3F-E Desmog guide is up (1 Viewer)

[FJ40Jim]

Wouldn't it be likely that a properly functioning EGR system wouldn't negatively affect power though? My thinking is that if the system is working the way it should and not hurting power, it'll allow you to advance your timing to the optimal setting without causing the engine to ping, which in turn would help with power.

The downside I see to having the EGR though, is the source of carbon buildup, and it took me a long time to get rid of as much carbon as I could after desmogging.

The EGR dilutes the charge. Diluting the charge lowers speed and pressure of combustion. To compensate for the retarded burn rate, the ignition timing will need to be advanced to achieve optimal power. Regardless of the ignition timing setting, the engine that is running at an effectively lower CR is less efficient.

For any combination of RPM & cylinder pressure there is an optimal spark timing. Generally an engine that has a less advanced ignition timing requirement (faster burn rate) is more efficient. Conversely, an engine that requires more timing advance (lazy combustion) is less efficient.

 

[Spook50]

The EGR dilutes the charge. Diluting the charge lowers speed and pressure of combustion. To compensate for the retarded burn rate, the ignition timing will need to be advanced to achieve optimal power. Regardless of the ignition timing setting, the engine that is running at an effectively lower CR is less efficient.

For any combination of RPM & cylinder pressure there is an optimal spark timing. Generally an engine that has a less advanced ignition timing requirement (faster burn rate) is more efficient. Conversely, an engine that requires more timing advance (lazy combustion) is less efficient.

Very interesting. I just found all my old (seemingly still working) EGR stuff, so I'll experiment around with it and see what differences their are, whether bad or good.

I'm sure you're right, but there's something to be said for finding out through your own experience

That said, I still wanna find out how much that work that Randy did costs....

 

[overhanger]

So I should be "happy" that my 3FE, with carbon free intake, valves, cylinders, new O2 sensors, yada yada, with 7*BTDC timing pings with ethanol laced 91 octane when ambient temps reach above 80*F? The snorkel lowers intake charge temps but the motor just likes ethanol free 93 octane which we can't get in CO. I've lessened timing to as little as 4* but there is a noticeble seat of the pants power reduction when retarding timing. Adding five or six gallons of 105 octane ethanol free unleaded makes the truck really happy but at the price of $9.99 a gallon my wallet begins to frown.
Thanks Jim for your thoughts on this topic. There are opinions and then there are facts from folks such as your self.

The EGR dilutes the charge. Diluting the charge lowers speed and pressure of combustion. To compensate for the retarded burn rate, the ignition timing will need to be advanced to achieve optimal power. Regardless of the ignition timing setting, the engine that is running at an effectively lower CR is less efficient.

For any combination of RPM & cylinder pressure there is an optimal spark timing. Generally an engine that has a less advanced ignition timing requirement (faster burn rate) is more efficient. Conversely, an engine that requires more timing advance (lazy combustion) is less efficient.

 

[Spook50]

So I should be "happy" that my 3FE, with carbon free intake, valves, cylinders, new O2 sensors, yada yada, with 7*BTDC timing pings with ethanol laced 91 octane when ambient temps reach above 80*F? The snorkel lowers intake charge temps but the motor just likes ethanol free 93 octane which we can't get in CO. I've lessened timing to as little as 4* but there is a noticeble seat of the pants power reduction when retarding timing. Adding five or six gallons of 105 octane ethanol free unleaded makes the truck really happy but at the price of $9.99 a gallon my wallet begins to frown.
Thanks Jim for your thoughts on this topic. There are opinions and then there are facts from folks such as your self.

How much higher than stock is your compression though?

 

[FJ40Jim]

So I should be "happy" that my 3FE, with carbon free intake, valves, cylinders, new O2 sensors, yada yada, with 7*BTDC timing pings with ethanol laced 91 octane when ambient temps reach above 80*F?

No, pinging is inefficient.

It's either pinging because the octane is insufficient for the engine requirements (detonation),
or it is pinging because the spark is too early (spark knock).

The snorkel lowers intake charge temps but the motor just likes ethanol free 93 octane which we can't get in CO. I've lessened timing to as little as 4* but there is a noticeble seat of the pants power reduction when retarding timing. Adding five or six gallons of 105 octane ethanol free unleaded makes the truck really happy but at the price of $9.99 a gallon my wallet begins to frown.
Thanks Jim for your thoughts on this topic. There are opinions and then there are facts from folks such as your self.

If you are saying that raising the octane rating of the fuel makes the pinging stop, then the CR is too high.

If retarding the timing a few degrees makes the pinging stop, then the spark is happening too early. If retarding the timing far enough to stop pinging results in noticeable power loss, then the CR is too high for the fuel octane.

