centar gas engine gears

[Frank Boyle]

Hi
The gears supplied have centres that are 5/16" over drawing dimensions and the larger gear would need a pocket in the side of the engine to be at 9/16" centres as drawing also the larger gear has a bore of .472" and the shaft is 3/8" ,If fitted will this effect the timing.
Frank

[Jo]

Morning Frank,

I am not sure what you mean by 5/16" over drawing dimensions as the skew gears are not on the drawings. The original ME article suggests acquiring them from a car distributor or speedo drive, they need to have a 2:1 ratio and if the distance is greater or less than the 7/8" to displace the camshaft upward and downward to suit. 

Yes you need to cut a pocket in the side of the sole plate to clear the larger gear. The smaller gear is keyed on the crankshaft so it needs a 3/8" bore. The larger gear on the cam shaft and that can be sleeved.

Jo

[Frank Boyle]

A good morning to you Jo
Thank you for a prompt reply.The drawing specifies 7/8" centres and the centres of my gears will be 1 3/16"hence the 5/16" differance.
Frank

[Jo]

Got you.... Ok you might have to think about the effect of the offset on the valve lift caused by the changed position of the rocker arms and adjust the position of the camshaft to compensate.

Jo

[Jasonb]

Frank what angle are your supplied gears cut at as depending on the angle the big one may go on the crankshaft. I think they have been supplied with several different spec gears over the years.

[Frank Boyle]

Jason the angle of the gear teeth is 44degrees .The large gear has an integral collar which looks to be the spacer from the bearing.I have just phone reeves and was told that the gears as supplied are commercial gears and they don't supply purpose made gears for this engine,if not satisfied they will refund the cost of the gears.
Frank

[Jo]

Frank this is the pair on my engine and they are about 1" between centres.

Jo

[Jasonb]

In that case the big one will definately go on the cam shaft.

As Jo said you will have to lower the cam shaft to suit the revised ctrs and then look at how that will affect the rods and rockers. Debolt sell a set of skew gears that have 1.097" ctrs which is not quite so far out and may be another option if you can get your money back from Reeves.

http://www.deboltmachine.com/id5.html

[Frank Boyle]

Jo,your gears are smaller than mine.The large gear is 1.613" and the smaller is .950" .what sticks in my craw is that Reeves have supplied the gears for this engine knowing that they are not as the drawing and yet no modification was made to the drawings.I have made all of the parts to the cylinder head and am dissapointed to find this discrepancy .It looks like I have got to make up my mind to try what I have and see if I can adjust what I have made to suit.Thank you all for your valuable input.
Frank

[michaelr]

I used a 1.123 dia 32 DPD x 24 teeth on the side shaft, and 12 teeth gear on the crank shaft, the gears are from HPC, the valve gear is made as the drawings show the inlet pushrod is slightly off perpendicular which makes no difference to the running of the engine.

Mike.