Poll: keep engine original or SR on 1970 Laurel?

KC30 · **Posted:** Sat Jun 19, 2010 3:38 am

Hey everyone! Well, for those who have seen it, I have recently purchased a 1970 Nissan Laurel coupe (KC30):
viewtopic.php?t=10077
I now have the vehicle, which runs on the original G18. However, I can already tell the engine is overdue a rebuild. The vehicle originally had A/C, but the compressor is shot and would either require a rebuild (at who knows what cost due to it's age) or a modern replacement. As I've been finding out, getting suspension parts and engine parts are going to be difficult, the engine being the worst. And taking to the US, makes it even harder.
So, I'm facing a tough decision, because I really want and SR20DET drivetrain. But I would also like to keep the vehicle original, I can't have both. What makes the decision harder, is that today I found a 180sx that I can get the entire S13 SR20DET black top drivetrain (engine, trans, ECU, front suspension, crossmember, driveshaft, rear subframe, diff, halfshafts, brakes... all of it) for $700.
I think I've decided that I can't pass this up. Though original would be great, I would enjoy what I could make it much more. It would also be much easier and affordable for me to maintain it in the long run with the new engine and suspension.

So if you had this decision facing you, what would you choose?

Edited to mention that the posted HP was wrong, it's actually ~99hp.

Garant · **Posted:** Sat Jun 19, 2010 7:35 am

get a 510 if you wanna sr

Rad2Ltr · **Posted:** Sat Jun 19, 2010 8:18 am

I'd keep the original engine and make it bad a$$! :twisted:

Yeah, it only had 105 hp, however bore the bottom end out, have someone build a bitchin head for it, and you will likely have 120 at the wheels if not more. A modern engine is a cut corner, an easy way out. I'm not sure if anyone makes a Mikuni intake for the engine, but a set of those with a built head, nice cam, and even a basic bottom end will be a big boost over what you have, plus it will be a semi-sleeper. On top of that, there will be no cutting on the body, no welding this or that to make the modern engine fit, it will look all stock and correct aside from the set of big carbs and a header (assuming you can find one or get one made) I bet if you went this route, you would end up with the same hp (ok, within 10 hp of a stock N/A SR) and it would cost about the same if not less.

An SR20DET will do a nice job of smoking one tire. That much hp and you end up with a lot of other broken parts or issues.
Will

datsun280c · **Posted:** Sat Jun 19, 2010 6:25 pm

i think better stay with original because this car is getting very rare now imo...

but choice is yours..

Eric · **Posted:** Sun Jun 20, 2010 1:16 am

I wont do the sr20det swap if i were you. i had the choice between sr20det or sr20de and chose de non turbo version because i wanted a more modern engine, with a few extra horsepowers offcourse but didnt want to build intercooler stuff etc. this sort of modifications cannot be done without modifying the body of the car, i dont think the diff and/or rest of the rear suspensio will take the much more extra power too.
offcourse you can modify all of that too but that will be a waiste of such a car.

i have my sr20de completely setup in the C30 now, with s13/s14 front suspension in front an i only had to drill 4 holes to fit the front stabilisor bar.
no other body modifications anywere.

if the hood is closed no one will ever know the original engine is no longer in the car.

KC30 · **Posted:** Mon Jun 21, 2010 8:35 pm

Thanks for the interest in the poll. It's been a tough decision, and I'm still agonizing back and forth over it. But I've decided to do the SR swap. The day I put up the poll, I went to visit the donor car, and the SR was in great shape. But when he started it, I knew I had to have it! I just love the sound of an SR or RB (I really miss my RB20!)
It's not a decision I've taken lightly or without considering the classic body. I DO NOT want to destroy that body, so I fully intend to follow Eric's footsteps in minimal body modification. I intend to find any way I can to route the intercooler without cutting holes. If I can't figure out a way right of the bat, it'll be without intercooler until I have. The same goes for the rear suspension, if I can't find a way in the short time I have to attach the rear subframe without major body mod, it'll go without it until I can find a way.
I still have to do some shipping research, but it's likely that I will be container shipping the vehicle, if so I will be able to have the original engine stay with it. At least that's my intentions.