The timing/CR/octane is correct when the engine doesn't detonate under load, and when advancing the timing makes no improvement in power. IOW, it's good if timing of 38* makes max power, and 40* makes rattling. It's bad if max power happens at 40* and it rattles at 36*.

 

[Spook50]

No, pinging is inefficient.

It's either pinging because the octane is insufficient for the engine requirements (detonation),
or it is pinging because the spark is too early (spark knock).



If you are saying that raising the octane rating of the fuel makes the pinging stop, then the CR is too high.

If retarding the timing a few degrees makes the pinging stop, then the spark is happening too early. If retarding the timing far enough to stop pinging results in noticeable power loss, then the CR is too high for the fuel octane.

The timing/CR/octane is correct when the engine doesn't detonate under load, and when advancing the timing makes no improvement in power. IOW, it's good if timing of 38* makes max power, and 40* makes rattling. It's bad if max power happens at 40* and it rattles at 36*.

So would you figure that an initial 13BTDC on a desmogged 3FE without EGR should be good with 87 octane fuel? I haven't checked my actual timing numbers, but I wasn't able to advance my timing much at all from stock before I got pinging. I know there's a ton of carbon and gunk in my intake and likely my combustion chambers too, so I'm going to clean that out as best I can and try again, if that's part of what's causing the problem (can't imagine it's doing me any good).

Though I am still temped to reinstall my EGR system and experiment around and see where that lands me, just for the sake of curiosity.

 

[overhanger]

To answer Spook's question, Robbie Antonson, the rebuilder of this engine, calculated the CR at 9.2 or 9.3, I can't remember which. Rebuild was about 60K miles ago and included 1.5mm over stock OEM pistons and shaving the head 1.5mm also. At the time, ethanol was a seasonal thing here in Colorado and in the summer, 91 octane ethanol free gas was the norm but it is ethanol laced year 'round now. No one sells 93 octane so when the going gets hot, about five gallons of 100 octane per tank brings octane up to about 93 the way I calculate it and pinging pretty much disappears and the engine performance improves according to seat of the pants impressions. Again, this is with stock 7*BTDC base timing. According to the advanceable timing light, 40* is where advance quits. Guess I need to move to Houston or somewhere else where 93 octane ethanol free gas is sold. Winter time driving yields no pinging, this is pretty much a summertime problem.

 

[overhanger]

Here's my throw up, Pirate Dave! You can see the "mod" I had to do on the drain plug on the bottom of the can - an alligator clip preventing the drain plunger from being sucked up by the vacuum created by the PCV system. You can also see that I hadn't gotten things tight enough and some sludge leaked on the valve cover when the pictures were taken. I had to change the original spring from the inside of the can to the outside and then swapped in a heavier spring and then had to add the alligator clip to keep the seal tight. The separator is designed to be pressurized and with vacuum running through it, you have to reverse the seal deal. Leakproof now. The location works well other than rubbing on the hood when it's closed. A little grinding on the top of the separator will fix that. I also added some scouring pad material that we got with some titanium pots and pans and it seems to help give the sludge something to cling to and not be sucked back into the PCV stream. The Craftsman was cheaper than the ones from Home Depot and Lowe's and included a mounting bracket which the others didn't. I really like the HMS but for about 80% less money, the Craftsman does the job.

Steve,

Throw up a pic of the setup on Bart! With my intake now nicely cleaned I want to install one tomorrow!

Dunbar

 

[matt.mcinnes]

My PCV valve breaths to a catch can and all I have left of my 3FE vacuum lines is this loop. The Blue silicon hose runs to the turbo waste gate.

The EGR is all gone. This 3FE was out of an early 80 series and is now part of my 2F-ETI

 

[PabloCruise]

Here's my throw up, Pirate Dave! You can see the "mod" I had to do on the drain plug on the bottom of the can - an alligator clip preventing the drain plunger from being sucked up by the vacuum created by the PCV system. You can also see that I hadn't gotten things tight enough and some sludge leaked on the valve cover when the pictures were taken. I had to change the original spring from the inside of the can to the outside and then swapped in a heavier spring and then had to add the alligator clip to keep the seal tight. The separator is designed to be pressurized and with vacuum running through it, you have to reverse the seal deal. Leakproof now. The location works well other than rubbing on the hood when it's closed. A little grinding on the top of the separator will fix that. I also added some scouring pad material that we got with some titanium pots and pans and it seems to help give the sludge something to cling to and not be sucked back into the PCV stream. The Craftsman was cheaper than the ones from Home Depot and Lowe's and included a mounting bracket which the others didn't. I really like the HMS but for about 80% less money, the Craftsman does the job.

Thanks Steve!

