AHTOXA's TJ Rubicon Page.

[watkins]

You don't need a garage in TX

[AHTOXA]

You do. You at least need a covered parking spot. Without it, you are getting into an over every day. This was a new experience for me, too. Gets damn hot inside a car.

[potownrob]

And for gits and shiggles, here's a pic of two jeeps. Mine and the gf's.

[img]http://img.photobucket.com/albums/v730/ ... 2a.jpg[img]

good job tony!!

[AHTOXA]

Discovered a problem that's making me uneasy.

For 05 and 06 model years, the TJs got a different oil pump drive assembly (OPDA). It's bee causing issues.

The OPDA gear is run off the camshaft, powering the oil pump. The following have affected all TJs with the 4.0 for the two production years
- upper bushing in the OPDA unit doesn't get enough lube
- drive gear gets worn and wears the camshaft gear
- lower bushing gets questionable lubrication resulting in shaft scoring

All of this leads to cam gear wear and in the worst case scenario, a major failure that results in having to replace the OPDA, camshaft, lifters, etc.

I am affected by this issue. The pictures below aren't mine but are nearly identical to the wear i'm seeing.


This is the gear on the oil pump drive assembly that's run off the cam gear.




While the OPDA gear is supposed to be the sacrificial gear, meaning that the cam get is made stronger by design, the cam gear still experiences wear.

Chrysler has no solution for this - just a TSB directing to replace to OPDA with the same unit that will fail. People are reporting issues with as few as 15k miles on the motors. There are no aftermarket companies making a replacement because the unit is patented by Chrysler.

While there aren't guaranteed fixes, there are possible solutions:
- modding to OPDA with a zerk to lube the upper bushing
- running a higher ZPPD content oil (consensus from reputable and knowledgeable companies lies in the lack of zink and phosphorous content in oil to lube a worm-style gear)
- and that's about it


I'm going to switch to a differnt oil with a higher ZPPD content and to a new OPDA and will check for further wear. Right now it's not looking very good for many of us, later TJ owners.

Rope - you ever got any wind of this?

[Rope-Pusher]

^ Blah-Blah-Blah long reply.

Blah-Blah-Blah must log in again.

Blah-Blah-Blah where did my reply go to? page back, page forward, page back again - spit, it's gone!

Blah-Blah-Blah I'll ask around, but that was over 6 model years ago, and before the great exodus by 25% of the employees, and two motors ago, so the odds on finding someone who followed that issue are getting slimmer by the day.

Chrysler slant 6 engine was known for longevity in general, and was in production for over 25 years, but every so often, there would be material, surface finish or heat treat issues in the oil pump drive system and supplier quality assurance would get called in to go beat-up the supplier until they fickset things and promised to never let it happen again, but nobody ever got the assignment to tweak or redesign the system so that it wasn't as sensitive to quality issues.

That's the problem with engineering - you're always $0.25 or $0.50 away from greatness, but so are 50 other parts of the car and when you build hunnerts of thousands a year it begins to add up to real money.

[theholycow]

Would a differently designed OPDA from a different year fit? What if you swap in more parts until it does fit? I guess if you take that far enough it becomes cheaper to just let it fail.

^ Blah-Blah-Blah long reply.

Blah-Blah-Blah must log in again.

Blah-Blah-Blah where did my reply go to? page back, page forward, page back again - spit, it's gone!

I hate when that happens. I never have the will to type it all again.

Sometimes I type long messages in Notepad and paste them, or just copy to clipboard before I click Submit, but usually I don't.

There are browser add-ons that can automatically save form data but I rarely dabble in them. I'm not sure why.

[Rope-Pusher]

There are browser add-ons that can automatically save form data but I rarely dabble in them. I'm not sure why.

I should hope not - it wooden bee a pretty site!

dab·ble verb \ˈda-bəl\
dab·bleddab·bling

Definition of DABBLE

transitive verb
: to wet by splashing or by little dips or strokes : spatter
intransitive verb
1
a : to paddle, splash, or play in or as if in water
b : to reach with the bill to the bottom of shallow water in order to obtain food

[AHTOXA]

Cow,

The OPDA from other model years does not fit. Major changes are required and at that point it will be easier to swap a 4.0 in it's entirety from a, say, '04.

