Little help with initial, mechanical, and total timing on my rebuilt 360

[Builderguy]

The id tag was not of the distributor. I will pull it and look at the mechanical advance and check the springs, but I have to wait until I have new springs for it. Is anyone familiar with these springs? Is there a better assortment set I should get?

 

[Mattax]

Those springs could be for Delco or Mallory but the secondary spring needed isn't there and won't be there. I'm not aware of any current commerical sale of those and even back in the day they were not generally retailed. You can ask Halifaxhops if he still has these "Blue Dot" spring sets available. I have a set but haven't experimented with them yet.

If rebuilt distributors were still available at the parts store for $25 that would give you a spare to run in the car while you open the other one up.

Lets look at what we do know about the distributor in the car.

There is at least 30 degrees in the governer.

It also looks like there is no long looped secondary spring. That's what slows the advance x number of degrees out from the initial.

So if we had to guess, that's what is missing.

If it was still in original configuration the advance should have had a shape that would fit closer to the specs plotted here for a '73 2bbl 318

Your distributor advance measurements in pink, using TDC at 800 rpm for the initial.

My guess is that using this distributor, what will be needed is weld up the inside of the slots AND get a heavy secondary spring AND a little tuning of the spring perches or loops.

An example of the weld up is shown here. The difference there is shape of the advance curve was good, but the initial advance was too long. There is also a possibility that its a Mallory built Mopar Performance distributor. That's uses different springs and is a little more complicated to set up.

Some more helpful pictures in the thread linked below. Keep in mind this is a preview to help you come up with a plan for the parts. Establishing the best initial timing still will need to be done iteratively, especially with an automatic transmision. But having timing that is stable at idle rpms will make it easier.

Post in thread 'Distributor curve help needed'

Jul 16, 2021

Made a goof in the graphs above (at 3500 rpm) when I plotted out the timing you measured.
Fortunately doesn't change the main point.

In gray is the range where I think the timing ought to be.

So the next question is how to get there.
The first thing to do is reduce the tension of the primary spring. That's the spring with tension when the distributor isn't turning, or turning slow. On a Chrysler distributor you do that by turning the spring perch (circled).

You don't have to disassemble the distributor unless its really stubborn.
You can file a...

• Mattax

 

[RustyRatRod]

I've been using the Mr Gasket spring sets for the Chevy distributors and have had great success...for over forty years. They work fine.

 

[Builderguy]

I did not think of using a rebuilt until my original is dialed in. Thanks
I could not find a rebuilt one so I ordered a new one, will be here Friday.
It was $57 but at least it will buy me some time.
Maybe I can find someone who has one of the Sun distributor test machines. They are still out there, somewhere.

 

[Mattax]

I did not think of using a rebuilt until my original is dialed in. Thanks
I could not find a rebuilt one so I ordered a new one, will be here Friday.
It was $57 but at least it will buy me some time.
Maybe I can find someone who has one of the Sun distributor test machines. They are still out there, somewhere.

Rockauto is showing Cardone rebuilds. I don't trust the new stuff will be as good quality as the old. people have posted some photos here.

If you're getting a rebuild, then it would be worth getting one that is supposed to be for a 4 bbl that didn't use a ridiculous initial timing like 5 ATDC or TDC. As far as I know, the best chance would be something from the catalytic converter era but not lean burn. edit: A possibility is a 1977 California Fury 360-4 bbl. That might have had an initial around 10 rather than something like 4 btc. I don't have '77 FSM or Sun card so its just an educated guess.

Not that hard to find people with a distributer machine, but finding someone close who also knows the Chrysler distributors will be your challenge in doing it that way.

 

[Mattax]

Halifaxhops sometimes has older MP distributors for sale. Those are decent.

 

[Builderguy]

Just got the FBO plate in the mail today. Now I have all the parts to change the timing curve and swap out the speedo cable. Plate, springs, speedo cable, and time. I will measure the plate openings to check with the info I have. 10* is .330, 12* is .350, 14* is .370, etc, etc.... I will do the initial timing again as the motor is a little more broken in now (not that it would change but I just want to be sure of my starting point). With the distributor apart I will be able to see the stamping on the VA and so I will know just how much that will add. The new speedo cable I purchased is 80" long, I don't
remember the original being that long. Will know shortly.

