In this episode of Steve Tech, Steve Morris breaks down what piston quench is and what kind of quench is ideal, as well as certain chamber modifications you can make to get better performance in your engine.
@@arthurking6549 I always understood quench to be cooling, as in you quench the fire or your thirst. Likewise I always understood squish to be squeezing the air fuel mix, as the piston is rising, towards the spark event from between the piston top and the flat surface of the cylinder head.
Yes I agree . I was taught in grad school that engineering a petroleum or related engine to perform a specific purpose which end results in improved power to fuel efficiency from the same amount of fuel input. There are several different things that are still being tried to gain a minuscule fraction of efficiency and is the difference in winning a NASCAR race especially the past restrictor plate races.
Oh, and by the way, if you need more ignition advance to gain power, the correct solution is to increase your combustion flame travel Rate so that advancement is not required...Some people do that with Squish.....
Yep. Few people realize it's optimum to have an engine that wants LESS timing. It means the combustion is happening quicker and the engine is more efficient.
I have zero deck height on my engine with cometic 027" headgaskets and my quench was near perfect. After 3 years of running the engine, the pistons barely touched the head. My heads took 003" of shaving to clean them up which is minimal if you're using cometics on aluminum heads. Zero knock at 30psi of boost.
@@nalley6815 I agree!! Unless you're Steve Morris or some other big high dollar engine builder, building race engines for big names, trying to run 0 quench is a very bad idea!! It's a really great way to find the limits of your engine in a hurry!
Impressive, it's easy to get it tight if your patient start tight but safe and slowly get tighter untill starting to whiteness marking the head 🤗🤗🤗 anyone that doesn't have the balls to push the limits will never be the best 😁
@@Grooty79 Just after my last post above, and before putting heads back on the engine, I found a cam lobe going bad while further inspecting the engine. I never got that engine back together. I decided to build another engine using an aftermarket block. I'm not planning to go so close this time on the piston to head clearance.
I feel like an idiot calling this squish my whole life lmao! Granddad always said if you learn something new everyday then you aren't doing something right! Awesome vid man!
Steve, I have a question about squish and squish velocity. Would you please react to this quote I read elsewhere? The author stated it better than I could. "Zero squish is a backward move. Squish speeds up combustion and pushes fuel from the outside of the cylinder back towards the center to be burnt. It reduces the chance of detonation as well. You'll have less unburnt fuel in the engine."
I have a Honda k20 engine. I have 1mm oversized dished valves on the intake and I have stock size flat faced valves on exhaust side. Is this a good set up?
Yes. smaller exhaust valve on anything actually makes more power. Because it wants to escape more than go in . . . real basic way of putting it, not why although.
I've wondered about this also...but my take was , i considered the big block head design to be 2nd chance on how to make a better flowing design than the small block. it's just par for the course that they had to be bigger to get those improvements. so i assumed the canted design was always and improvement over the sbc valve layout. but i don't ACTUALLY know
@@townsendliving9750i don't know what you mean by deleting the gap. But you still need a little space between the head and pistons because pistons do rock in the cylinder. Bearing wear is a not a big factor on an engine being rebuilt daily. But on a street engine if you have 0 head space as the bearings wear the pistons will eventually hit the head.
This is very serious race engine tech that nobody other than racers/engine builders who spend their lives doing this stuff should fiddle with!! For the common dude, you're just asking for disaster trying to get "zero" quench, and you don't gain anything from it anyway. Running in the safe zone of between .038 and .048 is plenty enough quench to accomplish good combustion, and you also don't have to worry when your engine is going to destroy itself. Unless you're Don Garlits or John Force, play it safe!!
So I'm curious to 6:41 know if I 0 deck my block .023 head gaskets 56cc chamber 4340 kit (306) iron heads with boost I wondering if I would be good on pump gas and yes I know the camshaft has alot to do with it aswell I'm going to try this combo with some help from my engine builder...Lol
Have you heard of the Somender Singh groove? Its a groove filed into the head/combustaion chamber that directs the energy back to the valve heads. I've done the modification to my Corvair heads and have noticed less knock propensity and slightly better mileage. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-PzMgPZxD7Iw.html
You say quench (or squish, whatever, same thing) is a bit of trial and error, but you don't say what a good starting place is? I realize it's a target that can't be accurately met during engine assembly, but some starting numbers would help. Cometic makes great gaskets in many thicknesses, but they're $200/pair so I'd like to get close first.
You could not be more wrong. If you make that cap tight there wil be a to high velocity mixture streem towards the sparkplug and that wil interfer whit the ingnition. The cap has to be calculaded. Pardon my poor english. It can be as big as 1mm and not cauce detionation.
Perfect quench is symmetrical about the axis normal to the wrist pin, AND symmetrical parallel to the wrist pin.. Anything else causes the piston to rock or tries to force the piston to rock against the ability of the wrist pin to rotate, aka, along the axis normal to the wristpin axis. I understand that people proud of their ignorance say "If it ain't broke, don't fix it." However this mentality or lack thereof is what fights ALL innovation and advancement. With people like them, we'd have never started riding horses, let alone building cars. I dismiss such childish braying out of hand. Quench is most effective when it is not only symmetrical on the axis parallel to the fore-and-aft axis of the cylinder, but also when the quench has radial symmetry, so it provides NO difference in force between the front and back and left and right halves of the piston. To maximize the evenness of pressure on the piston dome, the combustion chamber also needs to be completely symmetrical in all aspects, so the piston always experiences the same overall distribution of force about its center point, during compression and combustion. Now, UNLESS your intake and exhaust valves are miraculously placed kitty-corner from each other, with both exhausts opposite each other across the wristpin's axis, and both intakes opposite each other along the wristpin's axis, for example, you will experience an asymmetrical force at exhaust TDC, because the exiting exhaust is being released on the exhaust side of the cylinder while the quench area and intake valves on the opposite of the cylinder are still providing some degree of resitance to the piston's upward travel. The benefit of having a piston that has ZERO force trying to rock it one way or the other is that the piston rings can be smaller and the skirts can be smaller in size, thus lightening the piston. If it were possible, having both the center of mass AND the center of pressure on the cylinder both centered precisely on the wrist pin's axis would make piston skirts less necessary, as nothing the forces on the piston are doing (pressure or inertia) imparts any rotation or rotational force to the piston whatsoever. In fact, having the center of pressure below the wrist pins would be even better, were it physically possible. I know that these things are not covered much, but they are physical realities and can result in lighter, stronger pistons that have more reliability and absorb less power to run.
The difference between.038-.048 quench (much safer) and 0.001 quench (on the edge of disaster) is zero gains in horsepower/torque! Running zero quench is just a game of chance and the wait and see until your engine destroys itself! Good luck with that!
All the techy talk... yeah i get it. But all the time and expense of building an engine with parts needed or maching, are you a pro racer winning lots of money to cover all this? Or whats the purpose?
