Re-profiling Cam Followers

[Terrytuned]

Reprofiled followers with a radius of 1.5" for a race engine, a 3/4" radius on a std engine gives a useful increase in performance without sacrificing to much torque. Check internal depth of followers before grinding as some are drilled deeper not leaving much metal before the face, I have a photo of an example will find and post.

Terry.

[Austin in the Shed]

Lightening the followers too ,Ian.  Std They are around 62 grams.You can reduce them to almost 30,but there is heat treatment and drilling and re heat treatment involved.
You get a crisper exhaust note on an engine fitted with re radiused followers too.

[Rogerfrench]

Alan, there is more power, so the engine needs less revs to give the same output, it was very noticeable at first (going up local hills), but not so now as used to it as it is still noisy! And since fitting the c.r. gearbox the car is much more usable and much better hill climbing.

The fewer revs per mile are only due to your higher intermediate ratios, nothing to do with the tappets, and in top gear there's no change. Unless, of course, you have a very special gearbox with indirect top gear.

[Terrytuned]

Found photo of failed follower and one of a set I removed from an engine as they were too flat and to thin at the face.  Terry

[Greig Smith]

Hi Guys

Excellent info & pictures, thanks all !!

We're in the process of sourcing a new cam with a grind for a supercharged motor and it makes good sense to do the followers at the same time

Aye
Greig

[Ruairidh Dunford]

Robert Foreman has the correct profile for a supercharged camshaft lodged with a grinders local to him - well worth getting in touch with him to see if he can help you Greig.

[Bob Culver]

Some may be confused by the mention of extended duration or not. The two extremes are a flat follower and a knife edge. With no clearance both lift as soon as the flank lifts above horizontal. but with clearance the flat follower lifts much earlier than the knife edge. So large radius followers do extend the duration somewhat. The small clearance occupies a surprising camshaft rotation; about 10 degress for open and close totalled
The Seven inlet duration is modest but not exceptionally so. Hard to compare as many cars assume a special clearance often not stated. (The SAE standard was an extra .006"") to accommodate slow ramps.
A flat follower causes theoretical infinite acceleration, something which Edge or whoever designed the engine (or the FN it was based on) knew.

[Mark Dymond]

I wonder if its a side valve engine attribute, that a fast rate of opening, as apposed to a longer duration must have an advantage. On my Speedy engine the cam profile is, to my eyes, ridiculously aggressive in the rate of opening and closing.

[Malcolm Parker]

I've always used flattened followers with a standard cam and it must be the best performance modification you can get for £25!
The Ulster has a Pigsty trials cam with standard followers.  It has incredible torque but is quite clattery, I am advised by someone who knows about these things that this is due to the cam not having any quietening ramps. 
Whilst on the subject of cam followers and in an attempt to squeeze out every drop of information from the racing experts, have assymetrical followers been used?  I don't know how you would go about machining them but presumably it could be done?   Would you use them on the inlets only?

[Terrytuned]

Yes Malcolm we have tried a full set but it pushes the power band to far up the rev range but they work fine as inlets only,I don't do them myself but I know a man who does. Terry.