Explorer serpentine timing pointer

[Johnnyb]

I need to time my motor to 12° BTDC (I marked it with an orange line) and I have an explorer serpentine setup. The timing marks are on the harmonic balancer, and I have an article with a vague diagram of how to make a pointer to fit where the sensor goes.
My question is how do I determine exactly where the pointer should be?
Is the center of the hall effect sensor the pointer location?

 

[bax]

There is a factory pointer that goes over the crank sensor. It should be easy to get one.

 

[Johnnyb]

There is a factory pointer that goes over the crank sensor. It should be easy to get one.

Thanks for the tip, just ordered one.

Looking for some right now guidance, however, to set the crank 12° BTDC so I can install the Edelbrock distributor.

 

[Johnnyb]

Ok, got lucky and found the factory part but it fouls the harmonic balancer if I try to use the CPS mounting holes

 

[DirtDonk]

Looks like it could be bent out of the way pretty easy. Or completely modified to have just a small area pointing to the damper.
Generally though when customizing something like this, you make your pointer to match the existing marking if you can, but if that isn’t possible you simply re-mark the damper to match the pointer.
If you have to do that you can put the pointer and marker wherever you want so it’s easy to view from up top with the engine running.
Like you probably knew all that but sometimes talking it out can open up new options.

 

[Johnnyb]

Looks like it could be bent out of the way pretty easy. Or completely modified to have just a small area pointing to the damper.
Generally though when customizing something like this, you make your pointer to match the existing marking if you can, but if that isn’t possible you simply re-mark the damper to match the pointer.
If you have to do that you can put the pointer and marker wherever you want so it’s easy to view from up top with the engine running.
Like you probably knew all that but sometimes talking it out can open up new options.

I'm just struggling with proper indexing for TDC, so I can set the 12° advance I need. The mark on the pointer is quite a bit further to the right than where the sensor position is. If I bend the sensor that might affect the timing.

 

[bax]

Pull # 1 plug and bring the piston to TDC. You can stick a screwdriver in the spark plug hole and slowly rotate the motor at the balancer. You can feel the screwdriver stop moving up when you get to TDC.

 

[DirtDonk]

I thought I read you were using a carburetor. So why do you need the sensor?
Break in only maybe, and then EFI later on?

 

[DirtDonk]

Sorry, I see it wasn’t a carburetor I was thinking of. You were talking about a distributor.
So you’re running it on a TFI system?

 

[Johnnyb]

Pull # 1 plug and bring the piston to TDC. You can stick a screwdriver in the spark plug hole and slowly rotate the motor at the balancer. You can feel the screwdriver stop moving up when you get to TDC

Thanks bax,
Yes, that's a great role of thumb but there are quite a few degrees when the crankshaft rolls over. There's no appreciable motion in the piston. I marked the point when the piston seemed to stop moving up and the point when the piston seemed to start moving down, then selected the midpoint as my TDC. Maybe I'm obsessive compulsive but I would sure like a more accurate gauge.

 

[Johnnyb]

Sorry, I see it wasn’t a carburetor I was thinking of. You were talking about a distributor.
So you’re running it on a TFI system?

Thanks DirtDonk,
I decided on the Edelbrock pro flow 4 system, and it would like the motor static timed at 12° before top dead center during distributor installation.
I used the screwdriver method to estimate TDC and then advance it 12°, based on the marks on the harmonic balancer.
Like I said I'm being obsessive compulsive and I would sure like to have a reference.
Thanks,
JB

 

[bax]

Ok. then there is another way. Can you build a piston stop? Something that you can screw into the #1 piston hole that will impact the piston and stop it.Set up a timing pointer, install the stop rotate the engine till it stops on the stop you made. Make a mark on the balancer at the pointer. Then rotate the engine that other way till it stops. Make another mark. Half The distance between the marks will be TDC. Crank the motor by hand.

 

[Johnnyb]

Ok. then there is another way. Can you build a piston stop? Something that you can screw into the #1 piston hole that will impact the piston and stop it.Set up a timing pointer, install the stop rotate the engine till it stops on the stop you made. Make a mark on the balancer at the pointer. Then rotate the engine that other way till it stops. Make another mark. Half The distance between the marks will be TDC. Crank the motor by hand.

Thanks bax, I think that's the answer! I'm going to try that in a little bit and I'll let you know.
I only get to work business hours cuz I rent a bay in a shop which has its advantages and disadvantages, but I should be able to test this after 9:00 a.m. local time.
-JB

 

[Johnnyb]

So I did the piston stop thing and found a pretty good top dead center, within one or two degrees.
TDC proved to be about 45° counterclockwise from the sensor, way off of what I would have expected and way off of what would have been indicated had I mounted the factory pointer. The harmonic balancer is new, so it shouldn't be off, just made it rather challenging to build a pointer.

 

[DirtDonk]

I don’t suppose you have the original damper just to compare the marks?
Mismarked dampers are a super common problem with standard 302s but I’ve never heard of an explorer damper being mislabeled.
Which would make sense because they are a unique damper. They weren’t made to fit multiple versions of the engine.

Does anyone know how the factory timed this engine? It was unique with coil packs and a crank trigger so maybe the crank trigger tells the computer something based on it being approximately 55° before top dead center?
That’s a starting point, and the computer simply retards it from there based on how it wants it to run.
No idea of course, but it sounded very scientific so I threw it out there!

 

[Johnnyb]

I don’t suppose you have the original damper just to compare the marks?
Mismarked dampers are a super common problem with standard 302s but I’ve never heard of an explorer damper being mislabeled.
Which would make sense because they are a unique damper. They weren’t made to fit multiple versions of the engine.

Does anyone know how the factory timed this engine? It was unique with coil packs and a crank trigger so maybe the crank trigger tells the computer something based on it being approximately 55° before top dead center?
That’s a starting point, and the computer simply retards it from there based on how it wants it to run.
No idea of course, but it sounded very scientific so I threw it out there!

Yeah dirt I super appreciate the input. It's a 95 mustang block with the explorer serpentine setup including harmonic balancer.

I was expecting the top dead center mark to be somewhere directly below the water pump pulley or close to the crank sensor.

My very careful TDC test yesterday put the 0° TDC almost 90° over to the passenger side!

What's even stranger, there's a great write-up on the explorer serpentine conversion on this site which tells you that the sensor missing tooth is at 60°, my missing tooth is clearly right at the 30° mark.

 

[Johnnyb]

Ok. then there is another way. Can you build a piston stop? Something that you can screw into the #1 piston hole that will impact the piston and stop it.Set up a timing pointer, install the stop rotate the engine till it stops on the stop you made. Make a mark on the balancer at the pointer. Then rotate the engine that other way till it stops. Make another mark. Half The distance between the marks will be TDC. Crank the motor by hand.

The piston stop method worked well. Thanks for your suggestion!

 

[904Bronco]

Post#4 picture... That does not appear to be the correct pointer for an Explorer set up, looks to be an earlier 302 style.
Maybe a cause for your interference?
I will have to look for an extra pointer, that I have somewhere, to send you a picture

 

[bax]

The piston stop method worked well. Thanks for your suggestion!

Those are some of the first steps into the process of degree-ing a camshaft into the proper position.

 

[bax]