The V8 Owners Forum -

As today seems a good day for everyone to learn something, answer these questions:

1. I know the new pump is driven by the woodruff in the crank nose and I know exactly how the gears look, but how the hell does it work!

2. Why is it important the the gears are marked and aseembled with the same tooth engaging, but why? doesn't look any different.

adamnreeves wrote:As today seems a good day for everyone to learn something, answer these questions:

1. I know the new pump is driven by the woodruff in the crank nose and I know exactly how the gears look, but how the hell does it work!

2. Why is it important the the gears are marked and aseembled with the same tooth engaging, but why? doesn't look any different.

1. http://www.animatedsoftware.com/pumpglos/crescent.htm

2. I would assume it does not matter in the real world but is good practice

The pump should not be driven by the key - neither is the front pulley or timing chain. The key holds everything in line until you do up the big bolt in the end of the crank, then friction drives the components threaded on to the crank nose. At least that is the traditional engineering answer.

Dave

Thanks, that's a good demonstration.

pitsnow wrote:

adamnreeves wrote:As today seems a good day for everyone to learn something, answer these questions:

1. I know the new pump is driven by the woodruff in the crank nose and I know exactly how the gears look, but how the hell does it work!

2. Why is it important the the gears are marked and aseembled with the same tooth engaging, but why? doesn't look any different.

1. http://www.animatedsoftware.com/pumpglos/crescent.htm

2. I would assume it does not matter in the real world but is good practice

Erm, I think I know what you mean, as long as the fit is relatively tight I suppose.

davemgb wrote:The pump should not be driven by the key - neither is the front pulley or timing chain. The key holds everything in line until you do up the big bolt in the end of the crank, then friction drives the components threaded on to the crank nose. At least that is the traditional engineering answer.

Dave

The marking of the gears are for assy reasons, normally most gear displacement pumps are made with a "Hunting Tooth", this ensures that the number of teeth do not divide exactly into the other teeth so the wear is constant thrughout the running of the pump, IE if you have a 8 tooth gear running against a 8 tooth gear, the same teeth will allways fall on same teeth, if you have 8 & 9 teeth they will allways be rotating so the wear will be constant.

Neat.

ian.stewart wrote:The marking of the gears are for assy reasons, normally most gear displacement pumps are made with a "Hunting Tooth", this ensures that the number of teeth do not divide exactly into the other teeth so the wear is constant thrughout the running of the pump, IE if you have a 8 tooth gear running against a 8 tooth gear, the same teeth will
allways fall on same teeth, if you have 8 & 9 teeth they will allways be rotating so the wear will be constant.

Regarding lubrication of the gears before assembly, I know that normally just engine oil and I know someone on this thread said gear oil as it is thicker. I have had a brain wave, I bought rather too much cam lube and have loads left, you know the red thick stuff which is suppose to stick to the cam lubes pretty well. I could use that ? Worst case scenario is that this engine I am building may not be started for upto 12 months, I hope it will not be that long, but you never know.

davemgb wrote:The pump should not be driven by the key - neither is the front pulley or timing chain. The key holds everything in line until you do up the big bolt in the end of the crank, then friction drives the components threaded on to the crank nose. At least that is the traditional engineering answer.

Dave

I now what your saying but I don't agree that the parts wouldn't slip without the key being there. When there is slip there is wear, more wear more slip until you have no more friction and everything just spins. Granted the key isn't the only means of drive but its very important that its there and not just for alignment on assembly.

Guys

I think I canstop learning for a few days following this threadQ

Amazing knowledge on the forum as usual

cheers
Ian