Firing Order

[imtb]

Help, I been working on my 71 510 and just not happy with the performance of the 1978 L20B I was looking at the plug wires and the firing order trying to see if they are correct.

 

I looked up the firing order on the 620 site and checked it to mine and this is what i found.

 

My number 1 plug wire is in the position of where the number 3 wire is on the distibutor cab

 

#3 wire is in where the number 4 wire should be on the cap.

 

#4 wire is where number 2 should be on the dist. cap

 

#2 wire is where 1 should be on the dist.

 

The car starts up and runs ok idle is rough. I have checked the cam timing and it seems tobe correct. I've pulled the plug wires while it was running and each cylinder drops off a little.

 

If i put the the engine at TDC with the cam at 10 and 2 shoud the rotor be pointing to number 1 on the dist. cap.

 

Would it hurt anything if I switched the wires to how they should be?

 

I just think this thing should fly with cam, headers , dual carbs, its kinda of dog.

[Cuts metal like mad]

yes it's supposed to point to (or near) #1, if you have the L16 dizzy the firing order will match the dizzy not the motor, with no ill affect.

[imtb]

The engine is 1978 L20B with MSD box and electroinc dist. just a rotor no points.

[datzenmike]

Set at TDC compression, and the rotor should be under the cap wire that goes to the #1 plug. As long as it's close and within adjustment range for the proper 12 degrees advance it you're good.

 

If the spindle was installed in any random position, as long as the rotor is directly under any cap plug wire, call that one #1 and adjust the others: 3, 4 and 2 in a counter clockwise direction. The motor will run fine with the rotor in any position but we usually try to standardize everyone to the same. It makes it a lot easier when everyone is on the same page if trouble shooting or describing an ignition problem.

 

The standard position for the distributor drive spindle, (TDC, distributor removed) is 11:28 (almost eleven thirty) as shown here with the slot just off center to the left:

 

http://i138.photobucket.com/albums/q251/datzenmike/motorZseriesdistallignmentLarge.jpg[/img]"]

[Duke]

I agree with what Mike said. I bet the dizzy drive shaft was installed wrong. Watch Hainze's L-series video, he describes how to install the shaft really well.

 

Oh, and IIRC the firing order is 1-3-4-2.

Edited January 4, 2009 by Duke

[ggzilla]

Nearly all four inline 4-cylinder engine use 1-3-4-2, regardless of brand.

 

Make sure when pully is at TDC:

* the electronic trigger tooth inside distributor is lined up with pulsar tooth

* The rotor is pointing to 1 or 4, not in between 1 & 3 and not in between 4 and 2,. etc.

[Cuts metal like mad]

Nearly all four inline 4-cylinder engine use 1-3-4-2, regardless of brand.

 

Make sure when pully is at TDC:

* the electronic trigger tooth inside distributor is lined up with pulsar tooth

* The rotor is pointing to 1 or 4, not in between 1 & 3 and not in between 4 and 2,. etc.

 

 

He didn't say that it's a EI dizzy... Could be pertronix.

[ggzilla]

He said:

The engine is 1978 L20B with MSD box and electroinc dist. just a rotor no points.

What's is the difference between "EI" and "electronic distributor"? Pertronix kits use points.

 

In any case, make sure the rotor lines up:

* for electronic distributor, rotor tooth lines up "perfectly" with stator tooth

* for points, it's just starting to go up on the rotor lobe (check for spark)

To clarify, this is check at 5-10 before TDC, with pully at the timing marks.

 

* for crank trigger, ditto. Make sure the teeth match up perfectly.

I have a crank trigger on my white Datsun.

Edited January 5, 2009 by ggzilla

[Cuts metal like mad]

He said: What's is the difference between "EI" and "electronic distributor"? Pertronix kits use points.

 

In any case, make sure the rotor lines up:

* for electronic distributor, rotor tooth lines up "perfectly" with stator tooth

* for points, it's just starting to go up on the rotor lobe (check for spark)

To clarify, this is check at 5-10 before TDC, with pully at the timing marks.

 

* for crank trigger, ditto. Make sure the teeth match up perfectly.

I have a crank trigger on my white Datsun.

 

sorry but your wrong... Generally people refer yo the matchbox dizzy when they say EI, but Pertonix IS electronic ignition, does NOT use points, points come out, pertronix goes in, and with the dust cover installed... All you will see is a ROTOR.

Edited January 5, 2009 by zuum510

[datzenmike]

He said: What's is the difference between "EI" and "electronic distributor"? Pertronix kits use points.

 

I would think "EI" and "electronic distributor" are anything that isn't a points distributor.

 

The '78 would have had the remote igniter style distributor and separate box. The rotor assy would look like this:

 

http://i138.photobucket.com/albums/q251/datzenmike/EIdizzyremoteigniter.jpg[/img]"]

 

The black square shaped thing with four corners is also called a rotor, not to be confused with the high tension rotor that points the spark at the wire terminals on the cap.

Edited January 5, 2009 by datzenmike

[ggzilla]

Yep, I have both a matchbox and the earlier remote style (pre-79). They both seem to work equally well.

 

Thanks for the correction about the Pertronix.

