Rocker arm modification?

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sierra3dr
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Rocker arm modification?

Post by sierra3dr » Fri Jun 19, 2020 9:45 pm

Hello everyone. I'm in the e process of rebuilding my eichberg turbo cologne and was wondering if anyone has modified the rocker arm tip by adding a millimetre or two of whatever metal it is, probably cast iron?
Thanks
Paul

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stevemarl
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Re: Rocker arm modification?

Post by stevemarl » Fri Jun 19, 2020 11:08 pm

Are they not usually case hardened? In which case you`d need to do whatever mods (if even possible) and then find somewhere that can `re-harden` the contact surfaces. The problem would be if a tip broke off at high revs :shock: ?

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Re: Rocker arm modification?

Post by Mc Tool » Sat Jun 20, 2020 7:56 pm

Dude (read this to the wife :D ) If your even thinkin about welding a bit on to your rocker tips you NEED roller rockers . I assume this welding mod is to accomodate a bit more lift ?
Without actually knowing for sure but I would think the stock rockers are some sort of steel alloy and I guess a bit of a splatter with a hard facing welding rod (or similar ) could work with a bit of a polish.
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Re: Rocker arm modification?

Post by Stroker » Sat Jun 20, 2020 9:40 pm

Hmmm... Not sure what the idea of welding to the rocker arm is, but if you're trying to increase the lift or change the rocker ratio, lengthen the rocker tips won't work. That's because the colognes rocker assembly are fixed along with the distance from the rocker pivot point to the valve centerline, increasing the rocker length will only add weight to the rocker. The only way to increase the rocker ratio is to change the pivot ratio or move the rocker assembly.
Moving the rocker assembly up or down may slightly optimize the swiping action across the valve tip.

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Re: Rocker arm modification?

Post by sierra3dr » Sat Jun 20, 2020 11:47 pm

Thankyou gents. Yes,I am aiming for a couple of mm's of extra lift. Correct Stroker,adding the extra metal to the tip won't assist in my intentions,I can see that now,because of the 0.35/0.40mm clearance. Stroker,I did see your method in full on Capripower. I couldn't see the difference,but see it now,the rocker is more closer to the valve.

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Re: Rocker arm modification?

Post by Stroker » Sun Jun 21, 2020 1:16 am

I basically made the distance between the pushrod and the rocker shaft centerline shorter, and that has made a small change in the rocker ratio. It has moved the rocker closer to the valve center line, ideally I should really move the rocker assembly away from the valves and that would give another small increase in lift.

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Re: Rocker arm modification?

Post by sierra3dr » Sun Jun 21, 2020 12:08 pm

:cool:

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