Mix and match! Anyone have suggestions?

[Midri]

Sooo I've got 3 L28 engines now all out of cars and wanting to mix and match them to make the best 2 I can. I'm building one turbo engine and one na engine.

 

Blocks:

2x N42 (dished pistons)

1x F54 (brand new dished pistons, recently rebuilt)

Heads:
1x N42

1x N47

1x P79

Cams:
2x stock

1x Schneider 270-60F-14

1x Schneider 270-60F-14H (I think this one is for a hydraulic head.)

Turbos:
1x Stock L28ET Turbo

Any suggestions for pairing? Also I'm aware I probably should get some flat top pistons for the NA since all of these engines have dished ones.

[HuD 91gt]

P79 and a dished piston block for the turbo, stock cam or non hydraulic turbo cam

 

N42 and a dished piston for the N/a. Stock cam

 

 

No brainer if you've done any sort of research at all.

Edited October 22, 2015 by HuD 91gt

[Midri]

P79 and a dished piston block for the turbo, stock cam or non hydraulic turbo cam

 

N42 and a dished piston for the N/a. Stock cam

 

 

No brainer if you've done any sort of research at all.

Well I was looking for a bit more theory craft...

 

Why would you suggest dished pistons instead of getting flat tops for the NA? I was aiming for higher compression, but I'd probably need a new cam right?

 

Also if I could get an F54 block with flat pistons would it make more sense to use than the N42 with flat pistons, being I'd have to buy pistons for the N42?

Edited October 23, 2015 by Midri

[Tony D]

So these are apart in pieces and not assembles engines? 

 

Or were they assembled engines that you took apart.

 

Nothing you do will have any appreciable effect on anything material.

[Midri]

So these are apart in pieces and not assembles engines? 

 

Or were they assembled engines that you took apart.

 

Nothing you do will have any appreciable effect on anything material.

Complete engines that have been disassembled due to sitting for years, we're replacing gaskets, checking seals, etc. Just want to make the best engines out of all the parts (one of the engines is not going back together)

[HuD 91gt]

Well I was looking for a bit more theory craft...

 

Why would you suggest dished pistons instead of getting flat tops for the NA? I was aiming for higher compression, but I'd probably need a new cam right?

 

Also if I could get an F54 block with flat pistons would it make more sense to use than the N42 with flat pistons, being I'd have to buy pistons for the N42?

 

Sorry,  I didn't really answer your whole question. I was just mix and matching the pieces that you had.  You don't really have too many options.

 

Flattops and the N42 are great.  Unless you have some good ignition control, or a cam with some more overlap then the stock one you will probably have some detonation without bringing back the timing a good bit.

 

The N42 with dished pistons is going to give you a stock 280z engine.  The dished pistons and the P79 is going to give you a stock low compression L28et with funny shaped exhaust ports.   What you do from here is up to you since you'll have to be purchasing parts anyhow.

Edited October 23, 2015 by HuD 91gt

[Midri]

Sorry,  I didn't really answer your whole question. I was just mix and matching the pieces that you had.  You don't really have too many options.

 

Flattops and the N42 are great.  Unless you have some good ignition control, or a cam with some more overlap then the stock one your most likely going to get some detonation (Without bringing the timing back).   

 

The N42 with dished pistons is going to give you a stock 280z engine.  The dished pistons and the P79 is going to give you a stock low compression L28et with funny shaped exhaust ports.   What you do from here is up to you since you'll have to be purchasing parts anyhow.

Well the turbo cam is 270intake/260 exhaust, could it be used in the NA engine with N42 + flattops? I've tried to research how all the different measurements of a cam shaft play into dynamic compression ratio, but it's just not something I'm comfortable with yet.

 

Also I just got informed I can grab an '83 280ZX's L28 for cheap, which should be a flattop F54 block.

Edited October 23, 2015 by Midri

[Tony D]

My suggestion in that case is to keep the 83 Unmolested and just run it and forget about making work for no real benefit.

[Midri]

My suggestion in that case is to keep the 83 Unmolested and just run it and forget about making work for no real benefit.

 

How would an increase from 8.8:1 to 10:1 not be worth it? I'm legit wondering, since you are one of the pros on here Tony. I have no problem getting a different cam if I need to or having one of my stock ones machined.

[madkaw]

I'm confused, I don't see an option from your choices above for flat top motor, but you keep mentioning it. Yes a P79/54 flat top would be best for na , but your 54 has dish pistons as you stated.

