TheCrazySwede

Ok, so my build has taken a rather different turn. I've gotten to the point in my research where I have learned all the things I wanted to know in order to start off a build. I have spoken a lot with Dave Rebello and I have come to the decision that I did not want to take my motor down that route. This is not because of Dave's lack of professionalism or talent, but more in terms of needs. The different motor builds, the more I looked into them, all sounded nice, but none of them really fit what I wanted. The power figures were all nice, of course, but I decided that I didn't want an all out powerhouse of an engine....instead, I wanted a responsive one. After talking to a few people who have worked with him before, I have decided to go with Eiji at DSI. This guy is just great. I've never encountered customer service and eye for detail on his level before. After many, many lengthy emails and phone conversations, we finally have a build down that I am completely satisfied with....well, my wallet isn't, but that's a different story! I'll update this thread with the build details as they happen, but in short, the engine will be: - L28 Crank - N42/N42 - Block bored (89mm) - DSI Pistons and Rods (I believe they are 29mm Kameari Pistons (280g!!) with custom 139.5mm rods.) - *Cam is under consideration - Triple 45 DCOE Webers - Compression Approx. 10.5 - 11.0 - Power Approx. 260/250 I'll update this thread with any updates!

Same here!

So, I had another Juan-on-Juan with Dave, and (again) didn't recommend flat-tops with the P90 head, due to due deck height issues. Mr. Rebello is either an L-Series wizard or extremely well at selling a product, because I am (at this point) on the edge of getting my motor built by his shop. I always thought his builds run close to the $10k mark, but he wrote me up an estimate for around $5k. At this point, I'm still doing my research. I'm not really in a hurry, so I'll take my time with it all.

I've heard some people running N42's with flat-tops and pushing close to similar compression ratios, with no issues, while others have some serious pinging. If you're able to run on that setup with an N42, I think I'll be safe with the turbo head setup. Thanks for the input!

That's awesome! Well, glad to hear that my current motor is still going strong! As I mentioned, I try to keep it well maintained as possible, so I run through the usual tune-up list every 3-6 months, depending on when I get around to it. Seeing how this motor is doing after it's been running for almost 40 years, I'm even more excited now to see how the new build will do. To be honest, I have never revved past 4,500RPM in my Z, and yet that's where the engine actually runs the strongest, haha. Can't wait to see how the new setup will do! Thanks a lot everyone for helping me with this build and following up with ideas. Really keeps my spirit going knowing I'm not alone in this, haha. Cheers!

Yeah, I saw a post on that one Datsun Engine Mods website, and the guy has a stock L28 with SU Carbs and he got 145rwhp @ 5,200RPM. That's just like mine, only mine has EFI, which helps a bit. After a few mods, he pushed a lot more, of course, but got some nice numbers running stock. I'm not too concerned about power, but I sure am proud of these motors for still holding strong after all these years. I'll use the same dyno for the new engine, so I can see the power changes in effect.

No clue, but I know nothing has been changed that would allow 20 more horse. It runs on good oil, spark plugs and has a re-manufactured AFM (The first one crapped out) I know it's running a bit rich at the moment, but other than that, everything inside is stock. Stock cam, pistons, valves, etc. If I'm producing 20 more horse than stock, you have me curious! I honestly have no clue. Is it possible that the reading was wrong? I sure hope not. That would kill a bit of my enjoyment of the situation, haha. Are there any dyno sheets of other stock L28's on here? I wondering if their power curves are different than mine.

Here ya go! Dyno Sheet

It's all stock. I got the car from the original owner. I haven't replaced anything in the car, except for the exhaust. (I replaced the California one with a Federal exhaust. I use the Cali one for smog purposes ) I try to keep the engine as healthy as possible. I do plugs, dizzy cap, oil changes and a few other tune-up items every 3-6 months. It's my daily driver, so everything gets kept well lubricated and operational. I was hoping for at least 120rwhp, so I was really pleased!

I got my car on the dyno with its stock L28 inside to see how it performed. I was pretty surprised!

Thanks madkaw! That's just what I needed!

Ah, so you guys shave the head? That ups the compression, right? What else would have to be changed if you shave the head? Would I have to adapt everything to fit the new sized head? 200 to the crank is perfect. I'm not looking for some crazy numbers here. I'm going for the Lotus moto of getting more out of less. Ok, since I'd rather have the better head rather than the head that is known as the "not better" head in terms of operation, are there any reasons why I would want a P90 over a P79 or vice versa? Seems like most people run P79's due to availability. Either one is better than the N42, I assume.

