1975 Smog pump removed

[SamD]

The smog pump was removed when I bought my bronco and I'd like to make sure all the holes / hoses were plugged correctly. Does anyone have pictures or locations of where the plumbing went?

Is there a better alternator bracket than this?



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[DirtDonk]

Assuming the engine is an original Bronco engine (so that the water pump bolts are all in the same place) this is the standard bracket set: http://www.wildhorses4x4.com/product/Black_Alternator_Bracket/Bronco_Starters
It's easy to retrofit and will likely raise the height just slightly. All belts should still line up I would think. Not aware of different pulleys that might have been used on the water pump and crank that would indicate differently.

Paul

 

[DirtDonk]

Oh, and while you can, you should take some good photos of your engine decal(s) if you haven't already. The info isn't always critical, but it's nice to have sometimes anyway. Might just be for others to reference, since most of those decals have gone the way of the gooney(sp?) bird after all these years.

What are all the ground cables going to? Three seems like overkill to have them that large. I like overkilling grounds of course, but not when it gets messy and in the way. So you might be able to clean those up if they're not strictly needed.

The main battery negative should be to the engine block of course. But any body or frame grounds don't need to be that large, or can be mounted more out of the way if needed. Many of us that do use large size cable to ground the engine to the frame, do so down low at a bolt near the engine mounts or on the front cover under the pump. Just to keep them out of the way.

Winches use large cable too, but most winch manufacturers recommend a connection directly to the battery.
Just wanted to mention those bits in case mounting three large cables gets more awkward with the new mounting for the alternator.

Paul

 

[SamD]

Almost everything is original. Those grounds are on the list for cleanup, but just haven't got there yet.

Trying to keep things as original as possible. Doesn't have to be original to this one, but it needs to look like it came that way. If you have any pictures of the original battery ground connections that would be helpful.


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[tirewater]

Agree on cleaning up the ground cables. Perhaps it's the picture, but they look pretty close to catching on the alternator fan.

As for smog attachments, we'll need more pictures of your engine.

If you have the stock air cleaner housing, make sure the vacuum line that would've gone to the thermactor bypass valve is capped.

The smog ports on the cylinder heads would've been on the exhaust manifold side, a washer and bolt can be used to seal those.

 

[DirtDonk]

The original engine ground was a plain old 6ga cable (absolute minimum size in my opinion) down to the engine block beneath the alternator. I think there were various places they mounted it over the years, but that's where most of the ones I've seen were attached.

The original body ground was simply a clamp soldered or crimped around a bare part of the main cable and bolted to the wheel well just below and behind the starter relay. You'll probably see a smallish (1/4" or so) hole still there where it originally attached.
This was a clever (and cheap) way of both getting a body ground and holding the cable tight out of harm's way.
The first time the original cable is replaced, 90% of the people don't even bother adding a new body ground.

So our usual recommendation around here is, use a good 4ga or 2ga cable of your chosen length from the battery to the engine, but buy one that already has the little 10ga wire molded into the lug. Extend this "pigtail" down to the body, either in the original hole, or better yet just use one of the attaching bolts for the starter relay. Since it needs a ground to operate anyway, this is like killing two birds with one stone.

Then add an additional 10ga wire or one of those nice factory looking braided straps from the back of the intake manifold to a convenient bolt on the firewall.
Ford should have done this originally like they did on most other vehicles, but never did on the Broncos. It's just good practice since the welded seams between the fender skirts and the main body tub are right where rust tends to start early and break, or at least weaken the grounding bond between the metal panels.

I've even run into EB's that needed an additional ground jumper between the wheel well and the front radiator core support. The spot weld connections had just weakened to the point that the lights were dim and the turn signals didn't work reliably.

I'll see if I can find a pic I took recently of an original ground. It was melted and trashed, but you could still see where it was attached.

Paul

 

[DirtDonk]

Here you go.



Obviously the lug is one of those "temporary unless it works" kind, and not what Ford had.

Paul

 

[SamD]

The original engine ground was a plain old 6ga cable (absolute minimum size in my opinion) down to the engine block beneath the alternator. I think there were various places they mounted it over the years, but that's where most of the ones I've seen were attached.

The original body ground was simply a clamp soldered or crimped around a bare part of the main cable and bolted to the wheel well just below and behind the starter relay. You'll probably see a smallish (1/4" or so) hole still there where it originally attached.
This was a clever (and cheap) way of both getting a body ground and holding the cable tight out of harm's way.
The first time the original cable is replaced, 90% of the people don't even bother adding a new body ground.

