LD28(T) swap into a 1978 280Z.

[PanzerAce]

For very, very complex reasons having to do with income streams, internships that I did almost two years ago, aviation museums, very early mornings, and boredom, I am going to be getting my hands on a 1978 280Z for *very* cheap, and a zero mile (or close to it) LD28 for....free

After adding up the cost of some other parts, the only logical thing to do is to tear out the L28e engine and swap in the LD28, then slap a turbo charger and 280ZXT manifold on the car and have some fun with it.

However, since this isn't a common swap, I have some questions:

First, about EGTs. The only number I've found is that everything will be fine as long as they stay below 1300*F. Does this jive with what the members of this board know?

Second, boost. How much is considered to be the maximum? I know someone on here said this: "In uncharted waters, one usually crosses the edge in the quest to find it", but what is the generally accepted limit on the stock longblock?

Second (and a half): For those that have boosted these engines, what turbo did you use, and how is the power with it?

Third, fuel delivery. On a similar note to boost, where does the stock fuel pump max out? I've heard everything from 8psi to 12psi of boost.

Third (and a half): How easy is it to increase the flow capacity of the pump?

And, lastly: What is the redline on these engines? I don't plan on hitting it, so I'd like to know when to let off.


Finally: It seems like most people on here have been pretty conservative with modifications to their engine (which makes a ton of sense, considering the relative rarity, age, and lack of information). But, I'm getting atleast one LD28 engine for free. If I can pick up another, I promise I'll find just how far you can push the stock engine....and then how to build one of these suckers to make some serious power. Most of you guys approach the limit of these engines on tip toes. I'll take a flying leap off the edge and see how deep the water is for you guys

[asavage]

First, about EGTs. The only number I've found is that everything will be fine as long as they stay below 1300*F.

Banks, at least, is OK with an EGT number that high, but almost nobody else is. After considerable reading, my own "ouch" number is 1150°F for safe continuous duty. This would be a "pre-turbo" number.

. . . boost . . . what is the generally accepted limit on the stock longblock?

I know of only one member who has actually done the mod you describe and driven it (member Dslsmoke). I don't know his opinion. The block is probably not going to break, but you may have to have a copper head gasket made (easily enough done: there are several outfits that will make a copper gasket for you, if you give them an OEM one for a template. There is a one-time setup fee involved.).

Pistons are what are, IMO, going to give up first. If you're going high-boost, try to find ways to reduce the thermal load on the piston crowns. Compressing air makes the air hot. 12 PSI is probably going to put you over 200°F intake manifold temperature (a rather un-educated guess), and that's asking a lot of the pistons to absorb. Think intercooling, and water injection for the bursty stuff -- pressure switch(es), powered pump(s). I can point you to excellent online water injection component suppliers, I did this myself a few years back.

Third, fuel delivery. On a similar note to boost, where does the stock fuel pump max out? How easy is it to increase the flow capacity of the pump?

I addressed this somewhere else -- search on "Volvo". A very similar IP was used on the VW-engined Volvo 240 & 740 turbodiesels in the early-mid 80's. The boost compensating device, located in the top cover assy. of the IP, can possibly be swapped onto the LD28's IP. IMO, this should be done only by a professional rebuilder who is familiar with this series of IPs, as the IP will need to be recalibrated as well.

And, lastly: What is the redline on these engines?

The IP has a speed governor (as do all diesels I know of). I can literally hold my foot to the floor in neutral and the governor self-limits the RPM. I never got my tach installed in the dash. I can't recall the governed limit, but it's north of 4400 and south of 4900. With diesels, more RPM does not equal more power or faster trap times or whatever.

HTH

[PanzerAce]

Thanks for the info. For me intercooling automatically comes with turbos.

Didn't know that these were limited by the fuel pump RPM wise, I guess a good time to shift will be once it stops speeding up then

[240ZD]

My sources say to keep the egt below 1100 degrees farenheit, keep boost below 10-11 lbs, and that you can increase fuel flow with a simple small turn of the "smoke screw" on the pump. If you turn the smoke screw, turn it only a little bit, and you'll also have to manually control the fuel delivery closely with your right foot, otherwise you'll produce prodigious amoiunts of smoke. Basically, you only put your foot into it at the turbo spools and you get more air.

Some Aussies or Kiwis out there (they all look the same) talked about someone who supposedly runs 25 lbs of boost on his ld20 four cylinder regularly with no problems. Also, the engine will likely spin up above even 5k rpms when you're on it, despite the governor, when you turbocharge the thing.

I am very interested in how far you can push one of these...I just ain't gonna find out what it is with mine!

