Engine Rebuild

[Auston]

Hi. I am rebuilding a L28. (N42 Block and N47 Head)

I want to build a good NA motor. I'm young, and I am looking for your wisdom. I do not want to turbo, and I wanna make anything above 200hp. 

How should I go about this? 

Edit: I forgot to add, my budget is around 1,500 to 2,000 dollars. Any advice would be, very much appreciated. Thank you, and have a blessed day.

Edited April 8, 2020 by Auston
i did an oopsy

[heyitsrama]

grab a copy of this https://www.ebay.com/itm/How-To-Modify-Your-Nissan-Datsun-OHC-Engine-Book-ISBN-0895863537/143572353532?hash=item216d9441fc:g:H3kAAOSwdIVeZXSZ

that ebay listing for the book is pretty cheap...

If you are new around motors, check out some of the 10X videos from 

 

Whats the status of the motor? do you have it in a stand? Is it cleaned up? did you do a compression test // leakdown test on it?

I grabbed a concrete mixing tub a couple years ago when i was building my motor, and just lets the droppings / liquids fall into the tub. Helps when you want to clean your trans, or diff too.

https://www.homedepot.com/p/Plasgad-Black-Large-Concrete-Mixing-Tub-887102C/205451585

And a big bag of coffee filters (fiber free, easier to see the dirt, and cheap) and start cleaning, keep cleaning as you go.

you probably want a turbo, i want a turbo.

[siteunseen]

Agree with what was said above.  That book will walk you completely through tear down then rebuild yourself.  There's a few things you have to take to a machine shop and get done but I got out cheap there, about $200 if I remember right.  Take tons of pictures and write everything down you may not be sure about.  A roll of cheap painters tape was a big help for me on the connections, wiring and plug-ins.  You can do both sides with a piece of tape then add 1 & 1 or A & A.  Get a box of quart size zip-locs for all the nuts and bolts then write what it is on a piece of paper then drop it inside the bag.  I wrote on the outside with a Sharpie, bad idea as it smeared off.

A gallon of lacquer thinner and some small brass wire brushes for cleaning from your local hardware store is about as cheap as you'll find.  Cheap spray on oven cleaning foam also works good.  It's like $.99 at walmart.  A few 5 gallon buckets will be useful too.  All 6 pistons fit perfect in the bottom for me, poured about 2 inches of lacquer thinner in there and they came out like new.

Read, read and read.  You'll see something helpful every time, have fun young man!  Here's a days worth...

https://www.google.com/search?rlz=1C1BOFA_enUS494US494&ei=ueSNXvXSLrCwytMPxNeXiA0&q=l28+rebuild+parts+list+classiczcars.com&oq=l28+rebuild+parts+list+classiczcars.com&gs_lcp=CgZwc3ktYWIQA0oJCBcSBTEyLTc1SgkIGBIFMTItMTNQqKsBWP7KAWDq1gFoAHAAeACAAWSIAbsHkgEEMTIuMZgBAKABAaoBB2d3cy13aXo&sclient=psy-ab&ved=0ahUKEwi1k876idnoAhUwmHIEHcTrBdEQ4dUDCAw&uact=5

[Auston]

On 4/7/2020 at 10:50 PM, heyitsrama said:

grab a copy of this https://www.ebay.com/itm/How-To-Modify-Your-Nissan-Datsun-OHC-Engine-Book-ISBN-0895863537/143572353532?hash=item216d9441fc:g:H3kAAOSwdIVeZXSZ

that ebay listing for the book is pretty cheap...

If you are new around motors, check out some of the 10X videos from 

 

Whats the status of the motor? do you have it in a stand? Is it cleaned up? did you do a compression test // leakdown test on it?

I grabbed a concrete mixing tub a couple years ago when i was building my motor, and just lets the droppings / liquids fall into the tub. Helps when you want to clean your trans, or diff too.

https://www.homedepot.com/p/Plasgad-Black-Large-Concrete-Mixing-Tub-887102C/205451585

And a big bag of coffee filters (fiber free, easier to see the dirt, and cheap) and start cleaning, keep cleaning as you go.

you probably want a turbo, i want a turbo.

