L18 modifications advice

[Eriks]

Hello, I'n lack of L20B engines in Europe ( :crying:  )  I've purchased a Bluebird 910 With L18 engine and 5 speed gear Box. The mileage is a moderate 160.000 km. The plan is to put engine and five speed into my 510. The 510 is for everyday road use.

 

However the L18 feels lazy, so I wish to ask you what makes the engine more agile and fun ????

 

Fuel consumption - I do not care. A larger carb seems obvious. Yet I understad that a too large carb is a disadvantage when the car is for everyday road use. So what is larger but not too large? How about a single sidedraft  weber ?

 

Electronic distributor?

 

Replacement cam?

 

In short, I'm thankful for all ideas that do not involve major engineering.

 

Thanks !!! :)

[KlassicMotion]

My 2 cents:

Carburetion: You could go with dual SU's as on the SSS cars. The set I have off an L18 measures 38mm each. A favorite over here for pocket book economy, fuel economy, and mild performance is the Weber 32/36 DGEV. If you put a cam in, it might be receptive to a Weber 38 DGES. I've read on here, a lot of people warn against a single side draft, as they tend to run rich in #2 and #3 cylinders, and lean in #1 and #4. Dual Webers probably work best on mild to wild engines. I've been told dual 40mm's work better on stock to mild L16, 18 and L20b with 30mm chokes.
... Interestingling, the Weber carb source I use, does not list any dual side draft kits for Nissan anymore. :confused:
http://www.webercarbsdirect.com/

This company is discontinuing setups too!!
http://www.carburetion.com/Weber/Dataresults.asp

A late 70's and 1980 L20B electronic distributor will make life easier.

A cam would pep it up, yes. There are a number of re-grind configurations out there.
http://schneidercams.com/naturallyaspirated-7.aspx
http://www.crower.com/index.php/camshafts.html
http://www.camshafts.co.nz/Datsun.aspx
http://www.elgincams.com/c-dat.html
http://www.whiteheadperformance.com/products/datsun-l24-l28-adjustable-cam-sprocket-gear-2/

"Major engineering"?
Would that include a head swap?
Or, a basic rebuild?
Or, a rebuild with an overbore, using a larger piston, and or a flat top (higher compression) piston?
You could put on a turbo. I believe Jason Gray did a write-up on his in Dime Quarterly...
A lighter flywheel will allow the engine to rev faster and higher. Too much, and you loose low-end torque, and the ability to leave from a stop light. (My 225mm flywheel was lightened to 17lbs). It works well on the street).

Removing weight from the car is just as good as adding power....

Well, there is your first response. Hopefully that gets the attention of others to chime in...

[datzenmike]

The 910 in Europe either came with, or had an SSS option that included the L18 (probably with flattop pistons) fitted with dual SU carbs and a long dogleg (reverse above first) 5 speed. I'm not sure which, but if it was an option, find one and swap the S U carbs onto yours, maybe the complete motor? 

 

If just a simple L18 motor with Hitachi carb then as started previously, a Weber 32/36 with adapter plate is a nice up-grade and a reasonable compromise for daily driving.

 

An electronic distributor (or dizzy) won't up your performance but it does get rid of problematic points. Starting will likely be easier.

 

Any cam increase will move your motor farther away from being docile on the street. Harder starting, rough performance when starting and when the motor is cold, and at low speeds and idle. If selecting a 'larger' cam less is more. I wouldn't go more than 20 degrees extra duration, say up to 270 total, but increased lift is fine. Any duration increase will remove lower speed performance and move everything up in the RPM range. Just remember that you drive mostly in the below 3,000 range. You will be happier with a small cam wishing you had a larger one than the other way round.

 

Perhaps a larger muffler? with less restriction. Not a straight through loud thing though.

[Stoffregen Motorsports]

The mileage is a moderate 160.000 km.

 

However the L18 feels lazy, so I wish to ask you what makes the engine more agile and fun ????

If it feels "lazy" I would start by determining if it is worn out. 100,000 miles on a motor can certainly stretch a timing chain and wear out rings, both of which would contribute to the lazy feeling. Run a compression test and have someone check your cam timing (or just throw in a new timing set) before you start getting into performance mods.

[datzenmike]

Agreed. The carb might not be opening up all the way, the fuel filter part clogged, timing retarded, Valve clearances tight, points worn or mal-adjusted, exhaust pipe crushed flat, thermostat stuck open......

[KlassicMotion]

Perhaps a larger muffler? with less restriction. Not a straight through loud thing though.

 

Perhaps 1.75" or 2" pipe.

 

I wouldn't go any bigger than that.

[Eriks]

Many good advices, thank you :) I'll do a good check on the engine as is, and go from there.

[datzenmike]

If you rebuild it and can find L28 flattop pistons from the Z car. You need to over bore the block 1mm but this will increase your motor size from 1768cc to just over 1800 and raise the compression to almost 10 to one. If you can find an open chamber U67 head from a later L20B with the larger ports and valves this will drop the compression back to a manageable 9 to one. The L20B heads also have different cams than the L16 in fact the equivalent of the L16SSS specs.

[uberkevin]

Watching closely!

[jwerty1]

I vote for turbo, but you said no major engineering.  I give the weber 32/36 two thumbs up, very easy to work on and does a nice lil boost.  Electronic dist is very nice.  Definently though, do a full tuneup.  Plugs, wires, cap, rotor, fuel filter, set your valves and set your timing.  Also, double check for vacuum leaks.  This will all put you in a good spot to start modifying. 

[datzenmike]

 

Hello, I'n lack of L20B engines in Europe ( :crying:  )  I've purchased a Bluebird 910 With L18 engine and 5 speed gear Box. The mileage is a moderate 160.000 km. The plan is to put engine and five speed into my 510. The 510 is for everyday road use.

 

However the L18 feels lazy, so I wish to ask you what makes the engine more agile and fun ????

 

 

I'm sure the 910 is slightly heavier than your 510 so expect it to improve in the 510. The dogleg box is likely longer than your 510 4 speed so a drive shaft shortening in needed and the rear mount modified. If your dogleg is like our shorter ones, the gearing is identical to the stock 510 4 speed but with a 16% over drive 5th.

[Eriks]

Thanks everybody !!

 

I found the main problem - a rupture in the vacuum hose between carb and distributor. The car was immediately more responsive after replacing the hose. Also noticed leaks in the carb, so I followed your advice and replaced it With a Weber 32/36, and ordered a new water pump due to a worn out bearing.

 

All considered: BIG DIFFERENCE :)