Cam shafts for 3000

[Marvin Gruber]

I am rebuilding two late BJ8 29K engines. One is all std size while the other has been into and built before. It now has .040 over pistons. I get the cranks back Monday. My question is about one of the camshafts. The one that came out of the std engine measures 1.38xx, which I understand is correct for the BJ8 motor. I have two other camshafts that I have picked up, the bored engine was disassembled when I got it and did not have a camshaft in it. One cam measures 1.45xx with one lobe at 1.43xx, pretty sure I won't be using that one. Other one measures 1.48xx, will it help or hurt the .040 engine. Not trying for a high performance engine but will take the extra horses.

Marv

 

[SideShifter Tri-Carb]

Don't have a definite answer, but here is what I think. Larger bore, more air/fuel available for combustion. More lift, more time to get the air/fuel in and combustion gases out. But if you don't do proper head work, (larger valves, port/polishing), the ports won't be efficient to remove the gases. I would THINK that the duration is equally important if not more for the timing aspect.

 

[EV2239]

The BJ8 camshaft is generally agreed to suit the car best.

Power is a function of revs and regardless of carbs etc, a hotter cam will give more power at higher revs and less at lower revs, so normal driving is spoiled for the few occasions when you can Rev the engine to its peak.

Not only do hotter Camshafts push the power up the Rev range, they also narrow the power band, so that the huge gap between second and third gear is an issue.

Before you fit a higher performance camshaft to your Healey try to drive a car that has one and make sure it is what you want. Some who've fitted a BJ8 cam to the earlier cars regret it because they pulled so nicely from negligible revs.

IMO they're a nice old car in standard form and any attempt to improve them comes at a price. They'll never be a Boxster.