While hamfistedly tearing down my motor (I shall update that thread in due course) I broke the oil pump housing, but (with help from @Deefer66 ) I found a new cover and thought I'd be on my way. But after I put my pump internals in the new-to-me housing, nipped the 10mm nuts up and now can't shift a thing! It is ok just until the point of tightening up, but I really don't need to nip up much before it is solid. I've done a bit of measuring, but need some help with best way to fix it. Here's the gears in the old housing: They are about 0.2mm recessed from the casing. When I put the gears in the new casing it is about the same. However, the hole where the stationary shaft for the secondary gear (ie not the gear driven by the camshaft) is 0.2mm deeper on my new casing than the old casing Old casing 8.17mm New casing 8.39mm So, I think this means the stationary shaft going through the secondary gear in the pump body isn't acting as a spacer on my new housing as there is a 0.2mm gap at the bottom of the shaft and I guess there is is no room for the gears to move. I wonder whether I can shim the gap with a 0.2mm shim - which feels a bit of a hack, but at least is reversible - and this shaft doesn't move. Or whether I can tap the other side of the shaft 0.2mm further out. Obvs it is tricky to tap 0.2mm even with my smallest lump hammer. If I knock it more than 0.2mm will it push itself back when I nip up the housing? I'm concerned this is a good way to ruin my pump. Am I on the right track? Any other ideas?
Just checked and both casings have same part number 021.115.109a - so not that. But one does have 3c and the other 3h stamped on. The pump body has 2f stamped on (can see on last image of first post) - dunno if they mean anything. I can’t see anything on the googles to suggest anything.
If there's a recess above the cogs when in the case can't see how they can be "squashed " by the cover?? Weird... You could try engineers blue on the cogs to see if it shows up where's rubbing? Drive shaft?
I tried a bit of lapping compound which did help somewhat implying it was a straightforward clearance issue, but looks such a mess now it will take so much fine compound to get it smooth I admitted defeat and bought a CB performance Maxi pump. Was also worried about clearances and not really knowing what I'm doing, so a shiny new pump will keep my mind at ease. No time to waste any more! I might end up fixing the original pump one day, but just need to get on the road before summer - and the World Cup really isn't helping!
Is a gasket missing? The stock oil pump gaskets would be around 0.5mm thick or less on a T1 pump for instance. So your existing pump may have worn itself to the point that the extra clearance of the gasket is not needed.
Be careful using a Maxi pump, inspect and measure it. They are often undersize on the OD and leak pressure inside the crankcase. And if you’re using a bolt on cam gear it will probably need to be modified to clear the bolts.
The type 4 pumps have the gears inside the case with an o-ring. So no chance of altering clearances with gaskets.
Yes, I had read such. I’ll measure compared to old pump when it comes. The case is still apart, so easy enough to check clearances to cam bolts. Thanks
