Preparing 78 280z for Turbo Swap, Reusing stock block

[Challenger]

So currenty I have my 81 280zxt which is in running condition. Im doing all of the modifications that Id like to have installed once its in my 78, intercooler, mbc, FMU, fuel pump, etc. All parts are easily switched over. My 78 is being restored and is very close to finished but doesnt have an engine. I have prepped the engine bay to recieve a new engine, rewrapped the engine bay harness so its all looks nice, etc.

 

So heres the question and plan. I have the original 78 engine in the garage. N42 block, n47 head combo in good condition. The 81 turbo is obviously a f54 block, p90 head. I also have a set of 81 turbo pistons from my last turbo car that I parted out.

 

Id like to drive the 81 turbo for the rest of the summer since its all together and the car is fun to mess around with since its beat up and I dont care about how it looks but I want to get as much done on my 78 before school starts again.

 

Heres the two plans...

 

1) Leave 78 as is and wait to transfer entire engine and wiring who knows when, end of summer, winter, later.. I would have to clean up the block which would take even more time really pushing off ever driving this car.

 

2) Strip down n42 engine to just block, refresh the block, install turbo pistons, modify for turbo oil feed/return lines, and bolt it up in the car ready go. Purchase extra wiring harness and begin to do wiring for the turbo harness and ecu (I have a spare ecu). This plan would allow me to keep working on the 78 and in a way do the turbo swap while still being able to drive the turbo car and gain experience. I could push off actually transferring over the head and turbo till sometime this fall during school since this would be by far the easiest part of the swap. I would use the turbo pistons since from what I know they have the ring lands lower on the piston to help shield the rings from heat. I suppose Id need to find myself a turbo oil pump as well, but I have alot of the small engine parts left over from my last turbo engine to prep it to work with the turbo system. So this aspect should be pretty trouble free.

 

Im obviously leaning towards option two but please let me know if you see any problems or changes that woould need to be noted.

 

Thanks!

Edited June 30, 2010 by Challenger

[FlatBlack]

Option 3: N/A-T the N42 block, install intercooler, stay on stock boost and you'll be fine! I have a flat top motor with a 1mm HG and it's still ticking away at 180psi on all cylinders with 10 psi of boost.

 

Unless you are running the stock ECU, then I guess go with Option 2?

[Challenger]

Yes, stock electronics. Ill be running in the mid to low teens with the aid of a Begi FMU. So I really dont want to deal with the NA compression. Im intimidated already by tuning the low compression engine. haha

Edited June 30, 2010 by Challenger

[Pyro]

option 4) add megasquirt to the stock N42/N47 combo with 360cc to 400cc low impedance injectors. Then add turbo later.

 

why install a 25 year old efi system? get a good system with properly sized injectors and have ignition timing control.

 

Just need to swap the head to get the compression down to stock turbo levels, as the n42 already has dished pistons. match the head gasket to the block (use a head gasket for a N42)

 

if you plan to use stock boost then the stock N42/N47 compression (8.3:1) will be just fine. 8.3:1 is actually nicer for a turbo if you keep the boost under 10psi or if you plan to add a bigger cam (msa turbo stage 1 cam).

 

you will need a stronger clutch (240mm) for the turbo.

 

I use a bell engineering fmu on my turbo using the stock 76 efi system (na injectors with locked out ignition) and run up to 14 psi of boost. Takes a mean fuel pump to make that kind of fuel pressure (110 psi) with enough volume. I use a bosch 044 pump. Plan to go megasquirt as soon as the stock efi system goes out, been waiting for over 5 years now. hahaha

[Challenger]

To be honest my knowledge of electrical systems isnt there to do megasquirt. Im hoping to gain some knowledge/experience from the harness wiring but I am just not up to megasquirt yet. It will be done in the future though.. hopefully not 5 years though. haha

 

Im hoping to go to 15 psi with the stock compression so I wont be swapping out the cam.

 

I already have the 2+2 clutch, my cars a 2+2.

 

I have the bell FMU as well. Model 2022, (2025 with spring removed). Ill hopefully be turning up the fuel pressure in the next week or so. I also have a walbro 392 255lph so Ill have enough fuel.