 

[Builderguy]

 

[Johnny Dart]

12-14 initial 34-36 all in, is all you need for timing on your mild SB. You are improving it into a failure with your plates and springs and Uber High Timing Specs. Keep it simple.

With your new distributor, and vac advance disconnected.
Run your timing up to 34degs all in.
Now let it idle, and check your initial.
Hopefully it is around 12.
Leave the vac advance disconnected and carb plugged.
Take it for a drive, and burn rubber all the way down the street.

After you have done this, then you can visit the vac advance.

 

[Illahe]

I ran out of time after the road test so I could not even check what the mechanical advance was at the 26 degrees initial I road tested. I will check that tomorrow and post it. I was just checking another way of setting the initial and that resulted in 38 degrees but I thought that too high so I set it at 26 and road tested it.


Yes, it is a thermo-quad (9002 S IIRC) and there is a mild cam (there were no numbers on it). No EGR or Emissions. Stock 1977 360 heads that were rebuilt. So I don't screw this up, at 3000 rpm there should be around 30-34 degrees mechanical with NO VAC. Can I dial this down from 40 ish using the hex adjuster on the distributor vacuum?

Look up Newbomb Turks thread on ignition timing. He spent a lot of time on his Sun Distributor Machine chasing curves for different applications.

​

 

[Builderguy]

Started the car up, let it warm up, and made some slight adjustments to the idle air fuel mixture screws. Checked the initial timing again it now really likes when it is at 22*. Let is sit for about 10 minutes to get good and heat soaked. Hit the key and it fired right up, no bucking the starter at all. Marked the distributor and pulled it. This is some of what I found so far. There are some arc marks on the top of the rotor, cap looks good. There was no space at all between the reluctor wheel and the magnetic pickup (should be .008 IIRC), one tab was actually touching the pickup. I will be changing the reluctor wheel at minimum and maybe the pickup too. IDK yet. The VA has 11* built into it. I have to take a break as that little horseshoe spring clip and I are having a little battle.

 

[Illahe]

Started the car up, let it warm up, and made some slight adjustments to the idle air fuel mixture screws. Checked the initial timing again it now really likes when it is at 22*. Let is sit for about 10 minutes to get good and heat soaked. Hit the key and it fired right up, no bucking the starter at all. Marked the distributor and pulled it. This is some of what I found so far. There are some arc marks on the top of the rotor, cap looks good. There was no space at all between the reluctor wheel and the magnetic pickup (should be .008 IIRC), one tab was actually touching the pickup. I will be changing the reluctor wheel at minimum and maybe the pickup too. IDK yet. The VA has 11* built into it. I have to take a break as that little horseshoe spring clip and I are having a little battle.

View attachment 1716543932View attachment 1716543933View attachment 1716543935View attachment 1716543934

Don't you have to use a brass feeler gauges for a magnetic trigger?

 

[cookietruck]

You don’t have to replace the reluctor wheel. You can adjust the air gap.

 

[Builderguy]

Don't you have to use a brass feeler gauges for a magnetic trigger?

Brass is the "correct" way, but I don't have any so I will use paper that I mic'd up for .008" thickness.

 

[Builderguy]

You don’t have to replace the reluctor wheel. You can adjust the air gap.

When I looked close at the wheel, it took some damage from hitting the pickup, which is why I will probably change it. Once it is cleaned up, I can get a better look at it.

 

[Builderguy]

Quick question. The VA is stamped 11R. As I understand it that means it is turning to the right (clockwise) and the 11 for 11* but this is at the distributor, so that would be 22* timing at the crank, right??

 

[RustyRatRod]

Brass is the "correct" way, but I don't have any so I will use paper that I mic'd up for .008" thickness.

Fold a piece of printer paper in quarters. There's your feeler gauge. I WOULD put a new rotor on. That one has seen better days, but it's still working. Also, forget about the vacuum advance when looking at timing. Leave it disconnected until you get initial and total sorted out. Then, just plug it in and let it add "whatever" it adds. It's not uncommon to see 60 degrees total timing driving down the road at part throttle. Perfectly normal. With 20 or more initial, you will of course have to limit total to no more than 34-36 all in by I'd say 3000.

