Is it worth going back to the original camshaft on my 240z?

[jalexquijano]

Besides of the trouble i am having with the bad temperature and oil Reading on my 1972 240z i am also considering on reverting to the original camshaft as the car is tending to fail when it is between 800 to 2,000 RPM. Once it reaches over 3,000 RPM it is really stable.

The car actually has the following specifications:

New Datsun L24 motor with crank and rods from a L26, special oversized 84mm flat top black coated pistons from D.L. Potter Engineering with E88 Head and Far 311 New Race Cam.

2 original SU Hitachi round top carburetors rebuilt.

Is it really worth going back to stock cam???? if so what parts will i need to change?

Edited April 9, 2014 by jalexquijano

[CEgg11]

I think it is probably more the carbs not being properly set than it is the cam, and the carb would be much cheaper to fix. There are more knowledgeable carb guys than me, but maybe you are just running too lean at low RPM?

[TheGrimOne]

I know with fuel injection the ECU cannot compute extreme modifications like aftermarket cams, and the megasquirt FI is a must for aftermarket work like that. As far as the cam behavior itself, its sounds like a stage 2 cam and will want to be driven hard, rough at idle is normal for race cams, and the power comes in between 3k and 5k rpm. so if your just worried about the idle, the cam will make it a bit sluggish, and if you dont have good enough fuel delivery, you will not see any benifit to having aftermarket cams, and it may even be lean at WOT, and may even hurt something eventually with a flow restrictive exaust.

Anyone else have more knowledge on the effects of the carbs themselves ?

[jmortensen]

The FI comparison isn't a good one. Carbs can run pretty much any cam, although the specs on the cam will vary how the car runs in a particular rpm range. Wasn't able to find a "Far 311" cam by googling. I would suspect a carb tuning issue like balance, which causes low rpm issues or maybe a needle and seat misalignment issue or something like that.

I ran basically stock SUs with stock, high lift low duration, and a medium sized .490/280 cam and the car ran great with all three on stock 70 needles (which I don't think are available anymore).