How to change a distributor in a 318

[MaximRecoil]

My engine currently has a points distributor, and I want to swap in a Chrysler electronic ignition distributor. What do I need to know before doing this?

I've heard/read various things, not necessarily specific to 318 engines, about having the engine at TDC and such, but a Chrysler 318 distributor looks like it can only go in one of two ways, due to the way the bottom of its shaft is shaped like a flat-blade screwdriver. So if you have the rotor and the vacuum advance can pointing in the same directions as on the old distributor, wouldn't that automatically mean it is in the right way?

[flyinlow]

Normally you are correct. point the rotor and vacuum advance at some landmark under the hood and swap out the distributor. AS long as you don't disturb the distributor/oil pump gear under it its simple.  And of course don't crank the engine while it's out.

Consider saving the old distributor and resistor for road trips. Can get you home if the electronics fail.

[cowboy4x4n]

my 318 also had points when I got it.  I changed that out for a pertronix ignitor 3 multi spark electronic ignition conversion and matching coil.  it works great and an alternative to buying another distributor

[MaximRecoil]

I got the electronic ignition distributor installed today; very easy; I just pointed the rotor in the same direction as the old rotor was pointing in and it dropped right in. I also pointed the vacuum advance canister in roughly the same direction as the old one.

Then I did the rest of the job, which was converting to a General Motors HEI ignition setup. I used a 1970s style 4-prong HEI ignition module (Standard Bluestreak LX-301), and an E-core style ignition coil from a '92 Ford van (Motorcraft E73F-12029-AB, the same as a Standard Bluestreak FD-478). Here's a diagram I drew:



The engine started on the first try, and was already running smoother than before. My mechanic friend adjusted the timing by ear, and the idle smoothed out even more. The engine used to rock back and forth somewhat when idling, now it barely moves at all when idling. It feels like a different engine when driving, especially when stopped with it in drive; you don't even notice the engine running; no vibrations through the seat or anything. It is like driving my 2001 Dakota.

A couple of questions:

1. I have the vacuum advance hose connected to the port on the passenger side of the carburetor (stock 2 bbl; "BBD" I think it is called), just as I always have. Is this the correct place for it, or should it go on the small port that branches off from the main vaccuum port on the intake manifold (I have that one blocked off, as I always have)?

2. My mechanic friend set the timing by ear with the vacuum advance hose from the carburetor hooked up to the distributor's vacuum advance canister. I think I've heard or read somewhere that the base timing should be set with the hose disconnected and blocked off. Is that correct?

[A383Wing]

vac advance goes to ported vacuum nipple on carb....no vac at idle, vac when throttle is opened

[MaximRecoil]

vac advance goes to ported vacuum nipple on carb....no vac at idle, vac when throttle is opened

Is the ported vacuum nipple the one the arrow is pointing to in the following image?



Also, since there is no vacuum through the carburetor's ported vacuum nipple at idle, it wouldn't make a difference if the timing was set with the vacuum advance hose hooked up or not, is that right?

[flyinlow]

vac advance goes to ported vacuum nipple on carb....no vac at idle, vac when throttle is opened

Is the ported vacuum nipple the one the arrow is pointing to in the following image?



Also, since there is no vacuum through the carburetor's ported vacuum nipple at idle, it wouldn't make a difference if the timing was set with the vacuum advance hose hooked up or not, is that right?

1. I think that's the one . It has bin a while since I have messed with a BBD.

2. If you are at base idle and the port is not uncovered by the throttle plates there should little if any vacuum at idle. It is just standard procedure to plug it, to be sure it is not affecting the base timing. Some cars have a temperature controlled vacuum switch that ports manifold vacuum to the distributor to increase idle speed if the engine starts to get hot. So its best to plug when setting the timing.

[A383Wing]

yes...the side nipple where arrow is pointing is where dist advance hose connects to

[MaximRecoil]

2. If you are at base idle and the port is not uncovered by the throttle plates there should little if any vacuum at idle. It is just standard procedure to plug it, to be sure it is not affecting the base timing. Some cars have a temperature controlled vacuum switch that ports manifold vacuum to the distributor to increase idle speed if the engine starts to get hot. So its best to plug when setting the timing.

Okay, do you plug it at the carburetor nipple; at the distributor nipple; or both?

The engine is pinging when I accelerate; does that mean too much timing advance?

yes...the side nipple where arrow is pointing is where dist advance hose connects to

Thanks; that's where I have the vacuum advance hose connected.

[flyinlow]

Okay, do you plug it at the carburetor nipple; at the distributor nipple; or both?

The engine is pinging when I accelerate; does that mean too much timing advance?