So our usual recommendation around here is, use a good 4ga or 2ga cable of your chosen length from the battery to the engine, but buy one that already has the little 10ga wire molded into the lug. Extend this "pigtail" down to the body, either in the original hole, or better yet just use one of the attaching bolts for the starter relay. Since it needs a ground to operate anyway, this is like killing two birds with one stone.

Then add an additional 10ga wire or one of those nice factory looking braided straps from the back of the intake manifold to a convenient bolt on the firewall.
Ford should have done this originally like they did on most other vehicles, but never did on the Broncos. It's just good practice since the welded seams between the fender skirts and the main body tub are right where rust tends to start early and break, or at least weaken the grounding bond between the metal panels.

I've even run into EB's that needed an additional ground jumper between the wheel well and the front radiator core support. The spot weld connections had just weakened to the point that the lights were dim and the turn signals didn't work reliably.

I'll see if I can find a pic I took recently of an original ground. It was melted and trashed, but you could still see where it was attached.

Paul

Here are some additional pictures








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[DirtDonk]

Good time capsule photos! Please take as many as you have patience for, so those doing restorations of a '75 in the future. Including the smog stuff it sounds like you're trying to clean out.
This stuff really helps a lot of people out. Not just for doing restorations sometimes, but also when trying to get the engine running like it did from the factory when things just aren't working right after stripping stuff off.

You can see in a couple of the pics that the big sheet metal screw is still in the hole where the ground cable used to clamp. Nice.

Thanks for the pics.

Paul

 

[SamD]

The smog equipment was already gone when I got it, and I am trying to make sure everything is capped off correctly.

The three negative cables that all come together at that bracket go to:

battery terminal

frame

Engine block under below the alternator




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[DirtDonk]

Once you get the old bracket off it'll be super easy to clean that up.
You don't need an additional ground from one point to another on the block. Just put the main cable somewhere down below on a convenient bolt (not a head bolt though!) and you're good.
The closer to the starter motor you find one, the better the ground for that high current draw item. Just make sure the surface and threads are as clean as you can get them.

And if you buy new (recommended) and are just the standard off-the-shelf variety from an auto parts store, I like to use shrink tubing on the bolt ends. They're crimped very well, but not sealed away from nature. Sealing it off should make them last even longer than they normally do.

For the frame ground, even though just a small 10ga wire would normally do, if you want to use a short cable or braided strap that's commonly available too, one of the engine mount bolts on one side, to a bolt on the frame, would do the job now. Wherever your one frame ground is now, you could still use that connection point.
If it's closer to another engine bolt down low than it is to the motor mount, use whatever you like best.

Then run the body as described previously and you should be good to go for years to come.

Paul

 

[tirewater]

I posted a few pictures of my setup here:

http://classicbroncos.com/forums/showpost.php?p=2933710&postcount=10

It includes the two Thermactor valves that are attached to the side of the heads. In one of your pictures I can see a bolt stuck into the driver side Smog hole next to cylinder #8's exhaust port. Make sure this is not leaking and look at the corresponding hole on the passenger side cylinder head next to the #1 cylinder exhaust port.

You're missing the TVS valve (or TCS, I don't remember which) that goes from the air filter housing to the smog pump itself. Instead you have some wires running into the air filter housing, I have no idea what those are.

Your vacuum advance on the distributor appears to be plugged into the back of the intake manifold. The factory had it plugged into a port vacuum switch installed into either the thermostat housing or heater elbow. The distributor vacuum would use port vacuum off the carburetor for general driving and if the engine got to hot it would switch to manifold vacuum. This would increase timing, cause higher idle and increase speed of water pump.

I think the question is "how stock" you want things.

 

[jckkys]

The only emission equipment that was removed is the Thermactor pump and hoses. The EGR and associated plumbing is still there, as well as many other emissions parts. My '77 had no Thermactor from the factory, but did have EGR,a catalytic converter, charcoal canister, etc. The holes in the heads for Thermactor air injection moved over the years. The '75 heads, I think, had a large hole near one end of the exhaust manifold with a smaller threaded hole inside for a bolt to hold a hollow cap over the large hole. These were usually plugged with a sized washer held on with a shorter bolt, with the same thread pattern as the original. My '77 has a body ground cable bolted to the back of one head and to a bolt on the fire wall. The battery ground was as Paul said, bolted to the block behind the alternator. I'd love to know where all 3 ground cables go in the first picture.

