I've been hotrodding and building engines since the 80's and I always learn a thing or two on this channel. Thank you for explaining things in a way that is easy to understand.
Hard to find online, if you have “Aluminum” cylinder heads, Max DCR Dynamic Compression Ratio recommended for 93 octane is 8.70-1 I’ve seen people run DCR 9.00-1 on 93 octane but be WARNED the fuel must be verified and the tune has to be perfect! Not clarified is the Max DCR for iron heads but I would imagine it’s .50-1 lower compared to the aluminum heads. JD
Yes iron heads between 8.2 to 8.4 is ideal. I have crate gm 383ht with 190 dcr and also I run a high performance 383 with 12:1 and it has 190 dcr. All about cam selection set the dcr.
Thanks HeadFlow. Sorry I missed your comment from a moth ago. anyway, I think your points are correct. The DCR is a theoretical number based on many inputs and assumes zero leak down. The actual compression pressure measured with a gauge validates the calculations and measurements. I always err to the conservative side because I have no control of what happens one I deliver the engine. I am sticking to my 180PSI max. AG
No one answerers this question about Quench. So everyone says stay at .040ish on head gasket thickness.because of Quench. If you go thicker like .060 head gaskets. You'll possibly get detention. So my question is why does soft chambers help with tuning and detention. Well besides the soft chambers being 7° -14° and almost the size of bore . What is the difference? Thicker head gaskets would do the same no??? Thanks
Not sure if i understand your question but total quench us head gasket thickness plus deck height. The further the piston is down the hole, the thinner head gasket will be required. For a typical SBC, without decking, the piston will be down the hole about .030", so a .015" steel head gasket will achieve ideal quench. Hope this helps. AG
That was pretty cool, thanks for the video. Quench is an interesting topic, I think especially with some Mopar big block builders. I was going to do a 440 quench engine for this 70 Charger RT I have (completely disassembled). I wanted higher compression, got KB quench pistons, steel shim gaskets, etc. It's sitting here - some day. Motors and engines - well, there's the Ford motor company, General motors, Pontiac motor division.... so it doesn't matter, we know what we mean. Then there were vacuum wiper motors, Ford had a power steering driven hydraulic wiper motor. I've heard some people call the engine a mill - let's not even go there :)
Hey John, after looking at your comment I will have to make a correction in a future video. Electric motors are not the only kind, there are hydraulic motors and air motors and probably a few others. By definition they do not have combustion like an engine does. AG
A motor imparts motion to something. Engines are motors. Electric, pneumatic, hydraulic, etc. motors are motors. An electric motor isn't normally considered an engine.
except supercharged, turbo, or other boosted engines see less of a difference, this is why mountain climb races and pikes peak opt for boosted powerplants because the tune changes less even though less power is stiLL had. There are many small cars that would not make the climb naturally aspirated on many a mountain and ended up not running any further up a hill due to lack of power output versus weight.
@@goldsgarage8236 yet you seem to take the time and effort too teach these things. You seem to take some pride in creating good content for your audience. Surely it matters to you to some degree.
If I smooth the chambers on my old 390 heads to help keep down detonation, dus smoothing the chambers affect the combustion? I mean dus the ruf texture from the original casting help with the quality of combustion & dus smoothing the chambers make a less effective combustion?
Good questions Jesse. Unless you have very high compression pressure I wouldn't be too concerned about it. Also remember whenever you remove any metal from your combustion chamber, you will be reducing your compression. AG
No it shall not change combustion.just any pointy or sharp lines, like a corner, or the threads of a spark plug, or a sharp corner or point, or specs of carbon or anything like that, in the top of the bowls just above the valve to below the valve to onto the piston surface. See those cutouts for the valves? see any sharp lines or sharp points, all of those are potentiaL heat risers, or hot spots. buff all those sharp lines with buffing wheeL on a Dremel tooL if you have steady enough hands. A very confusing area can be the spark plug itself and or the exposed threads in the chamber. Also, the quench pad of the head just near the exhaust valve needs to be slightly smoothed into the chamber to create a hyper scavenge plateau coined by great engine builder and racecar build legend david vizard. A good angled roll on the sharp ledge is what i do as well. Smoothing all of the chamber is ideaL for detonation resistance and is the true reason for polishing everything. Polishing any other engine components are ideaL for quick oiL return and the elimination of stress risers. 🙂
@dennisllewellyn7805 OK, I get what ur saying. And I know exactly what ur talking about when you quote David Vizard. But still leaves the question about what I've seen on some pistons. For instance I bought a 460 ford engine from a mud bogger that was getting out. It had TRW forged pop up domed pistons. On each piston on the dome had small ding marks in them that wasn't part of the piston design, but put there by the builder. If one didn't know better they might think a small nut got loose inside & rattled around. But not the case, it was intentionally put there. To help stir up the mixture for a better combustion. Would that be simply for the dome where as a flat top it wouldn't be beneficial??
