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TheCrazySwede

Building an L28 (NA)

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What are you having done with your head?  

 

I would look into a P79, P90 (both at 53.6 CC combustion chamber) or MN47 (a maxima N47 which has about a 40cc combustion chamber) as they have a much better closed combustion chamber that resembles SBC aftermarket heads and many people feel work better with flat top set ups.  

 

I run an MN47 on my bone stock L28 F54 flat top set up  which produces about 11.5:1 compression!  yeah, its high, but it also produces a LOT of torque because of the compression ratio but also because the MN47 has 42mm intake valves as opposed to 45mm on the L28 stuff.  LOTS of velocity.  

 

I have not installed an aftermarket cam on this yet, and I do have to pull a bit of timing, but I am running megasquirt controlling fuel and spark, so my situation is a bit different than running carbs and a regular distributor.  I feel an aftermarket cam with more duration could be the hot ticket with this set-up.  

 

Actually, madkaw sent me a link to a very thorough. P79 build page. I suppose I can go with a P90, as well. At this point, it's whatever ends up in the garage. I've had many people recommend those heads, but when I spoke to Dave Rebello, he seemed pretty confident in the N42's operation, even though I specifically addressed my compression goals and fuel octane resources. So that stepped me back a bit. From what I've gathered, however, there seems to be a lot more non-pinging P90/P79 high compression L28's than N42/N47's, so I won't be trying to re-invent the wheel. 

 

So to put the project up to date. 

Got the crank polished and the block bored .20

I ordered a pair of flat top pistons, but they happen to be out of stock....tried purchasing from Clark's discounts. I figured I'd get them from ebay, so that's not too much of a worry. I also got new bearings when I got my crank back. 

 

My bottom end is where I want it, for now. At this point, I'm trying to do my research and find a head and go with it.

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Mack    1

If high compression with maximum ping resistance is what you are after, look into a maxima N47  It is a completely different animal than the Z N47.  they were available in the 1981 to 1984 datsun 810/maximas that came with an L24E engine. 

 

MADKAW  you have a PM as I didn't want to thread jack. 

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If high compression with maximum ping resistance is what you are after, look into a maxima N47  It is a completely different animal than the Z N47.  they were available in the 1981 to 1984 datsun 810/maximas that came with an L24E engine. 

 

MADKAW  you have a PM as I didn't want to thread jack. 

Hmm, interesting.

Haven't heard of that head before. Also, not sure if this relevant, but I my motor is carburated. I wanted to eventually go with Triple Webers, but that's once I'm more experienced. Are there any issues involved with high compression/different head combos with the use of SU Carbs?

 

According to OZDAT, I'll be sitting at around 10:1 (about)

I've heard that is a safe number for P79's and P90's to dish out. Of course the cam and all other aspects come into play, as well.

I'll be doing some research on the MN47, but as far as you know, is there a major cost-performance difference between the turbo heads and the MN47?

I figure that every dollar I save will contribute to a different aspect of the motor. If it's a night/day difference, then it sounds like a no brainer. 

 

Thanks a lot for the input. I'll have some more homework to do tonight! (Never thought I'd say that with enthusiasm)

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So, I had another Juan-on-Juan with Dave, and (again) didn't recommend flat-tops with the P90 head, due to 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.

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Xnke    21

I don't see why not, since you're running the combustion chamber as it was designed to run...I honestly think the P90 chamber with dished pistons was a kludge on Nissan's Parts Department's perogetive...it would have been "better" to run them with a dish that matched the chamber shape, but I guess it was not enough of a problem to be bothered to produce a special piston. It may come down to piston pricing and availability.

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NewZed    56

So the P90 is not just the P79 design with no-liner square exhaust ports?  I thought the combustion chambers were the same size.  Assumed that the chamber shapes were the same.  The valve sizes appear to be the same size also.

 

If they're the same, then the comments apply to the factory stock NA P79 head engines with flat-top pistons.  Deck height is a block measurement and relates to how close the pistons get to the head, so it sounds like he's saying the "quench" is wrong for a P90 with flat-tops.  Seems like it would then be wrong for the P79 too.

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So the P90 is not just the P79 design with no-liner square exhaust ports?  I thought the combustion chambers were the same size.  Assumed that the chamber shapes were the same.  The valve sizes appear to be the same size also.

 

If they're the same, then the comments apply to the factory stock NA P79 head engines with flat-top pistons.  Deck height is a block measurement and relates to how close the pistons get to the head, so it sounds like he's saying the "quench" is wrong for a P90 with flat-tops.  Seems like it would then be wrong for the P79 too.

