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Yeah that's it mate, cam manufacturers decided to specify the duration @ 0.05" lift, however this isn't the peak duration of the cam, its just a helping hand in dialing the cams in.

I see so many people choosing such wild cams like 280 degree's duration which just make them real lumpy and no bottom end power, when they could just opt to use a cam with a different LSA. Running a wide LSA gives a decrease in overlap making the cam much smoother and improved low-mid range, but limits top end power no matter how much duration of lift you have. Go the opposite way with a tight LSA the overlap increases meaning you loose bottom end torque, gives lumpy running but provides much better top end.

The stock inlet cam has an LSA of 110 degree's, exhaust is 112 degree's. Ivan Tighe billet cam's have an LSA of 114 degree's, as you can see here the LSA is widened for aftermarket billet cams to provide smooth running with increased duration.

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  • 3 weeks later...

I have recently acquired some 5E-FHE camshafts and over the bank holiday I took out my measuring tools.

The camshafts were first measured using a dial caliper and then to verify the lift was measured directly using a dial indicator with the camshafts sitting in vee blocks.

Base Circle + Lobe Lift = 40.85mm
Base Circle = 34.05mm
Lobe Lift = 6.80mm (Base Circle & Lobe Lift - Base Circle)

Base Circle + Lobe Lift = 41.05mm
Base Circle = 33.90mm
Lobe Lift = 7.15mm (Base Circle & Lobe Lift - Base Circle)

Base Circle + Lobe Lift = 41.60mm
Base Circle = 34.05mm
Lobe Lift = 7.55mm (Base Circle & Lobe Lift - Base Circle)

Base Circle + Lobe Lift = 41.35mm
Base Circle = 33.90mm
Lobe Lift = 7.45mm (Base Circle & Lobe Lift - Base Circle)

So 5E-FHE camshafts have
+ 0.75mm lift on the intake
+ 0.30mm lift on the exhaust

They are the only two sets of camshaft I have access to at the minute.

I will measure the duration of them one day too.


Edited by enzo_e492901
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  • 2 weeks later...

the 4E-F carb cams differ to the other 2 sets. they have less duration and or Lift as I recall. low end torque, workhorse engine ? I have a set. Wish I weren't so far out to sea, I'd donate them to be properly measured and updated in the database. had seen the specs on another forum before I had acquired the 4E-F though.

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