First L20B build need advice??

[NastyRay]

I bought my first datsun 510 coupe a few days ago with the idea in mind of a turbo charged motor like a ca18det.. The motor that came in it was a l20b and i am not ready to put that adide just yet when their is still hope of daisy datsun spooling up her turbo. I know everyone here has great ideas so lets hear them.. Here is what i am working with aroynd 1200$ and as far as my skills go i can fabricate almost anything and i can turn a wrench so please detailed ideas. My fellow datsu. Owners please help me build daisy the way she deserves

[datzenmike]

A sedan you mean? Two door left hand drive? $1,200 would barely rebuild an L20B to stock. You won't get an import CA18DET with transmission and ECU for that. If free you would spend more than $1,200 on the car getting it ready. This is a worthwhile project so enjoy the car and the L20B in it while you keep saving.

[Stoffregen Motorsports]

In today's world of cheap bolt on horsepower, you are almost always dealing with a great engine to begin with. Add twin turbos to a 4.8L GM LS V8 and make 700 hp, without even removing the oil pan and a rod cap to inspect the bearings. Yep, no problem.

 

While the L20B is a great engine, it isn't going to respond well to cheap power adders, at least not without a solid rebuild with some modifications. As Mike said, you can't even begin to make those mods with $1200. If your intention is to go big or go home, you could put your money to use with one of those $600 Chinese turbo kits and an intercooler. If you're good at fab work, you could have a pull through system plumbed up in a few days. This setup is almost guaranteed to blow up a stock L20B, but hey, have fun with it.

 

Of course I wouldn't actually do any of that, but I didn't want to crap in your wheaties on your first post.

[banzai510(hainz)]

$1200 x 4 would be better and spend it on having a nice 510

[datzenmike]

Cheapest import CA18DET was $1,500 but includes trans and wiring. You'll need a custom rad, engine and trans mounts, exhaust system, convert to internal regulated alternator, shorten the driveshaft, modify gas tank for EFI pump. Now you have a rocket ship that can't get stopped. Needs a big brake up-grade and suspension mods to avoid what you can't get stopped for. Include some big tires. X4 is right!!!!!

[Stoffregen Motorsports]

Seems like the 510s that get the highest auction sales prices all have L motors in them. I have always thought that a well built L motor looks way better in a 510 engine bay than any KA or SR.

 

If you've got $1200 to spend, and the motor is in relatively good shape, spend it on the head. Save some more money and buy a set of dual carbs. Build a nice exhaust system with a good header. Get your distributor re-curved and build a heat shield for the intake. You'll be into this setup about $3000-$4000 and have a 510 built in the classic style.

 

Worry about the suspension and brakes later.

 

Or...

 

Spend that money on the suspension and brakes first and have a car that you can flog to death, running headlong into any corner, without killing yourself.

[distributorguy]

I'm a huge fan of SU or Hitachi twin carbs on the L20b.  You can probably buy a set with manifold and rebuild kits for around $600-800?  Maybe far less, but you need to get really good rebuild kits or you'll hate them.  They'll greatly improve drivability and you can rebuild the engine later.  Spend the rest of your money upgrading the brakes.  

 

An incomplete car that can't be driven is no fun.  

[Tom1200]

Since you mentioned fabrication skills I'm going to reply based on parts being your only cost.

 

Take the existing head you have now, clean up the ports and install a more aggressive cam. Fabricate a manifold so that you can install motorcycle carbs (carbs on ebay are stupid cheap) For a two liter motor 41-42mm bike carbs will do for the power level we're taking about. After that install a header and appropriate size exhaust. Realistically this will add around 15-20hp but it will be well under your $1200 budget.

 

As for a turbo L-series, I generally concur that in otherwise stock trim it's likely to go kablamo. You can keep the motor together if you run really low boost but then the horsepower isn't going to be all that much of an increase so you might as well play with the option I mentioned above. 

 

As a fabricator you could also find a Nissan V6 and install that, I think those are around 160-175hp range but don't quote me on the exact figure. You should be able to find a wrecked truck for $1200.

 

The reality is even 140hp in a 510 will make it scoot nicely...……..it won't qualify as "stupid fast" but you'll no longer be out dragged by some guy in is Prius as one tends to be in a stock/stockish 510. 

[Stoffregen Motorsports]

Good point. While 510s are fun, they are drastically underpowered. I out dragged a 510 once while towing a car on a trailer behind my Vortec 7400 equipped K2500 Suburban. That's sad.