 

 

Forgot to mention it, but Dave said the same thing about the P79, so yes you are correct.

He mentioned that they've built hundreds of NA builds running on N42's and pump gas with no issues whatsoever. 

Edited by TheCrazySwede

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Tony D    143

I'm glad that was clarified as something appeared lost in the translation.

You can spend $10K there, but unless your making a turnkey complete package tested race motor, you won't get close to $10K.

What you posted is in-line with what others have paid, and is not much more than for a competently-built stock rebuild with a similar warranty support package would have.

 

The myth of the slapped together $1,500 stroker persists from people searching 20year old Internet builds (sometimes totally disregarding they seemed to be "rebuilt" every 10,000 miles or so...)

 

You can spend the money once, or let it bleed you continually over the years. I like the one-payment and drive setup myself! Good luck in the process.

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I'm glad that was clarified as something appeared lost in the translation.

You can spend $10K there, but unless your making a turnkey complete package tested race motor, you won't get close to $10K.

What you posted is in-line with what others have paid, and is not much more than for a competently-built stock rebuild with a similar warranty support package would have.

 

The myth of the slapped together $1,500 stroker persists from people searching 20year old Internet builds (sometimes totally disregarding they seemed to be "rebuilt" every 10,000 miles or so...)

 

You can spend the money once, or let it bleed you continually over the years. I like the one-payment and drive setup myself! Good luck in the process.

 

You see, I was always under the impression that Rebello wouldn't even touch your motor if you didn't show up with a bag full of cash, haha.

After talking to some people who are currently undergoing business with the Rebello team, and talking to Dave personally, I got a rough idea of the reality of the situation. Dave even mentioned that he doesn't need a full payment up front. A couple of grand is all he needs to get the ball rolling, and he can even cycle the billing or pay the rest once the motor is ready. Given that I live about an hour away from their shop, I was gonna bring in my L28 and have their talented hands put it together for me. 

 

As of now, I'm doing some research to see where I would go next, given that I do go with the Rebello route. Things I was curious about are things like ignition systems and accessories. I'm sure I can speak with Dave more about it. I've learned that I would need another starter (This one was recommended: http://www.rockauto.com/catalog/raframecatalog.php?tab=search&partnum=1870137) but I don't know much about anything else. I assume I can use the later modeled oil pump and such. I got plenty of reading to do!

Edited by TheCrazySwede

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Tony D    143

Get with Dave and get his recommendations... Yeah there's a lot of "talk" out there that guides people, but the reality is the "couple grand up front" pays for the hard parts...and for a shop owner that means money they aren't out so they can keep the lights on! Especially if they're bought through them so they make a little on markup...

 

I took business from my former employer because they put THE US NAVY on "credit hold"... They needed serious work on two machines, I wrote the stipulation in the service contract that the work would commence upon them buying the parts in advance. They accepted it... Some $60,000 paid to us up front for about $35,000 in our-cost parts. That made life for out little company MUCH easier not having to shell out our ENTIRE cash reserve to buy parts for a job that we wouldn't get paid for four more months or so...

 

Ended up lots of add-on work was necessary (consisting mostly of labor) which ended up invoiced daily to a CREDIT CARD meaning instant payment to US of $3,000 daily! Everything was "$3,000" at that point. We ended up billing 60k in parts, $24,000 in additional credit card purchases, plus a flat rate labor charge for two men and four weeks labor of $40,000.... With ZERO outlay other than technicians salaries, lodging and living expenses. It really helped the cash flow situation. And that's where you get "the few grand up front." Same as any shop, once the parts are bough and paid for UP FRONT (especially if you have margin on the parts) it's a zero sum game...you have enough money in your kitty for some prelim machine work...and really your final billing is labor...you get paid when it's all done. Since no money is out of your pocket, most guys can wait to get paid...especially if it's not costing them anything!

 

I digress...

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Get with Dave and get his recommendations... Yeah there's a lot of "talk" out there that guides people, but the reality is the "couple grand up front" pays for the hard parts...and for a shop owner that means money they aren't out so they can keep the lights on! Especially if they're bought through them so they make a little on markup...

 

I took business from my former employer because they put THE US NAVY on "credit hold"... They needed serious work on two machines, I wrote the stipulation in the service contract that the work would commence upon them buying the parts in advance. They accepted it... Some $60,000 paid to us up front for about $35,000 in our-cost parts. That made life for out little company MUCH easier not having to shell out our ENTIRE cash reserve to buy parts for a job that we wouldn't get paid for four more months or so...

