lightened radius lifter

Lightened lifter for Nortons with BSA style tappet block conversions. Chamfered 3/16" hole. 36 grams (stock Nort lifter is approx 75grams). Anyone with a drill press can do this himself.

How many grams do you save by drilling v. undrilled? Any reliability issues?

Very Interesting. A light lifter made even lighter.
Thanks JS
Cheers,
Cheers,
Thomas
CNN

Onder said:

How many grams do you save by drilling v. undrilled? Any reliability issues?

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Just weighed 4 lifters with no holes and got a total of 152 g, so stock they are 38 g each.

If you look at Triumph lifters, some are drilled all the way through the side faces of the feet. Some have the side faces scalloped. Personally, I'm not aware of either of these being any weaker than solid feet.

Some Triumph lifters (I believe from the 500 unit motors) had hollow stems, but these are weaker and the feet can break off.

Triumph lifters have smaller diameter stems than BSA, so are lighter. But I guess the thicker stem is stronger. The question is, does it need to be?

Fast Eddie said:

If you look at Triumph lifters, some are drilled all the way through the side faces of the feet. Some have the side faces scalloped. Personally, I'm not aware of either of these being any weaker than solid feet.

Some Triumph lifters (I believe from the 500 unit motors) had hollow stems, but these are weaker and the feet can break off.

Triumph lifters have smaller diameter stems than BSA, so are lighter. But I guess the thicker stem is stronger. The question is, does it need to be?

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The Triumph lifters can break. You don't want any failures at all so its the thicker BSA lifters - thats the best available option for Brit bikes and brand new quality lifters are available now from SRM. They went to a lot of trouble bringing them so lets help them out.

A few grams may not be much but every little bit helps. I haven't done any destructive testing but the lifter in the photo is used so I'd say its passed the test. The drilled holes reveals that the shank is hollow. This also helps get rid of any oil (weight) in the shank.

Presently I'm looking at some Harley cams and their roller lifter is .855" diameter. Thats too big to get into the Norton lifter tunnel. Space seems too tight to get a roller lifter in there with reliability. And as someone mentioned in another thread (who helped build Westlake speedway motors) - everything has to be perfect with the roller lifter or there is premature wear.

The other thing to consider is todays oil. The EPA has pulled out some additives because they damage catalytic converters. ZDDP is very important (according to the hype) for non-roller lifters. This means more wear with todays oil. The easy way to add ZDDP is the simple & cheap addition of STP which has ZDDP (zinc) as an ingredient.