Electronic Ignition Conversion

[atkinson40]

Just a sanity check after reading the conversion thread. My 620 is '72, with original dizzy, coil and resistor. This is the dizzy I picked up at the JY.

 

 

 

 

I got the base also. Can I use the old cap and rotor from my points dizzy?

 

Is this the wiring diagram I should follow?

 

 

Any updates on the Ignition Module. What part number? What do I do with the resisitor. Can I use my old coil? Thanks kevin

[metalmonkey47]

Yes and yes. Pints dizzy has the same cap/rotor.

[DanielC]

Pretty much any ignition system works the same way. Power is applied to a coil. that power creates a magnetic field in the coil. The coil in turn is grounded by a switch controlled by the engine, or a computer. When it is the right time for a spark plug to fire, the coil is switched off. The energy in the magnetic field has to go somewhere, so it usually fires a spark plug.

 

The points are just a switch. the GM HEI module is just a switch. A matchbox is just a switch.

 

If you use a coil that required a resistor, with a set of points, with a different type of switch, you still need the resistor. If you change the coil to a type that does not need a resistor, sometimes you can eliminate the resistor, but you may have another problem. eliminating the resistor causes the "switch" to have to handle more current. If it is a set of points, they burn up in a short time. if it is some type of electronic "switch", you could fry the electronics.

 

Your best bet is to try to "match" everything. For example, if you grab the Matchbox distributor out of a car in a junkyard, get the coil, and other parts in the ignition system as well. If you get a Datsun distributor with remote electronics, try to get the remote box as well.

 

In my experience, "electronic" types of Datsun distributorsare a larger diameter than the points distributor. Points distributor caps, and rotor are too small for them.

[atkinson40]

Your best bet is to try to "match" everything. For example, if you grab the Matchbox distributor out of a car in a junkyard, get the coil, and other parts in the ignition system as well. If you get a Datsun distributor with remote electronics, try to get the remote box as well.

 

Opps. Too late. I have the dizzy from the JY. The old coil and resistor. I need to buy the switch/module. Where would I add the resistor in the diagram? Thanks kevin

[metalmonkey47]

I think what he's saying is that if you have a points coil on the car now with a resistor at the coil, you need to leave it there until you get a coil that's designed for electronic ignition. All Datsun points ignitions had a ballast resistor @ the coil stock.

 

 

Also, you can open your plug gap a bit with EI from .35 to .45

 

 

 

 

 

 

 

EDIT: I used the same dizzy on my truck before I switched to a matchbox. Easiest thing to do is get a matchbox module and wire it in. Then just get an EI coil.

[datzenmike]

L18 and L20B caps are the same, the L16 may not be. L20Bs were larger diameter to space the terminals further away from each other because of the later higher voltages used.

[ggzilla]

1972 cap will be smaller than the 1974-up cap. The 1974-ish points distributor used low voltage but still had the larger cap. To prevent crossfire better.

 

When using the low-energy coil with the resistor, do not open your spark plug gap. That's only for a high-energy coil. If you go with a GM HEI switch, you can use a GM coil, then open the gap to 0.044".

[banzai510(hainz)]

If your going to use your stock datsun point coil and ballast resisitor. put the ballst in between the ON wire to the + side coil

[Pacific coast Datsun]

Tell parts store guy you need an HEI module for a 78 Camaro.

Id also buy a new cap & rotor plugs & wires.

The HEI must be grounded. On my 620 i made a metal plate it bolts to & that bolts to the coil bracket.

[atkinson40]

Got everything installed. Just need to get some wire at the swap meet tommorrow.

 

I had to take apart the electronic dizzy and rebuild. The plastic spacer between the plates that hold the bearings was toast so I needed a JY trip to find something that would work as a replacement.

 

Also needed to get another VA diaphram.

 

Also needed to drop the oil pump and rotate 180 to get the rotor in the right position.

 

How much clearance should be between the rotor on the shaft that has four points and the magnetic coil? Whats the little wiper thingy that rides on the shaft?

 

Thanks kevin

[banzai510(hainz)]

needed to drop the oil pump and rotate 180 to get the rotor in the right position?????????????????????????????????

 

just move the spark plug wires

where 4 was will now be 1.

[ggzilla]

Either way works.

 

Set the Air Gap to .008 to .016 inch.

[atkinson40]

Wired it up.

 

Wouldn't start.

 

Remembered reading about module maybe needing a dedicated ground.

 

Ran one and the pony fired right up.

 

Timing must have been set OK in what ever vehicle the dizzy came out of because that seems OK. I'm going to check it if I can coax my old light into working or I rent one from Autozone.

