Stumped in New Mexico

[Zed Head]

I'm not so sure that's an L28. Can't tell by the one picture in the thread. Maybe madkaw's assuming, because it doesn't look like an L24. That damper and timing marker might not be common to either engine. The L24's have a single pointer, with degree marks on the damper, and the L28's have a single mark on the damper with degree marks on the marker. But there are only six marks, in increments of five. -5, 0, 5, 10, 15, 20. You have something unusual.

Edited December 3, 2013 by Zed Head

[robox]

OK, thank you.

I will take a few more pix and would be super-appreciative if you guys could chime in and let me know what it looks like I've got.

The damper has 3 pointers, space 120º apart from each other. And also those weird looking sprocket teeth around it.

[madkaw]

Just post up the numbers on the block and head! I.E. N42, 54, P-79 whatever you see.

Looks like a zx damper to me, got one in the garage right now.

[robox]

Looks like I've got an N42 block and an N42 head. Does that make sense?

So... What have I got?

(I've got pictures too, which I can post a bit later...)

[madkaw]

http://www.classiczcars.com/forums/open-s30-z-discussions/48799-l-series-engine-timeline.html

[robox]

Oh... And it also says 0125A on the block.

[robox]

Thanks Zed Head.

I love forums!

[Zed Head]

madkaw is right, that's a 280ZX pointer. I have one too but had forgotten what it looked like. But the damper doesn't look like a 280ZX or a 280Z. Your engine and head numbers are for a 75 - early 77 280Z L28. So you do have a bigger engine than came in the 240Z. If it's stock, it would have dished pistons and ~8.3 compression ratio. Somebody could have swapped pointers from a ZX, and a damper from some other engine. Who knows. Welcome to the world of old cars.

[robox]

Thanks again for passing on the timeline link. Very informative.

I haven't pulled the damper off yet to see if there is a real problem there, but it seems like a reasonable possibility that the "clocking" attachment method (i.e.: spline, keyway, taper... I just don't know what's in there yet) is machined differently on the ZX damper such that the pointer is 30º off from what it's supposed to be.

Sometime soon (I think tomorrow) I will get some pictures and other information about an S30 (240, 260, 280... don't know yet) which is not much more than a parts car, but could be mine for the taking. Who knows... maybe it's got a good damper on it? (And bumpers and headliner and roof and door handles and tachometer and.... all the other stuff I need for my car!)

[superlen]

robox,

Glad you're back on the road to get everything tuned in. I just now noticed the thread & couldn't offer any more help than the others (particularly since I'm more of an EFI guy), but just wanted to say hi. My wife and I were in Taos in May for the first time & loved it. Other than a bit of altitude sickness from staying at TSV (probably would have been better to have slept at a little lower altitude), we had a great time & will be returning again this Spring sometime to explore some more & find that stinkin' treasure

Lenny

[madkaw]

So I'm stuck in a hotel in the blizzard of the midwest----so I had time to reread this thread. I'm still thinking you need to establish the clocking of the oil pump/dizzy shaft. To be off 30+ degrees and knowing that you bought the car from some idiots, I would be checking to see if things line up right. The PO could have pulled the oil pump, change HG, or any other item that caused them to get this wrong. This is more likely then the pulley slipping. It's a lot less work to check too!!!

[Zed Head]

It's not perfect, due to chain stretch, but you can get a pretty good estimate of how bad the mark might be off, or find the right one, by pulling the valve cover, turning the engine over until the #1 cylinder cam lobes are pointed up, then turning the engine a little more (in it's normal rotation - to keep the chain tight) and aligning the notch on the timing chain sprocket with the groove in the cam plate (as described in the Engine Mechanical chapter). Could be that the wrong pulley mark is being used. If the right one is on the damper pulley and nothing is damaged, and the cam shaft is installed properly, this would find it.

Another possibility is that the engine has a 240Z damper that is marked for the opposite side of the engine, and someone cobbled together a ZX style pointer because they lost the other one when they installed the 280Z engine. If so, the procedure above will end up with a damper pulley mark under the distributor somewhere. An early 240Z pointer might solve the problem. I don't know when they switched, and I can't find a reference but I've read that the early Z's had the mark on the driver's side.