Thanks man. I grabbed the book, torn it down and had a great laugh when they told me to use a 2x4 piece of wood for leverage to get out the last main bearing cap. I appreciate the advice a lot, I took the engine shop and waiting to hear back. I sadly don't want a turbo, I don't really want to go fast. I just wanna enjoy a stock Z, maybe turbo in the future. 

Also, the condition of the motor was running but it burned a lot of oil. Every time I'd rev over 3k it would smoke crazy. So I just decided to just rebuild. It had good compression though, 150 in all cylinders besides the second and third cylinder. It was around 130 to 140.

[Auston]

On 4/8/2020 at 10:55 AM, siteunseen said:

Agree with what was said above.  That book will walk you completely through tear down then rebuild yourself.  There's a few things you have to take to a machine shop and get done but I got out cheap there, about $200 if I remember right.  Take tons of pictures and write everything down you may not be sure about.  A roll of cheap painters tape was a big help for me on the connections, wiring and plug-ins.  You can do both sides with a piece of tape then add 1 & 1 or A & A.  Get a box of quart size zip-locs for all the nuts and bolts then write what it is on a piece of paper then drop it inside the bag.  I wrote on the outside with a Sharpie, bad idea as it smeared off.

A gallon of lacquer thinner and some small brass wire brushes for cleaning from your local hardware store is about as cheap as you'll find.  Cheap spray on oven cleaning foam also works good.  It's like $.99 at walmart.  A few 5 gallon buckets will be useful too.  All 6 pistons fit perfect in the bottom for me, poured about 2 inches of lacquer thinner in there and they came out like new.

Read, read and read.  You'll see something helpful every time, have fun young man!  Here's a days worth...

https://www.google.com/search?rlz=1C1BOFA_enUS494US494&ei=ueSNXvXSLrCwytMPxNeXiA0&q=l28+rebuild+parts+list+classiczcars.com&oq=l28+rebuild+parts+list+classiczcars.com&gs_lcp=CgZwc3ktYWIQA0oJCBcSBTEyLTc1SgkIGBIFMTItMTNQqKsBWP7KAWDq1gFoAHAAeACAAWSIAbsHkgEEMTIuMZgBAKABAaoBB2d3cy13aXo&sclient=psy-ab&ved=0ahUKEwi1k876idnoAhUwmHIEHcTrBdEQ4dUDCAw&uact=5

Thanks. I took the engine to the machine shop, same with the head. Letting them check over it and clean it, and making sure all the cylinders are fine. I'm waiting to hear back on the pressure tests and stuffs.

Anyways, I got the painters tape and lacquer thinner. Trying hard, and cleaning hard lol. Labeled everything too, just like you said. Waiting to clean the pistons though, want to hear back from the engine shop. Trying to find bolt kits online for the engine. I don't want to re-use some of the bolts. Too crusty.

I appreciate all your experience you've shared with me, I hope you guys have a blessed day. God speed.

[Jeff G 78]

My race car is right around 200 HP at the crank and I built it as cheap as possible. 

I started with an '82 F54 block/P79 head.  I got a great deal from a friend and only paid $500 for the engine (with matchbox distributor), 5 speed trans and 3.90 diff.  I had the machine shop measure and clean everything, hone the block, polish the crank, install new freeze plugs, do a valve job and mill the head 0.050".  My machine shop bill was about $500 and the bearings, rings, gaskets, oil pump, water pump, timing set, head studs, etc. were another $750 ish.  I already had an old header and the cam, rockers, springs, and lash pads, though if I had to buy new, they would have been about $700 more for all that.  The crank damper is between $150 for a rebuilt stock and $600 for a BHJ.  Finally, I had good SU carbs, intake and air cleaner housing, but that's another $500 if you need to buy a good set of rebuilt ones.  I didn't need pistons, but that's another $250 minimum if needed.  I added another $225 to get the flywheel lightened and $125 for a clutch.  Throw in another $200 for misc stuff like belts, hoses, plugs, thermostat, air filter, etc. etc. and you will be at roughly $3,000 minimum if you already have a good engine to start with and don't buy a fancy damper or lighten the flywheel.  Obviously, if you already have good carbs, it's a bit cheaper.  I have built dozens of Z motors, so I only had to pay for the machining and I didn't go overboard on any component.

