Building a L18

[Stoffregen Motorsports]

I want to add one more view-point. My racing Sprite is getting a stock motor for the first year or two. Why? Because I want to focus on the car instead. Going to the track for the first time in a 100% brand new car is frightening. So many things can and will go wrong. So I am taking the engine out of the equation so I can shake the car down without worrying about the motor. I am outfitting the engine with all the external stuff like bigger carbs, header, distributor, oil pan, alternator, oil cooler and lines. The reason for that is so that I know where and how each of those will fit and I can do the plumbing and wiring now, instead of when I get the new motor.

 

Maybe next year I'll build the motor and spend the $4k on the transmission gears. But for the time being, just being on the track will be enough for me.

 

So consider that. Get a good running L street motor, add the header, carbs, distributor and exhaust, maybe the oil pan so you know how it fits, then go racing. You will have to tune the carbs around a stock-ish motor, but that's easy.

[iceman510]

Lots of great input in these two posts.  I think the advice about getting out there before building (or while building) a killer engine is great.

 

I have one of those cast aluminum oil pans too.  Not sure I want to risk it on the vintage race car.  Might put it on the street car, or just mount it on the wall and admire it.  I had a set of brand new in box 44 Mikunis, but I sold them.  Instead I have 45 Webers.  Wish I had kept the Mikunis.  The old parts are definitely fun to mess around with.  My 69 street car has some Mullholland and Interpart parts on it.

 

OP- I have multiple headers here.  Not all perfect, but budget minded if interested.

 

 

[JDH6]

4 hours ago, Stoffregen Motorsports said:

I want to add one more view-point. My racing Sprite is getting a stock motor for the first year or two. Why? Because I want to focus on the car instead. Going to the track for the first time in a 100% brand new car is frightening. So many things can and will go wrong. So I am taking the engine out of the equation so I can shake the car down without worrying about the motor. I am outfitting the engine with all the external stuff like bigger carbs, header, distributor, oil pan, alternator, oil cooler and lines. The reason for that is so that I know where and how each of those will fit and I can do the plumbing and wiring now, instead of when I get the new motor.

 

Maybe next year I'll build the motor and spend the $4k on the transmission gears. But for the time being, just being on the track will be enough for me.

 

So consider that. Get a good running L street motor, add the header, carbs, distributor and exhaust, maybe the oil pan so you know how it fits, then go racing. You will have to tune the carbs around a stock-ish motor, but that's easy.

Thank you for all of the great advice, I totally agree with what you are saying, so let me ask this question, what should I start with now that I can swap onto a better and bigger motor later on. I have a stock L16 at the moment with a A87 head a weber downdraft. Should I get a header and dual 44's? I know that would be the ideal setup for a beefed up motor but how would that run on my current setup. Only reason I ask is I would prefer not to have to buy stuff like carbs twice. Should I get the head built up to a better spec and get carbs and then run the stock bottom for a while, then when I am ready build a L18 bottom? Ideally id love to do any upgrades that I can transfer over to a better faster motor now, if that makes sense. I really appreciate the advice. 

[JDH6]

3 hours ago, iceman510 said:

Lots of great input in these two posts.  I think the advice about getting out there before building (or while building) a killer engine is great.

 

I have one of those cast aluminum oil pans too.  Not sure I want to risk it on the vintage race car.  Might put it on the street car, or just mount it on the wall and admire it.  I had a set of brand new in box 44 Mikunis, but I sold them.  Instead I have 45 Webers.  Wish I had kept the Mikunis.  The old parts are definitely fun to mess around with.  My 69 street car has some Mullholland and Interpart parts on it.

 

OP- I have multiple headers here.  Not all perfect, but budget minded if interested.

 

 

Agreed, great two posts. Do you have any parts besides headers? Send me an email to jdh13001@gmail.com of the headers or any other engine parts and pricing at your connivence! 

[Stoffregen Motorsports]

17 hours ago, JDH6 said:

Thank you for all of the great advice, I totally agree with what you are saying, so let me ask this question, what should I start with now that I can swap onto a better and bigger motor later on. I have a stock L16 at the moment with a A87 head a weber downdraft. Should I get a header and dual 44's? I know that would be the ideal setup for a beefed up motor but how would that run on my current setup. Only reason I ask is I would prefer not to have to buy stuff like carbs twice. Should I get the head built up to a better spec and get carbs and then run the stock bottom for a while, then when I am ready build a L18 bottom? Ideally id love to do any upgrades that I can transfer over to a better faster motor now, if that makes sense. I really appreciate the advice. 