[PanzerAce]

So I was talking to my friend who used to work on these engines all the time back in the 80s, and got some different information from what you guys are saying. He says that so long as you keep the EGTs low, it doesn't matter how much boost is run through these, as the boost from a single turbo isn't going to be enough to get the engine anywhere near the danger zone (and that extra intercooled boost is good, since it'll help keep EGTs down by pushing the mix lean)

So where does this 10psi number I keep seeing on here come from anyway? Was there a guy that went to 15psi and destroyed his engine, or is it just one of those things that one person did to start with for some unknown reason, and everybody kind of latched onto it?

And now, onto the pictures of the shell that has been acquired for this purpose (Sorry for the quality, had to resize so that people didn't need 42" monitors to view them).




All the parts/body panels are in the garage in these pictures. Only rust on it is the normal battery tray area. Once the temperatures drop from the 110ish they've been these past few weeks, I'm going to be going to pickup the engine, rear end, and transmission for this swap, and finally get started.

[rlaggren]

Hot where you are, huh? Put you location into your profile so we can appreciate you problems... <G>

Good questions. I don't have the answers, but here's a thought: The 10#'s common wisdom may reflect how hard it is to keep the EGT's low as you raise the boost. If you get real good intercooling and maybe water injection, then you might find the few hundred degrees "cushion" for the EGT's which could allow you to play with higher boost. Another issue might be the rings and/or piston wear - but that's just a WAG.

But I got a question for your buddy: How many LD28's has he boosted over 15 which are driving around happy and usable as a DD (Daily Driver)?

Rufus

[240ZD]

I got that number from TurboMaster Pius, who says that it has to do with the fact that it is an "indirect" fuel injected diesel, which uses glow plugs. The super-boosted Cummins and such are direct injection, need no glow plugs, and have a computer-controlled fuel spray pattern that is very fine and controlled.

I guess that some research into IDI diesels could yield why 10-lb of boost is the reasonable limit for a daily driver.

I bet that if one had the pistons and such coated with some newfangled substance that reflects heat, one could run higher boost. Or one could have some high-dollar custom pistons forged that are designed for super-high temps and stresses.

Also, a single turbo can make huge boost. Many of the most powerful turbo cars I've seen have only one bigass turbo. Even mine is capable of more than 30 pounds, and it's normal sized and old.

[PanzerAce]

rlaggren, while the EGT issue was my first thought, but.....more boost = more working air for a given amount of fuel/power, which will actually lower the EGTs by pushing the mix even leaner. I'm starting to think it's more one of those things that nobody really wants to try to go beyond, and has become accepted as the upper limit.

As for the number of LD28(T)s he's built: None that I know of, but then, who has really? Sure, people modify them and push a little bit of boost, but has *anyone* actually tried to get some serious torque out of them? And TBH, I'd rather go with his knowledge of the LD in this instance, since he's been dealing with nissan and MB diesels for....well, decades. When he got out of the navy, he went right into working in a dealership on Datsuns/Nissans/MBs. Not to say that he is infallible, but if he's convinced that an LD can take the boost, I'm inclined to take his word.

Though, like I said, that's one of the reasons I'm doing this project: find out just where the limits are on these engines.

240ZD, how much experience does TMP have on boosted LDs (similar question as rlaggren). When we get down to it, for however old these engines are, they are basically unknown limits wise. It's unfortunate, but really, nobody *knows* how much the stock bottom end can take, because not enough (if any) of them have been pushed that far yet.

I agree though that modern pistons/head work/etc would provide far more potential to these engines. If I can grab a second LD28 alone with the first, I *will* rebuild it with modern pistons, (probably) rods, and some work done to the ports.



wow, reading back, this posts sounds defensive/confrontational. It shouldn't, I'm just trying to figure out the signal/noise ratio for info on the LDs

Oh, and it cooled off to the high 90s low 100s today, and it should be steady for the rest of the week. If it drops a little more, it'll be time to go get the LD

[rlaggren]

Merced, uh? Yup, gets a little warm there. <g> You guys in drought mode this summer?

No confrontation I saw. And your buddy's got as solid a resume as they get.

Now I think about it, you might want to consider the compression ratios in these (IDI) engines. IIRC, they are significantly higher than in the "direct" engines - that may have something to do with how much boost you want to add. Also, there was mention of failed con rod bolts in one thread.

Rufus

[PanzerAce]

ah, it's been a tad hot these past weeks. Cooled down nicely recently though, only got up to about 96 today.

con rod bolts eh? Interesting, only time I ever hear of those failing is when they get spun to fast. I'll see if I can find that thread. Worst case on those, I replace them with ARP bolts while I'm modifying my oil pickup.