I'm not saying you can't make 200 HP cheaper, but you would need to already have a vast stash of parts which I'm guessing you don't have and you'd have to cut back on some pretty important items like oil pump, water pump and crank damper.  If you start with a N42 block/N42 or N47 head, you can make the same power, but you will need flat top pistons and then the head isn't as knock resistant as the P79 or P90.  If you shave a P79 or P90 head, most people choose to change the valves and shim the cam towers.  I did not go that direction which saved money.  I modified the cam gear and chain guides.

Good luck with whatever you decide to build!

[Auston]

Hi, I need your assistance again. @Jeff G 78 @siteunseen @heyitsrama

I know I said I didn't want to go turbo, but I found a great deal. I recently acquired a L28ET. It's in pretty great condition. It came with another 5speed, harness ecu, and everything just to drop it i  n. Here is a picture of the motor.

That is a F54 block. Here is my block from the engine shop, a N42.

Anyways, my question is would it be okay if I swapped blocks? What is the difference between the F54 and N42? The N42 block I was building is bored 3 over, with brand new dished pistons and it's balanced. It's almost ready to be put together.

Could I use the N42 block, and the P90 head and run it? Would I run into any problems with the N42? Thanks again for helping me guys. BTW @heyitsrama I discovered I did want a turbo, XD 

[Zed Head]

I'm not on the notify list, but feel compelled to say that there will be little to no benefit from swapping blocks.  Besides that, you'd need new pistons, rings, etc. to fit the "3" overbore (is that mm").  It could get expensive and if the turbo engine is in good shape you're probably best off to leave it alone.

[heyitsrama]

Although his option was not requested, i would listen to @Zed Head , hes never led me astray.

All jokes aside,

I think you would be better off running the turbo motor as is.

from https://datsunzgarage.us/engine/

`The F54 has "siamesed" cylinders meaning that instead of coolant flowing between all the cylinders as on earlier models they are connected between 1-2, 3-4, 5-6 with cast webbing for more rigidity. In addition there isn't a special "turbo block", all Datsun did to make the F54 a turbo motor was to replace the flattop pistons with dished ones to lower compression and add a turbo head. `

but you know you said you did not want a turbo motor, so its better to just send it to one of us and continue your NA build

Edited June 17, 2020 by heyitsrama

[siteunseen]

I agree with what's been noted above. The F54 siamesed block is an upgrade from the N42. Nissan wouldn't do that for nothing, there has to be an advantage. 

I had a friend that's mom had a turbo zx back in my day and damn it was fun. Then Buick came out with the grand national Regal. Out ran everything people around here could afford.

 

[Auston]

3 hours ago, Zed Head said:

I'm not on the notify list, but feel compelled to say that there will be little to no benefit from swapping blocks.  Besides that, you'd need new pistons, rings, etc. to fit the "3" overbore (is that mm").  It could get expensive and if the turbo engine is in good shape you're probably best off to leave it alone.

The thing is, the N42 block is already built. The picture is old, but all new bearings, pistons, rings, everything. So, if there is no difference would it be better to just put the P90 head on it and run it?  Yes it's .030 btw. So the F54 block has siamesed cylinders? Is that the only advantage? I may just build the NA motor and drop it into a 240z or something. We'll see.
 

[Auston]

So I would have a higher chance of overheating if I use the N42 block? @heyitsrama I wouldn't be driving hard, maybe a pull every now and then more of just a daily.