@@jesseduke694 Yes. You want you a nice flat top to slap that combustion, you want the head runner, bowL, valve, and the chamber design all to work together to have enough roll and swirl and not too much of one or the other while banging that mixture in a flat quench and an angled spark plug pointed at the exhaust valve. You want a hyper scavange ramp at the exhaust valve and as much flat area left on the head and piston as possible. You may have some pop up, although not much. You may have some reverse dome, although not much, because you need that squish affect for an efficient effective combustion for more power per fueL and air and the more wall, the more the blockage. This flat top quench method drives efficiency. The 2 valve inline design demands this type for efficiency and the best results possible in the design constraints of it's own configuration. The answer for more compression is more stroke and or bore and or a smaller chamber and smaller valve reliefs within tolerances. You may mill your heads, then again, you can mill your pistons as well and the block's deck.
Keep your intake air temp as low as possible, your oil temperature below about 220F and your coolant temp below about 190F and use 92-or higher octane fuel.
i like using a 150* or even a speciaL 140* degree thermostat this keeps water and or coolant temperature usually below 160* to 170* water coolant temperature. Oil shall always be warm enough if water / coolant is right at 150* degrees. i am do not like running edge of temperatures to the extreme edge being 220* oiL temp with 190* degree water. Your oiL at that rate is as hot as it should EVER be, and is not ideaL. Engines running right at 150* degrees, on the dyno always make more power. High flow water pump and oversize bearings built in with a really long wide dual pass or other multipass like triple pass and 4 pass radiator are ideal. If you can controL the temp exactly you can plumb your heads to recieve the coolant first, this allows for high rpm and higher compression than normaL. Also a custom pure glycoL Sealed higher pressure coolant system with hard lines and high pressure radiator can keep anything cooLer for Any reason even if that be running up to a full point in static compression ratio, however these results are versus a probable inferior cooling system to begin with. A fuel cooler is always a great idea. However if your engine is really pumping power it may benefit from an oiL cooler, this is usually only desired if the discrepancy between oiL and water temperature are much greater than normaL and is not an excuse to run a blown head gasket hahahahahahah. Only if oiL is too hot. And trust me, once your water and or coolant temp has exceeded 200* to 220* + degrees = your oiL is cooked, it may stiLL be gold, however it's viscosity is gone. Once this happens, it is not working and shall wear your engine and heat it up and seep past gaskets. Automatic transmission oversized OIL coolers are a big must the largest RV cooler for an automatic transmission even in a light car are still inferior, so run multiple coolers for automatics and increasing stall speeds.
I understand how some terminology can get turned around, but really? If you're into this stuff you know what a guy is talking about. Next thing people will gripe about is " pounds feet as apposed to foot pounds" , " foot pounds per second, lbs foot per second. LOL! What if we complain to the DMV about calling a gas car a motorized vehicle? ENGINIZED VEHICLE? Have a great day my friend and thanks for the "content great"
I've been hotrodding and building engines since the 80's and I always learn a thing or two on this channel. Thank you for explaining things in a way that is easy to understand.
Very nice compliment, thanks toomanymods. AG
Hard to find online, if you have “Aluminum” cylinder heads, Max DCR Dynamic Compression Ratio recommended for 93 octane is 8.70-1
I’ve seen people run DCR 9.00-1 on 93 octane but be WARNED the fuel must be verified and the tune has to be perfect!
Not clarified is the Max DCR for iron heads but I would imagine it’s .50-1 lower compared to the aluminum heads. JD
Yes iron heads between 8.2 to 8.4 is ideal. I have crate gm 383ht with 190 dcr and also I run a high performance 383 with 12:1 and it has 190 dcr.
All about cam selection set the dcr.