 

[SamD]

The only emission equipment that was removed is the Thermactor pump and hoses. The EGR and associated plumbing is still there, as well as many other emissions parts. My '77 had no Thermactor from the factory, but did have EGR,a catalytic converter, charcoal canister, etc. The holes in the heads for Thermactor air injection moved over the years. The '75 heads, I think, had a large hole near one end of the exhaust manifold with a smaller threaded hole inside for a bolt to hold a hollow cap over the large hole. These were usually plugged with a sized washer held on with a shorter bolt, with the same thread pattern as the original. My '77 has a body ground cable bolted to the back of one head and to a bolt on the fire wall. The battery ground was as Paul said, bolted to the block behind the alternator. I'd love to know where all 3 ground cables go in the first picture.

While I want to keep the original "look" of the Bronco, I'm not planning to reinstall the smog pump. It runs fine, but I still want to make sure everything has been terminated correctly.

I holes in the heads at 8 & 1 look like they are plugged correctly. Not sure what the rest of this stuff is though.

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[SamD]

Looks like I also need to replace the pulley on my alternator with a single vs a double. Looks like there was a double to run the smog pump.

Anyone have a recommended pulley?


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[B RON CO]

Hi, your alternator will be fine as is. The plastic vacuum ports on the water outlets are so things like the flap in the air cleaner and distributor timing among other things only activate when the Bronco is at operating temperature. I know people got rid of a lot of that stuff, but it is not easy to tell if it made it run better. Two vacuum hoses and two wires at the air cleaner may not be a better idea, at least make sure the flap open when the motor is warmed up. Good luck

 

[jckkys]

The wires are from a temp sensor on the air cleaner called a catalyst protection sensor. It has nothing to do with air cleaner duct valve. It is part of the Thermactor system like the electric switch on the thermostat housing they activate a Thermactor dump valve. The air cleaner has a bi-metal vacuum valve on the bottom of the main body that maintains a 100 degree temp of intake air. It's a good thing that helps the carb produce a consistent A/F mixture. Rather than find a one groove pulley for the alternator you can simply get a longer belt that goes around all the accessories; PS pump, crank pulley, alternator, and water pump. The alternator is less likely to squeal under high amp draw. The water pump, crank, and alternator belt stays as is. To clean up up your engine compartment, you can get a pre-'73 intake manifold (ie no EGR), put plugs in all the PVS positions, a 1" rubber plug in the catalyst protection sensor hole, do the same with the cold weather modulator next to it, routing the vacuum hose without it, but keep the following; OE air cleaner that's better than any after market, the Duraspark ignition, and the electric assist in the choke thermostat. PCV ports in the front of the carb spacer are hard to find in non EGR engines, but Ford made a 3/8" steel tube to route PCV to the oil filler cap containing the PCV valve,

 

[SamD]

The wires are from a temp sensor on the air cleaner called a catalyst protection sensor. It has nothing to do with air cleaner duct valve. It is part of the Thermactor system like the electric switch on the thermostat housing they activate a Thermactor dump valve. The air cleaner has a bi-metal vacuum valve on the bottom of the main body that maintains a 100 degree temp of intake air. It's a good thing that helps the carb produce a consistent A/F mixture. Rather than find a one groove pulley for the alternator you can simply get a longer belt that goes around all the accessories; PS pump, crank pulley, alternator, and water pump. The alternator is less likely to squeal under high amp draw. The water pump, crank, and alternator belt stays as is. To clean up up your engine compartment, you can get a pre-'73 intake manifold (ie no EGR), put plugs in all the PVS positions, a 1" rubber plug in the catalyst protection sensor hole, do the same with the cold weather modulator next to it, routing the vacuum hose without it, but keep the following; OE air cleaner that's better than any after market, the Duraspark ignition, and the electric assist in the choke thermostat. PCV ports in the front of the carb spacer are hard to find in non EGR engines, but Ford made a 3/8" steel tube to route PCV to the oil filler cap containing the PCV valve,

Since the Thermactor is never going back in, I would love to remove anything that is only there because of it to clean things up a bit.

Can I remove the wires from the catalyst protection sensor?

What about the module plumbed into the thermostat hosing. Can I remove and install a brass plug?

Rather than replace the manifold, I'm assuming I can remove and plug the EGR?

Is there a good diagram that shows the locations of the "PVS" positions and the catalyst protection sensor and the cold weather modulator?

Thanks for the help!

Sam





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[typerformance]

Hi samD I am converting 76 back to smog right now, since we are in CA. I joined to gather info for this project and this seems to be a great avenue for pictures and details. I don't have much. If you or anybody else happens to have parts laying around after removal, I'd be happy to buy them from you. I only have charcoal canister & smog pump/ bracket right now. ...and an air cleaner with a buncha missing stuff.

 

[DirtDonk]

Hey there. Welcome to classicbroncos!
Seems a common thread these days. Lots of '76's and '77's changing hands apparently. Or some just coming out of hibernation to get re-smogged after sitting.

Good luck with the parts search.

Paul