There is a thermostatically controlled valve located on the back of your radiator that locks out the EGR valve until the coolant warms up. If it dies only after it warms up, this kind of suggests maybe the EGR valve is the culprit here. It is easy to service. I would be inclined to replace it if you can still get them. Do not remove it, as it actually improves combustion by lowering combustion chamber temperature. Get it working right.
Sam

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The CCEGR ("Coolant Controlled Exhaust Gas Recirculation") switch, yes. Everything could be hooked up correctly, but if this vacuum switch is stuck open, it'll cause poor driveability before the engine's warmed up, but won't cause stalling at low idle or poor idle quality, because the EGR valve, when hooked up correctly, is never open at closed throttle, only at moderate throttle under significant road load.
New EGR valves can still be had easily, yes, but:
No. Introducing exhaust into the intake tract is not intended to improve combustion, and it does not do so. It dilutes the intake charge so as to reduce cylinder pressure and temperature, which reduces the formation of NOx. This results in lower engine efficiency and output, not higher. 1973 was the first year for valve-controlled EGR. Later (much later) systems were designed as a part of a comprehensive engine design and management strategy, such that they're neutral or even beneficial to engine performance, but these early added-on systems are generally a negative influence on performance, economy, and driveability. Improvements in all three can usually be had by deleting the EGR (blockoff plate in place of the EGR valve) and, if necessary, altering the basic ignition timing or advance curves slightly.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

It's always nice to get straightened out on misconceptions. Everything I had read said the EGR valve lowered combustion chamber temps, and that was a good thing. Dan, I don;t doubt your info is correct. I have never had a slant with an EGR, so can;t speak form personal experience. I was slanting during the intro of the EGR though, with a 72 Duster(non EGR), and saw friends with EGR equiped slants make them run worse by removing all the polution equipment. I'm sure their approach was not very intelligent.

So is the underlying assumption wrong that lowering combustion chamber temps helps? I know I have read this many times. How does the combustion chamber temp effect the general efficiency of the engine? Obviously it has got to be pretty hot in there.Is there a perfect temperature? Is there a temperature that one should not exceed? Do the later EGR valves take this into consideration in a more intelligent way? Do they still put these on modern engines? I haven't looked recently, but there was one on my '95 Corvette, and when it got dirty, a check engine light came on.

Thje bottom line is, if Dan thinks it will run better with the EGR removed, it probably will.

Sam

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Lowering combustion temps can help to reduce detonation but the dilution of the air/fuel mixture also lowers the energy content of the combustion charge. With careful calibration of the timing curve you might be able to get some of it back but from a performance standpoint it's always going to be a net negative. It's no accident that the demise of the muscle car coincided with the introduction of emmission controls, including EGR. It wasn't until the advent of computer controlled engine management and more advanced catalysts that we began to see a recovery in engine performance.

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David Kight
'62 Valiant Signet, White
'98 Dodge Dakota
'06 Jeep Liberty

Growing older is unavoidable but growing up is strictly optional.

EGR does indeed reduce combustion chamber temperature, because the inert exhaust gas (cannot be burned) takes up some of the volume that would otherwise be occupied in the cylinder by burnable air/fuel mixture, which makes the "bang" less powerful and therefore less hot.
If you are trying to control NOx formation in the engine to reduce or eliminate the need for catalytic treatment (cleanup) of NOx after it leaves the engine, that's how you do it: by reducing peak temperature in the combustion chambers. If you're trying to maximise engine output and efficiency (and resultant driveability and performance and economy), then EGR in the form found on a slant-6 is, as some government regulators say, "disbeneficial".
Just randomly yanking out wires and widgets and splicing-together vacuum hoses doesn't work. Most of what you saw was the result of ignorant but determined individuals. See this old post.
See above. it helps reduce NOx formation -- NOx isn't good for us to have in our air, so from the standpoint of exhaust emission cleanup, reducing NOx is a good thing. However, a device or system that reduces NOx in such a fashion as to get the new car past 1970s-'80s Federal exhaust emission certification tests so that the cars can be sold, does not necessarily have much or any benefit as measured at the tailpipe of that car.

