Hello,

I have an 87 f-350 custom w/460 eng, holley 4180 carb, and 5 speed OD trans. My question is do I need the thermactor system in the truck or can I remove it and all it's components??

The reason I ask is? I also have a 86 f-150 w/351w and the thermactor system has been removed, and it passed NJ state inspection.

it's a real pain in A**, working on engine with all that Bull S**T on top of it.
If I can remove it, what changes would I have to make.

1, to the carburator, do I just plug the vacume line's that lead to the thermactor system?

2, then do I plug the manifold's where the thermactor connects?

3, The line going to the catalytic converter do I just cut it and plug it?


Any info would be greatful.

Thanks

AL

 

One of the most prolific inventors of all time was Charles "Boss" Kettering. Amoung other things, he invented the electric starter, founded Delco, and was head of General Motors Research.

He had a "nuts and bolts regular-kind of guy" manner about him, and was noted for his down-to-earth guidance to engineers, mechanics, factory managers, etc.

One of my favorite Kettering quotes is particularly appropriate here:

"Parts left out cost nothing, and create no service problems."

Basically implying that automotive designs should be as simple as possible, superfluous parts should be eliminated, and mechanics should not think they can just take things out as unnecessary -- because the designers would have done so already.

As much as you want to rip out the air pump, don't you think Ford would have removed it if they could? Think about how expensive all those parts are, and all the extra labor that went into installing it onto the engine. To make matters worse, the Federal Government mandated that Ford provide 5 year, 50000 mile warranty service on all emissions related components, including the air pump and all that irritating plumbing.

The air pump in your installation provides extra oxygen to the exhaust ports and the catalytic converter. Some of the CO and HC is burned within the manifold, with much of the rest reacted in the converter. Without the air pump, the original OEM catalytic converter has no source of excess oxygen to turn CO into CO2 and HC into H2O and CO2. It will not meet federal standards this way, though it may squeak by a typical state inspection programs, because the "pass" criteria is fairly loose for older vehicles.

It is fairly likely that your catalytic converter will eventually become sooted, and lose whatever remaining effectiveness it had without the air pump. Furthermore, the sooted converter will represent an additional exhaust restriction and your engine will lose performance.

The latest (2004 era) catalytic converter designs feature "3-way" operation to lower HC, CO, and NOx emissions. The NOX, once reduced back to N2 and O2, provides one source of oxygen to reacted against the HC and CO. With effective feedback controlled EFI, it is possible to dispense with air pumps, and today's engines have largely done so. But I don't think you could make this work very well with a carbureted installation, even with a PCM controlled feedback carb. Carbs just have too much variability in their mixture ratio and cylinder-to-cylinder mixture distribution.

No matter how painful it is to work on the engine with the air pump, imagine how frustrating it would be to rip all the stuff off, and then fail a future emissions inspection and be forced to put it all back.

You might be able to get your truck to pass the sniffer test, at least the first time, without the air pump, but if the inspectors ever look under the hood, they will fail the truck for obvious signs of "tampering". Do you want to run this gauntlet every year, year-after-year, when it comes time to renew the sticker? All it takes is one inspector a little less lazy than the average.

If you didn't have the inspection program, you could take off the air pump, block off all the air tubes, and remove the converter. (Although I think this engine had some form of EEC, and that you would have to live with a flickering "check engine" light, depending on how you handled the vacuum lines).

But with mandatory inspection, I personally think you would be reckless to take the risk.

 

fefarmer,

Thanks for the class on the thermactor system, in making my discision in keeping it intacked.

AL

 

sorry to bump up an old thread, but can the thermactor system be removed/disabled and still keep the air pump working?
Is there a way to remove the valve itself and just run straight lines to various components?
Thanks

 

The various valves in the system perform important functions and can't be left out.
(Re-read the Kettering quote).

For example, the diverter/dump valve is there to keep the exhaust pipes from popping/backfiring on decelleration. There are check valves to prevent exhaust reversion into the air system. If you start to re-engineer the air pump system on your own, you may not care for the resulting behaviour.

If you don't have inspections, and do not care about clean air, you can take everything out -- air pump, plumbing, valves, catalyst. But you can't take part of the system out and expect a good result.

 

Amen fefarms, I'm so tried of hearing about removing smog parts. If the hoses are in the way remove them, do your work, and put them back on. What are we talking about two hose clamps per hose. Also stop removing the egr valve it improves gas mileage and reduce NO emissions. we all could use to save some money and breath easier. Don't rig fix it! Okay putting the soap box away.

 

remove that stupid smog pump - half the time there not working anyway - and i would question why some states require it to be there in the first place - there has been alot of research and discussion on smog pumps - they simply don't work as intended and by puuting an xtra load on your engine consumes more fuel - i got rid of mine -truck runs better , better fuel mileage , and passes emisions testing with lower emissions than when it was installed - if you reallywant to do it post back and i'll give the info with the easiest disconnect.

 

rrust name a state that did not have the smog pump in 1987.

 

rrust, your post makes no sense whatsoever. The only thing that removing the air pump and everything does is make the engine run WORSE, and create possible exhaust leaks. If the engine is pre computer controls you can usually get away with removing the smog equipment provided that there aren't any inspections in your area. With the newer computer controlled vehicles is that if you remove the system it confuses the computer causing the engine to run full rich all the time, hence the increase in performance, but a HUGE drop (4 to 5 mpg) in fuel economy. The smog pump requires ONE thats right ONE horsepower to pull efficiently.

 

like i said my fuel mileage is better - i should know

the engine runs much better - i should know

removing air from the cats cuases then engine to run richer why would the computer richen it again - lean it out maybe - yeah i know so

when you know how to do something properly you dont get possible exhaust leaks.

 

Hello! russt

I agree with you! I have an 86 f150 w/351w that runs great without, the thermactor system, and it passes state inspection every time! Now I have an 87 f350 4x2 w/460 eng and a 4180 holley stock carb, with the thermactor system installed. How do I go about cutting it out completely?? and what do I need to plug up, or cap off

Thanks

AL

 

first you will obviously need a shorter belt - i cant remember the exact size but some auto parts stores have a belt size listing for vehicles without the smog pump - other than that cut the steel lines at the cat and have them brazed over at welding shop 30 bucks- remove the pump and bracket if you wish - my pump had rubber lines coming out of it so i just removed everything as far back as was easy enough to work with -then stuff in a doweling preferably metal with one end capped and snug it up with a hose clamp - if you dont have emissions testing you can lose the cats too , the diverter valve at the back of the engine shouldn't give you any leakage - at least i've never experienced nor has anyone i know - although the " mechanic" that works out of our truck yard suggests it will - and if it ever does you can remove that and plug the lines the same way - it's a bit of leaning over the engine and working by feel to remove. your set up should be pretty close to mine ,so it's a real straight forward done deal. and i say have the tubes brazed over because just pinching them off may work for awhile ,but eventually corrosion will create a gap and then u will have a leak.

 

Hello russt,

Thanks for that info, I removed all the pluming, and pluged all opened lines, But I need to know! where would I connect the vacume hose from the intake manifold? This hose went to the canisters down below under the Battery holder. it has a real strong vacume, do I plug it or leave it open?


Thanks

AL

 

Oh! for got the " b " in plumbing...lol

 

according to my diagram you shouldn't have any vacumm lines to plug except the one that came from the bypass valve, did you maybe just knock a purge canister line off ?

either way you dont want to leave a vacumm line open