Z Greek

Xnke I like the idea of stock L28 for you. Bolt your SU's on, and let her rip. I don't know about other parts of the country, but out here in Spokane, you can get an L28 complete for $150 at our pull and save wrecking yard (including alternator, and A/C pump if the car was so equipped). You have to invest a couple of hours of time to get it out, but I find it kind of fun out there. There seems to be about 1-2 280Z, or ZX that come in every month (and Spokane is NOT a large city). You have to watch inventory, and be quick to get out there. You can grab a 5-speed for another $50 if you are quick enough! If you want to play with your 240 block with 260-280 crank, I have a 280 crank you can have, but freight across the country would probably be more than you can find one in your neck of the woods. The free crank goes for anyone, it's just taking up space standing up next to the 'fridge in my shop. One comment you made I found interesting. You said you are new to this working on cars game, but that you could do your own machine work? Quality machine work is the bargain of the universe. Even if just re-ringing, you can have your block honed on a Sunnen machine for around $100 (I find Nissan blocks to be very hard, and by the time you run a hand hone long enough to end up with a decent cross-hatch, you no longer have a round, straight cylinder). A decent quality valve job can generally be had for $125-$150 plus parts. L-series cranks are tough as hell, and a quick polish is likely all you will need. Unless you want to spend a couple hundred grand to equip an automotive machine shop, let the pro's handle that part. Assembling an engine is fun, and ANYONE can do it. Buy a couple of books, be slow and methodical, and keep it CLEAN, CLEAN, CLEAN. As far as fuel. Detonation will destroy an engine quicker than anything. Contrary to some folks believe, there is NO detrimental effect to high octane fuel. You will not "burn a hole in a piston," running even racing gas in a stock engine, just the opposite. Think about your comment that you are on a budget, and premium fuel is out of your price range. 10,000 miles a year is LOT of driving in one of our cars. At 20 mpg, you would burn 500 gallons a year. Premium is, what, $.50 more per gallon? That is $250/YEAR. That is $5/WEEK. Just sayin', don't short yourself from running optimal ignition timing with the false economy of running rot-gut fuel. Good luck, have fun, and Enjoy the Ride!

Spent some time cleaning up my P79 head this weekend. Welded up the injector "divots," and did a little sanding/polishing/relieving around the valve seats, getting ready to take to machine shop for valve job, and mill all three surfaces. The pictures are not so good, took them with my phone.

I have a very similar project going. 1974 260, 3.1, with SU's. I am using a P79 head. I welded the injector "divots," in my head, but I agree, they probably do not hurt anything being there if you just use an intake/exhaust gasket for an earlier carbureted model from what I've read, and replies to a similar question I posted a couple of weeks ago. NEW QUESTION: Since I am running a P79 head, I have round intake, and exhaust ports. Does anyone know of a gasket with with round intake and exhaust, but without the injector holes in the top of the intake ports? Or do you just have to run a gasket with square exhaust ports? Thanks in advance!

I would vote for Dave Rebello. He ground the cam for my U20 in my Datsun Roadster, and it has NEVER ran better. He currently has the cam, and carb needles for my 3.1. He asked me basic parameters of my engine, and not only is he grinding me a cam to suit my wants/needs, he has worked out specific needle tapers for SU's on his dyno to match. He was also kind enough to give me some porting tips verbally over the phone. He told me what was worth my time, and what was not. He knows every head intimately, and will build you what you want, and/or need. My money is on Dave Rebello. Good Luck! Andy K

Thanks, I'll do that, sounds like good advice Andy K

Well, I had one for, and one against, so I welded 'em up.

Hey motorheads. I am building a 3.1 for my 74 260. I am using a N42 block, a P79 head, and a pair of N36 intake manifolds with SU's. Cam will be Rebello's grind specifically for 3.1, and SU's. I will probably pose this question to Dave Rebello also, but I thought I'd see if anyone had any input. My question revolves around the "divots," in the intake ports where the intake manifold meets the head. Since I am running carbs, I have no need for these divots. Any opinions on whether these "divots," disrupt airflow to any appreciable extent? Question, is it worth the effort to weld these up grind that area smooth?

Thanks for all the input guys. I am still searching for someone to rent me a torque plate to use while machining the bores in my block. Pete: I sent an email to McKinney a week ago, no reply, and then tried calling the number on their website, not a working number. I also spoke with Dave Rebello, he says he bored to 89mm for years without a torque plate, but uses them every time now, and highly recommends using one. He is not interested in renting one of his torque plates. Great guy, though, I used a camshaft from him in my U20 for my roadster, and I could not be happier. Any other ideas? I am about to throw in the towel, and have the block bored, and honed without a torque plate. Andy K

Thanks for the advice. Have a great weekend.

Thanks for the input Rossman. I appreciate it.

Just checked my math, must be getting old. Assuming flat top pistons. L24 with standard bore, and P79 head, 1mm head gasket would yield 6.7/1 (398.8 swept area, 53.5cc combustion chamber, 1mm head gasket) L28 with standard bore, and P79 head, 1mm head gasket would yield 7.65/1(458.9 swept area, 53.5cc combustion chamber, 1mm head gasket) Somebody get me a new pair of glasses, or a new calculator!

You were concerned about compression ratio. From my research (I am using a P79 on my 3.1 build), stock chamber volume of P79 is 53.5cc. Assume a 1mm thick head gasket, and you end up with a total chamber volume of 55.2cc. Swept volume of L24 with standard bore of 83mm would be 398.8cc. 398.8/55.2 gives you a static compression ratio of 7.48/1. Everything I have read says the P79 flows pretty damn well, despite the exhaust liners. All of these numbers change as you increase bore, increase/or decrease combustion chamber volume. There's my two cents. (might be worth a penny!)

Thanks for the input guys. I am really excited to get this thing on the road. Does anyone know where I might possibly rent a torque plate for boring and honing my block? I would be willing to pay a fair rental, shipping, and of course a deposit for the full value of the plate.

I am building a 3.1 stroker engine for my 74 260. I have read every article I can find, and read countless posts on this site. My question is about flywheels. Many of the builds I have read about use a lightened flywheel. Some even go on to say that a lightened flywheel is important for harmonic damper longevity. (?) Purpose of my build is purely a street car. I have spent 30 years working on, and restoring Datsun Roadsters, this is my first Z project. I have gathered most of the parts for the engine, but need to make a decision on a flywheel. My inclination is to go with a stock flywheel. Part of the draw for building the stroker was torque and ease of driving, so unless someone gives me a good reason, I'd rather not go with a lightened flywheel. Although I have to admit, even though I am pushing 50, I am still a bit of a speed freak, and that entered into the 3.1 decision also! Thanks in advance for any input. Andy K

New guy here. I am building a 74 260. The dash is so bad in it, that I don't think a cap will fit very well. (I had this situation when fitting a dash cap to a badly cracked 68 Datsun roadster dash) I am looking for a good, or very good 260/280 dash.