Desmog 3FE? (1 Viewer)

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landtoy80

landtoy80

Joined
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North Front Range, CO
I did a search and don't see anything about desmogging the 3FE other than "don't do it"

I desmogged the 60 and it ran 110% better but the exhaust stunk. So I ordered the 2 1/2" free flow cat from Downey and it made the exhaust smell sweet. More-better.

As I don't live in the smogged filled city I see no reason to have smog crap on.
Some research says that the cat causes a chemical reaction with the exhaust which increasses global warming gas BUT it does help on with big city smog reductions.
So you be the judge, kill everyone in the city and kill the earth OR visversa?

Now with that out of the way, what is done to desmoge the 3FE?
What are the pro's and con's?
 
if I was gonna do it I would take all the FI stuff off and do a 3F intake/exhaust and a Aisin carb............basicaly the motor the rest of the world got.
 
Pretty much every aspect of the automobile and it's supporting industry contribute to some aspect of environmental distruction/damage. But leaving the emmissions stuff on your vehicle will help a bit. And a 3fe with all of it's emmisions controls in place and working well runs very good.
 
What do you mean by better? If you like carb'd engines then yes. The 3F carb is big, and IIRC actually simpler in design than the 2F's. There are little if any emissions equipment on these. No catalytics, no air pump and rail, no EGR, and obviously no computer.

You can actually place a 2F's exhaust and intake manifold on the 3F-E head (with some slight work) and put 2F stuff on it. The only thing I'd think about yanking of the 3F-E setup however is the air pump. The EGR removal may be considered but might throw an engine code.
 
it was the replacement for the 2F in most markets, it came out in 84 I think.
better........I dunno, simpler yes. Its basicly like a de-smoged 2F. The guts of the 3F and 3fe are the same, its just the stuff bolted to it thats different.

Sporin said:
Pure curiosity, was the carbed, 3F that other markets got a "better" engine in any way then the EFI 3FE we got in the US?
Click to expand...
 
landtoy80 said:
Now with that out of the way, what is done to desmoge the 3FE?
What are the pro's and con's?
Click to expand...

Basic desmog for 3FE is remove/plug EGR and AIR system. Keep the evap & PCV, they're good things.

Pro's:
Slight increase in crankshaft horsepower due to reduced parasitic loss (AIR removal).
Slight increase in combustion efficiency due to increased cylinder pressure (EGR removal)
Slight increase in fuel economy and reduced fouling of T-body.

Con's:
It's illegal anywhere in the USA.
Slight increase in NOx under moderate to heavy loads.
The cat(s) should scrub out the increase in HC's from the lack of AIR, but at some loss of service life.
 
FJ40Jim said:
Basic desmog for 3FE is remove/plug EGR and AIR system. Keep the evap & PCV, they're good things.

Pro's:
Slight increase in crankshaft horsepower due to reduced parasitic loss (AIR removal).
Slight increase in combustion efficiency due to increased cylinder pressure (EGR removal)
Slight increase in fuel economy and reduced fouling of T-body.

Con's:
It's illegal anywhere in the USA.
Slight increase in NOx under moderate to heavy loads.
The cat(s) should scrub out the increase in HC's from the lack of AIR, but at some loss of service life.
Click to expand...

If you've eliminated the cats, that's one con you can eliminate; but to be perfectly honest, either way, I'd argue that your gas mileage will slightly decrese if you end up removing the EGR system as well. I'm still trying to get a good average of how much my gas mileage has dropped. Also, I have yet to remove the EGR hardware from my 3FE, but it is disabled, and the rest of the engine is completely desmogged. This includes having the cats replaced with straight pipes. Everything I've done is reversible too, which will come in handy in case it's ever registered off of a military base again.
I'm not sure of the exact differences between an FJ62 and an FJ80, but desmogging my 62 was (for the most part) a fairly simple task. I've noticed a big performance increase when at WOT, most noticable on uphill freeway onramps. I'm hoping that once I get my aftermarket ignition installed my mileage will go back up and give me even more of a performance increase.

Another benefit of desmogging a 3FE I should mention too is MUCH more real estate under the hood. I've freed up space for dual batteries, the isolator, and my ignition :D
 
The 3F and 3FE are the same basic motor but the heads are different. The valve train is the same and in/ex manifolds are different. I bought a "test" 3F head from SOR for $79 shipped and a in/ex to match the head for $120 shipped. Really cheap! Nardik in OZ sells a new 3F carb for either a H55F or A440F for around$350 USD.

