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[QUOTE=hightower99;743452]That is because your cadillac has crap combustion chamber design... [/QUOTE]
No, it just has a combustion chamber designed for premium (98 or higher) octane). Its design is fine; it just wasn't made for today's crap gasoline. ;)
[QUOTE]Think about it there are plenty of modern cars out there that run happy on premium pump gas even though they have CR ratios 11:1 or higher... Also because of advancements in manufacturering processes your cadillac has a much lower dynamic compression ratio then a modern car which runs 10.5:1 static.
They can do that because they have excellent combustion chamber design.
:p[/QUOTE]
As Matra said, modern engines can automatically adjust to prevent engine knock. A high-compression '60s engine is going to knock on regular-grade fuel- do they all have "crap combustion chambers?"
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[QUOTE=Ferrer;743490][url=http://www.allpar.com/mopar/new-mopar-hemi.html]The new Dodge Hemi V8 engine[/url]
Scroll down until you reach "General hemi engine notes", alomst at the end of this part.[/QUOTE]
The only mention of the new hemi engines not being real hemi's is a quote talking about emissions... Basically the new engines don't have true hemisphereical combustion chambers they are filled in around the edges.
[QUOTE=Fleet 500]No, it just has a combustion chamber designed for premium (98 or higher) octane). Its design is fine; it just wasn't made for today's crap gasoline.
[/QUOTE] You got that backwards it's the crap combustion chamber design that can't handle todays lower octane gas. The design is crap and it was made in the 60's
[QUOTE=Fleet 500]As Matra said, modern engines can automatically adjust to prevent engine knock. A high-compression '60s engine is going to knock on regular-grade fuel- do they all have "crap combustion chambers?"[/QUOTE] Modern engines can adjust themselves to stop knocking and yes most of the american V8s from the 60's had crap combustion chamber design. If you want to see good combustion chamber design from the 60's you are going to have to look at european and japanese cars-
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[QUOTE=hightower99;743585]
You got that backwards it's the crap combustion chamber design that can't handle todays lower octane gas. The design is crap and it was made in the 60's [/QUOTE]
Again, those '60s engines were designed to run on real gasoline. For instance, a Mopar 426-Hemi could be modifed to produce 700-750 hp running on pump gas (1960s pump gas) and unblown.
[QUOTE]Modern engines can adjust themselves to stop knocking[/QUOTE]
That's my point... you can stop or minimize knocking on '60s engines by retarding the timing, but it couldn't be done automatically. It still doesn't mean the engines were poorly designed... far from it- many '60s engines were excellent.
[QUOTE]and yes most of the american V8s from the 60's had crap combustion chamber design. If you want to see good combustion chamber design from the 60's you are going to have to look at european and japanese cars-[/QUOTE]
The engine (472-cu-in) in my '69 Cadillac first appeared in 1968. Cylinder bores were honed to a tolerance of .0002 (two ten-thousandths) of an inch, the entire range between the smallest and largest bore. Each bore was then matched with a piston of the same size. The maximum clearance for a piston pin, which fastens the connecting rod to the piston, was .00015 (15 one-hundred thousandths) of an inch. Every crankshaft was balanced dynamically (balanced while rotating). This was done to cancel damaging vibration and to aid performance.
All of this was done in air conditioned rooms so there would be no expanding or contracting of metal parts.
The crankshaft was a nodular iron casting that had an exceptionally fine surface finish for added durability. Two compression rings were molybdenum-coated for longer wear characteristics. The oil ring was chrome-plated for long life and better high-mileage oil economy.
It didn't have computers or sensors or high-tech electronics, but it was a dependable old bullet-proof V-8 with low-end torque that won't quit.
What were the engine clearances and tolerances on the '60s European and Japanese cars you mentioned?
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The boss 429 on dream car garage beat the 426 hemi and the 454
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[QUOTE=bullitt6312;743634]The boss 429 on dream car garage beat the 426 hemi and the 454[/QUOTE]
"Beat" them how?
The Boss 429 wasn't a very good street engine; it had huge ports (bigger than the Hemi's) and that hurt the low-end and mid-range. Then just about the time the big ports started to work on the top end, the restrictive carburetion and camming took over.
That was for 1969. For 1970, Ford engineers tried to upgrade performance of the Boss 429 by going to a more radical, 300 degree cam and solid lifters. But 1/4 mile times weren't helped a whole lot.
The fact is that both the Mopar 426-Hemi and the LS6 454 Chevy engines put out more hp than the Boss 429.