 

[FJ40Jim]

So would you figure that an initial 13BTDC on a desmogged 3FE without EGR should be good with 87 octane fuel? I haven't checked my actual timing numbers, but I wasn't able to advance my timing much at all from stock before I got pinging. I know there's a ton of carbon and gunk in my intake and likely my combustion chambers too, so I'm going to clean that out as best I can and try again, if that's part of what's causing the problem (can't imagine it's doing me any good).

Dunno about the initial timing. what counts is the timing at peak torque. Peak torque corresponds w/ highest cylinder pressure and likelihood of detonation. Set the timing to give highest torque. If engine rattles, then raise octane or lower DCR.

 

[me_tu05]

I just desmogged my 62 and wanted a belt to go around the alternator so that I had 2 belts on the alt. I found that this belt is a perfect fit if this is desired. I also had to route a vaccum line to the FPR because the VSV no longer supplied a vaccum to it.
NAPA 25-22570 is the belt.

 

[Dunbar]

Where is the writeup?

Dan -

When I click on the link to the writeup I get taken IH8MUD - Home instead of the writeup. This is from the link in your original post in this thread.

I also get the same going from a link you put in a different thread in the FAQ on de-smogging.

I am logged in to MUD but alas no, I have not re-booted;p

 

[PabloCruise]

I just desmogged my 62 and wanted a belt to go around the alternator so that I had 2 belts on the alt. I found that this belt is a perfect fit if this is desired. I also had to route a vaccum line to the FPR because the VSV no longer supplied a vaccum to it.
NAPA 25-22570 is the belt.

Doesn't the VSV modulate vacuum to the FPR? Where are you pulling vacuum from now? Is it modulated?

 

[Spook50]

Dan -

When I click on the link to the writeup I get taken IH8MUD - Home instead of the writeup. This is from the link in your original post in this thread.

I also get the same going from a link you put in a different thread in the FAQ on de-smogging.

I am logged in to MUD but alas no, I have not re-booted;p

Woody had reorganized the tech section a while back and the PDF file got moved is what it looks like. The link is fixed now.

 

[me_tu05]

Doesn't the VSV modulate vacuum to the FPR? Where are you pulling vacuum from now? Is it modulated?

I just pulled vacuum from one of the metal tubes that used to connect to the VSV. The only problem I have just found is that it doesn't like to start cold. My friend told me to make sure that there was vacuum to the FPR or it will be a gas hog, so thats what I did. Just have to figure out the cold start thing and the codes that popped, good thing I just shipped off my FSM. Anyone know what code 71 or 72 is?

 

[PabloCruise]

Anyone know what code 71 or 72 is?

My manual for 1988 3FE goes up to code 51. Are you sure you are getting 71 and 72?

 

[me_tu05]

I will check again but I'm sure thats what poped. Unless seven flashes means something else. I still have to delete my cats so that may be causing a problem.

 

[PabloCruise]

Here's my throw up, Pirate Dave! You can see the "mod" I had to do on the drain plug on the bottom of the can - an alligator clip preventing the drain plunger from being sucked up by the vacuum created by the PCV system. You can also see that I hadn't gotten things tight enough and some sludge leaked on the valve cover when the pictures were taken. I had to change the original spring from the inside of the can to the outside and then swapped in a heavier spring and then had to add the alligator clip to keep the seal tight. The separator is designed to be pressurized and with vacuum running through it, you have to reverse the seal deal. Leakproof now. The location works well other than rubbing on the hood when it's closed. A little grinding on the top of the separator will fix that. I also added some scouring pad material that we got with some titanium pots and pans and it seems to help give the sludge something to cling to and not be sucked back into the PCV stream. The Craftsman was cheaper than the ones from Home Depot and Lowe's and included a mounting bracket which the others didn't. I really like the HMS but for about 80% less money, the Craftsman does the job.

Was revisiting this as I want to revise my PCV setup on the mighty 3FE.

I also found this fancy catch can design: Accurate Machine Works

 

[Spook50]

Five years later, I finally got around to fine-tuning the desmog I did on my 3FE, and have eliminated about 80% of the vacuum lines and connections. The vacuum manifold (that mounts to the underside of the intake) is now completely unused, save for two of its hard lines (the larger one for the fuel evaporation system, and the one that connects to the fuel pressure regulator). I'm leaving the regulator control intact in hopes that it'll result in less fuel wasted when at low engine speeds, and I'm also leaving the fuel vapor/evap system intact since that helps with pollution control without any cost to mileage or engine performance.

More to follow as I finalize it, but it does look like this will help eliminate alot of possible sources for vacuum leaks by eliminating about half a dozen caps needed. And hopefully by reconnecting the control for the fuel pressure regulator (going to try just manifold vacuum first, and then get a control VSV from a junkyard and wire that up again and see if there's any difference having that controlled by the computer like it originally was), that'll help retain proper fuel economy.

Also, for the sake of using my homebrew PCV catch can, the PCV system is staying intact as well.