Distributor indexing help

Performance mods and Advanced Stroker discussion.
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Turbos10
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Joined: June 6th, 2018, 5:24 am
Stroker Displacement: 4.6L
Vehicle Year: 1986
Vehicle Make: Jeep
Vehicle Model: CJ7

Distributor indexing help

Post by Turbos10 »

I have searched and I am not finding a 100% conclusive answer...
I am working on getting my 4.6 finished up and I am having trouble figuring out the distributor indexing. I got this engine in a series of boxes and this is my first 4.# build, so bear with me if I’m missing something easy.

I have an aftermarket cam and I think the indexing is off just a little. I have read and found the procedure for pinning the rotor in place, but I can not figure out where the pin would go and I can not seem to find a picture of it. I have read about using a punch or other tool to lock the rotor, but I just don't see where it would lock in. I am attaching pictures of how the distributor sits right now. I took the wheel part off to see if I could see a place for an alignment pin and I just don't see anything lining up. What am I missing? This distibutor looks like a older renix but was on a 92 HO.
As best I can tell it is 8-10 degrees off of what is factory indexing, which brings up up the other question. From what I can tell the timing is controlled off of the crank sensor and the cam is simply used to verify cam phase and just has to be inside of a set parameter. So, the question there is, what is the parameter tolerance? Is this picture close enough? It lines up with the #1 terminal, so it is very close. I’d rather not grind tabs off.

Cam is a Howards I bought from Titan Engines if anyone knows how the indexing is on those. They claim to have no issues.

Any input or pictures are Appreciated.
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Cheromaniac
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Re: Distributor indexing help

Post by Cheromaniac »

Looks like it's a few degrees off. Hopefully this will help:

http://www.angelfire.com/my/fan/dist_index.html
1992 XJ 4.6 I6 - 5MT - Stroker build-up, Stroker "recipes" Sold
1995 Mustang GT - 4AT - Modded Sold
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Turbos10
Posts: 7
Joined: June 6th, 2018, 5:24 am
Stroker Displacement: 4.6L
Vehicle Year: 1986
Vehicle Make: Jeep
Vehicle Model: CJ7

Re: Distributor indexing help

Post by Turbos10 »

Cheromaniac wrote: June 14th, 2018, 12:26 am Looks like it's a few degrees off. Hopefully this will help:

http://www.angelfire.com/my/fan/dist_index.html
Thanks, yes, I think it is a few degrees off. I found Dino’s page and pictures. In my pic if you look close you can see a line scribed at 3cm like Dino suggests. I’d say the centerline on mine is about 2.5cm from the notch.

So, the question is, will this work or should I grind the tabs to move it around? I’ve read that timing is controlled from the crank shaft alone and injector phase is controlled with the cam sensor. I’m not concerned about a few degrees for injector timing.
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Cheromaniac
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Re: Distributor indexing help

Post by Cheromaniac »

I'm Dino BTW and yes, you'll need to grind one of the ears off and turn the distributor body slightly anticlockwise.
The ignition timing is fixed and determined by the CPS, while the cam position sensor inside the distributor is responsible for synchronizing the injector firing pulse with the spark.
Turbos10
Posts: 7
Joined: June 6th, 2018, 5:24 am
Stroker Displacement: 4.6L
Vehicle Year: 1986
Vehicle Make: Jeep
Vehicle Model: CJ7

Re: Distributor indexing help

Post by Turbos10 »

Cheromaniac wrote: June 15th, 2018, 12:31 am I'm Dino BTW and yes, you'll need to grind one of the ears off and turn the distributor body slightly anticlockwise.
The ignition timing is fixed and determined by the CPS, while the cam position sensor inside the distributor is responsible for synchronizing the injector firing pulse with the spark.
Haha, hey Dino! Thank you and great website by the way. I basically built the same short rod engine you did except I used the newer metric ring hypereutectic pistons. I hope to fire it in the next few weeks. Trying to get all of the little stuff figured out so I get a clean startup and breakin.
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Cheromaniac
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Re: Distributor indexing help

Post by Cheromaniac »

Sadly I had to sell my Jeep before I left the UAE at the end of 2016 to settle in Cyprus. I was only allowed to import one LHD vehicle into Cyprus so it had to be the Mustang. Shame 'cause I owned the Jeep for over 21 years and it had a lot of sentimental value. The new owner was a very lucky guy, especially as I left him boxes of spare parts as part of the sale.
The Mustang more than makes up for it though. It's great fun to drive, leaves me grinning from ear to ear, and turns a few heads as well. The 4.6L Modular V8 roar from 3500-6500+rpm is intoxicating. Decent fuel economy at least doesn't drain my wallet too much with 95 RON octane (91 US) costing almost $6 per US gallon!
Turbos10
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Re: Distributor indexing help

Post by Turbos10 »

Just to follow up, I ground the tab to get it a little further around, but it wasn’t 100%. Engine cranked the first try, idles perfectly smooth and runs like hell. I suspect as long as it’s pretty close no real difference will be seen.
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