Scat 1.4 Rocker Arm Pitting

[VW&MGman]

Hi Everyone,

Has anyone every experience pitting on the rocker arm faces, that contact the lash cap on Scat 1.4 rocker arms?

I installed the set of lash caps that came with the Scat 1.4 kit, and after approximately 10 miles of engine break-in, I adjust the valves, and I found one of the lash caps 'concaved' and a few others badly pitted. The rockers were pitted as well.

I'm running DRD L6 heads with their valve springs and chromoly push rods. Clearance was set to 0 loose.

Any thoughts or suggestions?

[Marc]

I have encountered lashcaps that were "soft" and prone to bird-bathing - the "good" ones are hardened. I'm not 100% sure I remember where they came from but it's probably been too long for the source to be relevant anyway. It sounds as though the metallurgy of the caps and the rockers is too similar, which promotes metal transfer between parts - especially where there's high contact pressure involved.
Do you think there's enough lubrication splashing onto the valve tips?
See how hard it is to nick the edge of a cap with a little file; you could use the same test as a crude indicator of hardness to compare some others...

You might also try to harden the caps yourself. http://www.practicalmachinist.com/vb/ge ... il-157901/

[VW&MGman]

I tend to agree with you...they seem to be very soft. I took a 80 grit flap wheel to the lash caps, and it created a slight recess in it.

I polished out the pitting on the rocker arm faces. It seems to be harder, but I'm just guessing.

Any ideas on how to check the hardness of the rocker arms?

[Marc]

I think the cheapest you can buy a Brinell or Rockwell hardness tester for is ~$400, but you might find a local shop or lab that could check your parts for a small fee.
Know any college students? If they're taking any science courses they might have access to a tester.

The file/sandpaper test is basically just a primitive form of "Mohs" hardness testing: http://geology.com/minerals/mohs-hardness-scale.shtml

[slowsixtyduece]

My Scat 1.4's are pitted on a few of the rocker arms as well from when they were on my last motor (1915 with a reasonable amount of miles). My lash caps are in perfect shape though. I decided to reuse everything on my new 2276 turbo. I have had no issues so far at ~1500 miles, although I wont be surprised if the pitting gets a little worse as time goes on. I thought about sanding the contact surface but decided against it incase I went too deep and lost some of the integrity of the metal on the surface. Not sure if thats correct way of thinking, but I couldn't bring myself to remove metal. Plus I would have had to go pretty deep to remove the pits and, at the end of the day, they weren't causing any scratching, gouging and so on since they were/are concave.

One thing that you did not mention is coil bind. What is your lift and did you (or someone) figure out how much lift your springs can handle before they "bottom out" or bind? This will be dependent on how you have them setup on your heads, ie: how your heads are machined, length of valve stem, spacers under the springs installed, and so on. You may want to ask Darren at DRD how he set them up and his coil bind values if you dont know. If you have a decent amount of lift and your springs are binding when the valve is all the way open, this may be causing damage to the rocker faces and lash caps.

[Piledriver]

Oil matters as well, even the stock style screws will pit if there is insufficient protection.

The tip to valve stem contact is as much if not more load than cam/lifter, esp. given the smaller contact area.

[buildabiggerboxer]

you may have excessive hot valve lash, motors with very cool oil temperatures would be candidates with minimal pr expansion, a change to ally pr may be an idea if so, do measure the hot valve lash tho', you are loosing lift/ performance as well as pounding the valve train if your hot lash is around .012"/016".
regards BBB.

[dunegoon]

What type of oil is being used? This sounds similar to a series of troubles and finger pointing that went on several years ago with cams and lifters. Then we discovered that the additives in motor oil had been changed, which at least contributed to the failures. We need to consider oil and oiling along with materials and operation.