datsun-roadsters
[Top] [All Lists]

Re: Found a L20b vs U20?

To: "Ronnie Day" <rday@airmail.net>,
Subject: Re: Found a L20b vs U20?
From: "Mike Kerr" <mikekerr@innercite.com>
Date: Tue, 2 Nov 1999 12:54:15 -0800
Obvious question is why not build an L-24 (four cylinder version) using
an LZ-24. You can, but it's a LOT more work

I happen to have a Z24 with solex carbs , has about 5000 miles on the motor.
S1000.00   for street use there is no need to change the head the stock one
works fine and it makes the motor shorter also for a better fit. the carb
come out on the other side so you will have to move the battery. have 3
distributors for it also the 8 plug , 4 plug,  and a point dist.



Mike Kerr
Roadster Restoration
3730 Todrob LN.
Placerville CA. 95667
Ph.# 530-644-6777
Fax# 530-644-7252
E-mail: mikekerr@innercite.com
Web page :  http://www.innercite.com/~wolfgang
Visa & master card
-----Original Message-----
From: Ronnie Day <rday@airmail.net>
To: Roadster List <datsun-roadsters@autox.team.net>; Bill Kenyon
<SRL311KA@aol.com>
Date: Monday, November 01, 1999 8:05 PM
Subject: RE: Found a L20b vs U20?


>Howard said:
>
>>One meaning of "imagining" is perceiving something fictional and I agree
>>with that.
>>
>>A ported U20 with the mods described and some valve machining can go to
>>170bhp and more,  I have one with similar mods that has been dynoed at a
>>little over 170 but the compression is actually lower than std (9.2 to 1)
>>(my Silver car).
>>
>>The mods on my race U20 are a little more exotic and mine pulls 228bhp (so
>>says the dyno).  (normally aspirated with 11.8 to 1 compression).  (My
Blue
>>and white race car on Gordon's site).
>>
>>I agree on the parts bit. I have used modified L series titanium valve
>>retainers on the U20.
>>
>>The design efficiency of the U20 is far greater, take the Heads side by
>>side and look at the huge ports on the U20 compared with the L series.
>
>Josh said:
>
>>It seems I will have to continue as devils advocate
>>for swaps.
>>From what I gather there isnt much more that you can
>>do to a U20 beyond going solexs, header and a cam.
>>Which is great power!  But thats only putting out
>>around 150hp, after some porting I couldnt imagine it
>>going up much more from there.
>>An L20b can get 170hp with the same efforts.  I have
>>not made the swap nor have I driven any Roadsters with
>>the swap but I can tell you the L20b in a 510 screams
>>and pulls hard!  Its also about the easiest engine on
>>the planet to get parts for (aftermarket or stock).
>>I would imagine Ronnie Day could tell you more about
>>the pluses and minuses of the L.
>
>I still say probably the best option in this situation is a KA-24, if
>you're going to do a swap. I don't know if I would or not. A whole lot
>depends on what kind of shape your current motor/trans are in. As for
>getting L-bits and 5-speeds cheap, maybe so, maybe not. The L-20b's are
>still relatively common and probably put in more mainland US cars than
>the L-16, certainly the L-18. I agree with Howard that you can probably
>get a properly setup U-20 to generate as much max power as a comparably
>tweaked L-20b, but I'm not sure either of them would be well suited for
>daily street use, and I think that's were you're headed?
>
>I thought we'd been through this here, I know we have on the 510 list,
>but in the daily driven on the street world there really isn't a
>substitute for cubic inches. That's why the KA-24, VG-30, and L-20b's or
>LZ-20's turned into L-22's are so popular in 510's, particularly the
>later option. Take an L-20b, bore it to 87mm, drop in LZ-22 pistons,
>rods, and crank, and boom, major torque. Very useful on the street. And
>the extra cubes can be free or close to it. Some prefer to start with the
>LZ-20, but (at least here) they're far less common than the L-20b and
>LZ-22/24.
>
>Obvious question is why not build an L-24 (four cylinder version) using
>an LZ-24. You can, but it's a LOT more work. Unless you have custom rods
>($$$) and or pistons (more $$$) made, you'd have to use an LZ-24 block
>which is 3/4 taller than the L-20b which is itself 3/4 taller than the
>L-16/18. You'd also need to fabricate a 3/4 taller L-type front cover,
>and finally (my personal favorite) you'd have to cobble up a timing chain
>as none long enough are (known to be) available. If you use the LZ-24
>crank in the L-20b block you'd have to clearance the pan rails and maybe
>the bottom of the bores, too, plus you'd have to have custom (short)
>rods, AFAIK.
>
>If you go with the KA, you have both the additional displacement and the
>late model functionality of fuel injection. You guys gotta see Bill
>Kenyon's car. Very nice. However you go, don't expect it to be easy,
>quick, or cheap to do a swap. I really believe that for a street L-22 is
>the rare combination that is inexpensive and yields impressive gains for
>the little money spent. If I remember correctly, Gordon built a similar
>motor a couple of years ago before he sold his 510. I definitely will be
>building one this next year for the '73, after the E/P car is going.
>
>
>________________
>Ronnie Day
>rday@home.com
>Dallas/Ft. Worth
>'71 510 2-dr (Prepared class autocrosser)
>'73 510 2-dr (Street Toy)
>


<Prev in Thread] Current Thread [Next in Thread>