Lowering combustion chamber temp does not help the engine run better.
Very directly: Higher energy content in air/fuel charge = hotter, higher-energy "bang" in the cylinder = more engine output or greater economy at any given output level.

There are other interrelated factors at work -- engine design and operational parameters, combustion chamber and cooling system heat-distribution and -carrying traits, ignition timing, cam timing, spark plug heat range, and others.
The valves themselves have gotten more advanced, with wider and more progressive ranges of opening and feedback sensors to detect valve position and resultant exhaust gas flow. But the major advances have been in the engine management systems that permit EGR to be used very precisely to control pinging in engines designed so as to be more efficient but also more prone to ping (high compression, aggressive ignition advance) in such a fashion that the performance and efficiency gains can be taken advantage of. Our '70s-'80s systems are wayyyyyy too primitive to offer this kind of benefit.
Many modern engines do use EGR, yep.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I replaced all the vacuum hoses, flipped the egr backwards, removed the vacuum relay thing and it's hoses and capped all unused vacuum ports, and it still stalls.

I'm still trying to borrow a tachometer from a friend of mine, to try to check the ignition timing.

Isn't there anyplace to get a cheap handheld tachometer?







I ordered a super six setup off of eBay.

http://cgi.ebay.com/ebaymotors/ws/eBayI ... 275&rd=1,1

Did I pay too much?

They aren't really making any promises about the condition of the carb.

What kind is it? When I was comparing to this picture,

http://slantsix.org/articles/supersix/bbd-2280.jpg,

I thought it looked more like the carter BBD but I'm not real sure.

What do you think? Rebuild it? Just try it out?

Does it look like it has all the throttle linkages and stuff I need?

What about a choke... what do you guys have? which is cheapest and easiest: stock, manual, or electric?

Hi everyone,

I'm new to the forum, and this is my first post:

I bought a 68 Dart GT with a 225 in it about a month ago, and have been having the EXACT same problem. It wants to stall when you apply the brakes to stop at a light or stop sign. (Maybe it just wants to go fast and is allergic to stop signs?? ) It doesn't seem to want to do it as bad when I brake VERY lightly, but the engine still sputters and goes a bit wonky. I found that when it stalls, it requires a sqirt to the carb to get going again.
When I first started investigating the problem, I noticed the timing was WAY off. (apparently the eqivalent of one jumped distributor gear tooth, about 120 degrees on the pulley)
So I put it all back together properly, and it ran great for about a week.(250 or so miles)
Then it started doing it again, so I checked the timing again and noticed that the notch has once again wandered south. Pulled the distributor to inspect for wear or broken bits, but it's like new. Timing chain doesn't seem to have stretched much either.
ANY IDEAS WHAT COULD CAUSE THE TIMING TO GO THAT FAR OFF?? (I'd guesstimate about 1/6 of the way round the pulley or 60 degrees, I guess)
I'm stumped, but it's nice to know I'm not alone....

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"That's not an oil leak, it's SELF LUBRICATING!!"

Well I borrowed my friends tach and it is the largest voltmeter I've ever seen. It looks real old too.. check it out



My timing was pretty close to specs at maybe a degree or two BTDC at 750rpm w/ the vacuum advance disconnected and plugged. I was getting about 1/2 of manifold vacuum(around 8 in hg) at idle from the distributor port on the carb(the one next to PCV one is the right one isn't it?) but when plugged in the effective advance was still remained just a couple degrees BTDC at idle. I tried adjusting the vacuum advance pod so that it kicked in earlier until I got near the beginning of the marks(I think around 10* BTDC) at idle and it seemed to run OK but it didn't seem to really help or solve the stalling issue.

It was a lot easier to see the marks w/ white out on em'

I couldn't figure out how to loosen up the distributor to adjust the timing that way. Think I should try that?





I got my super six setup that I ordered from eBay.


I painted the manifold

and tried to clean it up a little because it was a little rusty.


There's no tag and the carb doens't look like the right one for a slant, and it doesn't have any provisions for the charcoal canister . Is that going to be a problem? Is that a BBD for a 318? or something else?