 

 

firing order trying to see if they are correct.

My number 1 plug wire is in the position of where the number 3 wire is on the distibutor cab

#3 wire is in where the number 4 wire should be on the cap.

The firing order is correct -- it is still 1-3-4-2. But it will run correctly if the entire distributor body has been rotated 1/4 turn from normal when it was put into the engine block. Follow the confirmation steps below to see if you need to re-do it.

 

To confirm, with Electronic distributor:

1. the cam-rotor lobe/tooth should match *exactly* with the sensor (not even a little off), when front pulley is sitting on the timing mark. The photo above shows it lined up. This can usually be corrected by rotating the distributor unless installed too far off.

2. the spark rotor should be pointing close to the cap terminal that goes to #1 plug. Not partway between it an the next cap terminal. If it isn't pointing right after Step 1 is confirmed, you will need to remove the distributor and insert it correctly.

 

My Datsun engine with aftermarket cam idles roughly at idle, smooths out at 1,100 RPM.

Edited January 5, 2009 by ggzilla

[imtb]

Thanks for the responses.

 

My distibutor looks like the one in the picture but with the high tensor pointy rotor with the MSD 6 ignitor and it really ignites. When I pulled the plugged wires off while it was running it really sparks, and each cylinder dropped off about the same.

 

The plugged wires are in the correct order but I guess the distibutor was installed 1/4 turn off. I guess it really wouldnt affect performance.

 

Intial timing 5 advance about 28, if I give more intial it will slighty ping at WOT.

 

What else could be holding this engine back.

 

L20B, cam, headers u67 head, dual 40dcoe's. dogleg 5speed.

[banzai510(hainz)]

1/4 turn off?????????????What is a 1/4 turn.

 

I think that is alot,dont you.????????????

 

If distributor is turned to one side fully of the timming plate to get it in time then I say there could be a proplem.Usaully its in the middle of the the timming plate. But you know there.

 

But Im not there and it still could be fine as it is.

 

can you drive the car up to 65-70mph ????? if yes then i say its propable OK.

 

ck the cam timming also. make sure the V and the dash line up at TDC/ If a link off you coule affect the top end or bottom end.

[banzai510(hainz)]

you know what I started thinking?.You need maybe 12-15 deg BTDC on the timming . You got dual sidedraft carbs. You need more intial advance.

If you cant get that by turning the distributor then you have the wrong distributor mount or the oil pump/dist spindal is off a tooth.

remember there is a 8mm bolt underneath the dizzy where you can adv or retard the dizzy plate

 

Or maybe carbs are way off?

 

let us know

[racerx]

He said: What's is the difference between "EI" and "electronic distributor"? Pertronix kits use points.

 

In any case, make sure the rotor lines up:

* for electronic distributor, rotor tooth lines up "perfectly" with stator tooth

* for points, it's just starting to go up on the rotor lobe (check for spark)

To clarify, this is check at 5-10 before TDC, with pully at the timing marks.

 

* for crank trigger, ditto. Make sure the teeth match up perfectly.

I have a crank trigger on my white Datsun.

 

Petronix is not points it's like a magnetic pick up that replaces points.

[racerx]

Here:

 

http://www.pertronix.com/prod/ig/ignitor/default.aspx

[imtb]

On the firing order and dist. placement I ment that the number plug wire is in the bottom position pointing toward the carbs and not the header, but the plug wires are in the correct sequence. I dont think this would make a differece on how it runs since they are in the right order.

 

I can get 15-18 Initial advance but then the total advace is like 43 and if doent run as good. The more intial advance I give it starts to slighty ping. The PO had it set with that much advance but thats when there was no valve clearance and car wouldnt start when it was cold. I adjusted the valves with to .10 clearance. Starts right up.

 

The head has been milled and it has 10to1 compression. I did compression check and I am getting around 210 on the first three and 185 #4. I want to recheck this and do a wet check also.

[freaky510]

sounds like someone pulled the oil pump and the shaft fell out, then they coulddnt get it in the way it was.so they pulled the dist. put the pump and shft in the matched it up. i had the same problem. so since i was alone i wegded the dist a the #1 spot i want with the motor on tdc and matched it up

i a newb lol

[datzenmike]

I can get 15-18 Initial advance but then the total advace is like 43 and if doent run as good. The more intial advance I give it starts to slighty ping. The PO had it set with that much advance but thats when there was no valve clearance and car wouldnt start when it was cold. I adjusted the valves with to .10 clearance. Starts right up.

 

The head has been milled and it has 10to1 compression. I did compression check and I am getting around 210 on the first three and 185 #4. I want to recheck this and do a wet check also.

 

Yeah, I know you meant 0.010" valve clearance.:D

 

As for the timing That much compression will usually require less advance. Just keep backing it down till the pinging just goes away under load. Try a couple of degrees at a time.

 

The low cylinder is well within limits of 80% of the highest reading. You are close to 90%. That low cylinder may improve now that the valves are set properly.

[banzai510(hainz)]

if you can get the dizy at 12-15 deg intial adv then the dizzy I assume is lined up OK.

