My Desmog Thread (6 Viewers)

[FJ40Jim]

i've read through this whole thread and i can't find the reason why the dizzy needs to be re-curved?

The stock dissy curve is set for use with EGR. EGR slows the speed of combustion, so the ignition point must happen earlier to allow time for the retarded mixture to burn. When the EGR is inoperative, the flame front moves faster, so the dissy needs recurved to slow down the advance.

 

[mookie]

ah, thank you Mr. Jim.....well i guess i'll leave the egr in place for now. got the smog pump devaned, cat removed and all associated hoses and b.s. removed....still have to pull the air rail and plug the manifold i guess......i have to say, it's pretty darned satisfying taking all that stuff off!

 

[jeffsclan]

So after reading this entire thread (again) I have a few questions. What purpose does the choke opener and choke breaker serve, being that we have a manual choke. What is the consensus on using the HAC system vs just running more timing? Anyone have some rough number of turns the idle mix screw needs to be at for ~5000 ft. Does the idle mix screw block fuel or air? Thanks everyone for your help. New 60 in the fam time to make run right.

 

[FJ40Jim]

What purpose does the choke opener and

The CO will completely open the choke after the engine warms up, in case an inatentive operator does not remember to push in the choke knob.

choke breaker serve

The CB will "break" (partially open) the completely closed choke valve as soon as the engine is running, to prevent drowning the engine.

What is the consensus on using the HAC system vs just running more timing?

The hac system automatically leans out the carb and advances the timing at hi altitude. It is possible to just advance the timing 7* instead of using the HAC. It is also possible to vent the HAC ports on the carb to lean out the mixture. But overall, it is easier let the HAC valve handle those functions automatically.

Anyone have some rough number of turns the idle mix screw needs to be at for ~5000 ft.

3.5

Does the idle mix screw block fuel or air?

Turning the screw in blocks fuel.

 

[Kief]

Choke breaker question: So upon examining my carb and comparing to other carbs I have, the check valve which is snapped into a bracket on the carb and is in between the choke breaker and its associated port prevents vacuum from pulling in the choke breaker diaphragm and if flipped around allows the vaccum to pull in the breaker and it doesn't release. I checked the orientation on three different carbs and it was in the same position, blocking vacuum from reaching the breaker. I'm puzzled as what I have found seems correct or consistently incorrect..

 

[jeffsclan]

Thanks Jim. I really am trying to learn before I ask.

 

[mookie]

this might be a little bit of ghetto fab but instead of having to source and buy brass plugs to fill in where the air rail went i just cut the OE fittings off even with the wrench flats at the top, welded the hole up and re-used them. they stick up about an inch but it's not bothering me any. i also went super redneck and used a peice of 2 1/4" flex hose to replace my catalytic converter with....

 

[FJ40Jim]

Choke breaker question: So upon examining my carb and comparing to other carbs I have, the check valve which is snapped into a bracket on the carb and is in between the choke breaker and its associated port prevents vacuum from pulling in the choke breaker diaphragm and if flipped around allows the vaccum to pull in the breaker and it doesn't release. I checked the orientation on three different carbs and it was in the same position, blocking vacuum from reaching the breaker. I'm puzzled as what I have found seems correct or consistently incorrect..

If by "Correct", you mean "just as the factory intended", then yes it is correct.

The check valve is supposed to delay the action of the CB. It allows vacuum to pass immediately in the release direction, but slowly applies vacuum over a couple minutes in the apply direction.

So if the check valve is switched around, the CB will act immediately upon startup, as all non-USA applications do.

Or the check valve could be deleted altogether.

HTH

 

[ElliottB]

Ok, so I'm officially mid-desmog and will need your guys' expertise!

What is involved with removing the EGR cooler completely?

There is a wire coming off of the EGR/PCV tube thingy (the one that comes out of the intake manifold). My connector broke on this and I'm not quite sure what it does. Any ideas?

If I were to block off this opening completely (presumably with the man-a-fre block plate), how does this affect my PCV in terms of driveability?

What is the emissions computer and where is it? Also what is the green wire mod and how does it play into all of this?

My last question is about an air filter. Is it possible to run an open filter (without the huge assembly on top of the valve cover) on a stock carb? I know there are many vaccuum lines that run to it but I assume I could plug them somewhere else.

