Rocker sideplay, how much is too much?

[alex d]

I was going to do rocker geometry, and after discovering that those CB Perf. cro-moly head studs are way too long for a non-stroker (they hit the rockers!)and shortening them, I layed the rocker assembly on the head and noticed that rockers have lots of sideplay, didn't measure it but it sure felt like an awful lot, they are Scat pro-street 1,25s, brand new. How much sideplay would be acceptable? And how do I reduce it?

[richie]

I was going to do rocker geometry, and after discovering that those CB Perf. cro-moly head studs are way too long for a non-stroker (they hit the rockers!)and shortening them, I layed the rocker assembly on the head and noticed that rockers have lots of sideplay, didn't measure it but it sure felt like an awful lot, they are Scat pro-street 1,25s, brand new. How much sideplay would be acceptable? And how do I reduce it?

You can get different thickness shims to allow you to tighten it up,Scat sell them,i really do it through feel,tight enough so no noticable side play but just loose enough not to bind,cheers richie,uk

[John Rayburn]

I set mine like the feel on a valve adjustment. Not quite zero. Just enough movement so stuff is nice and free.

[Jim Ratto]

Me too, I try to set up like .002"-.003", and usually have to sand sides of rocker stands or aluminum end caps to get them "just rght"

Make sure you test them before you lay them on over pushrods, and make sure you torque to head, as the clearances will pinch after being torqued.

It's a "feel" thing 

[Harry/FDK]

And NEVER use the wavy or spring washers.

[alex d]

thanks guys, so, can I use the shims most vendors sell for stock style shafts or do I have to use the scat ones, which no one sells around here BTW 

[Jim Ratto]

I think Scat's are a different (larger) diameter than VW ones....

[richie]

thanks guys, so, can I use the shims most vendors sell for stock style shafts or do I have to use the scat ones, which no one sells around here BTW 

Scat uses 2 different sizes,1 size for the swivel feet style and another for the Pro rockers,CBs are different again etc,you will need to measure yours and compare them to standard,where are you in the world?am sure we could find a way to get you some if you cant find any locally

cheers richie,uk

[alex d]

they are the swivel feet ones, tomorrow I'll measure the shafts to see, richie, I'm in Spain, I checked with my usual supplier and they don't carry them

[alex d]

well, I spent all friday afternoon playing with my rockers, it turns out they use the stock shaft size, so I disassembled the rocker assemblies from my old (junk) 1200, and took the shims (no, not the wawy washers) and after something like 400 tries I found a combination of shims which gave it that  "right" feel, now I got to do the other head!

[Jim Ratto]

well, I spent all friday afternoon playing with my rockers, it turns out they use the stock shaft size, so I disassembled the rocker assemblies from my old (junk) 1200, and took the shims (no, not the wawy washers) and after something like 400 tries I found a combination of shims which gave it that  "right" feel, now I got to do the other head!

Cool glad you got it worked out. I disassembled mine last night, as I was never quite happy with the way my 1.25 Scat's (skuffer tip type) were set up originally. After some shuffling of shims and some light filing and polishing of rocker-shaft-stands, I got them all set in with about .002" end play, nice and quiet. Nice to have two genuine VW cylinder heads to use as mockup models if you run VW heads on your motor.

[alex d]

oh, well yesterday I was finishing the rocker geometry, when I was taking off the rocker assembly to change the shims it fell to the ground! 
one of the balls of the swivel feet fell altogether (at least it didn't get lost), I put it back in place (didn't take much force at all), it seems to move ok without binding, but how do I know it wont self-destruct at 6000rpm? What would you guys do?

[Jim Ratto]

oh, well yesterday I was finishing the rocker geometry, when I was taking off the rocker assembly to change the shims it fell to the ground! 
one of the balls of the swivel feet fell altogether (at least it didn't get lost), I put it back in place (didn't take much force at all), it seems to move ok without binding, but how do I know it wont self-destruct at 6000rpm? What would you guys do?

if you are using the swivel ball type (face that contacts stem is a ball with a flat on it), I would consider getting rid of those and getting a set of Porsche 911 adjusters, also known as "elephant feet." The Porsche part number is 901 105 370 02. The advantage is that the swivel ball type can mash up your stems or retainers if the ball rolls over in screw. The Porsche type can't do this.

[alex d]

thanks for your insight Jim, I've heard other horror stories of the courier type adjusters (and some praise too), but as I don't want to risk the engine for this stupid part I bit the bullet and have ordered the 911 adjusters, coincidently I had some credit in my customer account in a US supplier which was nearly the price for the 911 adjuster set...
now to wait for the postman 

[Jim Ratto]

thanks for your insight Jim, I've heard other horror stories of the courier type adjusters (and some praise too), but as I don't want to risk the engine for this stupid part I bit the bullet and have ordered the 911 adjusters, coincidently I had some credit in my customer account in a US supplier which was nearly the price for the 911 adjuster set...
now to wait for the postman 

good job! make sure you soak them in a bowl of good engine oil overnight before you install them. Watch backside of foot against rockers too.
You'll be much happier adjusting valves with those 911 screws! 

Jim

[alex d]

adjusters arrived yesterday, I played a bit with them, it seems I have quite decent rocker geometry, I'll probably grind a bit more off the rockers though