Back to life!
So, been looking at oil pumps, because I am putting together another engine.
This applies to 4G63 DOHC only (6 bolt)
Original straight cut gears are still available, both drive and driven.
MD121120
MD125361
But, the housing is not (MD129347). It is now under "conditional interchange" meaning they tell you to purchase the replacement (helical type gears and case).
Part numbers for those are (also shown with the bulletin Rausch posted above):
Case: MD175762
Gears: MD174581, MD174582
So, if you have a damaged early case, I guess you are out of luck to replace it.
There have been anecdotal statements both here and on other forums where people say it is fine to use the straight gears in a helical case, but the bulletin specifically states they are not interchangeable, and there are some machining differences in the case (not that you can see or even measure accurately, but they exist). I am loathe to do this of course.
Interestingly, there are aftermarket pumps that say the come with the drive gear, but you will have to use your driven gear. They don't specify if they use straight or helical, but I am betting on the helical. Then you would have to get a new driven helical gear (if replacing a straight cut pump) and hope it fits the aftermarket case (I'm sure they are copies, but identical?).
I have another core here I am going to tear down and check the pump first, but looking dire on continuing to use straight cut pumps.
