Changed OPDA but my camshaft gear has wear. Need a dose of reality.

fizzlebottom

TJ Enthusiast
Joined
Apr 21, 2019
Messages
298
Location
seattle, wa
The only CELs I've had were O2 sensor related. I did not have any squealing either. I've had a Crown unit in the garage for a while and finally got around to swapping it in. Things went well except for the very stubborn retainer plate bolt. Why is it so hard to find a 6-point 1/2in. box wrench?

When I pulled the original OPDA, it wasn't great looking. And then I shined a light down the block and saw the cam gear. It is ... uhhh ... also not great looking. I'm not going to post pictures because quite frankly it is embarrassing that I waited this long to swap them. To my credit, I had 0 symptoms. Just believe me that I think some people here would be screaming at me for not getting a new camshaft ASAP.

Anyways. I'm running the Crown unit now and took a 15 min test drive. I wound the motor up to around 4k and everything is just spiffy. No noises, no CELs. But I feel that with the worn cam gear that I am on borrowed time now. The motor made it 160k miles with a shit OPDA.

Maybe I'm looking for some sliver of hope here. Worst case scenario is that something is eventually going to grenade and I'll end up with a new motor. Best case I can get another few years out of this and change either just the camshaft or the whole motor on my own time.

Give me your thoughts. Punch me in the gut, reassure me, whatever. Think I just need to release some of this anxiety about having a worn camshaft gear and know how other folks might approach it.
 
I'm in a similar situation; 140k miles, O2 CELs, and no noise. I have a new one sitting on the shelf, but I haven't pulled the old one yet. My thought is; it's running fine, but what if I don't get it back in in the exact same position. :(
 
This OPDA shit has been blown way out of proportion in my opinion!
Look at it like this: you have a 2005 running good for 16 years and maybe did or did not need warranty OPDA work years ago? you changed it as a "preventative only" and now you are worried because you see your cam wear.
How many 2004 and earlier owners inspect their cam gear?
The truth is if you do your research the gear drive in the OPDA is harder steel than the cam gear steel so that is why the cam gear wears more! The OPDA problem was never a cam gear problem! if the OPDA was lubricated enough and turned freely it worked.

Story time :) When I was looking for a TJ Mr Google led me to this Forum every time with quotes from one person who said he would never buy a 2005 or 2006 because of the OPDA problem and said it for many years, well there is no study on just how many 2005/2006 TJ,s are in the wreckers yard compared to other years because of worn cams and failed OPDA.s only recall info on 2005/2006 fitted with a supposed band aid fix, well guess what that band aid fix has lasted 16 years and going strong.
I would guess your 16 year old cam is worn no more and possibly less than an 18 year old TJ cam.

Think Edsel or Tucker or even Concord lol Drive it into the ground til your cam fails or doesn't. :)

Edit: Just to add there are Thousands of 2005/2006 TJ,s in australia they were very popular years but there is no mention of OPDA or cam failure.
 
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The only CELs I've had were O2 sensor related. I did not have any squealing either. I've had a Crown unit in the garage for a while and finally got around to swapping it in. Things went well except for the very stubborn retainer plate bolt. Why is it so hard to find a 6-point 1/2in. box wrench?

When I pulled the original OPDA, it wasn't great looking. And then I shined a light down the block and saw the cam gear. It is ... uhhh ... also not great looking. I'm not going to post pictures because quite frankly it is embarrassing that I waited this long to swap them. To my credit, I had 0 symptoms. Just believe me that I think some people here would be screaming at me for not getting a new camshaft ASAP.

Anyways. I'm running the Crown unit now and took a 15 min test drive. I wound the motor up to around 4k and everything is just spiffy. No noises, no CELs. But I feel that with the worn cam gear that I am on borrowed time now. The motor made it 160k miles with a shit OPDA.

Maybe I'm looking for some sliver of hope here. Worst case scenario is that something is eventually going to grenade and I'll end up with a new motor. Best case I can get another few years out of this and change either just the camshaft or the whole motor on my own time.

Give me your thoughts. Punch me in the gut, reassure me, whatever. Think I just need to release some of this anxiety about having a worn camshaft gear and know how other folks might approach it.
It will run fine until there is too much slop in the gears and it throws a code for too much difference in the cam and crank readings.

You eliminated the chance of a seized OPDA destroying your engine due to lack of oil pressure.
 
I have a 2006 TJ Unlimited with 236k that was running then original OPDA before I changed it to the crown unit. I’m sure it probably wasn’t needed, but I did it for peace of mind. It ran great before the swap and runs great after.
 