Edited June 30, 2010 by Challenger

[stravi757]

I would strongly recommend if you go turbo to use the 300zxt ecu and MAF. I would never put the stock electronics back in my turbo swap again. its runs way better then it ever did with the AFM, plus warm ups/cold starts are so much better. And its very easy to install, I did it in under an hour.

[Challenger]

Well I was considering that. I think it would be worth while to do on my 78, pretty much plan 2 but with the z31 electronics.

 

http://forums.hybridz.org/index.php?/topic/49087-z31300zx-ecumaf-to-280zxt-swap-guide-1981-supplement/page__p__425643__fromsearch__1#entry425643

 

I was reading on the z31 swap for the last few days. Looks like Id still need to pick up an extra zxt harness.

[FlatBlack]

To be honest my knowledge of electrical systems isnt there to do megasquirt.

 

It is much much easier to install than you are making it out to be. It really is plug and play with the relay board. If you can solder, you can install it. It is much less work than splicing together the 28)ZXT harness I'm sure, plus troubleshooting that if it doesn't work is going to be a major pain.

 

I had all of the components for the swap, got cold feet and went MS instead.

 

It may seem over your head now, but if you plan on going with a standalone at some point later on, why do things twice when you can do it once?

Edited June 30, 2010 by flatblack280

[Pyro]

you can use the stock 280 efi for now with your fmu.

 

use an 8:1 ratio. 8 psi of boost needs 64 psi of fuel pressure

 

then lock the ignition mechanical advance and set timing at 26 degrees with 8.3:1 cr and 8 psi of boost.

 

I would get a fuel pressure gage mounted in the car so you can keep track of the fuel pressure.

[Xnke]

Also, if you go the Z31 route, you have Nistune as an option as well. Not a bad choice, and about the same cost (IIRC) as a complete megasquirt system, and you get a decent base tune too.

[Tony D]

I have run an L28 N42/N42 combination from a 1977 Nissan Cedric since 1985 in the 'mid to high teens' without changing pistons. (Ran 21 for a while...)

 

What is it that forces people to think that 20psi demands 7:1 CR or thereabouts?

 

If you are planning on going to 30psi with a block consider a compression ratio in the 7.X:1 range.

 

But for christs sake, 'mid to low teens' is NOTHING boost wise. A LOT of it depends on WHAT TURBO you are using, as well!

 

If you think the MS is harder than hacking together stock components and band-aiding fueling with a BEGI....you're off the mark a bit.

 

I wouldn't touch the inside of the 78 block, you stand to F-U more than you will 'fix' with mismatched components and (did you say new ARP Rod Bolts...no you didn't so...) old stock rod bolts waiting to ventilate your block.

 

In 9 out of 10 times people open a bottom end to make it worse than if they had just left the well assembled stock Nissan stuff in there undisturbed.

 

Does it make anybody else think when someone says they are 'not trusting their 170K mile engine' and then take it all apart to 'fix' something...then in less than 20K miles there are problems? Seems to me with the preponderance of 250K+ mile engines out there leaving it alone may not be a 'bad' thing!

[woldson]

Drive the 81. Ms the 78. You've done some good work on the cars you've aquired. Im certian you can do a ms.

 

You need to get over that hump anyhow. Just be a peace with the idea you won't be able to drive your (very nice, chick magnet) for a while..

 

You more then likely will not blow the 78 as you learn. Then transfer computer over to 81 and push it!!! This way when you transfer the turbo system into the 78 thier will be a lesser chance of "poof"!

 

I believe you tony on the engines. Just to cement it further, you can not even buy bearings as good as what was put in the car originlly?

[Challenger]

Thanks for the info everyone. Basically what Ive come to conclude is that whatever I plan on doing electronics wise I need to do it now to try and get it done this summer. I cant waste time driving the ZX around and modifying stuff that will be trashed once it goes into my 78. Ive began to pull the turbo engine in preparation to clean it up and bolt it into the Z.

 

As for electronics, obviously MS is the way to do it right and I really dont want to do something like this twice. From preliminary research it wont be a big problem money wise but I really want to price everything out and know exactly what all is required and involved.

[Gollum]

There's also the inevitable plane 2-B

 

Which goes like quoted

 

2) Strip down n42 engine to just block, refresh the block, install turbo pistons, modify for turbo oil feed/return lines, and bolt it up in the car ready go. Purchase extra wiring harness and begin to do wiring for the turbo harness and ecu (I have a spare ecu). This plan would allow me to keep working on the 78 and in a way do the turbo swap while still being able to drive the turbo car and gain experience. I could push off actually transferring over the head and turbo till sometime this fall during school since this would be by far the easiest part of the swap.