I was thinking about the compression as well, but on the other hand, diesels are designed to have high compression, and since it's supposed to auto ignite anyways, I'm not that worried about it. Also, look at it this way: alot of the factory DI diesels can be compound boosted up to 100psi from the factory, so the measly 30-40 I'm going to be running isn't that much, event with the extra compression. (and, similar to EGTs, the fuel is what really creates the pressure/heat. Keep fuel in the right range, and chamber pressures shouldn't be too bad).

Also, I'm not going to be increasing the fuel amount nearly as much as I am the amount of air, so while I'm going to be missing out on some power, EGTs and chamber pressures aren't going to be as high as they could be.

I should actually be picking up the engine this week or next week, along with the rear end/trans/misc. stuff as well. I still haven't found a trans solution I'm entirely comfortable with from nissan that is easy enough, so unless I can find a MB trans that bolts up, looks like I'll get good at changing out the 5spd 280ZXT trans...


EDIT: I presume you were referring to this thread: http://nissandiesel.dyndns.org/viewtopi ... od&start=0 ??

That doesn't seem like a problem related to the bolts themselves IMHO. I don't know what it would be, but the circumstances don't seem to line up with bolt problems to me *shrugs*.

[rlaggren]

> [link re. rods]

I think you switched something on the copy paste. The con rod link had to do with a guy reassembling his LD28 and poking a rod through the block w/in 20 minutes of running it in his Z. There may have been high revs involved, but it still seemed somewhat strange. IIRC there was mention of the OEM bolts being just "good enough" and I recall a recent post (from OZ?) that said with boost the engine would rev above the governor setting.

I think if you do a search on "EGT" here you'll find at least a couple members posted data on the SD22's and maybe also on the LD28 - sorry, it's been a year or so and I don't recall for sure. This doesn't directly answer you question but might add a few more data points to the mix and will probably confirm your view that the key is the amount of fuel.

Cheers, Rufus

[PanzerAce]

Huh, didn't see that link (and at coming up on 20 hours awake with no sleep, in no shape to find it). I'll try to find that tomorrow.

[PanzerAce]

Check page two. He tore it down, reassembled, and it threw #3 through the pan. I'm thinking that's the one you were thinking...*dunno*. I'm starting to think I might as well swap them for some nice bolts anyway, since I'm going to have to be flipping the engine anyway to modify the oil pickup so that I can fit a gasser L series oil pan (and maybe cut/weld that pan as well for an extra two quarts or so of capacity...)

EGTs I'm still not sure about what the real limit is, but unless I hear (and see, really), otherwise, I'm going to try to keep them below 1200.

Still not sure on the turbo though, what are the few guys on here that have done LD(T)s running? And where are you tapping for the turbo oil?

second, are there even options really for a tach? Or is it just a matter of to each their own there?


Lastly, I've seen a few threads now discussing the importance of using the correct filter because of the peculiarities of the LD, but does anyone know if it is possible to use one of those spin-on oil cooler line housing? With a turbo in the mix and the weather (and distances) I'm going to be driving, I'd really like to have one, but I'm not sure if I can run one normally, or if I should jury rig something with the turbo oil return....

[rlaggren]

> link...

You're right. Missed it.

> turbo oil...

Check out the pressure line to the vacuum pump behind the alternator. Also maybe the tapped hole for the sending unit. Al knows a lot more about the engine than I do and he may know other locations. If it were me I'd determine the pressure/flow requirements of the turbo, then hook some plumbing on a running engine with two little valves, one for on/off and one to set the flow flow to what the turbo requires and a tee above it to verify pressure at that flow. Connect this setup to the proposed source and dump the oil into a container you can use to measure volume and time it, say 1 minute or something; put it back into the engine and do it again until you get the flow you want for the turbo; then look at the pressure while it's flowing. Presumably pressure would be lower at idle, of course.

Rufus

[asavage]

Still not sure on the turbo though, what are the few guys on here that have done LD(T)s running? And where are you tapping for the turbo oil?

The natural place to look at is the OEM line that feeds the OEM vacuum pump at the back of the alternator. See this post for pictures.

second, are there even options really for a tach?

Covered fairly thoroughly in this post. Be sure to follow the links.

Lastly, I've seen a few threads now discussing the importance of using the correct filter because of the peculiarities of the LD, but does anyone know if it is possible to use one of those spin-on oil cooler line housing? With a turbo in the mix and the weather (and distances) I'm going to be driving, I'd really like to have one, but I'm not sure if I can run one normally, or if I should jury rig something with the turbo oil return....

The OEM 1983 Maxima oil filter is a dual-function filter that incorporates a sub-micronic bypass filter. This is better than anything you'll rig up for an inline filter for your turbo, IMO. See this thread for lots of info on the factory 1983 filter and its benefits. Also see this post for an oil circuit schematic of that system.