Can someone take a look at my geometry so far?

[Sigurd]

I'm setting up my Scat 1.25s this weekend. This is my current wipe pattern. The view is looking at the head as if the engine is just sitting there on the bench. I also have no fine motor control with a Sharpie, so ignore my finger.

I understand that the contact point is supposed to be slightly offset to promote valve rotation, but my pad is too far up. At half lift right now, the adjuster and pushrod are dead-in-line. Shimming out makes the pad shift even further up, and the half-lift alignment goes wacky. So I've come to the conclusion that I need to shave a bit off the bases, which I can do here at the house. However, while the pad may shift down, the half-lift alignment will go wacky the other way. What to do? Compromise? Run it?

Should also add that a valve job at 5,000 miles is not part of the plan. I've read that I may have to compromise with 1.25s, but I'd still like to get it as close as I can.

[Dougy Dee]

Was that pattern created with an adjustable pushrod or fixed length?
Do you have taller lash caps available?
Get the pattern on the lashcaps sorted out and the pushrod length should fall in to place.

[Sigurd]

I have an adjustable, and I tried different lengths (and readjusting the adjuster) to compensate, but it didn't make any difference. I have the adjuster at 1.5 turns from bottomed out.

Turns out that my pushrod and adjuster aren't quite as inline as I thought they were.

I'll shave the stands just a little bit.

[Sigurd]

I did a little more work tonight. I have cut about 0.060" off the rocker stands. The half-lift pushrod/adjuster alignment looks much better and the pad is getting closer to being centered up and down.

I'm also concerned on the side-to-side alignment. I don't have much room to shim, and certainly not enough to move it that far over. It seems like all the arms are twisted slightly, as they are only contacting on the right side. Is this as good as it will get with these rockers?

[Sigurd]

Anyone ever set up Scat rockers?

[mharney]

I've tried them a couple times. I don't like them because of the reasons you have illustrated here. Who should have to do all that??

Take a look at this - of course different valve lengths and cam lift matter and would affect things, but this is way out of line compared to Bergs and CB. The article is unfinished but I think you get the idea. The adjuster alignment could have been better on the Bergs but they have to fit a range of combos, so nothing can all be perfect. The CBs worked a little better for me, but are not covered in the article yet.

http://www.carburetorclinic.com/rockergeometry/rocker_geometry.htm

I like my rockers to contact just a little offset from center. Too much means the wiper might run off the edge of the lashcap, which means increased point loading.

CB and Berg rockers are much better.

[Sigurd]

Well, I really didn't want to drop the coin on yet another set of rockers. This is my second set already. But It doesn't seem like I can get the wiper centered unless I cut down the sides of the rocker stands either. Should I have just taken your advice earlier and done the FK7/1.4s? Or maybe a better question is realistically, how bad off am I right now?

[mharney]

I guess at this point, I'd just get them centered as much as you can left to right, which is not completely centered, and if your pushrods line up with the adjusters at half lift, and the wipers never pattern off the lash caps, just run it.

Dunno what to tell you about the advice and cost. I suggest what's worked for me in the past. People take it or leave it.

[Sigurd]

[nsracing]

You can shave the rocker pad bases some to gain some height on the valve stem. Or you can also "sink" the valves a little more into the seats = this will also give you some height.

You will not always get everything perfect. So get it to almost perfect.

I am not fond of having the rocker adjuster and pushrod "straight up" at half lift. I set up all my purpose-built engines to straight up or slightly over straight up alignment at FULL LIFT...when the spring pressures are the highest. I found this to be very beneficial and have less adjuster tip breakeage during HIGH RPM use.

I found a literature that offered the idea above and have converted ever since. Some literatures do not even care about angularity at all but only cared about the roller or tip wipe areas.

Hope this helps.

[Sigurd]

[nsracing]

"Straight up" is in-line as far as I am concerned. That is what I call it.

Why don't you post the side shots...show zero lift, mid-lift and full lift views? This will help a bunch so people can give the proper advice.

[Bajaman65]

I have had the exact same problem with the Scat rockers, I set them
like Nick said and they worked fine but I pulled the engine apart after
about 5000 miles due to a hydro-lock from a bad float and when I
put it back together I got some CB rockers. Much better.

[DarthWeber]

Ahh yes........more Scat quality testimonial!

Or should that be quality Scat testimonial?

[GDOG57]

Nothing wrong with Scat quality.People just need to know what they are doing when they build motors.I have Scat 1.4's and no problems.If it takes extra work,so what!!!
_________________
'57 oval window deluxe,Agave green(L240) 2276cc w/51.5 IDA's
'57 type 2 panel ( L31 dove blue) project daily driver,Singleport 1955cc
'69 Squareback (L30A Royal Red)

[Clatter]

Being off-center like that just helps promote rotation...
_________________
Bus Motor Build

What’s That Noise?!?

[Sigurd]

Here's what I have:

Zero lift

Half lift

Full lift

I should also point out that my rocker arm side clearance ranges from 0.014" to 0.022". I have about 4 spare shims, so there's no way to get down to the 0.005-0.008" range. Better looser anyway, right?

[GDOG57]

Wrong!That's too much clearance,you need the specified .005-.008.
_________________
'57 oval window deluxe,Agave green(L240) 2276cc w/51.5 IDA's
'57 type 2 panel ( L31 dove blue) project daily driver,Singleport 1955cc
'69 Squareback (L30A Royal Red)

[nsracing]

How about the side views of the valves and pads?

[Sigurd]

Zero lift

Half lift

Full lift

Obviously, the pads are still off, but the pushrod and adjuster are fine. I also discovered that the side shims from my Empi rockers will fit the Scat shafts, but they are all 0.030". I will shave down a few of them to make some custom shims and have another attempt at getting that clearance down.

And now that I've cut the bases down, my adjustable pushrod is too long, even at its shortest. Should I cut a few thou off the arms now too? This is a nightmare.