Distributor in a 3FE - Hypothetic

[jcarter]

Picture this (hypothetically speaking):

ON A 1992 LAND CRUISER WITH THE 3FE, YES 3FE ENGINE!

You pull out the distributor and turn it over a few times with the starter. When you reinstall the distributor, you do NOT follow the FSM! Also, you modify the distributor so you can turn it 360 degrees (with bolt out of course, but holding it down by hand).

You crank it with the starter while turning the distributor until it starts. Then stop the engine, pull #1 plug, check pressure (blows out with rotor pointing toward back left) so you know your near TDC (not out 180 degrees). Start it back up, warm it up, short the diagnostic, and time it per FSM (on the 7 BTDC mark).

Question: Does it matter?

In other words:
The axle of the distributor has a gear tied to a gear on the cam, cam is tied to the gear on the crank, crank is tied to the flywheel with timing marks. All of this is geared together so "dumb", RIGHT? Every 2 revolutions by the crank the cam revolves 1 time & hits TDC once. Does it matter the position of the distributor as long as you turn it to where it "thinks" it's at TDC at the right time?

The axle of the distributor talks to the ECU via pick-ups in the distributor. This is the "smart" part which sends spark at the right time to the plugs/combustion chamber/cylinders.

I think that it doesn't care if the distributor is in the correct location with bolt in like normal, or if the "adjustment gap" is 40 degrees off and held down by hand. Am I thinking right?

Please help me resolve an argument between myself and a buddy at work (both shade-tree mechanics).
Thanks,
Joe

 

[turbo5s]

If you haven't touched anything inside (cam/crank timing components) I don't think the distributor should be in a different position. As you said, the distributor makes one revolution per 2 engine revolutions, so if your cam was off 1 crank revolution, you could turn the diz 180 degree.

I think...

one shadetree to another

 

[jcarter]

Another way to put it

FSM shows this

And says at TDC, this is the position the rotor should be in. Let's assume this is TDC and not 180 degrees to take that issue out of the equation.

Here's my point and arguable:
As long as when TDC occurs and the rotor is pointing near that bolt hole (for the distributor cover) as shown in the FSM, EVERYTHING IS GOOD!

OR

Per the FSM the bolt hole is pointed toward the driver's seat. Say you set it at TDC, but put in the distributor WRONG and the rotor points toward the right wheel. As long as you rotate the bolt hole (distributor sides, NOT THE GEAR AXLE) such that the rotor points at the hole as shown in the FSM, all is well.

We've got bragging rights on this. Am I right?

 

[blkprj80]

I've been following this for quite some time now, wondering why you're a half tooth off on the distributor.

If I were you, I'd suspect the timing chain was off one tooth.

The timing chain has two odd color links, 180 degrees apart. If you set your timing mark on your front pulley at 0 degrees, the link at the camshaft should align with a mark on the bigger camshaft sprocket (or, the mark might be on the 180 away side). Either way, the odd color link should always be on the mark, or exactly 180 degrees away from the mark on the sprocket. Would it be very difficult to verify this?

Sure, you can time it for spark, but your camshaft may not be timed correctly (to the crank). It will run, but probably not optimally. You can still get it in electrical time by adjusting the distributor, but yours doesn't seem to want to land in between where you want it.

How many teeth are on the cam sprocket? How many teeth are on the distributor driving gear? One tooth on the cam sprocket might be half a tooth on the distributor drive gear?

Make sense?

Oh, and if it is off by one tooth, just jump it one tooth at the top. Nobody will know except you (and everyone else on 'Mud!).

 

[Pin_Head]

We've got bragging rights on this. Am I right?

You can't go wrong with doing it the way the FSM says. You have your distributor in off a tooth. I read your explanation of how that can't be, but I'm not buying it.

If you put your new distributor in wrong, you will have the same problem and if you put it in correctly, you will think that that solved your problem.

In the final analysis, the only thing that matters is if you can time it properly. I'm not familiar enough with this engine to know whether there is another crank or cam position sensor that determines the timing for the ECU or whether the pickup coils in the distributor are the only timing signals. If it is the latter, the timing is only set manually, so you have to rotate the distributor to set the timing mark with a timing light.

 

[jonheld]

As discussed in another thread that shall remain nameless, if everything else remains constant, it is only possible to have the engine fire within a narrow rotational window of the distributor. As you go further away from that window, the engine will misfire as the spark is being delivered at the wrong time to each cylinder. Eventually the motor will not run.

So to answer your question, when you find the spot where the motor fires, you're within the narrow window of correct timing. To get the timing factory correct, you need to follow the FSM as has been repeated about a thousand times.

Now the ECU will automatically adjust timing within that window for different conditions. However it can't operate beyond it's programming. I have no idea what the 3FE's ECU timing window limit might be.

The 3FE has timing gears, not a timing chain.

 

[jonheld]

I agree with Pinhead. He's a pretty smart dude and you should really pay attention to what he says.

You're either off a tooth or you're trying to adjust timing while the ECU is making constant corrections because you haven't shorted the correct pins on the check connector to disable this.