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[QUOTE=Fleet 500;743590]Again, those '60s engines were designed to run on real gasoline. For instance, a Mopar 426-Hemi could be modifed to produce 700-750 hp running on pump gas (1960s pump gas) and unblown.[/QUOTE] Yet it fails miserably when trying to make 400hp on today's pump gas? You don't design engines to run on certain octanes directly. You design engines to take advantage of the octane available and that is what they did. However to take full advantage of 60's pump gas you should be up at 14:1 static CR or more and I would understand if an engine running that high a CR doesn't like today's pump gas. However the engines you are talking about don't have static CRs that are any higher than today's engines and the dynamic CR of 60's american V8s are notoriously lower than what is achieved in modern engines. This is one of the reasons why I question why your engine can't handle today's gas. Some of the fault lies in the fact that your engine has poor combustion chamber design.
[QUOTE=Fleet 500]That's my point... you can stop or minimize knocking on '60s engines by retarding the timing, but it couldn't be done automatically. It still doesn't mean the engines were poorly designed... far from it- many '60s engines were excellent.[/QUOTE] You realise that modern engines automatically run themselves as close to the knock limit as possible... The systems are designed to increase efficiency and decrease emissions, not directly to increase the knock limit of the engine. The actual knock limit is defined primarily by combustion chamber design.
[QUOTE=Fleet 500]
What were the engine clearances and tolerances on the '60s European and Japanese cars you mentioned?[/QUOTE] Ever heard of the Honda S500? way back in 1963 it had an engine that had the crankshaft supported by needle roller bearings and could safely rev up to 11000rpm (factory redline was set at 9500rpm). 531cc engine making 44HP was pretty good for the time.
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[QUOTE=hightower99;743713]Yet it fails miserably when trying to make 400hp on today's pump gas? You don't design engines to run on certain octanes directly. You design engines to take advantage of the octane available and that is what they did. However to take full advantage of 60's pump gas you should be up at 14:1 static CR or more and I would understand if an engine running that high a CR doesn't like today's pump gas. However the engines you are talking about don't have static CRs that are any higher than today's engines and the dynamic CR of 60's american V8s are notoriously lower than what is achieved in modern engines. This is one of the reasons why I question why your engine can't handle today's gas.[/QUOTE]
I don't know what the '60s Hemi makes on today's gas. One muscle car magazine tested one using the old "gross hp" method and got 474 hp. But I don't know what octane fuel was used. Incidentally, the Mopar Max Wedge engines of 1963 (426-cu-in) were available with either 12.0:1 or 13.5:1 compression ratios. Needless to say, the 13.5 one needed at least 102 octane fuel.
When a 1968 car engine was being built, the engineers had no idea that for premium fuel would drop from 100 or 98 octane to 91-92 by the late '70s... how could they have "properly" built an engine without being able to see 10 years into the future? If an engine is known to be proven (can last for 100,000 or 150,000+ miles with no major repairs) and runs properly [I]with the fuel it was designed to run on[/I], then I would consider it well-built. Claiming that a 10.5:1 or 12.0:1 compression engine which knocks on 86 octane fuel has "poor" combustion chambers is ridiculous because they were built to run on premium fuel.
[QUOTE]Some of the fault lies in the fact that your engine has poor combustion chamber design[/QUOTE]
On what do you base your claim that my engine has "poor combustion chamber design?" It ran fine on the [I]gasoline it was meant to run on[/I]. A mild '60s V8 like a 318 or 327-2bbl could run fine on today's regular fuel- does that mean they are better engines than the high-compression V-8s?
[QUOTE]You realise that modern engines automatically run themselves as close to the knock limit as possible... The systems are designed to increase efficiency and decrease emissions, not directly to increase the knock limit of the engine. The actual knock limit is defined primarily by combustion chamber design[/QUOTE]
Still, the electronics of the modern engine will prevent knocking. On my Town Car, it's known as "Electronic engine control." Of course, it wouldn't be necessary if '60s-type fuel was still available.
[QUOTE]Ever heard of the Honda S500? way back in 1963 it had an engine that had the crankshaft supported by needle roller bearings and could safely rev up to 11000rpm (factory redline was set at 9500rpm). 531cc engine making 44HP was pretty good for the time[/QUOTE]
Sorry, but I think the info about the tight engine clearances on the Cadillac engine is much more impressive than an engine with a high factory redline. I'm more interested in an engine lasting 200,000+ miles than a 11,000 rpm redline. What are the tolerances of the cylinder bores and piston pins on that Honda engine? In general, a high-revving engine is going to wear out faster than a low-revving engine.
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[quote=hightower99;743713]You realise that modern engines automatically run themselves as close to the knock limit as possible... The systems are designed to increase efficiency and decrease emissions, not directly to increase the knock limit of the engine. The actual knock limit is defined primarily by combustion chamber design.[/quote]
:crying:
You have forgotten about fuel consumption :) ( ie "efficiency" :) )
"knock limit" is MUCH MORE reliant on fuel/air mix. You can adjust a mixture guaranteed never to knock in ANY engine. But you're over-fueling it for most cases and that increases emissions and decreases "efficiency" :)
So combustion chamber is a FACTOR in what fuel/air mixture and flame wave front. But stop making it sound as if it's the be all and end all jsut to try to make Fleet look "wrong".
