'72 521 L20B Swap Denver

[biggaryT78]

First time ever posting on Rastun guys. Sorry if I am messing this up, kill me in my sleep if I do. I will PM you my address.

 

Purchased my first Datsun the other day...  1792 521 truck with L18 in it. It ran.. but super badly with ZERO power I could barely get it home up a tiny hill it just wouldnt go. Compression was 40lbs on first three cylinders and 100 on the 4th. Carb is in rough shape and has electric choke. Leaking oil from valve cover and from oil pan area. 

 

 

Decided to swap it with a rebuilt L20B I found on C-list and bought it at $600. NO flywheel. UGH~! first problem I ran into really.

 

 

The wiring in this truck is horrible... No connectors, just loose open wires twisted together everywhere.  Whoever did it I want to punch in the face. 

 

I have already removed the L18 engine and will be keeping the 4 speed in the truck. Mounts in good shape for motor and trans right now.

 

 

I need Carb advice, Buy new...weber or rebuild the other one I have? This truck has manual choke should I keep it or is that easy to upgrade to electric?  didn't seem to be hooked up at all right now. 

 

 

I cannot see any noticeable difference to the oil pans on either engine... am I missing something?  I was about to switch the oil pans and they just look and measure identical... Have yet to look for any serial numbers or anything on either pan as they are hard to get to whilst on the engine.

 

I bought a reconditioned 225mm lightened and balanced flywheel from https://www.californiadatsun.com/ $150 and an OEM '78 200sx 225 24tooth Clutch kit. $100. 

 

The L18 had a 200mm on it and as we know. 5 bolts doesnt work in 6 bolt places.

 

I have cleaned the entire engine bay and did a few other little things in there to make it niceish...  This is original paint, sort of, and I am not doing any body work to this project beyond rust removal and touch ups when needed.

 

 

I will need parts, I will need advice and I will need LOTS OF NEW WIRE and connectors, my least favorite thing to do. yay. 

 

I will be documenting this project with pictures and prices of parts from start to finish. Hope it helps others on their journey into the Datsun community I know I already have enjoyed reading all you guys comments and helpful. knowledge on this forum.

[datzenmike]

Well first of all welcome to Ratsun.

 

I suspect that a 225mm pressure plate may rub the insides of your stock 4 speed. It's used to the smaller 200mm one. Test fit them together before trying in the 521. It you can't draw the transmission up against the engine or the engine can't be turned when bolted up.... this may be the cause. Back in the mid '70s I also slipped a car L20B into my 521 and everything was fine. I didn't know until much later that all cars use a 200mm PP also.

 

I would pull the L18 pan and oil pick up tube off and put on the L20B. Won't hurt to put a new gasket on it anyway. Cars are mid sump.... trucks are rear sump. Sump being the lowest place in the oil pan. Better safe than sorry, and you have the correct parts there any way so use them. Don't forget the oil pick up tube!

 

The L20B will have an electric choke so just wire it to the idle cut solenoid wire right beside it on the carb or any ignition switched source. Good to go.

[DanielC]

Lets start with this, a wiring diagram.

 

If you look at the whole electrical system, it is overwhelining.  Just break it down toindividual circuits.  Then electrical becomes much easier.

[banzai510(hainz)]

use the oil pan that was already in the truck.

 

using a 225mm clutch youll need the TO bearing and collor for that set up. The one in truck is set up for a 2oo mm

 

take photos of the parts close up as most people fuck this up swapping clutches installing wrong parts and clutch dont work right or dont last long /slip ect.....

[biggaryT78]

Thank you so much everyone for responding! and for the welcome.

 

I am already learning a lot and I plan to get this thing done so here we go. I almost put the engine in last night but seeing this I am glad I didn't get that far yet. Just more cleaning and prepping for now.

 

datzenmike

I will now be Switching out the oil pick ups and the oil pan from the L18 and thank you for the insight about the mid and rear sump. That was news to me.

 

I will be checking the clutch clearance tonight, while it is still off the engine. Can I do some grinding to free up enough space on the 4 speed if it does hit?

 

Genius thanks - The L20B will have an electric choke so just wire it to the idle cut solenoid.

