Harney's diatribe - rocker geometry to install & beyond

[mharney]

Thanks James.. I get by with a little help from my friends.

You know, I think I have beat this to death. I have read different things from different builders, and everyone seems to have different ways, based on different theories, and different designs. Take the 1:1 rockers with adjusters on top, for example. If you worry about the centerline and the adjuster being parallel with the valve stem at half lift, you think you got it all worked out. Well, how do you know that the other end is ok? You can't, really, not with any certainty, and if you wanted to correct for it, you couldn't get it exact.

Then on the other hand, suppose this style... how would you EVER get it all correct, without doing something like machining or welding the tip of the rocker arm? You wouldn't. So what do you do? Choose one theory over another? Choose one part to risk more than another? Basically yes, because there is really no perfect solution. But I am close, and I think I better leave well enough alone, or split the difference on the angles.

Maybe I should go into business perfecting rocker arms for different setups.

[mharney]

Max lift will be achieved by setting the bottom geometry the same way you set the top. You want a line drawn from the point that the pushrod tip pivots about through the center of the shaft to be perpendicular to the pushrod. THIS is what gets adjusted by changing the adjuster position / pushrod length. The problem with this is that it could throw off the geometry up top by changing where half lift is.

That angle between the pushrod and the adjuster doesn't look good, though. I'd almost be inclined to just back the adjuster out as much as practical and adjusting the pushrod to compensate. This might cost you some lift, but would make the adjuster less likely to break.



Steve

The adjuster is threaded out two turns. That's where I am leaving it.

The only answer here is going to be shims.

[boredandstroked]

If you want it done right do it my way

But seriously you should have the PUSHROD end corrected. How many people have had push rod and adjusting cup failures?? You wont be too far off of perfect and it should be damn good on the valve end after tweaking the pushrod end. The problem is that as you have it now you will have TOO MUCH angle at 0 lift and will put a lot of off axis to the centerline load on the pushrod and adjuster cup. If you had too much angle the other way you would have too much load at full lift. You need to split it at half lift so your pushrod tilts aproxamitaly the same to either side of center and therefore minimize the angle at both ends.

[Tom Simpson]

Just an FYI..
Personally, I know of several big motors out there running Pauter rockers on the street with Zero issues. I put them on these motors. They are probalby the highest quality rocker you could put on your stock casting head. I understand the oiling method and it works fine.
No oil problems at all.

[mharney]

There is nothing like figuring out that you screwed up and then having it fall in your favor. My pushrod had started coming unscrewed, and messed up my geometry (just this last time). After setting the shims up for standard valve width, I put it back together and got the dial indicator back on (been setting half lift by degree pulley from previous encounters). I measured lift at 0.572" (1.5 rockers are supposed to be 0.575" so I must be doing something right to get that much with what are supposed to be 1.4 rockers). When I go to half lift, the adjuster is spot on parallel (checked it with an allen wrench in the adjuster too - within a SMALL fraction of a degree. Perpendicular to the shaft center is within about 0.040", and contact is very close to center. I'm settling in with this. I actually have some CB rockers coming tomorrow. If they will get closer, I'll use them. I'll bet they aren't. I have a feeling the Berg's are gonna win my vote.

Tom, I appreciate that you know of several engines that have the Pauters on them with no problems. I'm not trying to badmouth them. You may return to your laughing at my position on them for my use at any time. It's clear that you don't like what I have decided about them and fortunately we don't have to agree. No hard feelings on my end.

Now on to another little problem. I realized I forgot to put the plug in the galley hole in the case where it leaves the pump (I have one in the pump, but did not put the one in the case that will keep the inlet from the full flow return from trying to pump it back down into the case through the pump outlet passage). I used Loctite 518 on the pump. The cover came off easy enough, but I broke my pump puller trying to pull out the pump body (it was a cheap taiwanese model with the rod tack welded to the end of the threadstock). I need a good puller. Yes, I loosened the adjacent case nuts. I think that stuff really must set up good. The uncured parts of it wipe off very easy with laquer thinner. The cured parts of it take much more work.

[Brian Murray]

I have a couple 1.4 rollers as paperweights layin around if you want em... the rollers are still greased. One's been clearanced and the other had a small snarl with a pushrod but the damage is only cosmetic (scratched "anodized" surface)

[mharney]

I think Tom wants 'em, cause he was willing to buy mine off me if I bought just one for testing.