Do BBDs normally have green throttle shafts?

It came missing an idle speed screw. It also came with an incorrect gasket installed so that there would've been a huge vacuum leak bacause some ports were exposed to the open, but I replaced it with the correct one. Unfortunately, while I had it apart this piece came flying out and I don't know where it was supposed to go.

Anybody know where it goes?
It popped out from near the float bowl area when I took the top off but I don't know where it goes and I can't find it in the exploded diagrams.

I also discovered while I had it apart that the top of one of the jets was all buggered up so badly that I couldn't get it out. I couldn't figure out the size of the one that would come out(it was also pretty gouged up on top) so I just put those ones back in and put it back together. How do you tell what size the jets are? What size of jets are appropriate for a slant BBD?

It also came with the kickdown linkage. Does this look like the correct one?




It came with a choke too, but to me it doesn't really look any different than the one bbl one I've already got. Is this the correct choke piece for a 2 bbl?


I wish I could get this thing running good again.

What do you guys think? Should I try putting this super six setup on it? Try to adjust the timing more?


Here's a couple pics I snapped of the car. It's a really dusty duster right now and it still needs lots of work. You don't even want to see the interior so I won't post any pics of it

I am recovering from surgery, and should be sleeping, but can't. Something's keeping me awake. That is why I am on here at 4AM.

Your friend's dwell-tach unit looks like about a 1975-'83ish unit.
You'd probably like it better at about 5° BTDC.
Probably, but what kind of carburetor are you running right now? 0.5" vacuum isn't usually enough to budge the vacuum advance, which is fine, because you don't want any vacuum advance at idle.
Why...?
Can you achieve 5° BTDC (w/o vacuum advance) without doing so?

Looks like a "remanufactured" '70 318 BBD retrofitted with the choke shaft and lever from a '76-'82 225 BBD. It'll bolt on and if it's in fundamentally good condition, you can make a 225 run well with a carb like this. One caveat would be the throttle plates. If they are drilled (each has a hole) you'll never get the car to idle down slow enough.
Green on a choke or throttle shaft usually indicates a Teflon coating, and it's usually only found on Holleys. Interesting.
Gee, I like this carburetor already! (not...)
That "hugs" the accelerator pump stem and lifts the bowl vent disc off its seat.
Eeyuck. Save yourself a ton of trouble and time; find a less-abused carburetor to start with. This one's going to be trouble.
By reading the stampings on the side. They look like "120-268s" and the numbers are neither intrinsically meaningful nor sequential (Thanks heaps, Carter...)
Yes.
Can't tell from this angle, would need to see it from the top. Whatever carb you wind up with, put in one of the Electric choke kits and save yourself a bunch of trouble.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I'm Sorry. I hope you can get some rest and get well soon.

It's a holley 1920.

It showed 8 in hg(which is 1/2 of manfold vacuum, not 1/2 in hg - sorry, I didn't really put that very clearly in my last post) at the vacuum advance port for the distributor at idle. Manifold vacuum was about 16 in hg. I wasn't getting any vacuum advance at idle before but I tried to activate the vacuum advance sooner because I couldn't figure out how to loosen the distributor(I thought there was just a little bolt to loosen up on the base of it somewhere but I was having trouble seeing and reaching way down there). I wanted to see if it could idle better with more advance so I adjusted the vacuum advance instead just as a test to see if it would run better at idle. It doens't seem like that really helped.

I'll try to set it up at 5* BTDC base timing and set the vacuum advance pod back so it doesn't activate so soon.


It was around 1 or 2* BTDC without any vac advance so I'll have to try again to figure out how to loosen up the distributor and advance it a few more degrees that way.

Do you still think that the timing settings could be causing the stalling problem?




Hmmm... 318..... That probably means that those jets that it came with are too big then right? What size jets would be appropriate? I might have to try again a little harder to get that one stuck jet out. Can you adjust for a jet that is too big by using different metering rods?

It looks like the holes in the throttle plates may have been filled. Are those dots on my plates where the holes normally are on a 318 BBD?


