Standard 6 timing gear backlash

[McNigel]

I am rebuilding my 1925 Standard 6 engine and just fitted a new camshaft with the original timing gears.

The backlash seems pretty high, I measured ~20 thou at the cam gear OD.

I am inclined to accept this and keep building, because of the limited availabilty of new or good used gears (especially here in europe).

Does anyone have any bad experiences with backlash this high

[Mark Shaw]

Backlash is not a problem with unidirectional spiral gears.

[Hubert_25-25]

I did not even check this on my car.  A Buick buddy found me a good used gear, and as you say, the choices are very limited.  I have had no issues.  I did reject a gear that had not failed because it did look a little worn in.  That one is now my spare, but I will have to decide if I lose the existing gear if I will install it or look for a new one.  "Then and Now" does sell replacement gears, but they do not have the steel hubs.  I also had the gear that was in the engine and that had good teeth overall, but had teeth that were damaged - I assume from the previous owner trying to remove the water pump shaft incorrectly.  A pity to lose a gear this way.

 

Do pay attention to the timing marks and the alignment that is in the workshop manual.  Current practice is that the timing marks are in alignment if you draw a straight line between the camshaft and the crank shaft And you are on TDC.   These dots are not on that straight line when you are on TDC.  The marks are several degrees before TDC when you look at the drawing.

 

Also ensure you have a good screen on your oil pump as you can recover from a lost gear with relative ease if the screen is in good shape.  

Hugh

 

  

[McNigel]

Thanks Hugh, that gives me a bit more confidence to carry on, cheers Nigel