Thanks for the input, guys. Yeah, pinging is something I'd rather avoid. I'm just curious, but how are you guys getting such high static compression ratios with your P90/P79 heads? Would it require major work to get those numbers? I'm just using calculation tools, so they might not be 100% accurate, but I'm not getting past 8.8:1 with either one of those heads. Would you guys mind sharing your secrets? I've looked around threads (and other forums) for builds with those, but every single one of them involves the builder knowing what he's doing, so they aren't asking the questions that I would be asking. Does anyone know a good build that wouldn't be too difficulty (although I am up for a challenge if needed) for a newbie to follow?

This is incredible. I am very, very jealous! Thanks for sharing your re-build. Looking forward to seeing how this goes The car looks great.

So according to my calculations @ OZDAT, If I grab my N42, have it bored .20", install flat-tops and a high lift cam and use a 2mm head gasket, I'll end up with 9.1 compression. (A 1.5mm gasket gets me 9.6 compression) Now, a P90 head with the same layout (except with a 1mm gasket) gets me 8.7 compression. Without flat-tops, I get 7.5 That being said, on paper at least, doesn't the N42 head sound like a solid build? Many of you here have a lot of experience with these builds, so I'd really like to know what you guys think. Rebello suggested the N42 route, but I want you guy's opinions on the matter. Again, I really appreciate all the help. As I've mentioned before, this is my first motor and my first "hands-on" experience with these things, so all of your help means a lot. Thank you.

Cool, glad to hear! I'll be sure to check those out. The site I used for my compression calculations is this: OZDAT.com Engine Design Utility Play around with the gasket height on that one.

From what I understand, that's I was told. As many of you know, and I've addressed this in my post, I'm not very experienced in these matters, so whatever advice I get from people who know what they are doing, I tend to blindly accept it. Maybe he told me about these things because he figured I wouldn't know too much about these things in order to work out a good combo, and he figured he'd save me a lot of trouble (and money) going with my own head, which I appreciate. He did, in fact, address his concern about clearance level. There might have been a few details here and there that I didn't understand (too many numbers for me to follow!) so I might not be telling you guys all of what he said, only what I remember.

Glad to hear! We're on the same boat on this one, haha.

So I visited the lads over at Rebello, and they advised against going for the P90, for a couple of reasons. To start off, he mentioned how the quench pads in the P90 wouldn't leave much piston clearance if I went to flat-tops, and Dave had no idea how these motors made it out the factory. He also mentioned how building a P90 head is not cost efficient at all, because you end up doing more work for not so much more performance. What I was recommended was to stick with my N42, use flat-tops, and just compensate with a thicker gasket. I know there are some 2mm gaskets out there, but I can't seem to find one...according to OZDAT, it will give me a compression of 9.1:1. I'm still debating if that's cutting it too close, running on Cali's pump gas. Would I have to run octane boosters? Do those things even work? Also, if anyone knows where I can find a good 2mm head gasket (getting the block bored .20 over, so I don't know if these things have to be retro-fitted after wards) I'd really appreciate it.

So, I haven't started on the head, yet, although I have stripped it apart. So far, just done work on the block. Should I buy another head? I hear a lot of people going with P90 heads. Which one seems to have the best design?

Thanks for the input, Chris! I looked into the compression changes due to gasket sizes, too. I wanted to higher the compression with the flat-tops, and then get a slightly thicker gasket, like you, to compensate. I'm in Cali, so I gotta make due with what I've got. Block still getting bored!

Ok, so a quick update. I dropped off my crank (w/ rods and pistons) and my block at a machine shop. Crank just needs a polish, but the block needs to be bored. So currently, I'm getting the block bored (0.020) and getting flat-top pistons to match. I figured I'd get the bottom end stable and ready before working on the head. Got new crank bearings, as well.

A few months ago when I was experiencing the hot restart problem, my local Nissan/Datsun mechanic suspected that it had to do with the fuel mixture used during winter time. I wasn't sure if that was true or not, because I can't remember if I experienced it last year. Now that it's summer (I live in CA, so it gets pretty warm) I've been driving my car, just the same way it was during the winter, in much warmer circumstances, and yet I'm not experiencing the hot restart issue anymore. I've tried to replicate it (Drove it hard, parked it in the sun...waited 10-15, and started it) but it just starts right up without a single moment of hesitation. Anyone else experience this? Perhaps in my case, the guy I spoke to was right.

The danger is not in the site, but in the way it encrypts information (Open SSL) There are a lot of websites that use that type of security measures, although most websites that are in charge of sensitive information (Email clients, Banking, etc.) use a different approach, and thus aren't in danger of being compromised. I'm not a huge fan of Norton (I've been a Microsoft Certified Technician for almost 3 years) but the way it is telling you what sites are vulnerable is by checking what type of encryption methods the site uses. Most websites have updated their measures, but I can't speak in behalf of this one.

I think you're right about the octane ratings. Their Cam kit is around $290-300, which isn't bad. I figure I'll go up there later this week and see what I'm in for. Ask any questions I might have an take it from there. I'll let you know how it goes! Cheers!