There is NOTHING ELSE that talks to the ECU regarding ignition timing on a 3FE. The ECU is getting ALL its timing information from the pick up coils in the distributor. There is no crank position sensor in a 3FE. It's a freaking tractor motor with fuel injection.

You need to follow the FSM. I believe that makes 1001 times now.

 

[blkprj80]

The 3FE has timing gears, not a timing chain.

My bad.
Thanks for the info.

 

[turbo5s]

So let's say you replace the pickups in the dizzy with an external sensor, and that would work, then I would say the 'window' you have depends on how wide the rotor tip is and how large the terminal on your distributor cap is. The spark still has to make that jump. That what you're talking about?

 

[Pin_Head]

So let's say you replace the pickups in the dizzy with an external sensor, and that would work, then I would say the 'window' you have depends on how wide the rotor tip is and how large the terminal on your distributor cap is. The spark still has to make that jump. That what you're talking about?

I don't think so, but Jon can speak for himself because he knows about these engines and I don't. Any spark fired engine can only run in a narrow timing range that changes with RPM and load. This range is about +/- 15 degrees from the optimum, so it is about 30 degrees total. The spark plugs on a 6 are 60 degrees apart, so this running range is about half of the distance between the cap wires.

The width of the rotor tip has to be wide enough to accomodate the range of advance.

 

[SiRaDuDe]

I still dont get WHY is it so hard for you to turn the CRANKSHAFT via a Wrench until you allign the TDC mark on the FLYWHEEL first!

I know that the little window is hard to see, but get yourself an extra set of eyes, friend... or wifey

Once you are in TDC via CRANKSHAFT everything should just slip right in... (ofcourse unless your DIST if out of wack as you think, but this is usually never the case)

Once your Flywheel TDC is on mark, at the same time your CAM & CRANK MARKS should also be at MARK (pointing towards each other) and DIST should just drop in with its own MARK pointing UP (notch on DIST shaft)... 1,2,3 boom... you are done..

I will repeat myself

Once your Flywheel TDC is on mark, at the same time your CAM & CRANK MARKS should also be at MARK (pointing towards each other) and DIST should just drop in with its own MARK pointing UP (notch on DIST shaft)... 1,2,3 boom... you are done..

Once your Flywheel TDC is on mark, at the same time your CAM & CRANK MARKS should also be at MARK (pointing towards each other) and DIST should just drop in with its own MARK pointing UP (notch on DIST shaft)... 1,2,3 boom... you are done..

 

[jcarter]

Caught me! I need a pen name. . .

Hypothetical or technically speaking: I was discussing this with a guy at work, REALLY. The whole point of this was to get an opinion. I think after Jonheld said the ONLY pick-ups are in the distributor, that makes me right! Thanks!

1/2 tooth: With all due respect (Pinhead found my fuel issue, Jonheld has explained the entire ignition system to me, and I'm VERY APPRECIATIVE), I've put that distributor in many, many times! I may be an idiot, but I'm telling you it ain't goin' in right!

Proper installation of distributor: Siradude, I put it at TDC (the line on the 2 little dots). When the distributor went in, it did NOT look like the FSM (rotor too far counter-clockwise). I put the distributor bolt in, turned the distributor as far as it could go (counter-clockwise) so rotor looked as close to FSM as possible. When I tried to time it I COULDN'T SEE ANYTHING! It was that far out. It idled nicely, but had no power.

Moved a tooth: Took the distributor back out, put it at TDC again, put it back in and the rotor was too far clockwise (28 degrees over). Moved the distributor clockwise to make it look like the FSM (no bolt in). Started it up, timed it per FSM, and bolt wouldn't go in. Ziptied the distributor in at the right timing position, then drove it to see if power was better. It was.

Next distributor: It'll be here Friday. Before I put it in, I'm going to compare the location of the gear on the shaft with mine. I'll bet the two are off 1/2 a tooth.

28 degrees per tooth: Just like a 6 cylinder sparks every 60 degrees (360/6), a gear with 13 teeth has 28 degrees per tooth (360/13).

You guys coming into St. Louis for the Holidays? I'd love to prove it to you.

 

[SiRaDuDe]

Proper installation of distributor: Siradude, I put it at TDC (the line on the 2 little dots). When the distributor went in, it did NOT look like the FSM (rotor too far counter-clockwise). I put the distributor bolt in, turned the distributor as far as it could go (counter-clockwise) so rotor looked as close to FSM as possible. When I tried to time it I COULDN'T SEE ANYTHING! It was that far out. It idled nicely, but had no power.

I got this from your other thread "which will remain unnamed"

I know you told me that you never removed the CAM when you removed your head, so you assume the CAM/CRANK adjustment did not have to be checked when installing the heads back on. But since I have OCD and the gears were RIGHT THERE, I would atleast checked them (or did you?) , well they have a cover on them now, and the only way to verify this would be to remove the gear covers, so I guess this will be added to the things that should be correct but never really checked list.

BTW: if this CAM was off 1 tooth you would be experiencing the same thing your are experiencing now with DIST out of spec... Since your DIST is geared from CAM. Just saying...

