anything bigger then a 68 to 70cc chamber.
@@danatkins6751 Smaller. NOT closed. Two different things.
I'm trying to do a build now its a 406 sbc with flat top 2 valve relief pistons I'm running a 6.125 rod with a custom roller 276int. 284ex. on a 105 with 710 int. and 660ex. Static is 11.6 with a .015 quench. Im trying to do it on 91 oct. Do you think its doable with that tight of a quench ?
@@danatkins6751 2 things. First, i would advise AGAINST .015" quench. Go .040". Will live a lot longer and be much happier. It will also drop compression to a safer 93 octane friendly 11.1. No need for 11.5.
Second, the valve events on that camshaft are way too long. I've made 700+ on pump fuel with over 10 degrees less on the intake 15 less on the exhaust. I also recommend a separation of 108. Intake center at 104 to 105. Your cam events are too long and will kill way too much cylinder pressure, AKA: Power.
The cam you have is designed more for 13.1... Hope this helps.
Can You Explan the HIP process . & . I bought a Used Motor . Can I have the HIP process Done to the heads on that motor . Thank You .
It is a high pressure compacting of the material as I understand it.
Makes it a little denser
The best heads for quench is big block chevy closed chamber heads. The quench is on both sides.
One Picture is worth a thousand words. ( Sharpy Squiggles don't count ).
Some Chambers easily lend themselves to your cryptic "description", and some don't.
The "~10-thousandths Clearance per Inch of Bore Rule" is not new to knowledgeable folks.
The relatively new trend of completely eliminating Quench on some Engines is interesting.
What circumstances this technique works for seems to still be some kind of a SECRET !!!
Turbulence normally makes Power all by its self, AND reduces Detonation as a bonus.
I'd be interested in finding-out if Port-Induced Tumble and Swirl can completely replace the
"Turbulence-function" of "Tight-Quench- Clearances" ,
and also reduce timing requirements at the same time .
Or, is this concept only useful under
extremely high Cylinder-Pressures, and/or, high-RPM conditions.
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Why you take cleetus video down.
Would be interested to see what you could do with a 427 SOHC FORD Motor.
I'll bet you'd be amazed at how fast he could use it as a paper weight!!! LOL jk
I always thought that the piston touching the cylinder head was a engine building myth but I ques not.
Thanks Steve!
Thanks for the video
Quench helps thermal dynamic efficiency
Thanks!
I'd like to see Steve do some HHO R&D. It would be interesting to see HHO in performance applications and if it lends to performance increases and cleaner output gasses.
QUENCH SIDE BEHIND EX V/ NEEDS SOFTIUNG TO TAKE SUPERSONIC EX AIRSPEED AT V/. OPENING TO USE HEW CLOW LIFT
Nice
Gotta love all the “comments” where it’s just people trying to show how smart they think they are....
Many are. My shop holds many records to prove it too. Your point?
@@tahcogunworks Why do you think I was talking about you???? Strange.
I thought it was called squish
MOPAR magnum heads!
Stevening
Squish is pressure
Quench is temperature
Read that dictionary again !!
Gatorade is a thirst quencher.....