I am thinking of building a reliable race motor from my stock L Jet 1.8. I am thinking of increasing the bore and going to flat top pistons and slightly higher compression ratio, keeping it below 2.0 liter displacement. Either single heavy duty or dual valve springs and stainless steel valves, etc. I am thinking of using the L Jet system that is on it now, going to 2.0 liter injectors. Are there any performance camshafts that will work well with the L Jet, or am I barking up the wrong tree. My other option is dual 40 IDF Weber carbs and a cam to go with them. I'd like to try to use the L Jet if a suitable cam is available. Anybody done something similar? All comments welcome.

What flavor of racing?

Vintage road racing..

Given there's no real historics rules...I'm giving serious consideration to swapping my 2L historics racer to Microsquirt, using either CB Performance throttle bodies or converting my Dells to throttle bodies. All the sounds and looks of dual carbs with none of the constant dinking with AFRs (I was running lean this past weekend and not happy with it).

I might even be able to do it for what I'd get for the Dells and all my jets/parts.

If you're building to SCCA VP rules they're pretty open. I'd push the displacement and compression to the limit and then decide what intake / cam combination works best. The Webcam 86b is a solid choice if the heads flow freely enough.
Other sanctioning bodies can vary a lot. Here in the PNW SOVREN mostly looks at the cars overall appearance. If it looks period correct they don't look much under the hood. SVRA is fussier. As with most club racing, the rules are mostly focused on safety, and only get into spec enforcement if there's a protest. All of the club racing bodies are light on entries so they'll pretty much let you run where you want to (within reason) and only step in when someone howls.
As for using LJet at least it's a timed system. I'm not familiar at all with how they work as I've only worked with Webers, and yes they can be fussy (carbs), but if in good nick they're quite tunable and reliable.
I know racers that have gone the micro squirt route and ended up taking it all off because of lack of computer skills. YMMV.
Start with the rules from the sanctioning body you plan to run with and go from there.
It appears you're in CO. If you're anywhere near Grand Junction I'd give Alen Johnsen (AJRS) a call or visit and get his input. There are few people more experienced with T4's than him. Incredibly nice guy too.

Concur with Charles' advice.

However, this caught my eye...



If you're aware of any of these systems hanging about, could you either send their info to me or vice versa? I'm well-versed in, and very comfortable with, these systems...I have a Dellorto 40 DRLA system we could trade...

https://tgadrivel.blogspot.com/2020/03/on-m...914-part-1.html

I also built and installed one on our Toyota MR2 HProd car.

I found the supplemental regs for Vintage SCCA in our region. VP1 is up to 1.9L displacement. This would allow you to go a tad bigger than your 1.8 and still be legal. It's a really fun group with Midgets, Healeys, Datsun 510's, Alfas and a whole host of other 4 cyl cars. My car, at 2.6L runs in VP2 which is up to 3.2L making it not a terribly fair fight with 6 cyl Porsches and the like.

It’s an RMVR vintage racer

So those rules :

No crank sensor
No programable fuel injection
No modern technology

It can run legally as a 2.0 if it moves up
Or 1.7/1.8 in it’s class

Response not to motorvated. But for others

The path to horsepower for those classes involves carbs A lot of head work. A lot of component lightening and balancing, with a lot of rpm and the camshaft for that. Bigger valves may be legal also I think….. but t would have to double check. Lower gearing will also help awake these cars on exits….

Think old school vintage racing with rules frozen at 1972. (Taken from the 72 GCR/SCCA)

Similar to CSRG or HMSA rules on the West coast

Alen Johnsen is definitely the go-to for those criteria. Lightened, balanced, ported heads, big valves. Right down his alley.

The stock injection will be a big limiter of hp. Carbs open the door to run more aggressive cams (stock injection won't like the overlap of an aggressive cam), and will allow you to better take advantage of head work you decide to do.

Agree with all of the above. Toss the Ljet in the parts swap bin or sell it all in the classifieds. The OE cam will make the heads run hot and its not conducive to power at all. Plus its almost 60 year old tech. If you want to stick with injection (where possible). There are a lot better options.

At a minimum carb swap with a proper race cam. 86b/163 is a decent place to start, but even that is a bit light for a race cam. Also need to have the heads worked to augment the flow.

A good race header will be required no matter what.

Now all of that said, the six makes a lot more sense in a race application. There is a reason you don't see tons of four cylinder race cars anymore. They just don't work as well. If you could stay in a small bore type class racing with MGs and 510s then the four will work reasonably well, but will require steady maintenance. Depending on the number of events you do, the engine will need to be opened for inspection frequently. Plan on bearing replacement on a regular basis.

I'll disagree and agree.

I intentionally left mine as a /4. I gave it a TON of thought, and really really really wanted to toss in a /6. But the costs of building a six are so much more, and there's really no end to the financial game on one of those (where is "enough"?)

But more importantly, as you point out, dropping in a /6 tosses you into the 911 group, where the wallets have no bottoms. It's really silly how much people spend on their 911s to go historics racing...and there's no real regs and if there is they're not enforced.

It was this last point that convinced me to stick with the 2L /4. I'd rather pay to play with the Fiata, Triumphs, and MGBs instead of the money (not that they're easy money spenders).

Of course, if you want to go faster and want the GLORIOUS sound of the /6 behind you, well, I salute you. I'd do it too, given the financial means.

So far I've not had any significant maintenance, although the build was (again, intentionally) a warmed-over build (2056, stock crank, rods, 86A cam, 9:1 compression). And given it only runs 2-3 times a year (I have another "real" SCCA race program) it should last for a while. I am giving serious thought to Microsquirting it though...that should asplode some heads (I'll make it look Weber-ish as much as possible).

GA

Just rebuilt my 1.8L to 2056.
AAA 96mm Biral cylinders with flat top Pistons
Hoffman RS heads
Rabby 9550 cam
Vanagon 50mm throttle body.
Let injection.
9.1 compression ratio.
2.0L crank and rods
I tried 2.0L injectors and melted the cold start injector and part of the wire harness! 1.8 injectors have the same flow rate.

Mallory distributor with silver springs
Adjusted the air flow meter large wheel 4 teeth counter clockwise
26mm CB Performance oil pump.

Would not be a legal vintage race motor due to displacement

So how about 96 mm cylinders flat top or domed pistons
Stock 1.8 heads ported and polished dual valve springs
Webcam 86b or 86b/c
Vanagon 50 mm throttle body
L Jet injection
9:0:1 - 10:1 Compression Ratio (?)
Stock 1.8 Crank and Stock 1.8 Rods
1.8 liter Injectors

Displacement stays below 2.0 liter, and no change in stroke, so engine is legal for Vintage, correct?

Check the rules
Might work
Check the rules

40 thousandths over bore is legal
That means you might run in the 2.0 class

You might do as well with a 2.0 crank rods and the big cam
Bigger than 1911 and still a high rpm build
On the 6 your allowed 1 mm of overbore. (81mm instead of 80)

Found it in the 1972 GCR

1.2 mm bore
So a 95mm cylinder would be legal
But not 96

It’s a rule created to allow water cooled cars to salvage their blocks
Not intended to create a performance advantage

The throttle body size is also regulated in the 1972 PCS
But carbs are accepted and solve that problem as well as work with a real race cam/high lift/more rpm. You can buy JE pistons in any compression ratio you want

Another consideration if you want to keep the L Jet injection - it will need to be tuned for the additional power and different powerband. I've heard it can be done, but you might have a hard time finding info since most people just toss the stock injection on performance builds. I recall on my stock '74 2.0 I was able to enrich it a little by adjusting the fuel pressure up. Not sure how much that buys you though.