(is it geared from CAM?) I think it is BUT, If its geared com CRANKSHAFT then, YES your DIST sounds to be wacky. I'm pretty sure its geared from CAM though and if CAM if off then DIST will be OFF. Just more crap to throw into your problem .

 

[jwilber]

I've said this multiple times you need to line up the oil pump slot correctly our it will never go in right. Every time you take it out it moves on you and it will only go back in right if everything is lined up. When you take it out and or put it in you have to rotate it a little and if the oil pump slot is not in the right place it won't drop in unless you turn it. then you will be off. if you put it in then bump the motor like you said before then you are no longer at tdc and not really sure where it fell in at. You can not be a half a tooth off !!! Unless your timing gears are off. If you spin your dizzy around to get spark time it might run but you valves will be off and you will have no idea bite to get then right so your motor will run like crap forever you need to verify all your steps to find the issue not try to find a way to get around it

 

[Pin_Head]

I've put that distributor in many, many times! I may be an idiot, but I'm telling you it ain't goin' in right!

If you keep doing it the same way, then yes: it will never go in right. You are forgeting that the rotor turns as the distributor drops down because of the helical gears and you have to have the oil pump slot lined up for where it will be when it is down.

Think about it for a good while: What could cause the distributor to be off by half a tooth? Nothing!

You just aren't doing it carefully enough.

 

[TrickyT]

...
You just aren't doing it carefully enough.

Yes, this!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[jcarter]

Sorry guys, but you're wrong. You're trying to convince me there is some magical way the distributor goes in right, but its just not true.

You're disregarding the 28 degree per tooth thought, but it's unarguably true. If you hit the wrong tooth, the rotor position will be 28 degrees out from what's shown in the FSM.

The line up oil pump issue is wrong also because the gears engage before the distributor mates with the oil pump. I positioned the oil pump properly everytime I put the distributor in, sometimes the distributor went in all the way, sometimes it stopped 1/4" or so away, if it stopped, I pulled it out and repositioned the oil pump. After doing this several times, I realized you can bump the engine to mate with the oil pump.

Since it wasn't going in right, I've had 3 different people double check how I did it and had them put it in also. Same result.

Let's look at it a different way. What's more likely 1) the distributor to cam gears being off, or 2) the crank to cam gears being off?

 

[Pin_Head]

The point is that you can explore the entire range of rotation of the distributor to find the position where the timing is correct if you do it correctly. There is some combination of tooth engagement and rotation of the distributor body that will work.

Yes, there is 28 degrees per tooth, but the slot in the distributor hold down allows you to turn the distributor 30 degrees or more, so once you find the right tooth, you can set the timing.
Check out this picture:

The slot is close to the center of the dist shaft, so it is easily long enough to allow you to turn it more than 1 tooth in rotation. In this picture, you are about 30 degrees off from getting the bolt in and setting the timing properly.


As Jon mentioned, you have to jumper the ECU so that it will not change the timing in order to set it correctly.

 

[jonheld]

(is it geared from CAM?) I think it is

Yes. The 3F is very close to a 2F. The cam spins the distributor which in turn spins the oil pump. Keep thinking "tractor motor". Timing gears, mechanical oil pump, etc. No fluff on this motor, circa 1987.

Assuming the cam gear and the crank gear have not changed AND WERE CORRECT TO BEGIN WITH (and this is an assumption based on what YOU HAVE SAID) it is PHYSICALLY IMPOSSIBLE for anything to be 1/2 tooth off.

Rotational position of the oil pump is irrelevant to anything as long as the flat blade of the distributor shaft mates with the oil pump drive shaft.

The distributor drive gear is held in place with a tapered through pin. It can SHEAR, but it cannot bend. However a fairly large force would be required for that to happen. Have you inspected the distributor drive gear? I don't recall if it is a solid pin or a spring steel rolled pin. If it is the latter, you should be able to sight through the pin. If you can see light through the pin, then it's straight.

 

[TrickyT]

Don't forget he (gently?) beat on the distributor with a hammer to get it out of the block when he first removed it.

...
Assuming the cam gear and the crank gear have not changed AND WERE CORRECT TO BEGIN WITH (and this is an assumption based on what YOU HAVE SAID) it is PHYSICALLY IMPOSSIBLE for anything to be 1/2 tooth off...

I read somewhere long long ago... I think maybe on the Yahoo 3FE list... about someone who had the fiber camshaft gear separate from the brass center insert that mates with the camshaft. So theoretically it may be possible for the cam and crank to get out of time. But half-a-tooth and still have the cam continue to rotate? I consider this *extremely* unlikely in this instance.

Joe, you need a helping hand from someone who has successfully removed and replaced the distributor on a 3FE before. As many of us have said previously, you're dealing with an engine whose basic design dates back decades and is simple by today's engine design standards. Nevertheless, if you've never done this kind of work before you can get easily misled into thinking you've done everything by the book, but yet you're still not doing it correctly. You're getting great advice from some wise and experienced people here on 'Mud, especially Jon Held and Pinhead. You need a fresh approach, and one idea is to get someone with more expertise involved. If for no other reason than to get you thinking out of the box you've put yourself into.