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Re: Smog Air Pump Ticking
nikothenomad #697020 October 02nd 2015 7:26 pm
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Niko, I think perhaps the dual item you're thinking about in your exhaust would be the aspirator valves/check valves. Earlier vans had one, later ones had two. I've seen air pump vans with two. Between them and the diverter, it makes the plumbing pretty congested!

I don't think of the catalytic converters burning up due to a malfunctioning air pump as much as clogging up from excess hydrocarbon accumulation. The extra air the pump injects into the exhaust helps incinerate and catalyze any unburnt hydrocarbons.

I would think that the air pump should be able to come apart if you have a really large vise and some massive tools like breaker bars, 6-point sockets, and possibly a gear or pulley puller.

I vaguely recall my FSM showing details of the process, but I can't look at it, as I lost my FSM on computer CD, and hadn't printed out that section, since I don't have an air pump installed!

The pump will simply have a series of flat, compressed Carbon vanes/blades which ride in and out in deep slots on a central eccentric hub, and against a smooth bore round cylinder surrounding them. As the eccentric hub spins and the enclosed volume between Carbon blades becomes smaller due to the eccentric, the air in that space is squeezed out of an exhaust port on the air pump, under pressure. Oil pumps can work in a similar manner.

The bearings are undoubtedly standard off-the-shelf commercial items. If you have a Timken, SKF, etc., bearing dealer supplying any local industries, they can usually match you up with an in-stock replacement bearing with little difficulty.

Once again, I haven't taken one of these MOPAR units apart, though I've had Gast units apart. With that in mind, what I suspect likely fails due to sitting unused for a while is that due to condensation, the smooth-bore metal cylinder the Carbon vanes ride against develops rust, which then binds up against the vanes, preventing them from rotating, and the central eccentric hub with the long slots for the vanes also develops rust, preventing the Carbon vanes from sliding in and out. There are quite a few vanes, with a *lot* of surface area engaged in the slots, so there would be a whole lot of binding to counter any rotational force of the pulley shaft.

Determination, Crocus cloth, and light machine oil could feasibly bring such a component back to serviceable status, though any residual rust pitting would lead to accelerated wear of the Carbon vanes. You can bet that the air pump cores going back for rebuild have a few pits...

A regular drill-driven piston sleeve hone with fine-grade abrasive stones could smooth out a large cylindrical bore pretty well, keeping its surface concentric in the process. Since the Carbon vanes slide out, automatically compensating for wear, a considerable amount of honing could take place.

Please keep us up to date on what you observe and decide!



-It's been such a LONG TIME... BlueShift>> 1981 Dodge Ram B250 Custom Sportsman Maxi Van


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Re: Smog Air Pump Ticking
nikothenomad #697139 October 04th 2015 10:55 am
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Ram, You are right I do have two check valves but my FSM also shows two pumps and says 'Dual Air Pump' (unless I am seeing things wrong which is likely since I am a crappy reader). I don't have two though as I have searched high and low and cannot find anything but the one with one diverter and two check valves.

So, I'm not sure I understand what you were saying about the catalytic converters. If I get what I've been reading and what you are saying, they can get clogged up if the air pump stops working. If I intentionally got rid of the air pump then I would obviously want to get rid of my two cats?? Right?

I've tried to do some reading on the pumps and taking them apart and it seems like something I could definitely do especially with the tools that I have available to me at this location. But we have been socked with rain and I have a few other things that 'have' to be done before we leave here.

In all cases, I will be sure to take plenty of photos.



Nicole
1988 Dodge B250 5.9l 360 Ram CamperVan / 727 Tranny / Rochester Quadrajet Carb
www.nikothenomad.blogspot.com
Re: Smog Air Pump Ticking
nikothenomad #697152 October 04th 2015 2:55 pm
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My CATCON was installed in late '04

I did not get the smog pump operational until late '07

I still pass smog tests easily.

Running rich can degrade the catalyst
Burning a lot of oil can do so also.

The most recent SN formulations of motor oil require lesser amounts of ZDDP to preserve the catalyst in Catcons.

Catcons are not going to clog up from running without an air pump, they can however have the catalyst degrade faster if one is running rich and burning a lot of oil.


Re: Smog Air Pump Ticking
nikothenomad #697166 October 04th 2015 6:05 pm
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Wrcsixeight said it; running rich and burning oil is the ultimate enemy of your cats.

From the amount of care you've given Annie, and for your not having ever mentioned black or smelly exhaust that I can recall, I think your cats are probably just fine.

Prrrrrr.... smile

I'd still be quite interested in seeing the passages under your EGR valve; those would speak volumes about the current and historical air to fuel mixture conditions.

I wouldn't pull a cat out unless it genuinely failed. They do help reduce pollution and odors. Their failure is pretty noticeable; they tend to overheat violently when they do fail, literally glowing red or even nearly white hot! Your engine temperature may soar during such an event, as you end up stomping on the gas pedal to try to keep your van moving forwards, and the extra work of pumping into the restricted cat is a horrific load on the engine.

I really don't get the need for a mini cat in front of your main cat. Is it only on the driver side of the Y-pipe, or is it after the Y-pipe joins? Perhaps it's actually a resonator. By chance is it where your air pump hoses terminate?

If it's only on the driver side, it may be an unnecessary restriction, since you have the second cat. Ever the ones to cut costs, Chrysler manufactured some vans with a mini cat on the driver side of the Y-pipe, but they let the passenger side exhaust manifold dump straight down the Y-pipe to the muffler with no cat in line. -Crazy or what? The emissions those years must have been just marginal enough they needed a little something extra to reel them in. Having it on the driver side would intercept the exhaust which comes through the manifold crossover during warm up, when things tend to be at their worst emissions wise.