Pull the vacuum hose off the distributor and plug with a golf tee ,bolt or Phillips screwdriver.

Pinging ( detonation ) means to much timing for the engine and fuel combination. You could try higher octane fuel, however you mentioned the engine was timed by ear. Use a timing light. Occasional pinging under light acceleration usually won't damage the engine, but heavy or prolonged detonation can.

[MaximRecoil]

I don't know if I even have timing marks, and I don't really know how to use a timing light either, nor do I have a timing light. I was thinking about just backing off the timing a bit, test driving it, seeing if it still pings, and so on, until it doesn't ping under acceleration. It didn't ping before with the old distributor, so the fuel isn't an issue (318s are low compression anyway).

I'm pretty sure the timing is advanced too far anyway, because to get the idle speed low enough at the current timing, the idle screw had to be backed out all the way, and even then, it is idling a hair too fast. With the old distributor it would stall before you could back the idle screw out all the way. My friend did note that it was idling a little too fast even with the idle screw backed out all the way, but he also thought the timing sounded too retarded if he backed it off so it idled slower. I think he's wrong in this case, even though he's "been doing it for a hundred years" as he likes to say; the timing needs to be backed off (he'll probably agree when I tell him it's pinging under acceleration).

[A383Wing]

Bet if he uses a timing light, he will find it's too far advanced...back it up to spec timing and re-connect vac hose and see how it runs and if you have any pinging anymore.

[ACUDANUT]

When you get your kit from Summit, it will have a easy step by step instruction.  Your making a great choice imo.
http://www.summitracing.com/parts/dcc-3690428

[flyinlow]

Your car came with timing marks, probable still there ,  just dirty.  For performance tuning , advancing the timing to close to the detonation limit will be part of it, but you should start with the stock timing. Youtube has several videos on timing.

Pre '72 318's where  9:1 compression engines. Add some cylinder deposit build up and you end up needing better gas.

For example,
Numbers for a 1970 318 auto.      Base timing, vacuum advanced plugged. -  TDC
                                                  centrifugal advance                                - 28* at 4000 rpm
                                                  vacuum advance                                   - 20* at 15 inches of vacuum to advance unit

[MaximRecoil]

Your car came with timing marks, probable still there ,  just dirty.  For performance tuning , advancing the timing to close to the detonation limit will be part of it, but you should start with the stock timing. Youtube has several videos on timing.

Pre '72 318's where  9:1 compression engines. Add some cylinder deposit build up and you end up needing better gas.

For example,
Numbers for a 1970 318 auto.      Base timing, vacuum advanced plugged. -  TDC
                                                 centrifugal advance                                - 28* at 4000 rpm
                                                 vacuum advance                                   - 20* at 15 inches of vacuum to advance unit

Thanks for the information.

My car is a 1969, but the engine has been replaced by a previous owner with one that is at least a 1972 (because it has an EGR valve, though I made an EGR blockoff plate for it; it has the '70s style air cleaner too, the kind designed for use with a heat riser). Whoever did the engine swap put some of the 1969 stuff back on it, like the points distributor, the mechanical voltage regulator, and the single-field alternator (I changed it to the electronic regulator and dual-field alternator a couple of years ago).  

I don't know if my mechanic friend has a timing light or not (he has pretty much everything, so he probably does); I do know that he believes he has no need for one.

Where should I look for timing marks?

[flyinlow]

Small block timing marks,  you may not have the magnetic timing tube, ignore it if you do. I clean and highlite the slot in the vibration damper.

[maxwellwedge]

Depending on what year the timing chain cover is on your engine - it could be on the opposite side.....which I think (not totally sure) that if the later balancer is used with a 69-earlier timing cover....the marks my be meaningless. Anyone out there know for sure?

[ACUDANUT]

Find number one plug. Remove spark plug and slowly crank until the cylinder blows air out. Find out where the rotor is pointing and that is Number one. Arrange plug wires in the correct firing order.  Start the engine and use you ear to find out if you need to turn the distributor one way or another.  IMO this is the best way to really make it run right.

[John_Kunkel]

Here's a diagram I drew:

Why the ISO relay? Why not just power it direct from the ignition switch?

[ACUDANUT]

What's wrong with the diagram from Mopar Performance and summit on upgrading to ECU (with kit provided). ?

[A383Wing]

Here's a diagram I drew:

Why the ISO relay? Why not just power it direct from the ignition switch?

What's wrong with the diagram from Mopar Performance and summit on upgrading to ECU (with kit provided). ?

I was wondering the same thing

[MaximRecoil]

Why the ISO relay? Why not just power it direct from the ignition switch?