Garant · **Posted:** Sat Jun 26, 2010 12:08 pm

i can understand about the sr20det's appeal, but the trend lately has been a return to oem or even modifying the oem motor, even turbo

when i first got my car i was all hot for a 4g63 swap, but now that i've had time to think about it, i've decided i'd be just as happy swapping the 2.0 for a 2.6

Eric · **Posted:** Sat Jun 26, 2010 12:26 pm

the sr20's appeal is the fact that it can be easy tuned to lots of hp, there are loads of them so oarts are available, even aftermarket.

Rad2Ltr · **Posted:** Sat Jun 26, 2010 3:12 pm

I bet with a well done head, hot cam and a set of Mikuni 44s, you could get close to 150hp at the wheels. You would also need a good set of headers and exhaust, but I bet it could be close.

A stock Sr20 puts about 125hp to the wheels. Will your stock 1.8L ultimately make as much hp as the SR (a fully tuned SR), no but you could get a reliable 130-140 at the wheels and more with some more work on the bottom end.

Just a thought.

Will

john · **Posted:** Sat Jun 26, 2010 6:36 pm

Rad2Ltr wrote:

I bet with a well done head, hot cam and a set of Mikuni 44s, you could get close to 150hp at the wheels.

And still have 60 less HP than the SR while spending more money?

Quote:

A stock Sr20 puts about 125hp to the wheels.

Not quite. A blacktop SR20DET is rated at 205-215hp stock. Crank up the boost to 10psi, build a good exhaust for it, and run an efficient intercooler and you're looking at roughly 250hp at the crank.

And if you can do the fab work yourself (or get a buddy deal), you're still finishing up cheaper than what hot-rodding the stock engine might cost.

If these are my only two options, I'd vote SR20DET, IF you can finish it. Lots of people don't... :wink:

If given no options and just asked "what would you do", I'd probably say built L18 or L20b. Looks stock, easy to fit (relative to the SR) and lots of aftermarket support in the US (unlike the stock engine). :tu:

Rad2Ltr · **Posted:** Sat Jun 26, 2010 6:42 pm

datsunfreak wrote:

Rad2Ltr wrote:

I bet with a well done head, hot cam and a set of Mikuni 44s, you could get close to 150hp at the wheels.

And still have 60 less HP than the SR while spending more money?

Quote:

A stock Sr20 puts about 125hp to the wheels.

Not quite. A blacktop SR20DET is rated at 205-215hp stock. Crank up the boost to 10psi, build a good exhaust for it, and run an efficient intercooler and you're looking at roughly 250hp at the crank.

And if you can do the fab work yourself (or get a buddy deal), you're still finishing up cheaper than what hot-rodding the stock engine might cost.

Um, I have seen a dyno chart of a N/A SR20 that was baselined at 120hp at the wheels. The bet was that my U20 could not make more than a stock SR20 black top, guess what, I won(by a lot I might add.) This was before I redid my whole exhaust system as well. Yes, the dyno runs between my car and the one with the SR20 were done on the same dyno by the same operator. A turbo is a different creature all together.

I don't see how anyone can do a motor swap correctly for less than $10K. Doing it yourself is still going to run $6k-8k. That will buy you a lot of correct engine that simply bolts back in place.

Will

john · **Posted:** Sat Jun 26, 2010 6:51 pm

Sorry, aren't we talking about an SR20DET???

As in turbocharged?

Rad2Ltr · **Posted:** Sat Jun 26, 2010 6:55 pm

Sorry missed the DET portion in the original post. Even so, you need a locking or very good LSD for the rear end to be able to harness the power, along with some wide tires. Brake upgrades would be smart as well.