 

[Tom1200]

Yes I seem to recall L16-L20s being between 60-70hp at the wheels, 510s are light but you'd need around 90whp just to keep with a Miata.

[datzenmike]

10 hours ago, Tom1200 said:

Since you mentioned fabrication skills I'm going to reply based on parts being your only cost.

 

Take the existing head you have now, clean up the ports and install a more aggressive cam. Fabricate a manifold so that you can install motorcycle carbs (carbs on ebay are stupid cheap) For a two liter motor 41-42mm bike carbs will do for the power level we're taking about. After that install a header and appropriate size exhaust. Realistically this will add around 15-20hp but it will be well under your $1200 budget.

 

 

 

 

 

R-1 carbs, home made intake, L16 4 into 2 cast manifold, modified 240sx KA dual down pipe into single pipe, EI distributor, home made 2" diameter velocity stacks, electric vacuum pump, 280zx air filter and home made filter box. Otherwise the engine is completely stock. U67 head drilled for water cooling/warming the R-1 carbs. Didn't notice any difference.  Pulls hard all the way to 6,000 now but very loud..

[G-Duax]

The vacuum pump is too shinny, doesn't go with the rest of the engine bay.

Good job on the air filter set up.

Edited August 23, 2019 by G-Duax

[datzenmike]

I have  to find a vacuum switch. One that shuts off at a set vacuum, and perhaps adjustable. Right now it's on with the brake lights. It only really needs to be on to keep the reservoir topped up with vacuum. Agree, doesn't look right as much as the R-1s do look right. Any ideas?

[G-Duax]

I have a small reservoir, and once that is pulled to nearly a full vacuum, those pumps shut off by themselves.

Somewhere around 20 inches of vacuum, if memory serves me correctly.

[G-Duax]

47 minutes ago, datzenmike said:

Agree, doesn't look right as much as the R-1s do look right. Any ideas?

 

On the pump?

Maybe burry it on the sea shore for a few months, so it ages,

or polish up the rest of the engine bay to match it.

 

I should talk, my engine bay was rattle can pained flat black over the original orange years before I bought it,

and in the 15 years I've had it have made few half ass attempts to cure the on-going exposed orange poking out from where the black is flaking off.

[datzenmike]

11 minutes ago, G-Duax said:

I have a small reservoir, and once that is pulled to nearly a full vacuum, those pumps shut off by themselves.

Somewhere around 20 inches of vacuum, if memory serves me correctly.

 

This one never does and will get too hot to touch. I put my thumb over the suction side and it never shut off. I changed from on all the time to just when brakes are on but I don't like long stop lights.  What I need is a simple vacuum switch. When it gets to 20-22 in it breaks the circuit. It's rated to 28-29? I think.

[G-Duax]

Yeah, somewhere around there.

Is that an Audi pump, or from some other euro car?

Edited August 23, 2019 by G-Duax

[datzenmike]

GM. 😄

 

So any idea on a vacuum switch to better shut this off when vacuum is reached???

[G-Duax]

I've seen them, but not sure where off the top of my head.

So a quick trip to eBay found this:

Superior adjustable vacuum switch

 

Too bad it costs what I paid each of my Audi pumps, that have it built in....

[Tom1200]

I'm assuming the vacuum pump is for the brake booster?   Note the 1200s don't have power brakes, so the loss of the vacuum port wasn't an issue when I installed the Flat Slides.

[G-Duax]

Yes sir....

I haven't even installed my replacement booster diaphragm yet, and for the most part don't miss it,

but every once in a while, I crest a hill at 85-90 mph, and find stopped traffic, and then I really miss it...

[datzenmike]

4 hours ago, G-Duax said:

I've seen them, but not sure where off the top of my head.

So a quick trip to eBay found this:

Superior adjustable vacuum switch

 

Too bad it costs what I paid each of my Audi pumps, that have it built in....

 

Amazon has them too. Thanks.

[Beowulf]

On 8/22/2019 at 9:37 PM, datzenmike said:

 

 

 

R-1 carbs, home made intake, L16 4 into 2 cast manifold, modified 240sx KA dual down pipe into single pipe, EI distributor, home made 2" diameter velocity stacks, electric vacuum pump, 280zx air filter and home made filter box. Otherwise the engine is completely stock. U67 head drilled for water cooling/warming the R-1 carbs. Didn't notice any difference.  Pulls hard all the way to 6,000 now but very loud..

any pic of the manifold? 
 

[datzenmike]

Yes many but not at home, remind me in a week or so.  

[Beowulf]

Love to see those pictures of you intake