SETTING THE CAM

[Fireman049]

I'm about to fit a new Piper camshaft to my TR3A. I'm a bit confused about setting the cam.

According to the manual all I need do is align the two dots on the timing wheels.

The camshaft specification states that the cam. should be set at 110 degrees.

Without vernier type timing wheels, how do I achieve 110 degrees?

 

Tom.

[MCOOPER53]

Tom,

 

First off forget about those dots as they only apply to the original factory spec cam.

 

This is how I set the cam on my 3A, the engine was out of the car btw. I measured the circumferance of the flywheel, in milimeres, divided that figure by 360 them multiplied that by the angle stated for the cam, in yourcase it would 110. That gave me a distance in millimetres I needed to measure around the flywheel, the flywheel has a factory scribbed line on it for TDC, so I measued away from that. I attached a pointer to the block and aligned it with factory scribbed line then rotated the flywheel till the mark I made aligned with the pointer on the block, the crankshaft is now in the correct position. You know need to set the camshaft so you have maximum lift on the inlet lobe on number one cylinder, use a dial gauge for this, when that is done you can attach timing chain and wheels.

 

Martin

[Fireman049]

Thank you Martin. The engine is out of the car so I'll follow your advice.

 

Regards ~

 

Tom.

[Ashley James]

By far the easiest way and what Kent suggest in their cam manual is to set one and four cylinders at TDC according to marks on flywheel and crankcase rear and pulley/pointer on front and with cam inserted and pushrods tappets in cylinder four, rotate cam backwards and forwards until the reach the point where one push rod is falling and the other rising. You put the chain on at the exact point of changeover. At this point cylinder one is on the firing stroke, so the distributor can be inserted and timed up as well.

 

If you use any other timing method, this is a good check.

Edited May 3, 2013 by Ashley James

[Fireman049]

Thank you Ashley.

 

Tom.

[Ian Vincent]

Buy a camshaft setting protractor (very cheap) and download the instructions from the Moss catalogue or from Piper's own web site. I have a Piper fast road cam and the timing settings are the same as for the original TR camshaft so you can use the original factory marks if you have a re-profiled cam.

 

Also, search the forum there have been numerous other posts on how to set the cam timing.

 

Rgds Ian