Removing emissions controls - '84 302

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BigIrish

Well-known member
Joined
Feb 1, 2009
Messages
1,382
Location
Houston, TX
I'm trying to figure out how to get all the damn vacuum lines & crap off of my '84 302 donor engine (from F150) and still have it run well. Bought a Chiltons manual, but its not clear what effect removing & capping all these will have (just tells you how to repair). My main question is on the carb fuel bowl vent that vents bowl vapors to the charcoal canister. If I cap this off at the carb will this cause any problems? Not sure if this is needed to relieve pressure inside the carb.

What about EGR valve? Can this be removed from the carb spacer and capped? Don't quite understand how exhaust gas somehow comes through the intake manifold, through the carb spacer & EGR valve. Where does this exhaust come from - is this blow-by or actual exhaust from the cylinders?? If I had been selling vacuum lines in the 80s i'd be rich!

Thanks!
 
The float bowl needs to be vented but you vent it into your air cleaner or just leave it open. Better to replace the spacer with an aftermarket one but the EGR valve can be eliminated without effect. You will have to plug the crossover at the back of the heads. If you remove the tube the heads are threaded and you can just put a bolt in there to plug that off. If you want a little more power and the heads are off the engine you can grind out the thermactor ports that block off half the exhaust port and let the engine breath a bit better. The only lines from the carb and manifold on my 302 are to the brake booster and the distributor. I removed the canister entirely and plugged any other vacuum ports under the hood. Seems to me there was a line that went back to the gas tank from the canister that had to be plugged off as well. My engine came from an 89 Grand Marquis and went into an 81 Granada and I'm using a 650 Holley double pumper carb instead of the one that Ford used in 84 (had one and threw it away .. you can't adjust them). I'm using an HO cam with the 351 firing order and timing set at 15 degrees at idle. Engine runs great.
 
Awesome, very helpful. I'm thinking I can just disconnect the vac line to the EGR, so it will remain closed, but correct me if I'm wrong. The engine is currently in the truck and running well, so trying to clean it up without taking it all apart.

You mentioned the Thermactor. I guess this system injects air into the exhaust ports through the heads, or is it through the exhaust manifolds? Its hard to see how this works b/c its at the back of the engine. If I disconnect that do I also need to block off the air supply tubes - will exhaust come back out of these if not blocked off?

Thanks for the help....
 
Remove?

Irish,
I'm sure you didn't want to really remove your pollution controls but were just wondering how that would be done if someone were so inclined... correct?!

BoB
 
I want to get all the emissions stuff off while its still in the truck, so I can verify it still runs. Then I'll transplant it to the Model A. They didn't have Thermactors and carbon canisters required in '29 did they?:cool:
 
"I want to get all the emissions stuff off while its still in the truck, so I can verify it still runs"

It will run fine .. better actually .. without all the emission stuff. Don't even worry about it. You may have to make some carb adjustments however.

"If I disconnect that do I also need to block off the air supply tubes - will exhaust come back out of these if not blocked off?"

Yes, you will have a major exhaust leak if you don't block these off. If you remove the air supply tubes from the back of the heads (real awkward if its still in the truck) you will find that the heads are threaded and can easily be plugged.

"I'm thinking I can just disconnect the vac line to the EGR, so it will remain closed"

Yes, but make sure you plug the lines. I would just remove the EGR spacer and replace with an aftermarket carb spacer.
 
Well I got all the emissions crap off and strangely enough the truck runs better! ;) Anyone interested in 40 feet of used vacuum line?
 
emissions

i have the same engine, where the gas tubes on the backs of the heads are, there is a threaded hole and a larger one. will the bolt in the threaded hole seal off the larger one. new to fords.

john
 
It's amazing how much better an engine will run without all that crap. I drive an '85 Toyota P.U. and it finally got to the age of no more emissions testing. I gutted the cat converter, unhooked the distributor retard, and went to town on all the rest of the vac hoses. It runs better and picked up 3 mpg. It's been 300,000 miles and is free to run now. :D
 

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