Cam compatibility

[al'z]

Before anyone "sermonizes" (is that a word?) me for asking this question , let me just say that I've spent a fair amount of time searching the previous threads and came up empty.

Intro; I bought a 72z with matching #s to use as a daily driver (I miss my z) while I take my time restoring my '73, after which I will swap cars:p. I started prepping the car to be driven by doing a valve job/head gasket. My problem is that I found the cam from the L24 was badly worn. I had the machine shop use an N42 from a '75 L28 (I understand this is very compatible), but this one also had a flawed cam. The machinist told me that his supplier could provide one designated for a '78-'84 L28.

My question; Is it or is it not compatible with my N42 head from a '75 L28? I do realize I can go to MSA and buy a cam kit but I am trying to stay focused on the '73 restoration before spending undue monies on the '72 motor. So long as it is designed stock for an L28 can anyone provide some validation to what I think is a straight up compatible swap?

Thanks in advance,

al

[jtl260z]

The cams are compatible.

[beandip]

The thing is if you use old rockers it is likely that you will destroy the new cam. The old rocker might be resurfaced , depending on there condition. Use new lash pads. That's the rub. Cams are cheap it's all the other stuff . Nissan is really in love with there rockers $$ .

[sblake01]

The cams are compatible.

I don't completely believe that as a blanket statement. According to the the microfiche, there's conditional interchangeability with the early N47 cam and none with the later one.

[jmortensen]

The thing is if you use old rockers it is likely that you will destroy the new cam. The old rocker might be resurfaced , depending on there condition. Use new lash pads. That's the rub. Cams are cheap it's all the other stuff . Nissan is really in love with there rockers $$ .

This issue is overhyped and has more to do with Schneider using crappy cam billets than anything else in my opinion. Even ISKY now regrinds cams for Z cars. I've used the same set of rockers on 3 cams now. They ran for 250,000 miles on the original E31, then I put them on one aftermarket cam, and finally a second. Still running fine. I'm thinking about changing the cam again, and if the rockers still look good they'll go on a 4th cam. Every one of my friends running 510s or Zs has done the same, none have changed their rockers, and I've never seen a cam lobe go flat in person.

As far as compatibility, if the head you have doesn't have a cam spraybar to oil the lobes, then you need a drilled cam (holes in the lobes where oil comes out). If it does have a spraybar, you can use either the solid cam or the drilled cam.

[al'z]

Thanks for all the feedback. It will help in my next decision.

al

[Ksteve]

Al,

I have an N42 head on my 73 L24 block and am very happy with the combination, but it is not just a direct bolt on. The N42 has slightly larger valves (intake and exhaust) than any of the L24 heads and the valves are just barely to wide for the cylinder bore on the L24. If your block has had a rebore in it's past it may already have enough clearance but if not you will need to grind small releifs/eyebrows into the rim of the cylinder bore to prevent the valves from contacting the block. There were a couple threads here in the past describing the details, it's not as difficult as it may sound.

As for cams, I sent my worn stock cam to Delta Camshaft for a slightly more agressive regrind (.460/272) and was happy with their service. It was relatively cheap, compared to an aftermaket cam, at about $70 and very quick service, they received, reground, and shipped it back out the same day. They will also resurface your old rockers for about the same amount.

Steve

[al'z]

Steve, that is some great advice. Thanks.

I had read something about the valves tapping the top of the stock bore heads but I didn't realize I had that situation. I thought I could bolt the N42 without mods.

You are a total work saver. Thanks again,

al