You can if you want to, but the relay is better. The GM HEI module wants a steady 14 volts or so (no ballast resistor is used), and with the thin factory wires combined with going through the crappy 44-year-old bulkhead connector twice, and through the key switch as well, you're likely to have significant voltage drop just powering it from the ignition switch. Here's a good explanation from "Olafla" on a thread about this particular type of conversion on the Slant Six Forum:

A stock GM HEI module can draw up to 4 amps, depending on engine revs. An aftermarket hi-perf module can draw up to 7.5-8 amps. There can be a power surge at startup, in extreme cases even above 25 amps, but surge time is very short. Current draw means heat, so it is necessary to use a heat transfer paste between the module and some kind of heat sink. There have been reports in various forums about damaged modules from overheating.

The voltage required to make the module produce a spark is quite low, app. 7.5-8V, but there is much better and stable output from the module at it's ideal operating voltage, 14-14.2V.

I generally agree with Charrlie_S on most occasions, but I don't agree with him on the point about [not needing] a relay. The voltage in the old ignition circuit may be very much lower than at the alternator/battery, as I showed in a picture of my own readings, linked in posts on the previous page. You can get away with low voltage just to make a spark in a 'portable' system, but for a permanent installation, a relay transmitting power from the alternator/battery, will be better for the module's longevity and efficiency.

Link

What's wrong with the diagram from Mopar Performance and summit on upgrading to ECU (with kit provided). ?

Nothing's wrong with it, but I'm not using a Mopar ignition module + ballast resistor; I'm using a General Motors HEI ignition module and no ballast resistor.

About the timing, I backed it off a bit today and now it doesn't ping. It's all good for now, but I would like to get everything "dialed in" eventually, which includes using a timing light and also messing with adjustments on the carburetor (specifically the idle mixture). My mechanic friend couldn't find his timing light; the only one he could find was missing its power and ground cord (I might see if it will work if I install a new cord in it). He said he had a bunch of them at one point, but he's given them away and lost track of them over the years.

Thanks for the information that's been posted so far (and that diagram showing the timing marks); very helpful.

[John_Kunkel]

You can if you want to, but the relay is better. The GM HEI module wants a steady 14 volts or so (no ballast resistor is used), and with the thin factory wires combined with going through the crappy 44-year-old bulkhead connector twice, and through the key switch as well, you're likely to have significant voltage drop just powering it from the ignition switch. Here's a good explanation from "Olafla" on a thread about this particular type of conversion on the Slant Six Forum:

The same argument could be made of the stock ignition or any other system, if the wiring/switch is causing low voltage I'd say "fix that". The relay adds complexity and offers another component to fail and leave you stranded.

[MaximRecoil]

The same argument could be made of the stock ignition or any other system

Not really, given that the stock ignition system is fed low voltage anyway by design, due to the ballast resistor. That defeats the purpose of putting a relay in there.

if the wiring/switch is causing low voltage I'd say "fix that". The relay adds complexity and offers another component to fail and leave you stranded.

A failed relay wouldn't leave me stranded; I'd simply plug in a new relay. If I had to, I'd rewire it on the spot, bypassing the relay, but I wouldn't have to, because I have extra relays in the car. By the way, I'm willing to bet that a quality ISO relay is more reliable than the ballast resistor that the Mopar ignition system has, and is also more widely available. People with stock Mopar ignition systems are well-advised to keep extra ballast resistors in their car because of their significant likelihood of spontaneous failure.

You can't match the low resistance of the relay circuit by a "fix that" procedure without replacing all the original wiring in the stock ignition circuit with impractically heavy wire (because of the long run) and bypassing the bulkhead connector, and you'd probably negate any gains you made by using heavier wire when it goes through the 44-year-old ignition switch. Using a relay is much easier.

On the topic of the timing: I spliced a new cord onto my friend's timing light; found, cleaned, highlighted, and verified the timing marks on my car, and the timing light worked fine. The way I had it adjusted (from when I backed it off a bit the other day to stop it from pinging) turned out to be only a couple/few degrees BTDC. I set it to TDC and it runs fine. It idles much smoother than it did with the old points distributor, but it still doesn't idle as smooth as I'd like. The engine still rocks slightly back and forth when idling. I'm not sure what else to do to make it idle smoother though. I suppose I could mess with the idle mixture, and maybe get some new spark plugs. 

[A383Wing]

you still got 12v to the OE ballast resistor....via the ignition switch....

now you added a relay to the car, via the ignition switch....and now you got 4 more connections that you didn't have originally that can fail along with the relay...I really don't follow your logic on adding more stuff to go wrong.