[Midri]

I'm confused, I don't see an option from your choices above for flat top motor, but you keep mentioning it. Yes a P79/54 flat top would be best for na , but your 54 has dish pistons as you stated.

I mentioned that I was open to the idea of getting flattop pistons, but later in the replies I also pointed out that I have located a L28 out of an '83 ZX that should have a F54 with flattop pistons as well.

[HuD 91gt]

8.8:1 vs 10:1 on different head, with different flow characteristics. I've been through what your searching, and tearing down, or "rebuilding" a motor is not worth it for the minimal performance increase you will see.

 

 

As for the turbo cam in the N/A application.  The wider lobe separation will certainly not help with your detonation issues.  Having no experience using two identical cam profiles other then lobe separation I can't really say what it will do.  But all the articles tell me you will be losing power.  Whether it's worth it over the stock cam?  Who knows.  I probably wouldn't spend $100 on lash pads to find out.

 

 

If your willing to do some DIY headwork, and N42 on flattop pistons could be a great option for you.  But if you are just doing some mix and matching with parts, it's not worth your time or money.   The '83 N/A motor should be a good runner.  If it is, let it be and build a turbo motor.

Edited October 23, 2015 by HuD 91gt

[Midri]

8.8:1 vs 10:1 on different head, with different flow characteristics. I've been through what your searching, and tearing down, or "rebuilding" a motor is not worth it for the minimal performance increase you will see.

 

 

As for the turbo cam in the N/A application.  The wider lobe separation will certainly not help with your detonation issues.  Having no experience using two identical cam profiles other then lobe separation I can't really say what it will do.  But all the articles tell me you will be losing power.  Whether it's worth it over the stock cam?  Who knows.  I probably wouldn't spend $100 on lash pads to find out.

 

 

If your willing to do some DIY headwork, and N42 on flattop pistons could be a great option for you.  But if you are just doing some mix and matching with parts, it's not worth your time or money.   The '83 N/A motor should be a good runner.  If it is, let it be and build a turbo motor.

The engines are all being torn apart, regardless of if we plan to mix and match them. 4 of them have been sitting for 5+ years and the one that was running is a franken engine already and we're wondering how well it was put together so we're taking it apart (it was originally going in a different Z than the one it came out of, I got a rust free one a while back and my current one is about 99% rust, so it was going to be pulled anyway.)

[NewZed]

The engines are all being torn apart, regardless of if we plan to mix and match them. 4 of them have been sitting for 5+ years and the one that was running is a franken engine already and we're wondering how well it was put together so we're taking it apart (it was originally going in a different Z than the one it came out of, I got a rust free one a while back and my current one is about 99% rust, so it was going to be pulled anyway.)

You're probably going to convert several decent-to-good engines in to many boxes of parts.  The engine in my car now runs excellently and is in great shape and it sat for 10 years, never started, before I got it.  Actually the guy I got it from got it running after the ten year spell and probably did a poor job of resurrecting it.  But it's still in great shape.  1978 280Z N47/N42 engine.  The factory assembly mix-and-match, and assembly, processes are probably much better than yours, done to a set of specifications.  Your franken-motors will be no better than the one that you're wondering about.  You're just mixing and matching parts that may not be within fit tolerance specs.  And they're all essentially stock parts anyway, so it's kind of a pointless exercise.

 

If you're just having fun with puzzle pieces that's one thing but if you're expecting something significantly better than what you already have, the odds are against you.  You should build a test stand with engine management and test run all five of them.  That would be fun and you'd learn something, without wasting too much money.  You'll probably realize that you have at least four and maybe five good-running engines.  Modify one and keep or sell the rest.

[Tony D]

You're probably going to convert several decent-to-good engines in to many boxes of parts, none of which give you anything more than that completely assembled engine you consider.

 

This really is not worth the effort, there is no 'magic bullet'.... Look at the  raise in potential performance of the CR change... something like 0.2% per compression point or something like that.... The  N42 flows MARGINALLY WORSE than the P90, offsetting any perceived gains. You are trying  to out think engineers that has millions in their budget to get the most power under the curve.

 

Unless you want to spend money, you aren't getting anything earth-shattering. In fact, you likely just end up with a list of parts to keep straight later on because everything is mismatched. I took an engine out of a 1980 280ZX 2+2...225,000 miles on it. Put it in my stock 76 2+2 with stock EFI on it, and then ran around 145 to the rear wheels on the dyno with the stock manifolds and a crush-bent partially collapsed, QUIET exhaust system (quieter than stock, in fact!)