I would start off with the parts you want to use. Get the Mikuni 44's and the intake, and install them. You will need smaller chokes to run with a stock L16. Maybe you could swap in a small cam while you're at it.

 

I wouldn't start mixing and matching cylinder heads. A race head is built to be be used with the bottom end it is installed on. The shape of the pistons and compression volume are factors that make it difficult to swap a racing cylinder head onto an entirely different engine.

 

Why not look for a used built street engine? Out here on the west coast, they come up for sale from time to time, and it's not uncommon to find a built L20B for cheap. The headers for L20Bs are different though (because of the added block height) so I would build my race exhaust around an L20B, knowing that a shorter L18 would be installed later. The 1900 combo I mentioned early on is a very cheap engine to build. If you wanted something to use while you're figuring it out, and have a couple thousand bucks you're willing to throw at it, it would be a quick way to get on the track with some HP. And you could always sell it when you're done. or keep it as a backup motor.

 

Apologies for these long winded replies. There are so many options.

 

 

[Stoffregen Motorsports]

21 hours ago, iceman510 said:

Lots of great input in these two posts.  I think the advice about getting out there before building (or while building) a killer engine is great.

 

I have one of those cast aluminum oil pans too.  Not sure I want to risk it on the vintage race car.  Might put it on the street car, or just mount it on the wall and admire it.  I had a set of brand new in box 44 Mikunis, but I sold them.  Instead I have 45 Webers.  Wish I had kept the Mikunis.  The old parts are definitely fun to mess around with.  My 69 street car has some Mullholland and Interpart parts on it.

 

OP- I have multiple headers here.  Not all perfect, but budget minded if interested.

I would use the aluminum pan on the race car. It would be a shame to see it get  hit on a curb, but so what. Are there other guys using the aluminum pans? I bet not.

 

I once visited the shop of Doug Barnhold in Fontana. He was the guy who built all the bodywork for Nissan Motorsports race cars. His shop was an old chicken ranch and reminded me of Harry Hogge's barn in Days of Thunder. This was back before the Nascar track was there and the smog was so bad that I was there a whole day before I realized there was a mountain range just behind his shop. He had tons and tons of old racing parts literally laying around. There were also a handful of cars that we would all give a left nut for now. Factory 240Z racer, sleeper experimental "Corvette Killer" 300zx, which was supposed to have been crushed but was in hiding in a chicken coop. Plus others. That's where I picked up the carbs and intake from the BRE 510. He died a couple years ago, and I'm sure his stash was parceled off appropriately.

[JDH6]

4 hours ago, Stoffregen Motorsports said:

I would start off with the parts you want to use. Get the Mikuni 44's and the intake, and install them. You will need smaller chokes to run with a stock L16. Maybe you could swap in a small cam while you're at it.

 

I wouldn't start mixing and matching cylinder heads. A race head is built to be be used with the bottom end it is installed on. The shape of the pistons and compression volume are factors that make it difficult to swap a racing cylinder head onto an entirely different engine.

 

Why not look for a used built street engine? Out here on the west coast, they come up for sale from time to time, and it's not uncommon to find a built L20B for cheap. The headers for L20Bs are different though (because of the added block height) so I would build my race exhaust around an L20B, knowing that a shorter L18 would be installed later. The 1900 combo I mentioned early on is a very cheap engine to build. If you wanted something to use while you're figuring it out, and have a couple thousand bucks you're willing to throw at it, it would be a quick way to get on the track with some HP. And you could always sell it when you're done. or keep it as a backup motor.

 

Apologies for these long winded replies. There are so many options.

 

 

I appreciate the long and insightful replies, what intake would you recommend? I think I should find the carbs and do an exhaust first then later swap to a motor upgrade!

[JDH6]

1 minute ago, JDH6 said:

I appreciate the long and insightful replies, what intake would you recommend? I think I should find the carbs and do an exhaust first then later swap to a motor upgrade!

Or where I can source a L18 motor ? I have seen some L20B for sale but not any L18, I live in PA so that does not help!