I guess you could de smog the 3fe but I doubt you will gain much except room.

The 3F series weigh less, have higher compression and a shorter stroke. The power band is at a higher RPM than a 2F. I think it is the best of all the F series motors.
 
Spook50 said:
If you've eliminated the cats, that's one con you can eliminate; but to be perfectly honest, either way, I'd argue that your gas mileage will slightly decrese if you end up removing the EGR system as well.
Click to expand...
Feel free to argue. The fact remains that the purpose of EGR is to reduce combustion chamber temp and pressure, thereby reducing BMEP. Lower BMEP equates with higher BSFC.

Glossary:
BMEP- Brake mean effective pressure, a measure of the force of combustion on the piston averaged over the cycle.
BSFC- Brake specific fuel consumption, the measure of power produced divided by fuel consumed.
 
Is not the increase in gas used from you having more power and using that power?

Its like going from my 60 to the 80. If I drove the 80 like I did the 60 (the 60 needed it floored all the time) I think my mpg in the 80 would be less than 11mpg I get now.
Its the "power trip". If you increase power, you will use that power.
If you drive like -B-, you mpg will go up :D
 
desmog and climate change

Well I've looked into it and as far as I can tell the argument that
catalytic converters worsen global warming is BS. Converters
convert NOx to N2 and O2, and hydrocarbons and CO to CO2 and H20.
The global warming argument is that converting CO to CO2 adds
net CO2 to the atmosphere and therefore worsens global warming.
However it turns out that CO turns into CO2 by itself - the life of CO
in the atmosphere is ~ 1 month. So the catalytic converter just
does it immediately, and thereby avoids having CO hanging around
where people might breathe it.

If you care.
 
So what I need to do to desmog my "off road use only" is get the belt "22528 (Dayco) V Belt size for running without the smog pump" (from 3fe board).
I don't have to do anything else to the AIR system other that not having the belt on it anymore?

EGR system: Just plug the exhaust port so it won't recycle exhaust, right?

Will I get the check engine light from doing this?

Do I have to change the timing?
What can/should I set the timing at?

I will leave the cats on as I don't like the smell of the exhaust with out them.

Is there anything else???
 
FJ40Jim said:
Feel free to argue. The fact remains that the purpose of EGR is to reduce combustion chamber temp and pressure, thereby reducing BMEP. Lower BMEP equates with higher BSFC.

Glossary:
BMEP- Brake mean effective pressure, a measure of the force of combustion on the piston averaged over the cycle.
BSFC- Brake specific fuel consumption, the measure of power produced divided by fuel consumed.
Click to expand...

Well, it turns out you are indeed correct. I figured my mileage for my last couple full tanks and although it hasn't increased, it hasn't decreased either, like I expected it to. I'm hoping it'll increase now that I've got the Mallory working though :flipoff2:
 
landtoy80 said:
So what I need to do to desmog my "off road use only" is get the belt "22528 (Dayco) V Belt size for running without the smog pump" (from 3fe board).
I don't have to do anything else to the AIR system other that not having the belt on it anymore?

EGR system: Just plug the exhaust port so it won't recycle exhaust, right?

Will I get the check engine light from doing this?

Do I have to change the timing?
What can/should I set the timing at?

I will leave the cats on as I don't like the smell of the exhaust with out them.

Is there anything else???
Click to expand...

You can go ahead and remove the cats if the smell's all that you're concerned about. There IS more of an exhaust odor, but only if you're standing right there at the tailpipe with the engine running.
For the engine desmog, you've got the right idea. There was a LOT of stuff I removed though, and once I finish up with the EGR hardware, I'll take some time to do up a good tutorial (hopefully with some pics too). No need to adjust the timing at all. I kept mine right at the factory setting. Also, no check engine light so far. It'll idle high for a little bit when you first eliminate the air injection system, and any time you have the battery disconnected for extended periods afterward; but it never lasts more than two or three half-hour drives on mine.
Back to the EGR, I'm trying to find a plug for the connection on my exhaust manifold and get a block-off plate made to put on my intake manifold. Looks like it may prove tricky, but I don't see any real problems arising.

Props on posting the part # for that belt, too. I had no idea there was one that was just the right size. Gonna go out and get me one right now :D
 
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