 

banzai510(hainz)

I have the [Reconditioned flywheel/Clutch disc/clutch/new throw-out bearing/new sleeve] that all match each-other for the 225 but I hope it fits without touching because I will be out some $ or shopping for a 5 speed which wouldn't be too bad I guess.

 

 

DanielC

Thank you for that wire diagram in color I will need this!

 

Photos:

https://www.dropbox.com/sh/umw1zkmvesehpvh/AAA5_8qTRA8czh_HsMTP7aITa?dl=0

[datzenmike]

Can you grind clearance? Within reason, I don't see why not.

[biggaryT78]

Yeah I figure it will only hit a couple places and I bet I can get those off of the bell housing pretty easily with some grinding. Thank you!

[biggaryT78]

Update:

Ordered the oil pan gasket and they are coming in today. $10.99 I bought two for safety.  Will be removing the pans and switching them out.

 

Checked bell housing for Clearance on 225mm clutch, seems tight but still okay.  More accurate measurements must be made to verify this as I do not want to install engine twice if I can help it. 

 

I will be working all weekend on this truck and I will document better with pictures from this point on using my real camera and update this as I go. 

[datzenmike]

Don't forget the metal spacer plate sandwiched between block and transmission and be sure that the block has the two alignment 'dowels', one on each side to slip into the trans bell. They look like 1/2" lengths of pipe. 

 

Did you get a new pilot bushing for the crank???

 

Was this originally an automatic??? If so there may still be a small round 5 hole spacer plate clipped over the end of the crankshaft that needs removing.

[biggaryT78]

Weekend update on this little blue 521.

 

PICTURES WEEKEND ONE:

https://www.dropbox.com/sh/e3dnegxrquuoqqt/AABLdt2bUqI9k_r6gj8F0OTRa?dl=0\

 

---DAY ONE---

 

Oil Pan from L18 is on the L20B:

Despite only one Engine hoist setup by mounting the L18 to an engine stand and hanging the L20B from hoist.  The L18's drain plug and front wall of the bubble is approx 1.5" to the rear compared to the L20B's pan so good call on not trying to use it (ratsun win)   All went according to plans, except there was one bolt on the corner of the block that was sheared off.  I had thought it was just a missing bolt until I tried to put one in the hole. Leaving it for now but I will fix it asap especially if it leaks. :(

 

 

 

Flywheel on the shaft

Yep I remembered the metal spacer and it had two alignment dowels too. I forgot I would need ONE extra bolt for your new L20B flywheel but the L18's 5 bolts are correct so you can use them (always best to get new bolts). I forgot this important piece but was lucky to have an L24 that nobody will buy, so I took off the transmission and there was a 6 bolts and a flywheel just like the one I bought... Why did a I buy a new one? I guess I do have a whole new setup mine is lightened a lot! and now so that's 'piece of mind' at least.

 

 

Clutch on the flywheel

New clutch kit came with a new pilot bearing throw-out bearing, disc, clutch and some spline grease.  I removed the pilot that was in the crank using a homemade slidehammer  (Socket and long bolt with 2 nut and washer) and then installed the new one with a 12 mm socket and... LIKE A GLOVE.

 

 

Engine into the truck

Engine went in without much issue, but I couldn't get it to slide home before I gave up.  Next time I will probably remove the control arm so the engine gets level slides back into place a little easier. I removed the left engine mount and loosened the right engine mount while installing the engine. 

 

 

---DAY TWO---

 

Engine slides home!

I had to raise up the transmission a lot! to get the correct angle to get shaft in then splines in and drop the pan behind the control arm thingy. I feared breaking off those rusted bolts so I left it but next time I wont. Once I had the engine positioned i was able to turn the engine a bit and get all splines and the pilot to slide home without much issue.  I put a couple bolts in just enough to align the engine better and jiggled it a bit and it slid home pretty well.  I turned the engine to check the clearance of the clutch in the bell housing and it moved freely.  I installed all bolts and the Start and turned the engine again to make sure nothing was impeding and it turns free!   NICE!  Mounts bolted up. I used L18 mount on right side and used the L20B right sides mount on the left side. and it fit perfectly. 

 

 

Alternator, Starter, Carb

Got the alternator mounted back up using the L18 bracket that I cleaned up a bit but left the patina on it. The Carberator is old and I will be replacing it, but for now maybe it will work as it was working before on the other engine So I mounted it up.  