Will

john · **Posted:** Sat Jun 26, 2010 6:56 pm

If you read his build thread, you'd see he's doing all that already. :wink:

KC30 · **Posted:** Sat Jun 26, 2010 7:52 pm

It has been a very hard decision, one that I still find myself swaying back and forth on. I find it very hard to swallow that I intend to remove the original engine, that it won't be what it was. Something I really don't want to do.
But then I tried searching online for G18 parts... they're VERY rare. And I'm just speaking of basic rebuild parts, for aftermarket/performance, I have yet to find those. I'm currently in Japan, and can't find parts here, all the garages/tuners/shops I go to do their best to find things and do the typical apologizing for not being able to help. If it's like that here, I'm really F'd in the states, where this car and engine were never released.
I really came to parts issue realization this week. I'm trying to get the Japanese safety inspection completed so I can get it registered here. I took it in and it failed for the clutch slave cylinder that decided to start leaking. I'm thinking fine, that's an easy rebuild, just get the parts from Nissan... Even the Nissan dealer (in Japan) was surprised by what car this is. They look (it took them a day to research) and there are two different slave cylinders, one that was discontinued and has no parts available, and one that did have an overhaul kit, luckily I have the second one. So I ask for that... special order because only one warehouse in mainland has it, 1 week wait.
This alone made me realize that I would not be able to keep the Laurel running in the US on the original engine. As much as I honestly would like to. If this came with an S or L series, I would keep the engine... the support for those engines is there.
I actually have had a friend recommend going with an L18 or L20B as well, but if I'm not going to keep the original engine, what goes in doesn't match and it's down to personal preference. I like the old engines, but I want the SR DET I've been craving. I know that I can find the parts and aftermarket support needed. I'm very familiar with it, being able to tune and work it well. Plus, like I said before, when I visited the donor car and the shop owner fired it up... I had to have it! It's been tuned, granted it hasn't been on a dyno, but the shop owner thinks it's putting out about 260hp. I'd tend to believe him as he works primarily with SR and RB engines. Another reason is because I would not have been able to get either of those engines in good running condition for anywhere near the price I'm getting the S13's entire drivetrain. It really was a deal I couldn't pass up. That's why I didn't list any engines in the poll other then the two I'm debating on.
It gets me excited, thinking that my Skyline was about 2900lbs and had about 280hp. Now I'm looking at the Laurel's about 2200lbs... and running 260hp. That's something I really look forward to driving. And it doesn't help that I've got friends here egging me on, because they want to see it as well. Even the shop owner I'm getting the engine from wants to see it and has offered to give me a hand and help out where he can.

john · **Posted:** Sat Jun 26, 2010 10:04 pm

KC30 · **Posted:** Sun Jun 27, 2010 8:02 am

Well,I was just reviewing the tech specs, and the first HP figure I found and listed in the poll is wrong. The G18 was only 100ps, or ~99 HP, granted that's when new, so what it's pushing out now is even less.

john · **Posted:** Mon Jun 28, 2010 6:19 pm

KC30 wrote:

The G18 was only 100ps, or ~99 HP, granted that's when new, so what it's pushing out now is even less.

And if it's anything like some of their other engines of the era, that might even be overrated... :wink:

KC30 · **Posted:** Mon Jun 28, 2010 9:41 pm

I found the reason for my confusion on the peak HP rating at 5600rpm. The Japanese Nissan tech brochure lists 100ps (~99hp), which having a J-Spec model/engine, I'll trust as the original HP rating on this engine 40 years ago. I found why a site listed 105hp for the Datsun, because a Datsun shop manual for the C30 (European model) listed it.
Anyways, I used one of the dyno apps that I had. (Something I got mainly out of curiosity, if it would even work) Which we used on a rental car and got pretty accurate results most of the time. I had to drive it around and tried it several times. And it's averaging 26hp at the wheels... with a peak of 28hp on one run. And how it's currently running, I believe it. I already knew to get near the stock hp it was rated for so long ago, I would have to pretty much do an engine rebuild. As it is, it's well overdue for a Carb rebuild and engine retune.
I'm just looking forward to trying it on a new engine as see what it does.

Poll: keep engine original or SR on 1970 Laurel?

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