And then

The "tool" you were using to hold the timing chain tensioner in place falls out and you're up a S$%^ creek without even a flathead screwdriver to paddle with. Then you end up having to get a loaner car while BOTH your cars don't work and you have to pull the crank pully off, oh joy. Then proceed to remove the entire front timing cover off, get it all fixed and assembled only to find a water leak because you skimped on a new gasket for the timing cover because you didn't want to wait for shipping.

You finally get the thing back together running just in time for summer to be over and have missed all the good driving conditions.

This is just hypothetical though. Nothing like this ever happens to anyone!

A little interesting tidbit though, when my tensioner DID pop out and I pulled the front apart to get it out, I did some practicing watching what's going on, seeing if it was theoretically possible to get the tensioner back in without removing anything, and indeed I COULD get it back into it's home without removing everything. BUT... it would be nearly impossible to get the timing chain back into the correct spot, so you'd just have to verify TDC and trust your marks. Big Phil did this and mentioned the method of correction on one of his videos.

And no, I didn't really have any leaks, I'm just being funny.

[280zbeeT]

I was reading your post, abbout one member building a turbo n42 block with p90 head and you made the comment he would need a... you made the comment that it depends on the turbo, I have the same setup finished installing it this weekend, with a GT30R turbo from Garrets, can you please explain what you meant but this? and how it effects what happens to the block? Im guessing the bigger the turbo the easier it is to blow the rings? You got a lot of good advice here but as usual, its what you feel and want for your car is best for you, so if you have a crazy dream or idea to be done to your car that will make you happy, Do it, and give yourself a nice treat! just do it right

Edited July 3, 2010 by 280zbeeT

[Tony D]

You got a lot of good advice here but as usual, its what you feel and want for your car is best for you, so if you have a crazy dream or idea to be done to your car that will make you happy, Do it, and give yourself a nice treat! just do it right

 

Crazy Dreams many times conflict with the reality of physical laws. People need less encouragement to 'feel' and more stress needs to be towards the 'think'...

 

If you have a 'crazy dream' that is always busted and you never drive it is that still a 'dream' or is it a 'nightmare'...

 

The key to any turbosystem is to be realistic in expectations, and engineer to a set of defined goals. Once you reach them, be happy for a while, and DRIVE the car reaping the 'treat'... But too many times, too often in fact, I watch guys tear into perfectly good long blocks under misguided assumptions left over from the 1960's about what 'needs' to be done to a turbocharged car.

 

Take a good look at Saabs. If they have a 'low pressure' turbo system (by their definition, less than 1 bar positive pressure) they don't even include a boost gauge because they don't consider that stressful enough to warrant the gauge!

 

Coming from the turbocharged small displacement VW world, everybody was running a 20 or 25psi wastegate (and this was the 80's!) Now it's even higher.

 

The stock Nissan OHC is a damn stout engine, and with no modification will easily return 'lifetime' reliability (100K+) at the 300HP level. What boost level is needed to achieve this is dependent on turbocharger and top end breathing. But that horsepower level barely gets this engine to 100HP per litre. And it's built to handle that all day long.

 

Keep if from detonating (that means FUEL AND SPARK far more than static compression ratio at this power level!) and it will live literally 'forever'!

 

It saddens me to see people throw a bunch of money at a car because they were 'told' stuff was necessary, when in fact, they could have saved that money and used it for far more important things (like a chassis modification to better handle the power, or gawd forbid a much-needed driver improvement class/track time!)

 

In fact, if guys would leave their car alone, and take the first $2000 they normally would have put toward 'car mods' and invest them in "driver mods" like a driving school they would reap driving rewards in EVERY car they drove. And in many cases they would realize how far beneath the potential they have been driving the car they had already sitting in their hands! This is especially true for the younger set, in many cases they have not been exposed to the FULL capabilities of even a stock S30. If they knew, and could extract it, think of the treat...the joy they would get from what they have-and everything from that point onward!

 

Put $1500 into a turbo and a set of pistons, and one plugged injector and you're back at square one...