Perhaps if we can devise a "human knock management" we can stop you pouring too much fuel before igniting yourself again :) :)
[quote]Ever heard of the Honda S500? way back in 1963 it had an engine that had the crankshaft supported by needle roller bearings and could safely rev up to 11000rpm (factory redline was set at 9500rpm). 531cc engine making 44HP was pretty good for the time.[/quote]
Now, THAT Is a "Fleet argument".
Good find on one VERY state-of-the-art example.
That's comparable to matching the Veyron with a Ford Taurus engine :)
PS: FLeet, I'll try to find the specs, but I'm certain you'll find the Honda is to as close as if not closer tolerances. They brought their experience in bike racing engines to the market :)
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i agree with ht99's point of view that by utilizing the maximum effective compression ratio will increase thermal efficieny and fuel consumption. I read that this maximum effective compression ratio depends on where the first 'hotspot' occurs hence leading to reliance on combustion chamber design. Soooo while knock limit relies an awful lot on the fuel mixture (its temperature and air/fuel ratio) surely a better design combustion chamber and well placed spark plugs would help - plus a not so hot exhaust valve helps. It could be twoddle, just what my books say :).
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You are right j.
Combustion chamber and plug location ( and spark size ) HELP.
Of course that's not quite what ht is slapping on Fleet about, claiming it is THE thing.
To claim "bad design" instead of realistically identifying as "good for the day" reflects badly on ht :)
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[QUOTE=Matra et Alpine;743717]
Now, THAT Is a "Fleet argument".
[/QUOTE]
Please don't compare his arguments with mine. At least mine are realistic. ;)
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[quote=Fleet 500;743806]Please don't compare his arguments with mine. At least mine are realistic. ;)[/quote]
:) yeah OK :)
But you have to admit he HAS pulled ONE example to support a very broad claim !!!!
You and me on the same side of a discussion -- who wouldhave thought :D :D :D
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[QUOTE=Matra et Alpine;743817]:) yeah OK :)
But you have to admit he HAS pulled ONE example to support a very broad claim !!!!
You and me on the same side of a discussion -- who wouldhave thought :D :D :D[/QUOTE]
Yeah, who woulda thunk? :)
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[QUOTE=Matra et Alpine]You and me on the same side of a discussion -- who wouldhave thought [/QUOTE]
[IMG]http://www.avclub.com/content/files/images/Apocalypse-Now.jpg[/IMG]
*Heads for cover
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[QUOTE=Matra et Alpine;743717]:crying:
You have forgotten about fuel consumption :) ( ie "efficiency" :) )[/QUOTE] No I didn't it is under the word efficiency in the part you quoted...
[QUOTE=Matra]"knock limit" is MUCH MORE reliant on fuel/air mix. You can adjust a mixture guaranteed never to knock in ANY engine. But you're over-fueling it for most cases and that increases emissions and decreases "efficiency" :)[/QUOTE] You are making a point in a very odd way! First I said that whether or not an engine starts knocking is affected by fuel/air mixture (I was subtle and mentioned it indirectly). But the ability to handle leaner and or less homogenous mixtures can be attributed to combustion chamber design and ignition timing. Yes you can make A:F ratio rich enough that it won't knock in any given engine but that isn't the point. The point is that these engines fail to run on today's pump fuel even though they have design parameters that are the same as or lower than many modern engines. One of the contributing factors is the combustion chamber design. I have not said this is the be all end all of the arguement just that it is one of the major contributing factors along with the several other factors you have mentioned. It seems your problem with my posts has more to do with your interpretation of my tone then what I actually say?
[QUOTE=Matra]So combustion chamber is a FACTOR in what fuel/air mixture and flame wave front. But stop making it sound as if it's the be all and end all jsut to try to make Fleet look "wrong".[/QUOTE] I am just trying to make it stand out as one of the major points of interest in the question/problem/arguement. I am not trying to make Fleet look "Wrong" I am simply tired of his idea that IC engines had their technological golden age in the 60's.... in america.
[QUOTE=Matra]Now, THAT Is a "Fleet argument".
Good find on one VERY state-of-the-art example.
That's comparable to matching the Veyron with a Ford Taurus engine :)[/QUOTE] Damn Straight! I figured that I would spare his intellect and give forth an example that appeals to his form of thinking...
[QUOTE=Matra]PS: FLeet, I'll try to find the specs, but I'm certain you'll find the Honda is to as close as if not closer tolerances. They brought their experience in bike racing engines to the market :)[/QUOTE] Yeah sorry I couldn't find the actual specs but I figured they would be close... for basically the same reason you mention.
[QUOTE=Matra]To claim "bad design" instead of realistically identifying as "good for the day" reflects badly on ht [/QUOTE] Ok it was "good" for the time and the market they were sold in, however they are not by any means anywhere close to good for today's standards and global markets. Good design only is so for a short time... Great design is timeless (almost) ;)