 

Should have rotated the wires on the dizzy vs dropping the oil pump. Pony's now pissing oil out around the pump bolt heads and I'll have to cut a new gasket.

 

Next task I'm contemplating is replacing that big blue beast of an air cleaner. I think its the source of a narly vibration racket at about 65MPH. Besides it covers up stuff I want to see better. Any donors I can look for at the JY? Thanks Kevin

[banzai510(hainz)]

O rileys sells Felpro oil pump gaskets or dial up Felpro on the O rileys website and put in Datsun 620 and youll get a SKU number to order a few gaskets. You should have extras anyway, front cover sets ect.......

[atkinson40]

Coaxed the old timing light into working and set the timing to 12 BTDC.

 

Idles kinda rough.

 

I pulled the wires one at a time off the D-Cap and noticed #3 and #4 didn't make much difference(if any). I put the timing light on the wires going to the plugs and all wires fire the light so I know I'm getting fire to all plugs.

 

I'm still using the old coil and resistor. Would this cause a weak spark?

 

The truck pulls up a hill in 3rd.

 

I've done rings and pistons and had the head rebuilt recently. I could do compression check. Maybe valve adjustment is off.

 

I'm hearing an exhaust leak, but not sure if this would cause my symptoms.

 

Any ideas what could be wrong? Thanks Kevin

[ggzilla]

Old coil & resistor should not cause a weak spark. But you won't get a high-energy spark, so keep the spark plug gaps at 0.035 inch.

 

DEDICATED GROUND -- more importantly, you need to bolt the HEI module to a heat sink so that it won't overheat. GM used the distributor shaft platform, but they burn out a lot more often than other brands. Bolt it to an aluminum plate bolted to the firewall or inner fender.

 

Do a compression test and get back to us.

[banzai510(hainz)]

D-Cap and noticed #3 and #4 didn't make much difference

 

you got 1 3 4 2 CCW fire order?

 

ck the spark plugs or ck the valave lash on 3 and 4.

[atkinson40]

DEDICATED GROUND -- more importantly, you need to bolt the HEI module to a heat sink so that it won't overheat. GM used the distributor shaft platform, but they burn out a lot more often than other brands. Bolt it to an aluminum plate bolted to the firewall or inner fender.

 

Do a compression test and get back to us.

 

OK. Back on track.

 

To get rid of the exhaust leak I replaced the in/ex gasket and resurfaced the ex manifold in another thread.

 

Also did the HG while I had it that broke down.

 

Here's how I mounted the control.

 

 

I sanded the metal down and bolted it with the grease.

 

Still thinking I'll need a heat sink to keep it cool.

 

Where its located isn't too far from the exhaust manifold and it and the wheel well metal recieves radiant heat,

 

Three different JY trips looking for a smaller air cleaner was fail.

 

Autozone was success. Now I can see WTF. No more vib noise at 65, or any speed. Yippie

 

 

Runs better after E conversion, but still shakes a bit at idle. Not sure if its carb or compression.

 

Next step compresion check. Back on track

[banzai510(hainz)]

Ck for tightness of intake

valve lash ck

adjust the cab and timming and see if that get rid of it.

 

I can swap 3 different weber carbs and get 3 different tresults in idle quality. Your dealing with 40 year old part now.

[ggzilla]

That's a good install. The fender metal will act as a large heat shield. Consider that finished.

 

Why'd you replace the head gasket? Well in any case you need to adjust the valves after changing a head gasket.

[atkinson40]

Ck for tightness of intake

Done

valve lash ck

Need To Do

adjust the cab and timming and see if that get rid of it.

Done 12BTDC

[atkinson40]

 

Why'd you replace the head gasket? Well in any case you need to adjust the valves after changing a head gasket.

 

Was weeping oil between the head and engine. My OCD wouldn't let it be. Don't see any leeks yet.

[atkinson40]

!@#$%^&.

 

Compression check shows every cylinder at 100PSI. No more than 2 PSI variance between the 4.

 

I've done cylinder hone, pistons, rings and head rebuild. WTF.

 

Checked valve rocker clearance and only one is a bit loose, but couldn't get the lock loose so left it alone for now.

 

Plugs all look tan and dry after about 30 miles. No gas, oil on them.

 

Am I doing something dumb?

 

Only thing I could think is the compression gauge is fail? Thanks kevin

[banzai510(hainz)]

the rockers should wiggle a little when the lobe is cam lobe is pointing up. This shows the valves are fully closed. If too tight then valve is not closing all the way and compressipon will be blowing out.

 

I assume your doing the comp ck wrong.

[ggzilla]

You forgot to do the wet compression test. That will tell you more than the dry test.