[Tom Simpson]

Aw man, no hard feelings. I was just throwing out an FYI so people reading could hear both sides of the fence.
If you have plugged the pump and the oil pump fit is good (tight) into the case. You can just leave it. One plug or 2... it will work fine.
Sounds like you got it all figured out now. BTW, I have found Scat rockers to be very good quality as well and setting them up no problem...
I'm going to go out on a limb here and say that I hate lash caps. It's hard to find good ones that sit flat. If they are cocked at all, they will not let the valve rotate on its seat. Some will wear a spot in them that will hold the valve in place, others just don't fit right.
I have been using ratio (bottom adjuster) rockers for years w/o lash caps. After many years, the valve stems look perfect (with evidence of rotation).

[rcb78]

Regarding the replies about setting geometry based on rocker tip to valve stem or adjuster to pushrod. The theory that I stand behind is that it's more important to set the geometry so that the rocker tip is normal (perp) to the valve stem at 1/2 lift with the stem sitting as near the center of the contact patch of the rocker tip as possible, basically what Mark was saying. Doing this helps to ensure minimal wear at the valve stem/guide by splitting the loads over the half lift point.
If you set geometry for the PR/cup side, then you will likely have uneven loading of the valve stem causing excessive guide wear. Adjuster cups receive pressurized oiling if you set them up right, so there should be minimal wear there. And if you paid attention to the oiling hole in the adjuster and made sure it lined up with the oiling hole in the rocker itself, then the adjuster is held pretty deep in the rocker arm. So deep in fact that there's not much exposed and at risk of breaking. I think more people break adjusters by having them too far out of the rocker arm trying to tweak geometry that way instead of with shims. --Ryan

[mharney]

Well, I did get the pump off. I took my crappy oil pump puller, ground the threads off the end to make a flat spot to drill through, and drilled through the threaded shaft. Then I cut off a piece of an allen wrench and tapped it into the hole. With that and a little coercing with a hammer and a wood block, I got the pump to come out. Then came the cleaning. Good god, that Loctite 518 is a pain in the a$$ to get off. I tried all kinds of solvents, and finally found one that would loosen it up enough that I could scrape that stuff off without scratching things up. MAN!

But it's all clean and ready to go back together. I'm too tired to mess with it any more.

Nighty night kids.

[mharney]

Ooook... here is an update.

My CB rockers came in today. Some good and some not so good about them IMO:

1. Lash caps - they fit tight.. Measured 0.226 overall. The depth of the inside was 0.141, leaving 0.085 for the lash cap. I could not get them to seat down all the way due to slight interference fit. They have a hole in the center of them.

2. Rockers - they look to be a real fine piece of work, but the advertisement seems to have thrown me for a loop.

"Forged from 4340 Chromoly steel and CNC machined to an exact 1.4:1 ratio! The rockers feature hardened tips, bronze bushings, and H-11 Tool Steel adjusting screws. The absolute strongest adjusting screws available! The rockers feature 100% pressure oiling to eliminate the problems associated with splash oiled rockers. The hardened shafts are a gigantic .984" in diameter, 38% larger than stock rocker shafts! The rocker shafts are cradled in forged Chromoly rocker blocks."

When you read this, what part of the shaft do you think is 0.984" in diameter? The shafts where the rockers ride? Well, think again. They are 0.760" just like everyone else. The center part is 0.984" (or so).

Well made though, and with a lift of about 0.550", I'd say their ratio turns out to be about 1.43 on my setup. Add a little lash, and there you are.

Alignment was slightly better than Berg 1.4's, in terms of centering of the tip and parallel of the adjuster, and the centerline of the shaft is pretty good too. I think these might win it, but I have to figure out how to make the lash caps work right. They are so close, and look to be made of the same tool steel that the adjusters are.

I guess I shoulda known that 0.984 couldn't be the rocker areas, since they are already pretty close at 0.760, but you never know.. gotta lay some trust down. And they were right.. the shaft is 0.984. In the middle that is.

[Maui Air]

Mark, I can't believe I am having the same problem getting the geometry right. Same cam, pretty much the same setup. Following the thread, your problem disappeared when you switched from Scat to Berg rockers. I'm using CB's. Have you tried your CB's to see if you can get anywhere close? Like you I'm leaving it alone for a while to grind some intakes and hope when I go back to it something will fall in place.

[mharney]

The CB's and the Berg's were a lot the same. They both worked pretty well. The Scats were the ones that were such a problem for me.

[Steve Arndt]

You should be fine without plugging the case and only plugging the pump. I've ran many engines this way. Just make sure the pump fits nice and tight, and that it completely covers the hole in the case. Sometimes they don't fit perfect and this is a disaster.

[mharney]

Yeah, I went ahead though, because I didn't want to risk backflush - I've done everything else as correct as I could, didn't want to stop here.