L20B mods

[NeoLokie]

Hey guys,

any of you had worked an L20 or know anything about em? Looking at doing one up and I'm curious what sort of hp i can expect etc.

Thinking about stroking it with a z24 crank etc too, but that might be down the track a little.

the plan to start with is headwork, valves/springs, cam, extractors, zorst, twin webbers. if I can find some webbers at a reasonable price that is! haha

Thanks

[Duncan]

hmmm, www.ozdat.com is definately the place for these questions...

personally I think you could spend your money on better engines these days, the l20 was great for its time but is very out of date now....eg a ca18det half cut would be under $1500....

The only question I can answer for sure is the z24 crank can be fitted but it does require some light machining to the block for clearance, as well as limiting the revs significantly.

From my research a pair of webbers and a lumpy cam is the most common place to start but that would still be 800+

[BigDatto]

L18 head onto L20 block raises the comp ratio, combined with higher lift/duration cams & redrilled/reneedled twin Hitachi SU's from the SSS + extractors is a very cheap power up combo, hunt around wrecking yards for the parts.

If you want more from the L20 - you'll reach the point of diminishing returns, and Duncan's suggestion is spot on

[NeoLokie]

yeah thats the thing really, how far do i really want to go. But as long as it goes ok, and doesn't really cost a bundle, I think thats what i want. i have a DR that I'd much rather spend the money on really. A ca18 front cut would be good..but theres all the other costs like engineering and dicking around with it etc the bother me.

But under 1500 is mighty tempting. I'd love to build the l20 with huge compression and cam and whatnot though, just for fun Oh, and its the missus' car, and I don't want it faster than mine

[NeoLokie]

oh, and why would the z24 crank limit the revs?

[Duncan]

apparently the stroke is a fair bit longer, sorry I don't have the exact dimensions here. the 200b standard is good to 7200ish but the navara tops out at about 5500

One other suggestion.....find someone who has already been through this and built a great l20....and then got pissed off and bought a turbo motor instead....nice and cheap to pick up the whole thing with a bit of luck

[180bfj20det]

L20B is a great sounding engine on full song with webers. Its a great old skool engine and such deserves this respect. I had one, but it went like crap. But you can make good horsepower out of these engines. Ive seen 200 rwkW with standard rods, actually standard everything with just forgies running like 30psi. But ask yourself: are you after horsepower reliably, or are you wanting to build a classic? The L20 is a piece of sh#$ compared to the CA or SR and would not even touch an FJ. These latter 2 can make 200rwKw reliably at 14 psi and not that expensive to build. Changing cranks, blah blah blah, what for, to geet beaten by a 1600 with a stock N/A CA18??? Not worth it and you'll be the one biting your fingers when you lose. However, if you are after that particular L20-with-weber sounds and wanting a classic, then go right ahead. Classics rock, but Im preformance biased.

[NeoLokie]

Well this is the wifes car, she wants it to be a bit grumpy, actually she wants it really really angry, and i reckon it'd be a bit of fun. I like the L18 head idea that someone mentioned earlier, sounds like a nice easy way of getting some decent compression. In a bluebird it'd still be reasonably quick I'd reckon, and if some little punk beats me with a stock ca18, oh well. The skylines for sorting them out

[race_snooze]

I have had a mate of mine stroke his l20 out to a 2.4l with extractors webbers, the thing was nuts, lots and lots or touque, rev range was still good, these motors are just about unbreakable, keep the oil and water up to them if they leak and they will go for ever.

I also had my dat 1600 with an l20 twin webbers and exaust they go really well, but one down fall of webbers is that you have to tune the prick all the time.

[NeoLokie]

well..I've scored a factory nissan head with all the porting and stuff done for an L20, big cam and some 42mm webers, so i guess that helps out a lot.

The guy I know that ran the stroker motor got 9k rpm out of it, and it was there a lot cause they were racing off road with it. I have access to a machined 2.4 crank and bored block if I want them too. He did say the rear main used to leak a little due to cracnk and lock flex at those revs..but you've gotta expect that I suppose

I looked into the closed chamber L18 heads, apparently they're the sss heads that everone wants, and therefor no one can get oh well.