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Thread: What happened to these valve/rocker arm shims?

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Posts: 11-20 of 22
2012-04-06 01:01:17
Feeler gauge?
2012-04-06 01:05:34
2012-04-06 04:38:16
^^^ lol
2014-01-02 12:19:18
Bumping for an update as this also happened to a friend of mine. He did the Tomei solid lifters and everything was installed/measured professionally and the exact sized shims were ordered from Tomei. After a couple thousand miles a bunch of the shims were dished in like the ones pictured in the OP.

Originally Posted by 2_Liter_Turbo
I wish it were that easy, lol. These are tomei/oem Nissan shims. The cupping happened on the rocker arm side, not the valve side. I might send them out for hardness testing and compare them to the hardness I got from old used shims (60 rockwell c scale), but used shims will always be harder due to the work hardening over the years. When i made my own shims a couple years ago, I was able to get up to 70 scale using O1 tool steel and heat treating, lol. The worst shim gap measured at .28mm I believe it was, lol
2014-01-05 02:46:52
Ahh, lol. It turned out to be that I was running the wrong cams. They were cams designed for the factory hydraulic lifters (which can be more aggressive due to the "give" in the lifters). I knew this which is why I ordered solid lifter cams originally... but was shipped hydraulic lifter cams and never knew about it. Which is why I was chasing my tail for YEARS trying to figure out what the heck was wrong with my setup, lol. I finally broke down, bought a new set of cams, and voila! Quiet as a mouse. She runs great now, and is even quieter than factory (other than the exhaust/intake). Make sure your friend has the right cams, they need to be designed for solid lifters! You can't run stock cams (except GTiR ones).
2014-01-05 02:54:42
Very important to have the correct cams for these engines. Quite a nuisance but this thread proves how valuable it is to know what stuff is going on.

That is a huge shame you had no idea the cams were incorrect and this happened but at least it was figured out and with a minimal amount of "damage".
2014-01-05 03:19:45
Yeah, the paperwork said they were solid lifter cams and everything (bought them new from phase2motortrend) but never thought to double check the P/N on the Tomei boxes when they came in. I do now on everything! Ha ha. Oh well, you live and learn. I had to get the head redone because the valve step tops were worn out from all of this. Now I have Ferrea +1mm valves all around with supertech valve guides, lol.
2014-01-17 14:49:45
What spring pressure are you running? What size cams?
2014-01-17 15:09:01
If I remember correctly they are seat pressure: 90 @ 40.5 (Open: 202@ 10). Cams are 12mm lift 260 duration. I originally thought it was the spring pressure, but it wasn't, lol.
2014-01-17 15:11:35
I further read into the thread. You can technically run the hydraulic cams in a solid lifter setup, but yes it will cause this problem. Also hydraulic cams in a solid lifter setup makes an loud tapping,ticking noise constantly, makes it sound like something is loose in the valvetrain.
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