[Stoffregen Motorsports]

There are three different race manifolds to choose from. There's the BRE intake which is medium length and has straight runners which point the carbs up a bit. There's the long runner Nissan Motorsports/Datsun Comp manifold which levels out the carbs more than the BRE, then there's a medium length manifold that Rebello makes using a cut up six cylinder manifold. It looks like an old Cannon manifold, but is straighter. Then, of course, there's the CNC'd billet manifold that Troy sells. Any of these would work great, but note that the long runner Comp manifold points the carbs right at the master cylinder. This won't matter so much as you're probably going to modify the masters anyway.

 

I don't know where to buy a used engine. Put a post on FB marketplace or even a want ad on NorCal craigslist.

 

See the pics below. This is a street car I built decades ago for a friend, Notice how the master cylinder reservoir was relocated to clear the velocity stacks. This is a Comp manifold. It's not the best pic, but it's the only one I've got.

 

Here's a pair of carbs I set up fro that same friend just last year. Brand new NOS Comp manifold here with modified soft mounts. You will want to find soft mounts too. You can still get the offset soft mounts, but the straight soft mounts have been NLA for years. I did hear that someone is reproducing them though.

 

And while I'm logged into Photobucket, here's a pic of the difference between modified forged pistons and out-of-the-box pistons.

 

 

 

[JDH6]

22 minutes ago, Stoffregen Motorsports said:

There are three different race manifolds to choose from. There's the BRE intake which is medium length and has straight runners which point the carbs up a bit. There's the long runner Nissan Motorsports/Datsun Comp manifold which levels out the carbs more than the BRE, then there's a medium length manifold that Rebello makes using a cut up six cylinder manifold. It looks like an old Cannon manifold, but is straighter. Then, of course, there's the CNC'd billet manifold that Troy sells. Any of these would work great, but note that the long runner Comp manifold points the carbs right at the master cylinder. This won't matter so much as you're probably going to modify the masters anyway.

 

I don't know where to buy a used engine. Put a post on FB marketplace or even a want ad on NorCal craigslist.

 

See the pics below. This is a street car I built decades ago for a friend, Notice how the master cylinder reservoir was relocated to clear the velocity stacks. This is a Comp manifold. It's not the best pic, but it's the only one I've got.

 

Here's a pair of carbs I set up fro that same friend just last year. Brand new NOS Comp manifold here with modified soft mounts. You will want to find soft mounts too. You can still get the offset soft mounts, but the straight soft mounts have been NLA for years. I did hear that someone is reproducing them though.

 

And while I'm logged into Photobucket, here's a pic of the difference between modified forged pistons and out-of-the-box pistons.

 

 

 

Awesome! Thanks for all of the advice it really has been helpful. Now the hunt begins for some mikunis! 

[Stoffregen Motorsports]

Call Mike Malone. He specializes in Mikuni and Solex carbs. He's on Instagram @topkart11. He and I used to race 510s together.

[JDH6]

1 minute ago, Stoffregen Motorsports said:

Call Mike Malone. He specializes in Mikuni and Solex carbs. He's on Instagram @topkart11. He and I used to race 510s together.

Will do, best of luck with your race car!!

[Stoffregen Motorsports]

Thanks. You as well.

[iceman510]

Jeff Winter of Rallye-sport in Colorado used to make a nice high-rise manifold for sidedrafts.  I don't see it on the website anymore, so not sure if he still has it in production.

 

https://rallye-sport.com/

 

 

[JDH6]

5 hours ago, iceman510 said:

Jeff Winter of Rallye-sport in Colorado used to make a nice high-rise manifold for sidedrafts.  I don't see it on the website anymore, so not sure if he still has it in production.

 

https://rallye-sport.com/

 

 

Any pics of the parts you have? shoot them to my email jdh13001@gmail.com. thanks!!

[kerleybird]

On 10/1/2021 at 9:36 AM, Stoffregen Motorsports said:

I assume you're building this for vintage racing, and depending on which group you're running with there are more and less strict guidelines ad to what parts you can use. Some groups will allow 1980's GT4 style cars, while others want 2.5TA or BS style cars.

