CerealWars

I'm trying to sort out the lash cap sizing soon by buying a big one and grinding it down until I find the right size. And thanks a lot for that diagram, I had a pretty good understanding before of how to measure the lash but now I understand perfectly. If I can find a practical way to measure the springs I'll report back on the spring rates (of the VG at least).

Now that is probably the most trustworthy advice one could give.

I've heard that the vg30e springs are about 10 lbs/in (only a slight increase) stiffer than stock l series. Another thing I've read in a few places is that the valves start to float a little before 7000 rpm with stock springs. I don't have stock springs, but I have vg30e and vg30et springs laying around. And the aftermarket springs on it now look kind of overkill for a cam with a reputation for having soft lobes. http://www.zcar.com/forum/10-70-83-tech-discussion-forum/115576-msa-cam-kit-questions.html I found posts numbers 1 and 5-10 to be informative to my situation. You guys think I should trust the mystery man who assembled this engine a few years ago and forgot to install lash pads? I'm just concerned with the way this thing was conceived when it was rebuilt. As much as I love working on engines, I don't really want to tear this thing back apart until it's time for more upgrades.

Well hey, thanks hainz. The rockers do look like pretty sturdy OEM ones. And yeah, I've heard of a few instances where in some of the top shelf camshafts they'll go to the trouble of nitriding them and those things never wear out.

according to zdoctor's post in the aforementioned thread, high spring pressure is causing excessive wear rates on the cam. I've heard vg30 springs fit (and they look like they do, I've got some laying around), I was hoping for more info on this. apparently they're stiffer than stock (7k redline desired) but not by much. anybody else hear anything on this?

CWC cams were a billet produced by CWC textiles in Michigan some years back. After the "Japan"-stamped cams reservoir was all dried up, CWC made tons of these and sold them to various cam vendors who ground them to be sold to the public from there. There is no writing on the back of the cam. "C2", "D2", "F13", and "EP" are the only things besides "CWC" embossed into the casting, and haven't done me any good researching my cam. After reading this thread,http://www.zcar.com/forum/10-70-83-tech-discussion-forum/125256-cwc-cam-castings.html and considering my un-stock looking valve springs, I'm hesitant to just throw it back together. Especially when I have VG springs laying around that just might fix the problem for essentially free. Mike, I totally agree on the necessity of oil being number one priority. Anybody out there running some super secret oil that keeps the old l-series happy? I just want to put my l28 back together and not have to stress about the rockers munching the cam.

I agree with the break-in strategy and appreciate the suggestion on spring pressure, i never considered the effects of too little spring pressure. Anyway, the whole cam will not be heated, just taking a $7 bottle of mapp gas or propane to the outer layer of the cam lobes, so I can't see it yielding too much distortion. Hopefully I'll be taking the cam to my materials professor today if he has time. The guy worked for GM for twenty years or so, and knows WAY too much about metal treating processes.

When I took a material science class we studied them as the same thing (since their effects are so similar) and it was not clear to me that they were two completely separate processes. My fault, dumb mistake.

Sorry Mike, should've been more clear, I meant flame induction hardening. http://en.wikipedia.org/wiki/Case_hardening#Flame_and_induction_hardening

What's up Datto brethren? I bought a '77 280z this summer with a mystery engine in it. The deeper I tore into it the more it seemed like someone was building a badass little l28 but gave up along the way. I've been spending some serious time with her lately, trying to piece it back together properly on a microscopic budget (goddamned college, z cars are far more important). I have an N42 head that's been freshly rebuilt and apparently milled (it had cam tower shims). After discovering that I was missing lash pads, and that I had a unknown aftermarket CWC billet camshaft, I have a few questions. After researching all I could, I discovered that CWC cams have been known to wear out quickly, except for applications used with stock valve springs, as well as a few camshafts produced by another company using the CWC billets that nitrided them. I saw in another thread that someone mentioned using VG30 springs, saying that they were slightly stiffer than stock L-series springs. I used to have an old z31, and still have a spare set of valve springs laying around. Does anyone have any more experience with this? Also I have both an oil spray bar as well as galleries in the cam/cam towers, not sure if additional oiling would be sufficient to keep the cam from wearing. Speaking of oil, I plan on running something with a high zinc content to keep wear to a minimum. Finally, and hopefully someone can chime in on this, but I was thinking of at the very least induction-hardening the camshaft. This would be done with map gas torch, (told you I'm pretty broke). But I don't see how that could hurt it. This is what GM does with their differential and (manual) transmission gears to produce high surface hardness (limiting surface wear) while keeping the core of the gears ductile enough to sustain some abuse. The cam is made of ductile iron. Alternatively, do shops exist where I could go to to have it nitrided? Alright, I know I'm killing you guys with all these words and shit, so here's some head. ;) Thanks to anyone who can contribute to my budget build, trying to get her on the road before spring!

Agreed, that'd make a sweet little daily slider, that coupe on meshies looks too sick.

how's this thing going? any updates?

I wouldn't wire up an F.I. pump made for fifty-something PSI with a regulator taking it down to five. Buy a twenty dollar electric pump for a first-gen RX7. Should be easy to wire up and has a much smaller chance of annihilating something with an excess of fuel.

So where do I get my pot leaf oil cap?