New Distributor won't index correctly.

I have a 96 with 4.0 and the current distributor shaft is shot and the rotor made contact with the cap post.

I ordered new one from Napa and attempted the installation today. Here's what I did:

1. Pulled plug #1
2. Manually cranked motor over with finger in plug hole to verify compression stroke and set motor to TDC on #1
3.Lined up Harmonic balancer mark with 0 on degree marks.
4. Pulled old distributor.
5. Set the oil pump drive thingy to 11 o'clock position.
6.New distributor has a plastic pin to keep the rotor aligned to the dizzy body.
7. Insert starting a 1pm position and let it rotate in as it drops.

Here's the problem:

When it rotates in the clamp won't line up and is off by a 1/4 inch or more. :flamemad:

If I follow the exact procedure above I can install the old one with no issue (I use a 3/16 punch in the cam sensor alignment hole to keep things lined up).

Could it be the new one has the helical gears incorrectly installed? Anyone else encounter this with a replacement?

Thanks!

New distributor - old cam?

Wondering if the camshaft is worn along with the gear on distributor -- would make sense why the old worn,matched parts align easily and a new distributor with new drive gear won't mate with the worn cam gear

When I did mine (also '96 4.0) I found the plastic pin just made things harder, so I pulled it out before I even started. The distributor shaft also has a tab on the bottom, so you don't even have to go to the trouble of setting the engine at the correct position. Just pull the cap on the old one, note which way the rotor is pointing, and drop the new one in while making sure that the tab on the bottom indexes correctly, and the rotor is pointing in the correct position. Re-install the hold-down bolt and go drink beer.

I had a similar problem when I installed a new distributor in my 96.
It seemed that the hole for the roll pin in the gear was off a little, or the gear itself.
I ended up using the gear off my old distributor and then it went in correctly.

ID96XJ said:

I had a similar problem when I installed a new distributor in my 96.
It seemed that the hole for the roll pin in the gear was off a little, or the gear itself.
I ended up using the gear off my old distributor and then it went in correctly.

Click to expand...

Winner, winner, chicken dinner. I read this before and thought about it but when you posted it I decided to give it a go. Sure enough that fixed it.


Thanks.

I've also heard of the gear being installed 180 degrees off at the factory. It can be removed and rotated one half turn and reinstalled on the shaft. Apparently the roll pin hole isn't symetrical to the gear teeth...

Runnin'OnEmpty said:

I've also heard of the gear being installed 180 degrees off at the factory. It can be removed and rotated one half turn and reinstalled on the shaft. Apparently the roll pin hole isn't symetrical to the gear teeth...

Click to expand...

You are correct. I called the MFG and they mentioned the same thing. I am running it with the old gear in it and will just leave it like that.

Runnin'OnEmpty said:

I've also heard of the gear being installed 180 degrees off at the factory. It can be removed and rotated one half turn and reinstalled on the shaft. Apparently the roll pin hole isn't symetrical to the gear teeth...

Click to expand...

I tried that on mine and it was still off.

The guys saying they re-used their original distributor gear have the best answer.

From the factory the difference between the 2.5L and 4.0L distributors was the gear was about a half tooth offset. However, the aftermarket shops like A1 Cardone only list one part number for both 2.5L and 4.0L engines.

You might try returning the one you bought and getting another one and see if it works.

md21722 said:

The guys saying they re-used their original distributor gear have the best answer.

From the factory the difference between the 2.5L and 4.0L distributors was the gear was about a half tooth offset. However, the aftermarket shops like A1 Cardone only list one part number for both 2.5L and 4.0L engines.

You might try returning the one you bought and getting another one and see if it works.

Click to expand...

I already put the old helical gear on the new distributor and it works perfect. I wanted to post in the event someone else runs across this problem.