 

Ended up lots of add-on work was necessary (consisting mostly of labor) which ended up invoiced daily to a CREDIT CARD meaning instant payment to US of $3,000 daily! Everything was "$3,000" at that point. We ended up billing 60k in parts, $24,000 in additional credit card purchases, plus a flat rate labor charge for two men and four weeks labor of $40,000.... With ZERO outlay other than technicians salaries, lodging and living expenses. It really helped the cash flow situation. And that's where you get "the few grand up front." Same as any shop, once the parts are bough and paid for UP FRONT (especially if you have margin on the parts) it's a zero sum game...you have enough money in your kitty for some prelim machine work...and really your final billing is labor...you get paid when it's all done. Since no money is out of your pocket, most guys can wait to get paid...especially if it's not costing them anything!

 

I digress...

 

Yup, true that.

 

I'm not complaining. The build time usually takes a good 6-8 months, depending on how many times you decide to bug Dave about it. That's more than enough time for me to pay off the motor and have it ready. 

 

As I mentioned in my original post, this is my first motor and my first "real" experience with restoration. I'm giggling like a school girl at the mere thought of a Rebello motor, so I'm obviously very excited! Still reading up on all the things I'll have to do to get the engine ready to run in the car. I'm sure I can ask Dave all the questions I'll have (I doubt I'm the only doofus he has dealt with) but I would rather arrive prepared and not naked...figuratively speaking, of course.

 

Thanks a lot everyone for all the help and support! I'll keep the thread going with any updates.

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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!

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"I didn't want an all out powerhouse of an engine....instead, I wanted a responsive one."

 

That is a confusing statement. Can you expound on that a bit? Torquey? 

 

Nah, not necessarily torquey.

I'm thinking more in terms of engine speed. I asked about the different pistons and rods, etc. that Rebello uses on his builds and then looked around and found some Japanese pistons (Kameari) that weight around 280g (compared to the 432g pistons Rebello uses.) Eiji uses those and his own rods, too, which weight in about 300g lighter than the L24 ones. I wrote down all the specs from both engine builders, and when comparing the two, I liked the numbers I was getting from Eiji. Included in the build is also a 9lbs Flywheel, which will drastically help regardless of what else you're rocking inside.

 

In short, I like the idea of having lightweight and strong internals that can handle a high-revving conditions and get there in a quick manner. That's what I mean with responsive. The same power figures with Rebello has me running on race gas (~12:1CR) with a LD28 crank and some sacrifice in every day drive ability. Eiji's build (because of the different parts he uses and how he works the heads) has me getting close to the same power figures, can run on pump gas and the engine operates extremely quick for a street motor. I've spoken to a few people on different forums, and one guy has had motors built by both parties (Rebello and Eiji) and he preferred the way the lighter engine operates. He has, so far, ordered 3 builds from him. No idea what he's up to with those, haha. He emailed me videos of his car (it's a white 240 with a black hood), so I'll ask him if it's ok if I share them.

Edited by TheCrazySwede

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rturbo 930    27

Where's it going? Eiji or Rebello?

 

Edit: Didn't read, it's going to Eiji. Keep us posted on your experience with him. I've heard tons about people who have dealt with Rebello, but not much about those who have dealt with Eiji.

Edited by rturbo 930

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Where's it going? Eiji or Rebello?

 

Edit: Didn't read, it's going to Eiji. Keep us posted on your experience with him. I've heard tons about people who have dealt with Rebello, but not much about those who have dealt with Eiji.

 

Will do!

So far, I've had about 50+ emails sent back and forth with Eiji on the other end. He is very professional and courteous. I'll keep things updated as the build commences.

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Ah I was considering ordering someJE pistons with a similar compression height to use with maxspeed's fj20 140mms rods. I believe they are actually lighter than DSI's and a helluva deal at $450. Figure I could get most the advantages for about half the price.

 

Very curious to see how your build turns out. I've shared a few emails with Eiji a few times, very nice guy. His SPL heads are gorgeous.

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Ah I was considering ordering someJE pistons with a similar compression height to use with maxspeed's fj20 140mms rods. I believe they are actually lighter than DSI's and a helluva deal at $450. Figure I could get most the advantages for about half the price.

 

Very curious to see how your build turns out. I've shared a few emails with Eiji a few times, very nice guy. His SPL heads are gorgeous.

 

I believe the 139.5mm Kameari FJ20 Rods are the same ones Eiji uses, along with Kameari Pistons.

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