Rocker arm oil bump

[jareness]

Want to install .348 Webs, and the news is that the rocker arm oil bump has to be removed. Wha? What is this, and is it hard to get rid of?

[Homie]

The rocker arm oil "bump" would be the tiny oil orifice adjacent to the cam lobe contact face on the rocker. Its there to keep the cam lobe / rocker arm contact face lubricated.

I have not heard that it needs to be "removed".

The only issues with the rocker arms that I am aware of are: a) with higher lift cams and heavier valve springs rocker arms with "hardend" contact faces are recommended to prevent premature contact face / cam lobe wear, and; b) longer adjustment screws may be needed for high lift small base-circle cams in order to ensure that locknut fully engages the adjuster screw.

Maybe a more knowledgeable race engine builder such as Ray or Terry might be able to enlighten you (us) on the oil "bump" subject.

[jareness]

Oil bump

Thanks Homie. I saw what you're talking about on a picture of a rocker. The suggestion was from Web Cams. Maybe I just need to grind it down flat?

[rapidray]

Yes, grind it flat. Ray.

[Greg B]

They are easy to grind down with edge of a small Dremel cut-off wheel.
Be sure to chamfer the oil hole after grinding the bump away.
Of course you will have the rockers out the head. And clean them
thoroughly before you re-install them. In the same locations they were
removed from.

[jareness]

Oil bump

Thanks Ray. Advice I got was to put them in at 106 In, 108 Ex, for a little more grunt on the low end. 1166, flatslides, 0.030 shaved from head...does this sound right to you?

[jareness]

Oil bumps

Thanks Greg. They're going in tomorrow. Pretty stoked, since I've already gone 10.30 @129 with the stock cams.

[rapidray]

Thanks Ray. Advice I got was to put them in at 106 In, 108 Ex, for a little more grunt on the low end. 1166, flatslides, 0.030 shaved from head...does this sound right to you?

That's about right. What was the set up that you ran 129 mph with?!!! What was done to that motor & how much do you weigh? Make sure you measure the piston to valve clearance!!!!
Ray.

[jareness]

Set up

I think the reason the bike ran the 129 was due to the (stock) cams being degreed by Scott at S & K. The first time I lined it up I had the low rev limit at 4500. When I let the clutch out it died. Next time I set it at 5K and it took off like underwear after the prom. I had also just put on a 43 tooth rear I bought from one of the guys in here (from the 51 tooth I had on it) and a set of 38mm flatslides. I think both helped a ton on top. The 10.37 was the result of me not launching the bike very well (1.75 60 ft.).
As for me, I weigh almost 200 lbs. But I just put a 7" slick on it (had a 5” on the good run) with a monocoque wheel that weighs less than half of the 5" wheel I just posted in here.
I was going to put in the cams tonight with the help of a fellow racer, but for reasons I won't mention it's going back to S & K so I know it'll get done correctly.
Dreaming of nines...

[bellucci]

Me too....ZZZZZZZZZZZZZZZZZZZZZZZZZZZZ
Curt