 

Does this have a vacuum advance? Try running the truck it with and w/o the vacuum advance and see if it changes.

 

Look at the cam timming next time u open the valve cover.

http://www.guba.com/general/search?query=hainz&set=5&x=46&y=10

 

 

be honest I know nothing about total advance on these distributors. I just stick them in and all mine seem to work.

I do ck to turn them to make sure the rotor spins around w/o obstruction. I seen one where the weight fell off and the springs were binding. also another the vacuum adj was locked up but both seem to still run the truck it was on.

 

43 degs seems a little high on the total advance Maybe somebody else can awnser this question.

 

The the vaccum advance plate mounted OK. Not loose or the bolt/screw holding it solid?

[imtb]

This is kind of off subject from the timing but kind of related.

 

I installed an o2 sensor trying to tune it and I found it running really rich at idle I even change idle jets and still idling rich. I think i have the progression stage of the carb coming causing it idle rich. Could this be casued from not enough intial advance on the timing?

[banzai510(hainz)]

thats hard to say about the idle jets as I know nothing about Weber DCOE carbs. Plus you say you have a MSD so that shold help complete the burn.

 

This is me I would ck my cam timming

Then make sure the distributor is timed or swap another in there if you think the advance is bad.

 

Ck all the valve lash and spark plugs.

 

Ck to make sure all the carb jet blocks are tight and not loose and the airhorn venturis are nice and tight inside the carb(remove aircleaner and stick finger in there and make sure the inner venturies are not wiggling in there).

 

Maybe put a Weber DGV carb on there, to help isolate this proplem.

 

I seen bad jetted carbs make a good motor run like shit.

 

But anything else is just a guess untill you start doing some cks

[datzenmike]

43 degs seems a little high on the total advance Maybe somebody else can awnser this question.

 

 

He doesn't state at what RPMs the total advance is at. It is possible to have maximum advance if the RPMs are low enough and throttle light enough to have high vacuum advance (as in no load) Initial advance is 18 degrees, add to that another 10-12 vacuum advance, plus 5-8? (depends on RPMs) mechanical advance and you have just over 30 degrees. This wouldn't happen under a load at the same RPMs, because the manifold vacuum would be lower. In the absence of vacuum advance the mechanical advance would add to the initial advance and build to a maximum of 30-35 depending on the spring rates and weight sizes and RPMs. The balance weights and springs determine how soon the advance occurs. weaker springs advance starts sooner, stiffer spring later advance. The slots that the weights slide in determine how much the maximum advance is. A longer slot allows more travel so more advance. Shorter travel means less mechanical advance.

 

I took some pictures of a Nissan distributor to show the springs, weights and the slots they slide in, because everyone likes pictures.

 

Here is the mechanical advance assembly. The first picture is at rest position and the springs hold the weights close to the shaft.

 

http://i138.photobucket.com/albums/q251/datzenmike/720%20stuff/720distributor026Large.jpg[/img]"]

 

Here are the weights as they are thrown outward by centrifugal force. Note that the dowel near the spring has, besides moving away from the shaft, also rotated slightly counter clockwise. (advance)

 

http://i138.photobucket.com/albums/q251/datzenmike/720%20stuff/720distributor027Large.jpg[/img]"]

 

 

Here's the mechanical advance rotor. It sits on the distributor shaft but is turned only by the dowels on the advance weights. As the RPMs rise the weights move outward and forward pushing the rotor in advance of the shaft position. All of the distributor EI, (or points) are mounted on the rotor and advance or return with the mechanical advance. The outer end of the slots in the rotor determine the maximum advance. Once the dowels slide to the outer end, advance stops no matter the RPMs.

 

http://i138.photobucket.com/albums/q251/datzenmike/720%20stuff/720distributor019Large.jpg[/img]"]

 

Springs stiffness and weights, determine how soon or late the advance comes in.The slot length, determines how much advance.

Edited January 5, 2009 by datzenmike

[imtb]

Ok Datzen Mike, I think i am on to something. I've reading the hotrodders forum on Vacum advance, you may have referred to me in earlier post. Anyway, I do not have the vacum advance hooked up to the distibutor, Can I put it on the cannon intake maifold? It has spot that plugged only on one runner. Would it be better off Both runners to a T then to the vacum advance unit. How should I set up the vacum advance, Here are my current setting below.

 

My setting right now is 4-5 degrees initial advance, really rich idle. Total mechincal advance 28-30 degrees. It jumps right into the total advace as soon as the rpms climb from about 2000 rpms.

 

The car starts better with more advance but runs crappy with to much intial and total advace. I am still reading about the atrical on the vacum advance and timing but havent quite put it all together.

 

Any suggestions.

[ggzilla]

imtb, i agree the firing order is OK, even if distributor is put in 1/4 turn off, the wires are moved over a 1/4 turn to match. No problem.

 

You probably want 35 degrees total advance. With 10:1, you will need to run at least mid-grade, but probably premium. Then you should be able to get the intial advance up a bit without pinging.

 

* Check advance at IDLE (under 900 RPM) with vacuum advance disconnected.

* Vacuum advance does nothing for full throttle (or even heavy throttle). It only affects part throttle.