powdered rocker ball broke

[Clem Z.]

Re: powdered rocker ball broke

They aren't, but the ones Clem found have a sliding barrel trunnion, similar to F**d rocker arms. They would be permitted, if the dimensions are usable.

Jim

with the difference in price i think the one i posted about are true roller bearings. the picture they show is not what i believe they are.

[Michael H.]

Re: powdered rocker ball broke

it is a stamped steel rocker so i would read the rule real close ing.

Ok, I understand.

[Jim L.]

Re: powdered rocker ball broke

with the difference in price i think the one i posted about are true roller bearings. the picture they show is not what i believe they are.

Oh. That changes things. I was going by the picture. A rocker arm as illustrated would be permitted by HMSA and General Racing, the two left coast organizations that hold the most appeal for Jerry.

Jim

[Clem Z.]

Re: powdered rocker ball broke

Oh. That changes things. I was going by the picture. A rocker arm as illustrated would be permitted by HMSA and General Racing, the two left coast organizations that hold the most appeal for Jerry.

Jim

i am not sure the one you are referring to would be of any advantage over the chevy PM ball pivot type as i would guess that the pivot would also be PM.

[Clem Z.]

Re: powdered rocker ball broke

i don't know how close they check but i would build a shield to deflect the oil onto the rockers that would cover the fulcrum and just show the stamped steel rocker tip. but i may be a little sneaky.

[Joe C.]

Re: powdered rocker ball broke

GM was working it way up SLOWLY on rocker ratios as in 1997 the LS engine series came out in the C-5 with 1.7 rocker ratio. now the ZO-6 engine uses 1.8 rocker ratio. GM does not move swiftly !!!

Because the LS "cathedral port" heads flow so much better than the old style heads.

The reason that the LT4 used 1.6:1 ratio rockers was because of its redesigned and much improved head design. If the gen II smallblock continued to live on in high performance Corvette applications after 1996, you can rest assured that the LT4 heads, and the high ratio rocker arms, would have eventually found their way into "lower performance" versions of the Corvette engine when hypothetical "LT6, LT7, LT8, etc" iteratations would have been developed.............

Check out the differences in the LT1 vs the LT4 heads here:

http://www.grandsportregistry.com/lt1vslt4.htm

Properly ported double hump heads respond VERY well to high lift rocker arms. Additional work on the block itself, in conjunction with the head work is also necessary to make the heads deliver maximum flow.

[Clem Z.]

Re: powdered rocker ball broke

just adding 1.6 rockers to a SBC is no guarantee it will make more power as there have been several magazine articles where adding the 1.6 rockers caused valve float to come in earlier than with the 1.5 rockers on the same cam.

[Jerry G.]

Re: powdered rocker ball broke

jerry did you do this ????

Not yet, still putting the engine back in the car. Have to load up for Portland race on monday. One trick being used is to utilize Ford rocker balls which are larger and have more surface area. They have to be lapped into the base of a Chevy rocker. This all gets pretty silly for vintage racing. One of the problems with the ball system is that it doesn't locate the rocker arm very well so the rocker moves around and accross the valve tip. Even with adjustable pushrod guides. I think the Ford barrel system does a better job of locating the rocker arm.

[Clem Z.]

Re: powdered rocker ball broke

Not yet, still putting the engine back in the car. Have to load up for Portland race on monday. One trick being used is to utilize Ford rocker balls which are larger and have more surface area. They have to be lapped into the base of a Chevy rocker. This all gets pretty silly for vintage racing. One of the problems with the ball system is that it doesn't locate the rocker arm very well so the rocker moves around and accross the valve tip. Even with adjustable pushrod guides. I think the Ford barrel system does a better job of locating the rocker arm.

all use a PM pivot material and i still think your broken one was just a freak as i build lots of SBC and BBC chevy engines with the stock type rocker system for racing and never saw a pivot break like yours.

[Joe C.]

Re: powdered rocker ball broke

just adding 1.6 rockers to a SBC is no guarantee it will make more power as there have been several magazine articles where adding the 1.6 rockers caused valve float to come in earlier than with the 1.5 rockers on the same cam.

That is VERY true....................but who said that adding 1.6 rockers guarantees more power?

Same argument holds true for any engine. Even MORE true for the Mark IV series engines with their feeble valvetrains! Adding 1.8 rockers to a BBC is a fatal mistake in many instances.

[Clem Z.]

Re: powdered rocker ball broke

That is VERY true....................but who said that adding 1.6 rockers guarantees more power?

Same argument holds true for any engine. Even MORE true for the Mark IV series engines with their feeble valvetrains! Adding 1.8 rockers to a BBC is a fatal mistake in many instances.

you need to get a cam designed for 1.6 rockers because the only reason to use them is the lift on a SBC cam is limited by the bearing journal diameter and you can only reduce the core diameter so far before complete cam failure enters the picture. this is why roller cams can have more lift as the core is stronger than cast iron. the newer bow tie blocks have a 55 MM cam bearing dia to allow more lobe lift.

[Joe L.]

Re: powdered rocker ball broke

All------



I have some NOS GM #3744340 rocker balls. This part number dates back to about 1957 and was discontinued from SERVICE in June, 1994. After inspecting these carefully, I'm virtually certain that they are manufactured from powder metal.

[Clem Z.]

Re: powdered rocker ball broke

All------



I have some NOS GM #3744340 rocker balls. This part number dates back to about 1957 and was discontinued from SERVICE in June, 1994. After inspecting these carefully, I'm virtually certain that they are manufactured from powder metal.

i think the one that broke for jerry was just a defective ones as i was pretty sure they were PM for a long time.