 

I typed out a good reply yesterday, but I don;t see it here. Wonder what happened to that...Anyway. Cost-wise, a fully prepped race engine costs in the neighborhood of $6k-$9k, with roughly $3k each into the bottom end, the cylinder head and the intake/carburetion. 44PHH Solex or Mikuni carbs are the most accurate vintage carbs, and can be purchased from guys like Mike Malone or Rebello or Ermish. Mike Malone build very nice carbs, which look better than new when done. You will also need an appropriate intake, like the rare BRE intake or Datsun comp intake, which are both very expensive. Troy Ermish is now selling custom, CNC'd billet long runner intakes that are very close to the Datsun Comp intakes. I believe he sells them for $600. Weber side drafts are also an option, but everybody expects to see Solex/Mikuni carbs on a vintage 510.

 

There are about four different cylinder heads you could use, A87, 219, V912 or even a U60. Any of these heads are going to need massive amounts of work done to them, and not just in the porting. The chambers need to be fit to the piston domes too. A large race cam and a sturdy valvetrain round out the package. Expect to replace valve springs every four or five races, or even at the track if you break one from an over-rev.

 

Everyone thinks the bottom end is the least important piece of the puzzle, but that's absolutely not the case. I mentioned earlier knife edging and nitriding the crank, possible custom H-beam rods (Carrillo) are both good insurance against failure. Custom pistons withe pop up domes will give you the roughly 12:1 CR, but as mentioned, they come "rough" and need to be fit to the combustion chamber and possibly cut for piston to valve clearance. The block should be o-ringed and the crankcase should be ground and prepped. Bearings need full grooves, with enlarged oil holes and clearances meticulously set. If you're going to use a distributor for spark, you'll need a brass drive for the crank, as the steel ones break under the stresses of racing.

 

I would not attempt your first engine build here. There are so many areas that can cause headaches or failure if overlooked or mis-measured. Full disclosure here, I worked for Dave Rebello for a decade building engines, and I do recommend them to build yours. Yes, there are other competent Datsun engine builders out there, but Rebello has built the winningest Datsun L motors for decades. You could also have them build you key parts, like the cylinder head, block machining and crank prep, and assemble the engine yourself, but for the couple thousand you may save going that route, it may not be worth the effort. Once you have a custom built engine, you could always do the rebuilds yourself, but I even advise against that simply because rebuilds are not very expensive (assuming you don't break anything on the track).

 

As far as Mike's suggestion to use motorcycle carbs and a stock exhaust manifold, due respect Mike, those parts will not fly on a vintage race car. For everyone I know, vintage racing is as much about the car as it is about the racing, and again as much about the people you race with. You have to at least try and build it era-correct.

 

Troy Ermish makes a very nice stainless header for about $600, or save a few bucks and buy his mild steel header. Both of them are near copies of the Datsun Comp headers of yore. A 2.5" exhaust will be required too, with or without muffler (mufflers actually work better than an open pipe, at least that's been my experience). And then there are other pieces like the correct distributor (Mallory tach drive being he coolest, and can be modified to use MSD internals for reliability), crank dampers, valve covers, water pump pulleys, etc that all lend to the overall effect.

 

Really, what it boils down to is how correct do you want the car to be? If you're into it for the vintage vibe, spend some time on the phone and scour the classifieds for the cool vintage parts. We haven't even discussed the trans or differential yet, and those can be quite expensive too. Should you be lucky enough to find a close ratio direct drive 5 speed and R180 limited slip, expect to shell out another $6k or more for those.

 

I've had some super rare Datsun race parts and there really is nothing cooler than the OG stuff. When I got out of the Datsun world, I sold everything I had to Troy for a lump sum. I had over 11 legal size pages of parts, ranging from an NOS finned aluminum 7 quart oil pan with the part number sticker still on it, to a pair of carbs that were actually on the #35 BRE 510, to NOS DD 5 speed rebuild parts, magnesium 13x7 Libres, R160 and R180 LSD diffs plus tons of other hard to find parts. I almost had my hands on a one-off oil to water heat exchanger that BRE used in the '70s, but I couldn't afford it at the time. Do I miss Datsun racing? Yes, but I will never own another 510. As Thomas Wolfe said - "you can never go home again", which is why I'm now building an Austin Healey Sprite to go vintage racing...

 

this is absolutely huge info. thank you lol

[Stoffregen Motorsports]

13 hours ago, kerleybird said:

 

this is absolutely huge info. thank you lol

Any time.