Does anyone have any information on the Gould underdrive? I have this underdrive but I need more information about it please?
I am also trying to set the valves using the piston height method but don't know whether I have standard pistons or high compression ones, so can someone please tell me what is the height of the standard piston above the block?
The standard piston is flat with beveled edges and rises about 5/16" over the deck plane:
(aluminum replacement piston shown)
The high compression pistons I've seen has a rounded top:
thank you Roger
Several problems exist with using the piston height method of valve timing. This system worked with the original cam shaft, block, pistons, and timing gear.
Many years have passed since the engine was new and camshafts have been replaced or reground to different dimensions Such as the Stipe camshafts. Pistons have been changed and might not have the same heights. Some timing gears have been altered to advance the valve timing. And lastly, the block might have been decked.
Anyway, if you use a new or reground cam, follow the directions from the manufacture for setting the clearance. If you don't know what you have, you can use the piston height method, but also check with a feeler gauge to see how much clearance you have. You might need to do a compromise between the piston height and the clearance. Important to get the four cylinders as close as possible to the same timing for smooth operation, however, the greater the clearance the less valve lift you will have and the noisier the engine will sound. You should have at least .010 clearance or more so that the valves will close completely. Also take into consideration whether the valve timing has been changed by using an advanced timing gear.
I gave up clearances to great so set at 12 &15 thanks NormanT
So what is the Gould underdrive? Pictures?
Drive carefully, and enjoy, W2