in the 1960's what exactly was it? Thinking breathers?
cleaner air package
- Thread starter halifaxhops
- Start date
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I know that with the Darts and the HP273's, the CAP started in 1966 with a valve cover vented into the air cleaner. There was a PCV valve in the other valve cover also. I don't have any info on the slant 6 and 2 barrel engines though.
Emission controls.
Air pumps and in your case fart canisters.
Air pumps and in your case fart canisters.
I had an unmolested 67 318-2 Coronet back in the 80's and my research from FSM came up with- PCV only.
That particular engine burned so clean it actually produced a fair amount of clean water out the tail pipe.
It averaged 17-18 MPG and got north of 22 on the highway.
That particular engine burned so clean it actually produced a fair amount of clean water out the tail pipe.
It averaged 17-18 MPG and got north of 22 on the highway.
famous bob
mopar misfit
Daves69
Well-Known Member
Intro in the 1967 year..........
MyMopar - Mopar Forums & Information - Browser MTSC by Topic - Engine
MyMopar - Mopar Forums & Information - Browser MTSC by Topic - Engine
That's a really good book about the introduction. Note the MTSC introduction is Dec '67. but some cars already had CAP. With '68, it looks like most all cars got it.
1967 Imperial & Chrysler CAP System Repair Book - Session 241
and more complete MTSC: Master Technician Service Conference - Chrysler's Training for Mechanics
PCV was added much earlier - replacing the draft tube.
According to that booklet, the closed breather (hose attached to air cleaner) was initially a CAP item.
Most changes focused on idle and deceleration. Smoothest idle was exchanged for lower CO and HC. That meant leaner idle mixes. It also meant less initial timing, and reducing advance on decel for manual transmissions. Less initial puts more heat into the engine and exhaust (combustion starts later than it previously had).
Late 60s CAP carb idle specs are 14.2 AFR. These carbs tend to use air bleed adjustment instead of fuel restriction which allows finer tuning of the idle mixes, and less chance of the tech getting it too far out of tune.
Thanks guys that's what I thought, believe it or not it uses different distributors with or without! at least on a 66.
Makes sense. The needs of the engine for efficiency and power remain about the same. So with less initial timing, more advance is needed to get the same timing once the throttle is cracked open.
This is all before the major emphasis shifted toward knocking down the nitrous oxides ( the big ingrediant for smog).
edit: Here's the '68 mechanical advance curves for a 318 with and without CAP. The non-CAP 318 have higher initial timing. I'll post that up later
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To understand the effect of fuel ratios on combustion products, I find it helpful to look at a graphic like the one posted here: Heat riser affect wideband? - Page 2 - racingfuelsystems.myfunforum.org
You can see that leaner mixes at idle reduce CO and HC but increase NOx.
This is just 60s stuff. Later changes to try to address everything include the higher idle speeds (requiring the idle stop solenoids) to deal with relatively retarded initial timing, temperature controlled air intakes, EGR, cats, etc.
You can see that leaner mixes at idle reduce CO and HC but increase NOx.
This is just 60s stuff. Later changes to try to address everything include the higher idle speeds (requiring the idle stop solenoids) to deal with relatively retarded initial timing, temperature controlled air intakes, EGR, cats, etc.
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Here's the same advance curves on the engine using the initial timing and specs of those same distributors. As far as I can tell, neither of these use any vacuum advance at idle (the distributor vacuum is attached to a 'timed port').
The timing curve makes up for the 10 degree difference in initial timing.
The timing curve makes up for the 10 degree difference in initial timing.
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Sure is helpful the imperial club shows the dates.
So now looking at the 1967 Plymouth Sevice Manual. It lists the "Closed Crankcase Ventilation" as all California and extra for other states (Lube and Maint chapter). It lists both standard and CAP ignitions for all engines. In the '68 book, there's a lot less engines with standard (non-CAP) ignition.
So now looking at the 1967 Plymouth Sevice Manual. It lists the "Closed Crankcase Ventilation" as all California and extra for other states (Lube and Maint chapter). It lists both standard and CAP ignitions for all engines. In the '68 book, there's a lot less engines with standard (non-CAP) ignition.
67Dart273
Well-Known Member
PCV only was pretty much federal up through 67, in 68 all manufacturers had engine emissions. Chev had air pumps, "Ma" just retarded/ recurved the timing, leaned up the carburetor, and may have diddled with the carb heat system
CA cars started this crap in 66.
Same deal on the evap stuff, CA required this in 70, I think Federally might have been 72, but you seem to run into cars that were "in between" dates.
CA cars started this crap in 66.
Same deal on the evap stuff, CA required this in 70, I think Federally might have been 72, but you seem to run into cars that were "in between" dates.
The downdraft tube was replaced with a pcv in 1959 as far as the parts books tell but here's a more accurate history written by no other than our own @slantsixdan for Alpar. Read up. There will be a test when you're done! LOL
CAP/CAS Distributor Vacuum Advance Control Valve
CAP/CAS Distributor Vacuum Advance Control Valve
slantsixdan
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Nope, no PCV until '61, when it was mandatory in California, optional elsewhere. In '62 it became mandatory in New York. In '63 it became standard equipment everywhere.
There was a bit of a name game: Chrysler originally called PCV "Closed crankcase ventilation", but then in '64 when California required both the inlet and the outlet of the crankcase to be ducted to the engine intake (breather w/hose to the air cleaner instead of just vented to the open air), that was called "closed crankcase ventilation" industrywide. That fully-ducted, really-closed system became standard equipment for '68.
I need to.
It was basically phasing out of the road draft tube and phasing in of the closed PCV system.
famous bob
mopar misfit
I`ve been wondering about the effect of the pass. side being hooked to the air cleaner, on a car w/ a scoop on it > Any theories ?? ??????
slantsixdan
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What kind of effects are you wondering about?
slantsixdan
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No, the Clean Air Package was a carburetion and ignition timing deal, almost completely separate from the evolution of crankcase ventilation.
Cool. Thanks Dan. Would you elaborate a little further?
famous bob
mopar misfit
hi air pressur ein the scoop at speed, trying to ram air into the pass side valve cover. would it not fight the pcv valve on the other cover , by trying to pressurize the inside of the block?
slantsixdan
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Please read the Allpar link provided further up the thread (post № 15), and the Popular Mechanics link in the Allpar article, to learn about the origin and development of the Clean Air Package. Also here's another magazine article testing a CAP-equipped '63 Dart and going into detail about the workings of the system. And this 1967 MTSC booklet describes the system a few years later, while this one from 1971 describes the evolution after a few more years.
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