Thanks for all the help guys!

 

[GLTHFJ60]

What is involved with removing the EGR cooler completely?

There is a wire coming off of the EGR/PCV tube thingy (the one that comes out of the intake manifold). My connector broke on this and I'm not quite sure what it does. Any ideas?

If I were to block off this opening completely (presumably with the man-a-fre block plate), how does this affect my PCV in terms of driveability?

Removing the EGR cooler entirely only involves removing the two bolts that hold it on and taking it off. One tube goes to the bottom of the exhaust manifold near the firewall, and the other goes to the EGR valve, which I'm sure you've removed already.

The wire you're talking about is the carb fan sensor wire. Take that wire and ground it to something, and your carb fan will run for 30 minutes after shutdown no matter what. Arguably easier than finding another place to mount the sensor after removing that bracket.

Your PCV system needs either a filter on top of the crank case vent ( without PCV valve ) or the valve needs vacuum. Without one of these two things, you will get excessive crank case pressure and more oil burning + backfiring will occur.

 

[ElliottB]

So I will remove the EGR cooler completely. How do I plug the hole in the back of the exhaust manifold (where the EGR cooler pipe goes)?

I will just ground that broken connector wire. Having the carb fan run after shutdown is no biggie.

I will figure out the PCV issues. I may just put a filter on it for the short term as I know this is not ideal.

Anyone got suggestions for the other things? Thanks!

 

[Trapper50cal]

Buy the gasket for it ( I think Remflex has the best one ) and a plate ( or make the plate to match ) and bolt 'er up.

 

[GLTHFJ60]

Yup, gasket and a plate will fix it up. Put a filter on the PCV line and it'll be good.

 

[ElliottB]

Yup, gasket and a plate will fix it up. Put a filter on the PCV line and it'll be good.

The PCV line on the passenger side right?

(Would have to be assuming I block off the entire EGR/PCV assembly)

 

[GLTHFJ60]

The PCV line on the passenger side right?

(Would have to be assuming I block off the entire EGR/PCV assembly)

Yes. Block off the EGR / PCV tube with a block off plate, like Trapper said, and on the other side of the engine near the firewall is where the PCV line comes out of the crank case. Take the silver PCV valve off and put a filter in it's place, then you're golden.

 

[FJ40Jim]

PCV is a good thing. Keep the PCV connected to the PCV fitting on the intake manifold, if possible. Cut the EGR pipe off the manifold side plate and plug it w/ weld or a rubber expansion plug.

Removing the PCV valve and vacuum source will leave junk in the crankcase which can cause acid/moisture to build up inside the crankcase.

 

[GLTHFJ60]

PCV is a good thing. Keep the PCV connected to the PCV fitting on the intake manifold, if possible. Cut the EGR pipe off the manifold side plate and plug it w/ weld or a rubber expansion plug.

Removing the PCV valve and vacuum source will leave junk in the crankcase which can cause acid/moisture to build up inside the crankcase.

I thought having a vent was good enough, no?

Guess I'll be keeping that system. I have been running mine as Jim described since I did my desmog, but I thought it didn't make much of a difference. I was wrong!

 

[FJ40Jim]

A 2F will run long time, even if things are not optimal.
Might run 250K w/ good PCV and air filter. Might run 150K w/ no PCV and open element filter.
150K is still a long time to sit in the driver's seat of a Cruiser.

 

[ElliottB]

.
150K is still a long time to sit in the driver's seat of a Cruiser.

Especially considering that this truck will see about 1000 miles a year and oil changes every 6 months.

Thanks for your input Jim. (Can't wait to get my carb and dizzy back from you!)

 

[micnicholasj]

first off, this has helped a ton and thanks to all you learned folks.
okay, my 86/60 smog pump siezed up. deveined it and now it squeels like my neighbor and his pig late at night once the rpms get up there. now I carry a gun for the misery long trips bring on but can't afford the ammo. frikken loud, louder than my woman even. anyways, read 13 pages of desmog and didn't see what you do when you removed the smog pump? rumor has it it's still good to have the water pump turn.
somebody mentioned jim may sell an idler pulley to replace it, is that true? does he have more? where please?
saw elsewhere that you can get an alternator with a double pulley and run the water pump off of that. anyone had luck with that. can you buy just the double pulley and put on your good alternator?