Building A L28 (Na)

[Jeff G 78]

That's close to 170hp at the crank which is about 20hp over SAE Net when the engine was new.

[TheCrazySwede]

That's close to 170hp at the crank which is about 20hp over SAE Net when the engine was new.

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.

Edited June 30, 2014 by TheCrazySwede

[madkaw]

Yep, that's a healthy engine. Maybe just leave it alone-ha!

I guess there is always the arguement that one dyno reads higher then another. I wish more guys would dyno there engines so they have a number for reference anyway. So now for future projects if you use the same dyno you can see (real) improvements.

Now take it to your local dragstrip and see if can get 15's

[TheCrazySwede]

Yep, that's a healthy engine. Maybe just leave it alone-ha!

I guess there is always the arguement that one dyno reads higher then another. I wish more guys would dyno there engines so they have a number for reference anyway. So now for future projects if you use the same dyno you can see (real) improvements.

Now take it to your local dragstrip and see if can get 15's

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.

[madkaw]

My L24 ran 155 with SU's, but a lot of mods. Didn't have the torque of the L28 , but close. I've driven a stock well maintained L28(77) and I was impressed

[TheCrazySwede]

My L24 ran 155 with SU's, but a lot of mods. Didn't have the torque of the L28 , but close. I've driven a stock well maintained L28(77) and I was impressed

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!

[Zedyone_kenobi]

As far as an N42 head with flat tops, my engine came home with 10.6:1 compression with N42 and flat tops, and I can tell you the most timing I can run is 30 degrees at max advance without fuel additives. (NOS brand is a viable option BTW). I would like to dial in more advance, but I start to get pinging in 3rd and 4th if I load the engine up at low rpm. My problem is very narrow and usually I do not notice it. But one day I will probably pull the head off and get some work done to it, while I do that I will probably put on a 1.5mm head gasket and drop the compression to 10:1 and be happy with it.

[TheCrazySwede]

As far as an N42 head with flat tops, my engine came home with 10.6:1 compression with N42 and flat tops, and I can tell you the most timing I can run is 30 degrees at max advance without fuel additives. (NOS brand is a viable option BTW). I would like to dial in more advance, but I start to get pinging in 3rd and 4th if I load the engine up at low rpm. My problem is very narrow and usually I do not notice it. But one day I will probably pull the head off and get some work done to it, while I do that I will probably put on a 1.5mm head gasket and drop the compression to 10:1 and be happy with it.

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!

[TheCrazySwede]

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.

[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!

[Torby]

This sounds like a great project! Looking forward to updates on this!

I went the Rebello route myself, but bought all the parts and built it myself. But my goals are similar to yours, ~200 hp and a responsive engine. Good luck! :classic:

[TheCrazySwede]

Glad to hear that you're happy with your motor, Torby!

I am a bit curious, though. You went with Rebello, but you built the engine yourself?

Maybe I'm reading it wrong, haha.