Thanks HeadFlow. Sorry I missed your comment from a moth ago. anyway, I think your points are correct. The DCR is a theoretical number based on many inputs and assumes zero leak down. The actual compression pressure measured with a gauge validates the calculations and measurements. I always err to the conservative side because I have no control of what happens one I deliver the engine. I am sticking to my 180PSI max. AG
No one answerers this question about Quench. So everyone says stay at .040ish on head gasket thickness.because of Quench. If you go thicker like .060 head gaskets. You'll possibly get detention. So my question is why does soft chambers help with tuning and detention. Well besides the soft chambers being 7° -14° and almost the size of bore . What is the difference? Thicker head gaskets would do the same no??? Thanks
Not sure if i understand your question but total quench us head gasket thickness plus deck height. The further the piston is down the hole, the thinner head gasket will be required. For a typical SBC, without decking, the piston will be down the hole about .030", so a .015" steel head gasket will achieve ideal quench. Hope this helps. AG
That was pretty cool, thanks for the video.
Quench is an interesting topic, I think especially with some Mopar big block builders. I was going to do a 440 quench engine for this 70 Charger RT I have (completely disassembled). I wanted higher compression, got KB quench pistons, steel shim gaskets, etc. It's sitting here - some day.
Motors and engines - well, there's the Ford motor company, General motors, Pontiac motor division.... so it doesn't matter, we know what we mean. Then there were vacuum wiper motors, Ford had a power steering driven hydraulic wiper motor. I've heard some people call the engine a mill - let's not even go there :)
Thanks for sharing John. AG
Hey John, after looking at your comment I will have to make a correction in a future video. Electric motors are not the only kind, there are hydraulic motors and air motors and probably a few others. By definition they do not have combustion like an engine does. AG
Pistons should be good depending on power level.
Interesting. I did realize I was riding an engine cycle. I always thought it was a motorcycle. Language is a strange thing.
That is very funny! Thanks for adding a little humor to the subject Lyall.
I guess I ride an engine cycle too. 😄
. . . wait, witch engine cycle? ☺
A motor imparts motion to something. Engines are motors. Electric, pneumatic, hydraulic, etc. motors are motors. An electric motor isn't normally considered an engine.
Thanks for the comment. AG
Thank you again, I built my hot rod with a tight quench, well worth the results but takes much extra engineering and machining to achieve.
Thanks Bobby, a tight quench is not easily achievable, but worth it if you are running high compression. Thanks for watching. AG
Thank you for your knowledge and videos USA 🇺🇸 USA 🇺🇸
Thanks Patrick, you keep commenting and I will keep producing videos. AG
I'm very pleased to look back after first seeing the dyno video.
Great, thanks for watching, I hope you found it interesting. There are more videos on this subject on my channel, please check them out. AG
NO dijiste nada
So i assume a guy living at 6,000 feet elevation can run more compression because of less air density?
Yes gentile, I think that is true. I live about 800 feet so not a problem. You will also make less power. AG
except supercharged, turbo, or other boosted engines see less of a difference, this is why mountain climb races and pikes peak opt for boosted powerplants because the tune changes less even though less power is stiLL had. There are many small cars that would not make the climb naturally aspirated on many a mountain and ended up not running any further up a hill due to lack of power output versus weight.
If you get bent out of shape whenever you hear somone refer to an engine a as a motor, you have issues.
Thanks Shooter. I don't think it matters if everyone knows what we are talking about. AG
@@goldsgarage8236 yet you seem to take the time and effort too teach these things. You seem to take some pride in creating good content for your audience. Surely it matters to you to some degree.
If I smooth the chambers on my old 390 heads to help keep down detonation, dus smoothing the chambers affect the combustion? I mean dus the ruf texture from the original casting help with the quality of combustion & dus smoothing the chambers make a less effective combustion?