Even w/ the wrong jets I suppose I could at least put it on and see if it idles better or doesn't stall at idle with this carb to try to determine if the carb is causing the stalling problem. Having the wrong jets wouldn't affect the idle would it?



Thanks, I'll probably take your advice on the electric choke. Here's a better pic of the one that came w/ my setup from eBay anyway.

Thanks. Turns out the pain meds that were supposed to knock me out and help me sleep, wound up keeping me awake and far too aware until 6:30 this morning when I finally got to sleep. Uhhh...time to call the doc and change meds.
H'mmm. That's not what's wanted. You want zero or near-zero vacuum at the carb's distributor advance port at curb idle.
Kinda low. What is your altitude above sea level?
The distributor has a rectangular metal plate at the bottom of the body. One end of this plate is bolted to the underside of the distributor body. Both bolts go through slots, rather than simple holes, in the plate. The other end is bolted to the block. If you cannot get the range of adjustment you need by loosening the plate-to-block bolt and rotating the distributor, you can loosen the plate-to-distributor bolt and rotate the distributor relative to the plate. There is a special wrench that makes \6 distributor adjustments (using both bolts) really easy, see here.
Probably not.
Naw, there's generally not a jetting problem running 273-318 carbs on 225s as long as you're not too high above sea level. But I see you do indeed have drilled throttle plates, which have been filled (with...???? Hope it's heatproof and fuelproof) and together with the other ways you've described this carb being brutalised, I would encourage finding another rather than putting effort and/or money into this one.
The one that came with your setup is indeed a factory 2bbl choke unit...these are non-adjustable.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Mine doesn't get that low. The port for the egr and the port for the charcoal canister purge both show zero at idle though. Could that be indicative of a problem with this carb?

Yes. It is. I'm around 12xx ft.


Ok thanks. I couldn't figure out how to loosen either bolt. I might have to try to clean it up a little down there because it's way down there and pretty dirty. Know what size the bolts are?


It looks like somebody put some rivets over the holes. One of them popped out pretty easily when i pushed on it with my fingernail. I wouldn't want that in my engine! The other one seems like it's in there pretty good.

Is there any good way to fill the holes?
I'd like to at least give it a go.

Where would you recommend looking for a better BBD?

Well, those two ports should show zero or near-zero at idle. Your finding 8" of vacuum at the distributor vacuum advance port at idle suggests the throttle plate is open farther than it ought to be in order to keep the engine idling, which in turn (and together with the low manifold vacuum reading at idle) suggests the timing is severely retarded, and that could cause a stalling problem. Generally when the timing mark slips, it slips in the other direction (i.e., you're getting more advance than is indicated) but there have been a number of different crank pulleys and timing indicators over the years, and sometimes the crank pulley has "phantom" markings that look like the timing mark but really aren't, and then there's always the possibility of a stretched timing chain.

So, I think probably you will want to verify TDC. Remove the frontmost spark plug, put a straight line into the spark plug hole so it's resting atop the piston (slim screwdriver, unbent coat hanger) and manually turn the engine using the fan and fan blade until your straight line stops moving up. If the timing mark is nowhere near the "0" indicator, rotate the engine until the piston goes down and comes back up again, and retry. This is easier with all six spark plugs removed because then you're not fighting compression.

Most of the ones I run into are 7/16"-head bolts.
Eek! Yeah, definitely not.
Well...yeah, swapping-in a pair of unholed throttle plates works OK Seriously, I have closed-up these holes with high-temp solder and a microtorch, but it's dodgy work...really easy to warp the throttle plates, and they need to be unwarped, plus the solder plug can come out of the hole just like the halfway-rivet you described. I think if I needed to do this again, I'd find some really small brass screws and nuts and install one in each hole, with Loctite.
That's a good question. "Reman" units are generally terrible. I run into new ones from time to time as I dig slowly through my accumulated parts. Sometimes they're advertised on here. I wish I had a time machine to go on a big parts shopping trip to 1970!

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Thanks, I'll definitely check that.


Thanks for the info. If I go that route I'll have to make darn sure they aren't going to come loose again