 

I digress...

[Challenger]

Alright, well the engine is out of the 81 turbo and is on an engine stand being cleaned up. Ill hopefully get the oil pan, motor mount brackets and valve cover sandblasted and repainted tomorrow. My goal is to get the engine mounted in the car this week...

 

Also, I decided to take the plung on megasquirt. I will be following twoeightythreez's guide for installing megasquirt using the stock harness.

 

http://forums.hybridz.org/index.php?showtopic=48292

 

I have tried to contact the poster to get more info on all the parts needed, rather what he used but he hasnt got back to me yet.

 

Anyways heres the list Ive come up with...

 

MSII- Trying to decide If ill get it assembled or not. Either way Ill either need to tell them or do it myself to have it set up to run the coil directly.

 

http://www.diyautotune.com/catalog/bosch-bip373-coil-driver-mod-kit-p-230.html

 

Ill have to see if when you order it there able to install this for you, assuming I buy the assembled one.

 

Wiring harness: http://www.diyautotu...ready-p-43.html But get the short version in order to have the plug because Ill be using the stock wiring harness.

 

82 Distributor- Since MS will be directly controlling the coil will this work? Turbo or NA?

 

IAT sensor- Any GM sensor

 

240sx TPS

 

coolant temp sensor- Any GM sensor

 

wideband- LC1 sensor? Now I will only need the sensor itself since I will be able to read out my AFR on the laptop?

 

Thanks for the help guys. Ive been doing alot of reading.. alot of info to absorb.

 

Thanks!

 

tuning cable http://www.diyautotu...-thru-p-35.html

Edited July 6, 2010 by Challenger

[FlatBlack]

 

82 Distributor- Since MS will be directly controlling the coil will this work? Turbo or NA?

 

IAT sensor- Any GM sensor

 

240sx TPS

 

coolant temp sensor- Any GM sensor

 

wideband- LC1 sensor? Now I will only need the sensor itself since I will be able to read out my AFR on the laptop?

 

Thanks for the help guys. Ive been doing alot of reading.. alot of info to absorb.

 

82-83 CAS Dizzy is going to be "easiest" [because that is what is most popular]. You need the Turbo one, the N/A F54 dizzy is the E12-60 unit.

 

You need an LC-1 Controller AND LSU-4 Sensor. [super cheap LSU-4 wideband sensor - go to AutoZone and look up a O2 sensor for a Audi TT, it's $55 8) ]

 

I've been having issues with my LC-1, I know for a fact XNKE had to get his replaced as well. I've just heard bad things about them. You might consider doing a PLX or other than Innovate controller, maybe do some google searching about it.

 

Now might be a good time to convert to one of your shaved manifolds, ported out to 60mm I went to a cable throttle setup, it's much more responsive than the mech linkage. Might consider it, plus that solves the "240SX TPS" issue.

 

I got my board assembled. I didn't have time to mess with it and I was frustrated dealing with other issues. If you do go pre-assembled, go with the V3.0 board, NOT the V3.57 - if something goes wrong on my main board,

A: I can't see it and

B: I can't fix it.

The 3.0 board has 'floating' components. If they burn out, you should probably be able to inspect them for damage.

 

Why do you want to mess with the stock harness? I feel that it's going to be a major headache, but I applaud your tenacity

[Challenger]

Were there issues with the 240sx TPS because it was on a smaller throttle body?

 

I actually thought the stock harness may be alittle bit easier.. Ive got a wire by wire write up to go by and everything worked on my car before so I feel it should be fairly plug and play... hopefully... haha

Edited July 7, 2010 by Challenger

[Xnke]

In the end, it will be less work to start with the ZXT harness, not to mention less component cost. All he has to do is change the ECU connector, really.

 

Yes, if you go with the LC-1 controller, follow the directions EXACTLY. I bought my controller used on Ebay, which is why I had to send mine off to get repaired; it was replaced for free by Innovate. DO NOT try to cheat the grounds, or you will either burn it up or it will read funny.

 

Yes, the LC-1 controller does not need a gauge. You'll be reading it in Megatune/Tunerstudio, you just need the controller and the LSU-4 sensor.

 

The thing with the 240SX throttle body is that the TPS bolts up, and you might have to fiddle a little with it to bolt it onto the ZXT throttle body.