TIII oil pump failure causes?

[powermaxx]

Read a few posts on this as common for the TIII motors. I know the TIII oil pump is overdriven (compared to the TII,etc..) 2:1 vs the 1:1.

So do the gears strip on the pump or I shaft? Does the gear on the pump shear the pin that holds the gear to the oil pump drive shaft?


Or all of the above?:D Enquiring minds want to know.

Mine will also be driving a distributor so I'll have a "Safety" shut off as oposed to the DIS stuff.

[LowSL2]

I asked this same question a while back. It seems that the failures come from the oil pump being overdriven, pump being installed incorrectly, pump gears bound up inside the pump housing, or a loose timing belt causing damage to the I-shaft bearings which could cause the drive gears on the pump to get chewed up.

I think it was Jackson that recommended using an 8V I-shaft gear to get the oil pump to spin at normal speed. And to help save the I-shaft bearings. This is what I plan to do when I re-build my TIII as well as examine the new pump I get for any problems. Then I'll probably use an oil pressure cutoff switch so if pressure gets too low, a light will come on and the engine will shut off.

[turbovanman²]

http://www.turbo-mopar.com/forums/showthread.php?t=17717&highlight=pump

http://www.turbo-mopar.com/forums/showthread.php?t=11788&highlight=pump

http://www.turbo-mopar.com/forums/showthread.php?t=10876&highlight=pump

[zin]

Mine killed the pump, shaft and bearings... :yuck: I suspect that the bearings went and allowed the pump/shaft gears to not mesh properly, with predictable results. The oil pump had been replaced under the recall, though I'm not sure what issue the recall (and new pump) were supposed to fix, seems like if you just replace one part with an identical one, the problem still exists.

Anyone know exactly why Mopar overdrove the oil pump? I expect the 16V engines needed more flow, and a smaller pulley would be cheaper than a specific hi volume pump for just these cars, but I've never had an official explanation.

Mike

[turbovanman²]

Anyone know exactly why Mopar overdrove the oil pump? I expect the 16V engines needed more flow, and a smaller pulley would be cheaper than a specific hi volume pump for just these cars, but I've never had an official explanation.

Mike

I bet it was packaging. Running the 8 valve int gear makes the belt longer and the engine wider so to speak, and I can't run the idler pulley on the ps pump unless I can find a longer belt.

[Lotashelbys]

IMO the reason the oil pumps fail is mostly from too loose of a timing belt tension. The way the TIII belt is ran it causes alot of harmonics,especially the longest run between the intake cam and I-shaft. We all know that the TIII has too much sping pressure and the cams are already working hard against each other causing most of the nasty harmonics. Then if you put a loose belt into the senario you have the poor little teeth on the I-shaft(which is already spinning 33% faster than the 8V)and the teeth on the pump getting a thrashing put on them. That is the weakest link in everthing that is being ran by the timing belt if you think about it. Then the TIIIs are 5spds so you are on and off the throttle most of the time when driving them so that just intensifies the problem more. The on the other side of things the I-shaft bearings get beat up almost as bad as the shaft and pump. How many of you uys have pulled a TII with a decent amount of miles on it and not have pieces missing otu of the bearing at around the 11 0'clock position? I think the same thing is going on there with the bad harmonics and spinning too fast. Then if you think about it the I-shaft bearings are the weakest point since there are only a big and a small bearing and there are 5 mains on the crank and plenty cam bores to evenlt distibute them out in the head. I think too tight of a belt also is bad on these bearings causing them to "burn up" faster as well. I hope this makes sense because I just was kinda babbling on.....

Another thing that someone should try is to move the idler pulley to between the intake cam and the I-shaft. To me this makes sense that it would take away some of the harmonics on that run. This is just a thought me and Bryan(yogart-slinger) had when I stopped at his place last might on my way home and we were looking at an SRT4 motor he had sitting there. this might be worth looking into.....

[Blue Iroc R/T]

+1 ^; Well said Jackson. I agree 100%. The only thing I would add is, I think that the NEW Titanium Valve Spring Retainers that help reduce tension on the cams (due to changing the closed height on the valves), is a big help in reducing the harmonics on the timing belt. IMO, the Ti retainers and a properly tensioned timing belt will greatly reduce chances of bearing and oil shaft failure. :nod:

[Lotashelbys]

+1 ^; Well said Jackson. I agree 100%. The only thing I would add is, I think that the NEW Titanium Valve Spring Retainers that help reduce tension on the cams (due to changing the closed height on the valves), is a big help in reducing the harmonics on the timing belt. IMO, the Ti retainers and a properly tensioned timing belt will greatly reduce chances of bearing and oil shaft failure. :nod:

Thanks Ralph,I agree with you 100% as well with the Ti retainers. If every TIII owner had a set of those and their belt tensioned to 95 at all times they would have alot longer belt and I-shaft/oil pump life.

[LowSL2]

So to keep the oil pump happy the consensus is...


8V I-shaft sprocket
Titanium valve spring retainers
Timing belt tensioned to 95 lbs at all times


Did I miss anything?

[turbovanman²]

The only problem running the 8 valve sprocket is you remove the idler, so too me, that causes more harmonics. My belt likes to buzz at a certain rpm.

We need to find a longer belt, sigh. :(

[Lotashelbys]

Simon,idler between the intake cam and I-shaft........You know you want to do it.....

[powermaxx]

Good stuff!

[turbovanman²]

Simon,idler between the intake cam and I-shaft........You know you want to do it.....

Well, I have to change my head, move my distributor so maybe! :eyebrows:

[mock_glh]

I've had a similar experience with my 8v motor that I run at 6500-7000 rpm. The bypass passages in these pumps is not big enough to relieve the pressure above a certain rpm. The TIII pumps are driven 33% faster and thus 6000 rpm is like 8000 rpm to the pump. The amount of power that takes is more than the gears can tolerate and they strip. High volume oil pumps make this problem worse. An external high flow bypass valve would be a good idea I think.