Mine was clicking like valve train noise so I replaced it. I saw it was worn a little so I purposely didn’t look at the cam gear because I didn’t even want to know what it looked like. It will work until it doesn’t. I had no cels or anything other than the noise.


6AA11E14-7C1E-47C3-A5D2-957D21B296D5.jpeg
 
I've heard about the issue being blown out of proportion but the anxiety of a blown motor was weighing too heavy on my shoulders. Good to know I'm likely worrying too much. I went to inspect the old OPDA the other day and it spins freely and quietly; no noise, nothing that feels like a binding bushing or bearing. I'm wondering if this unit was treated to the pre-Crown TSB of drilling a hole in to allow oil lubrication. Haven't looked closely to see if there are any extra holes yet.

Regardless, I'll run it til the motor takes a dump and then start looking at a replacement from the likes of S&J or Jasper or something similar. I'm in Seattle and S&J is in Spokane, so they'll be on the top of my list.

Thanks for the peace of mind folks.
 
096D5038-3F40-4515-A687-0D6D204045D1.jpeg

Here is my factory one with 236k. If was labeled Rev. E if that means anything.
 
I'm in a similar situation; 140k miles, O2 CELs, and no noise. I have a new one sitting on the shelf, but I haven't pulled the old one yet. My thought is; it's running fine, but what if I don't get it back in in the exact same position. :(
I'm in a similar situation; 140k miles, O2 CELs, and no noise. I have a new one sitting on the shelf, but I haven't pulled the old one yet. My thought is; it's running fine, but what if I don't get it back in in the exact same position. :(
I was the same! I had it sitting in a box for ages, it was ordered from Rockauto not long after I bought my 06 but in the end it was a simple install, no harder than taking out a distributor.
Two people are best although I did mine alone and the reason I say two people are best , the secret is to getting the old unit exactly Top Dead Centre but if you miss it you need to go around again, If you have the plastic pin in the new unit you fit that pin into the old unit before you take it out and it locks it at TDC so if you get cold feet half way through or the old one doesn't come out easily you can simply drop the old one back in place.

Start by taking the cap off the old one and the new one just to see how simple the design is, its a distributor without points. The retainer bolt is the hardest job, you need to be blind a contortionist so I would attempt the bolt first on a a dry run. :)
 
Mine was clicking like valve train noise so I replaced it. I saw it was worn a little so I purposely didn’t look at the cam gear because I didn’t even want to know what it looked like. It will work until it doesn’t. I had no cels or anything other than the noise.


View attachment 269126
If you would have seen a worn cam gear you would be forever worrying about it being a ticking timebomb as much as you were the OPDA, I didn't look at my cam gear either :)
 
A deep offset wrench will make getting the bolt out much easier.
I had to go to 3 different shops to find a 6 point 1/2in box wrench. That retainer bolt was a real beast to remove because it's in such a tight spot. I ended up using a 6in clamp to pull the wrench towards the motor mount. Other than that, everything went by the book.

I did it all alone. Once the alignment hole was close, I moved the crank by very very small amounts until I could use the pin that came with the Crown unit. Got that in, old opda came right out and new one went in without any timing problems at all.
 
"I did it all alone" Same as me! now you need to forget about it! Its totally blown way out of proportion on this forum by those who have never had an 05/06. The problem vehicles were 16 years ago! Enjoy your late model TJ :)
 
My daughter and I did two, hers and mine, a couple of weeks ago. it’s very easy once you get the bolt broke free. Hers was very tight. Not a single issue other than that. It’s hard to go wrong if you use the plastic pin that comes with the new Crown unit to align the holes in the old one coming out and the new one going in.
 
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"I did it all alone" Same as me! now you need to forget about it! Its totally blown way out of proportion on this forum by those who have never had an 05/06. The problem vehicles were 16 years ago! Enjoy your late model TJ :)
I own a 2006 LJR. I have put 30k miles on it this year. It has the original OPDA, but I did buy a Crown unit. I opened the hood and showed the new OPDA to the old one and also showed it a wrench. I think the threat is enough to keep it in line.
G'day!
 
Never had an issue getting the bolt back in at all.
I think its because I have fairly big hands and the TJ is higher than other vehicles I have worked on, I had to feed it onto the hole holding it with just 2 fingers and my eyes shut! lol
 
I think its because I have fairly big hands and the TJ is higher than other vehicles I have worked on, I had to feed it onto the hole holding it with just 2 fingers and my eyes shut! lol
I definitely had a slightly tough time getting the first thread in place. Large hands as well. After that it was all gravy.
 
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