There are now some considerations I must make.

[Rope-Pusher]

Cow,

The OPDA from other model years does not fit. Major changes are required and at that point it will be easier to swap a 4.0 in it's entirety from a, say, '04.

There are now some considerations I must make.

Dry Sump Oiling! Keeps the bearings moist even as you cartwheel down a hill.
http://www.4x4jeeptruckaccessories.com/ ... 97229.aspx

...or, go with what you know and give it a stroker

http://titanengines.com//titan-monster- ... orque.html

[AHTOXA]

Stroker doesn't resolve the issue, neither will a dry sump.

The upper bushing on the OPDA doesn't get enough lubrication. It's a closed bushing, as opposed to an open bushing design from the previous few years. Lack of lubrication causes drag on the shaft, putting wear on the OPDA drive gear as well as the camshaft gear.

What we need is a redesigned OPDA that can with with this version of the 4.0.

[1974Alfa5spd]

If that's the case, it sounds like the best thing to do is have it modded for a zerk fitting.
Is there any kind of warranty left on this thing that might be voided by doing such?

[AHTOXA]

If that's the case, it sounds like the best thing to do is have it modded for a zerk fitting.
Is there any kind of warranty left on this thing that might be voided by doing such?

You are right on the money, my friend. There are many folks who have done just that - installed a zerk fitting to keep the upper bushing lubed. Only time will tell but this is still not the fix, according to those who have attempted this. It's only a preventative measure. There's still an issue of the camshaft gear and the OPDA drive gear wearing, even with modded upper bushing. While replacing the OPDA is a job of 30 minutes (I had it pulled in about 10, once I broke the 1/2" bold loose). It's the wear on the cam gear that is the biggest concern. Camshaft replacement isn't cheap and some people ended up doing this every 50k miles, which is absurd.

While my issue isn't as tragic as some, it's still bad enough to cause grave concern.

[Rope-Pusher]

Sure the dry sump will work - you don't drive anything off that gear on the cam anymore! Yanno, a dry sump isn't always just draining your oil and running the engine until it blows, right?

Stroker motors can be bought as short blocks or long blocks - hopefully with oiling systems from more robust years of production. I'm sure you could axe them.

http://www.moparproshop.com/inc/sdetail/5036/5044

or save some money and move on up in the world:

http://www.moparproshop.com/inc/sdetail/5036/6044

[AHTOXA]

The other day when I started the Rubi early in the morning, she exibited the metallic screeching sign of faulty OPDA. THe upper bushing dries out and makes the noise. Overheating and seizing of the bushing is likely if ignored.

Yesterday I decided to pay the extra $40 and get the new OPDA from the dealer, vs. having it shipped and waiting until early next week while rising serious collateral damage.

Thankfully I was able to use the g/f's garage last night. Pulled in, got the motor to TDC, removed the old, swapped in the new - no problem. Timing was aligned. I go to start her up, she cranks for about 5 seconds (very long), fires and runs. Check engine light's on. I disconnected the battery, reset the ECU, reconnected - same problem - cranks for a while, then fires. Went for a drive around the block and discovered that she's in limp mode, cutting fuel off at 2500 RPM.

Got back to the garage and started checking timing. Nothing looked off. Then I notice that one of the 3 wires from the cam sensor in the OPDA is cut! It was sliced at about 45* angle about a quarter inch into the harness - I happened to tug on it and that's how I noticed. What the f**k! I saw the guy at the dealer open the vendor-sealed box right in front of me so I could make sure it's the part that I need.

I swapped the sensor from my old OPDA into the new OPDA, which immediately resolved all issues and cleared the CEL.


Next step: today I'm on a search for dieselt motor oil with the right viscosity, which will contain a greater amount of zinc and phosphorous, which is suspected to be the culprit in OPDA gear wear. Modern oils have reduced the quiantity of the two, which is likely contributing to the issue.

[Rope-Pusher]

Whale oil was used in GM ATF for many years!