Hi - I’m building an XK engine and I very recently got a new reproduction version of the Oil pump/Distributor Drive shaft (C8646). Several companies sell that repro part. Mine had a serious problem that is not visible to the eye - it’s only when tested that you see the problem. I don’t know if it’s a one-off defect or what but better safe than sorry.
The issue is that the offset slot that engages the drive-dog teeth is too close to the center by a few thousandths. Thank goodness I was messing around at the bench and tried to engage the bottom of my original, low mileage 22d6 distributor with it - it would not go without forcing!
That prompted me to drop it in the block without the bronze gear and try to mesh the distributor. Not happening. I also found after some more messing around that the ‘head’ of the shaft that meshes with the dist drive dog is too thick by a few thousandths so that if you do get the dizzy in it has no clearance and may push the head against the bronze bushing and cause excess friction until it wears the bushing down - all of this is a great way to break a bronze gear among other things.
I will spare you the details of my attempts to modify it to make it work and various adventures in measuring… just please, to anyone building an XK motor with that reproduction part - save yourself ALOT of potential cursing and extra work/money/aggravation: Try to fit it to a distributor out of the car first. If it works, drop the shaft into the block and test fit the distributor and bolt the dizzy down. It should fit easily and rotate perfectly with no appreciable friction…
5 minutes of test fitting will save your sanity.
~Mike
1972 Series 1 XJ6 (x2)
1973 Series 1 XJ6
1985 Series 3 XJ6
1984 XJS
Hi Mike. Parts that don’t fit are never fun. I hope you’ve passed this information on to the supplier so they can get with their manufacturer to resolve the problem.
I use a cube of alloy against each flat side in turn to align the drive and driven shafts before putting the hollow connector sleeve over both ends and hiding any misalignment.
A picture would help but I don’t have sny and the engine is assembled so I can’t take pix now.
Basically, there are two square drives connected by a short sleeve with a matching square ID. Depending on exacf oil pump dimensions (some are ‘generic’) and whether the three mounting bolt holes are drilled accurately, the square drive on the oil pump and the distributor may not line up perfectly It can be hard to spot but there’s not much room for a conventional straight edge. o I use a short piece of square bar and by trimming it you can place it into the small space and see if all four faxesv
The original poster is talking about the top end of the dizzy drive shaft having an improper off-set for the dizzy’s drive dog, and being too thick to the point that bolting down the dizzy removes all end float between dizzy and drive shaft…though I don’t know how the second problem was determined if proper engagement(full dizzy seating) was not achieved. In any case, it sure looks like the replacement part is defective.
I believe Crespin is talking about the bottom end alignment issues of the short drive coupling as between the dizzy drive shaft and oil pump. Any potential binding here is easily check upon oil pump installation simply by wiggling/turning the coupling as oil pump is tightened down. There is some wiggle room between the oil pump bolts and their holes so I found it no problem getting a satisfactory fit. The coupling itself is not a super-tight fit…at least mine wasn’t.