 

I've run consistent 15.50's @ around 90mph all day long at the drag strip, and get 22-27mpg towing a small trailer. I've taken it across the country 2X over 32,000 miles (16,000 miles each trip, when I say 'around' I mean 'AROUND' the USA!) It starts like a stock car,  runs quiet like a stock car, and gets me sworn at by guys that have all sorts of go-fast  goodies  still basically stock and a lot of effort put into it...but not much else.

 

Sell the parts to people with a like mind who think they can change the world with a conglomeration of magic bullets, and take  that money to put it into proper tune up of the stock engine you get. You have not mentioned once your induction  choice...which, on a stock intake really limits what you  will do N/A, period. 

 

You have an 83ZX Flat-Top long block....meaning a  head that flows maybe  190cfm at 450-500"?, and an intake that maybe flows 190cfm. 

 

You cam it to optimise power, and the stock EFI won't like it.

 

The power is not where you think it is. The parts are all the same. It's how you tune  them  to work as  a proper package  that makes power. 

[Midri]

You're probably going to convert several decent-to-good engines in to many boxes of parts, none of which give you anything more than that completely assembled engine you consider.

 

This really is not worth the effort, there is no 'magic bullet'.... Look at the  raise in potential performance of the CR change... something like 0.2% per compression point or something like that.... The  N42 flows MARGINALLY WORSE than the P90, offsetting any perceived gains. You are trying  to out think engineers that has millions in their budget to get the most power under the curve.

 

Unless you want to spend money, you aren't getting anything earth-shattering. In fact, you likely just end up with a list of parts to keep straight later on because everything is mismatched. I took an engine out of a 1980 280ZX 2+2...225,000 miles on it. Put it in my stock 76 2+2 with stock EFI on it, and then ran around 145 to the rear wheels on the dyno with the stock manifolds and a crush-bent partially collapsed, QUIET exhaust system (quieter than stock, in fact!)

 

I've run consistent 15.50's @ around 90mph all day long at the drag strip, and get 22-27mpg towing a small trailer. I've taken it across the country 2X over 32,000 miles (16,000 miles each trip, when I say 'around' I mean 'AROUND' the USA!) It starts like a stock car,  runs quiet like a stock car, and gets me sworn at by guys that have all sorts of go-fast  goodies  still basically stock and a lot of effort put into it...but not much else.

 

Sell the parts to people with a like mind who think they can change the world with a conglomeration of magic bullets, and take  that money to put it into proper tune up of the stock engine you get. You have not mentioned once your induction  choice...which, on a stock intake really limits what you  will do N/A, period. 

 

You have an 83ZX Flat-Top long block....meaning a  head that flows maybe  190cfm at 450-500"?, and an intake that maybe flows 190cfm. 

 

You cam it to optimise power, and the stock EFI won't like it.

 

The power is not where you think it is. The parts are all the same. It's how you tune  them  to work as  a proper package  that makes power. 

Thanks for the info, I was going to use the N42 intake manifold (pre egr) and find a 60mm throttle body to put on it, if I go with the P79 head I'll use my 6-1 or 6-2-1 headers (they're both round). As for the actual induction I was thinking running the stock airbox without the top half (the flat flute) with the filter held in place by a custom mounting bracket. I'd think the larger rectangular body into the hole design would put more pressure into the intake than a "ram air/cold air" tube would when moving, but I'm going to play with that I guess.

 

We've taken L28s apart before, for valve and cylinder wall repairs; I'm not to worried about parts getting miss matched. Also I have so many gasket kits... really want to use them... lol

 

I'm wanting to put a Megasquirt 2 in the NA at some point, have a wide band O2 sensor and some other misc parts sitting around that could be put to good use.

 

Mainly I just wanted to get as much out of an NA engine as I could and since I had all these misc parts I know people have done some crazy combos and gotten interesting results. Needed to know if it was worth doing a high CR on an L28 (read a few forum posts on it, and agree retarding the timing to get high cr engines to not knock kinda defeats the overall goal.)

Edited October 25, 2015 by Midri

[Tony D]

"I know people have done some crazy combos and gotten interesting results."

 

Cite one that is quantifiable backing up horsepower claims with verifiable timeslips and not just some sketchy dyno number that could be nothing more than filter adjustments to the dyno program to flash high numbers by the dyno op to make a masturbator feel like he's accomplished something more than just wasting time.

 

Consider this: ITS engines have to be more or less stock. Meaning no swapping parts like "good flowing" P90 (low compreession) head etc. The  E31 headed L24's can make 209HP stock. STOCK.

 

My suggestion is until you reached that point, perhaps screwing up the mix is probably just a big waste of time.