Good questions Jesse. Unless you have very high compression pressure I wouldn't be too concerned about it. Also remember whenever you remove any metal from your combustion chamber, you will be reducing your compression. AG
No it shall not change combustion.just any pointy or sharp lines, like a corner, or the threads of a spark plug, or a sharp corner or point, or specs of carbon or anything like that, in the top of the bowls just above the valve to below the valve to onto the piston surface. See those cutouts for the valves? see any sharp lines or sharp points, all of those are potentiaL heat risers, or hot spots. buff all those sharp lines with buffing wheeL on a Dremel tooL if you have steady enough hands. A very confusing area can be the spark plug itself and or the exposed threads in the chamber. Also, the quench pad of the head just near the exhaust valve needs to be slightly smoothed into the chamber to create a hyper scavenge plateau coined by great engine builder and racecar build legend david vizard. A good angled roll on the sharp ledge is what i do as well. Smoothing all of the chamber is ideaL for detonation resistance and is the true reason for polishing everything. Polishing any other engine components are ideaL for quick oiL return and the elimination of stress risers. 🙂
@dennisllewellyn7805 OK, I get what ur saying. And I know exactly what ur talking about when you quote David Vizard. But still leaves the question about what I've seen on some pistons. For instance I bought a 460 ford engine from a mud bogger that was getting out. It had TRW forged pop up domed pistons. On each piston on the dome had small ding marks in them that wasn't part of the piston design, but put there by the builder. If one didn't know better they might think a small nut got loose inside & rattled around. But not the case, it was intentionally put there. To help stir up the mixture for a better combustion. Would that be simply for the dome where as a flat top it wouldn't be beneficial??
@@jesseduke694 Yes. You want you a nice flat top to slap that combustion, you want the head runner, bowL, valve, and the chamber design all to work together to have enough roll and swirl and not too much of one or the other while banging that mixture in a flat quench and an angled spark plug pointed at the exhaust valve. You want a hyper scavange ramp at the exhaust valve and as much flat area left on the head and piston as possible. You may have some pop up, although not much. You may have some reverse dome, although not much, because you need that squish affect for an efficient effective combustion for more power per fueL and air and the more wall, the more the blockage. This flat top quench method drives efficiency. The 2 valve inline design demands this type for efficiency and the best results possible in the design constraints of it's own configuration. The answer for more compression is more stroke and or bore and or a smaller chamber and smaller valve reliefs within tolerances. You may mill your heads, then again, you can mill your pistons as well and the block's deck.
@@zAvAvAz thank you!
Hello
What coolent temperature range is ideal for a high comp engine to try to provent deternation?
Keep your intake air temp as low as possible, your oil temperature below about 220F and your coolant temp below about 190F and use 92-or higher octane fuel.
Good answer, thanks PRETTYWICKED.
i like using a 150* or even a speciaL 140* degree thermostat this keeps water and or coolant temperature usually below 160* to 170* water coolant temperature. Oil shall always be warm enough if water / coolant is right at 150* degrees. i am do not like running edge of temperatures to the extreme edge being 220* oiL temp with 190* degree water. Your oiL at that rate is as hot as it should EVER be, and is not ideaL. Engines running right at 150* degrees, on the dyno always make more power. High flow water pump and oversize bearings built in with a really long wide dual pass or other multipass like triple pass and 4 pass radiator are ideal. If you can controL the temp exactly you can plumb your heads to recieve the coolant first, this allows for high rpm and higher compression than normaL. Also a custom pure glycoL Sealed higher pressure coolant system with hard lines and high pressure radiator can keep anything cooLer for Any reason even if that be running up to a full point in static compression ratio, however these results are versus a probable inferior cooling system to begin with. A fuel cooler is always a great idea. However if your engine is really pumping power it may benefit from an oiL cooler, this is usually only desired if the discrepancy between oiL and water temperature are much greater than normaL and is not an excuse to run a blown head gasket hahahahahahah. Only if oiL is too hot. And trust me, once your water and or coolant temp has exceeded 200* to 220* + degrees = your oiL is cooked, it may stiLL be gold, however it's viscosity is gone. Once this happens, it is not working and shall wear your engine and heat it up and seep past gaskets. Automatic transmission oversized OIL coolers are a big must the largest RV cooler for an automatic transmission even in a light car are still inferior, so run multiple coolers for automatics and increasing stall speeds.
I understand how some terminology can get turned around, but really? If you're into this stuff you know what a guy is talking about. Next thing people will gripe about is " pounds feet as apposed to foot pounds" , " foot pounds per second, lbs foot per second. LOL! What if we complain to the DMV about calling a gas car a motorized vehicle? ENGINIZED VEHICLE?
Have a great day my friend and thanks for the "content great"
Thanks so much for your comment nakedshorts. AG