Slight Set Back

[ChrisD]

After developing a humming/buzzing noise from the under the inlet manifold and starting to overheat on the way to the garage, it appears I didn't locate the pump fully on the Jackshaft when refitting the pump after having it refurbished. A a result I have ruined the teeth on the jackshaft and pump

Hopefully my car will be back on the road in time for local Classic Car show at Kirkleatham Museum, Redcar on Sunday 22nd September.

Chris

[stagmuffin]

ouch!! good luck for the refit .

[flying farmer]

I had the same thing happen on a Dolomite Sprint engine several years ago (same pump)

Teeth were perfect when I fitted a new seal set at about 80,000 miles, 3000 miles later they were knackered, so was the jackshaft.

The pump can only go in one position vertically or it will catch the pump cover, assuming the bush in the block is OK then there can be no lateral error either.

The only thing I wonder is wether the pump and shaft teeth bed into each other in a certain position, removing the pump and refitting on another tooth means they are running on a very small contact area and wear rapidly. A quick count up of jackshaft and pump teeth reveals a ratio of 12 : 8. By my reckoning each pump tooth contacts three jackshaft teeth only over the course of two jackshaft revolutions.

Think of it like a 24 hour clock, and three 8 hour shifts, midnight, 8am, 4pm then back to midnight.

Cannot for the life of me think why perfectly good teeth self destruct in such a short period apart from this. Maybe if rebuilding a leaky pump, we ought to note which teeth are in mesh on pump removal, and try and put them back in the same place.

I still prefer to throw the bl**dy things away though!

Neil

[Westfaling]

I had the same thing happen on a Dolomite Sprint engine several years ago (same pump)

Teeth were perfect when I fitted a new seal set at about 80,000 miles, 3000 miles later they were knackered, so was the jackshaft.

The pump can only go in one position vertically or it will catch the pump cover, assuming the bush in the block is OK then there can be no lateral error either.

The only thing I wonder is wether the pump and shaft teeth bed into each other in a certain position, removing the pump and refitting on another tooth means they are running on a very small contact area and wear rapidly. A quick count up of jackshaft and pump teeth reveals a ratio of 12 : 8. By my reckoning each pump tooth contacts three jackshaft teeth only over the course of two jackshaft revolutions.

Think of it like a 24 hour clock, and three 8 hour shifts, midnight, 8am, 4pm then back to midnight.

Cannot for the life of me think why perfectly good teeth self destruct in such a short period apart from this. Maybe if rebuilding a leaky pump, we ought to note which teeth are in mesh on pump removal, and try and put them back in the same place.

I still prefer to throw the bl**dy things away though!

Neil

Is that really possible? As the gears have different numbers of teeth isn't this constantly changing?
Nick