I almost wonder if it was a mini cat, and it clogged, then someone rodded it out, then added the big cat downstream to cover the bases? That would let them keep from replacing or doing a lot of work on the Y-pipe, while still passing emissions. Consider that one cat is more than adequate for both sides of my 318 engine.

One way to tell if a cat has been added on as a modification is that it's illegal to modify the exhaust system leading up to one... though it still happens! If everything is stock, you'll typically see a nice flange on the Y-pipe for bolting up to the cat. If you see a bunch of non-factory looking welds on the end of the Y-pipe, especially right at the input to the cat, or no flange at all for the cat to bolt onto, with the Y-pipe welded directly to the cat, somebody has been hacking at it...


We've received a lot of rain and frigid air from Canada this week, so I've been slowed down too. Plenty to do in the garage though - I'll take whatever progress I can! smile


-It's been such a LONG TIME... BlueShift>> 1981 Dodge Ram B250 Custom Sportsman Maxi Van


[Linked Image]

It's what you learn after you know it all, that counts...

Are you living to work, or working to live?

[Linked Image]

Learning from my own mistakes is good, learning from yours would be much better! [Linked Image]
Re: Smog Air Pump Ticking
nikothenomad #697246 October 05th 2015 7:14 pm
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Our Mini-Ox is only on the driver's side and prior to the Y. From what I've read (and there isn't much out there) this was done to aid the big Cat during cold-warm-ups. Apparently, it helped the big Cat warm up even quicker.

I talked with my local mechanic who is familiar with our van today and asked him if I could remove the belt for now until I had time to open up the pump and investigate. He said it would not be a problem. So, I'll pull the belt and if I have time to open her up before we leave here then I will. If not, at least everything will still be there for my future explorations but not causing further damage.

In that regard, more investigations as to the actual location of the noise indicated it is definitely in the rear of the pump and so if I am lucky it is just the bearings back there. If I am not it has already caused damage to the vanes. So, let's hope for lucky!

Here's photos of the mini-cat and cat.

[Linked Image]

[Linked Image]



Nicole
1988 Dodge B250 5.9l 360 Ram CamperVan / 727 Tranny / Rochester Quadrajet Carb
www.nikothenomad.blogspot.com
Re: Smog Air Pump Ticking
nikothenomad #697259 October 05th 2015 7:53 pm
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Keep us posted on the air pump rebuild, I know you can do it. bow lol cheers

Re: Smog Air Pump Ticking
nikothenomad #697275 October 06th 2015 8:58 am
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Thanks, Sammy! :o) Will do.


Nicole
1988 Dodge B250 5.9l 360 Ram CamperVan / 727 Tranny / Rochester Quadrajet Carb
www.nikothenomad.blogspot.com
Re: Smog Air Pump Ticking
nikothenomad #697470 October 09th 2015 12:59 am
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I believe I actually see one of your air pump hoses. Are they the type which enters the rear of the exhaust manifolds?

Your mini cat has definitely been patched in; check out that epic welding job, and the newer section of pipe ahead of it.

I bet all that heat does wonders for your starter! I wonder if the starter heat shield from one of the later vans might fit? I have one I want to try to install on mine, just due to proximity to the Y-pipe. Hopefully it fits. If it does I'll let you know.

Your great pictures actually speak directly to what is currently installed; since you have the original factory heat shield over top of your main cat, it most definitely wasn't a shade tree mechanic add-on. The welding around it doesn't look stock, but at least it does belong there.

What you read about the mini cat makes great sense; when cold, the thermal riser valve inside the passenger side exhaust manifold closes, routing most of the exhaust from the passenger side through the intake manifold, underneath the carburetor and choke, to warm things up quicker. All of that rich exhaust will travel under your EGR valve and into the driver side exhaust manifold, so the driver side gets a double whammy. A small cat would heat up much faster than a large one, so it should help prevent the main cat from loading up with hydrocarbons.

If you do have the system with the air pump output going into the exhaust manifolds, and there are aspirator valves inline, I'd be highly tempted to try to pull those and plug the opening in the manifolds, if you're defeating the air pump. No sense in baking your aspirator valves unecessarily. Now, if the injection fittings or bolts at the manifold won't move due to corrosion, I'd stop right there; the last thing you want is a snapped bolt in an exhaust manifold!


-It's been such a LONG TIME... BlueShift>> 1981 Dodge Ram B250 Custom Sportsman Maxi Van


[Linked Image]

It's what you learn after you know it all, that counts...

Are you living to work, or working to live?

[Linked Image]

Learning from my own mistakes is good, learning from yours would be much better! [Linked Image]
Re: Smog Air Pump Ticking
nikothenomad #697485 October 09th 2015 9:27 am
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Hey, Ram!

Yes, I have both hoses and solid pipe. The hoses come off of the air pump and run into the solid pip which houses the check valves and eventually terminate at the manifold.

I know what you are saying about removing and blocking them off but not sure I'll be able to. The original bolt on the passenger side was already busted off in the manifold when I got the van.

I RTV'd around the tube and jury rigged it back into place and it has held so far. I wouldn't attempt to remove the driver's side until I am also ready to attempt to remove the manifolds and work on them.

I could definitely use more heat shields around the engine. One of these days I'll look into that. It is on my list of things I'd like to do. While we are here in GA I am trying to find time to go to the pick n pull here. It has been hard to find places that actually let you go in, wander around and pull your own parts. Last time we went to the one here they did but we were not yet ready to know what sort of things we were looking for. Now we know.

I'll see how hard or easy it is to disconnect the check valves from the solid tubes to the manifolds.



Nicole
1988 Dodge B250 5.9l 360 Ram CamperVan / 727 Tranny / Rochester Quadrajet Carb
www.nikothenomad.blogspot.com
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