 

[RustyRatRod]

12-14 initial 34-36 all in, is all you need for timing on your mild SB. You are improving it into a failure with your plates and springs and Uber High Timing Specs. Keep it simple.

With your new distributor, and vac advance disconnected.
Run your timing up to 34degs all in.
Now let it idle, and check your initial.
Hopefully it is around 12.
Leave the vac advance disconnected and carb plugged.
Take it for a drive, and burn rubber all the way down the street.

After you have done this, then you can visit the vac advance.

I agree with you a bajillion, a hundred fifty trillion, 875 million percent in over 90% of the cases out there...BUT there are exceptions. In the case of a stone stock, low compression engine with any kind of non stock camshaft, you're going to have LOW cylinder pressure and you'll need all the help you can get.

 

[RustyRatRod]

Is this a STOCK ENGINE like you say in post #23 or does it have some sort of performance cam? So far, you've been VERY VAGUE about the engine build, yet you want SPECIFIC answers. That AIN'T how this works. Good info in, good info out. Garbage in, garbage out. Understand?

 

[Builderguy]

Is this a STOCK ENGINE like you say in post #23 or does it have some sort of performance cam? So far, you've been VERY VAGUE about the engine build, yet you want SPECIFIC answers. That AIN'T how this works. Good info in, good info out. Garbage in, garbage out. Understand?

The original 318 was long gone when I got the car. The PO knew were little about the 360 that replaced it. The only thing he said was that he knew it had some cam in it and that it had been rebuilt just before he bought it. That is all he knew. From the engine numbers it matches a 360 from 78 or 79. Being the ID plate is blank it could have come from a LRT but I think it was from a Magnum. IDK but the heads were not from a LRT! I had the cam out and it looked good, not new good but good. I found no numbers on the cam. Pistons are stock as are the rods. Crank turned 10 and 10. Heads are stock, but rebuilt. With the bearing being destroyed as it was this engine did not run long after being rebuilt, or at least not long after failing and the rest of the bearings looked new, so I think it went to **** shortly after the "rebuild". I remember seeing a bill of sale for the engine in the paperwork that came with the car. I will rummage thru my files to see if I still have that. If the sellers name is on that I can try and dig up his info and contact him directly.

I did find out why the MA is so high. The stop plate is stamped R17, so that is 17* at the distributor meaning 34* at the crank at least that is my understanding. Not much room for initial if one only wants 34-36* total.

 

[Johnny Dart]

im going to try again, because you asked.
Initial 12-14
Total 34-36
Vacuum advance disconnected
Carb plugged.
Try it.

That's what is a sooooo frustrating about this site.
Someone asks for help, you give them sound advice.
And they completely ignore you.
You can lead a horse to water, but you can't make them drink.

 

[CRUZE 418]

Why can't a stainless steel feeler gauge be used?

 

[RustyRatRod]

Why can't a stainless steel feeler gauge be used?

It depends on WHAT type of stainless it is. If it's non magnetic, it's ok. But not all stainless is non magnetic. That's why I just use the folded paper method and go. It's so easy.

 

[RustyRatRod]

im going to try again, because you asked.
Initial 12-14
Total 34-36
Vacuum advance disconnected
Carb plugged.
Try it.

That's what is a sooooo frustrating about this site.
Someone asks for help, you give them sound advice.
And they completely ignore you.
You can lead a horse to water, but you can't make them drink.

I get run over like a freight train on a regular basis. Don't feel like the lone ranger. I actually agree with your point. He can always readjust it if it doesn't run well. It's not like the distributor suddenly locks down. lol Also, if that 17R governor really means 17 distributor degrees, he needs something different right off the bat. I'm unsure that's what it means, though. It's easy enough to measure with a school protractor and see just how much the distributor has, then times 2 for crank timing.

 

[CRUZE 418]

Okay. I do know that some grades of stainless are magnetic and will rust. Didn't think that my feeler gauges were of that grade, so I will check.
Thank you!