 

 

NOW FOR MY QUESTIONS!

I have no idea where all these vacuum hoses go... IS THERE A DIAGRAM?

 

 

 

Wires and more wires, I have no idea, I do mechanical stuff. WIring diagram one at a time to come tonight. 

[biggaryT78]

Update! 

I got it all hooked up I think.  My truck doesn't have a carbon filter so had to delete some of the vac hoses etc. It has been interesting so far trying to figure out what all my truck does not have but the engine wants it to have.   So far I believe I have it all right. 

 

Issues the accellerator cable seems too long it is extended all the way out as possible on the mounting bracket and has some slack still works but not well and will need adjusted but seems to be a solid cable with no adjustments beyond the mount.  Do I need shorter cable?

 

Also I was wondering if anybody can help me figure out what this extra fuel line goes too for my conversion?  Not sure what or where this is supposed to connect too.. I have only one Fuel line from tank so a bit confused why this return is here.  I do not have a return pipe on my Hitachi like some of the Weber images I have seen on here.

 

Any help is appreciated. 

 

[biggaryT78]

Sorry again for being such a NEWBIE. Did some searches, although I had no idea what I was looking for and found out that hose is the Fuel Return Line of which my truck did not have in 1972.  Plugged that shit up for now, might run a new line back there before summer.

 

Going home and going to pull the water pump and install the L18 water pump and pulley to mount up the fan I have. I will get the other larger multi-blade fan and attache to the fan clutch version of water pump later. 

 

Ready to fire this thing up tonight though. Charging battery Double checking the plug wires and then trying to start it. 

 

I will need to get the exhaust worked out ASAP after this fires up to get tuned in right and maybe make a little riser back at the gas pedal or bend the mounting plate back to get a little closer to tight on the Accelerator cable. 

 

Noticed the rear brake lines are not actually hooked up to the wheels.  That's probably bad right?

[biggaryT78]

No start situation. :(

I wish it had just fired right up but such is life with a swap I guess. 

 

The engine cranks very well, after I charged up battery.

I primed carb.

Did not have any starting fluid to spray but I will be trying it. 
Double checked plug wires they seem correct from all Forum searches. Possibility of 180 off noted.

 

Distributor was already on this engine and looks really good.

Has electric ignition installed, possibly the trucks coil is not powerful enough? or I have it hooked up wrong so will check that again on wiring diagram.

 

Pulling plugs when I get home tonight also. 

 

I really need this thing to run but I have the whole weekend coming up so should be close to fixing this with any luck.

 

still not confident I have all the right vacuum tubes hooked up to the right places and or plugged.

[biggaryT78]

No spark coming from Coil at any of plugs or from the coil wire to the dizzy.  :( at least that explains the no start situation for now. 

 

Power to coil with test light on "run" although it does dim when cranked. "Start"

 

I will post pictures tonight after reading all the topics that relates to this, but there seems to be 50...  I guess just pick one and go with it.

 

No idea what my Dizzy is, I think it has a flame thrower into it.   I bought a new Ignition coil so will be attempting to hook it up directly and remove the resistor. 

 

I guess wish me luck and I will let you all know how it goes.   I really will need help with this after this next round of trying to DIY from the info on here.  My situation seems slightly different but mostly the same as the rest. 

[datzenmike]

Set to TDC. Rotor should point to #1 plug wire on the cap. If not move #1 wire there and arrange the others 3 4 2 in a clockwise direction.

 

Check ignition is wired like this for the matchbox...

 

 

For a coil get a matchbox compatible '79 200sx or A10 or an '80 720 coil. I have no faith in after market shit at all. I know and trust Nissan designs, because ... they work. Later Z20/22/24 series coils will also work.

 

As this is a c/l engine and nothing is known about it or if it can run, I would take the cap off and crank the engine and see if the rotor is even turning.

[biggaryT78]

Thanks Mike!
This didn't work with the dizzy that was installed on engine and with my volt meter determined the Electric points were not working... so I swapped out with the physical 'Dual Points dizzy I had from the L18.  I have spark again!! and I am using the ballast resistor and stock setup of the wiring.
 
Re-Checked each plug wire and am getting spark there now too.   Now the car will not start.  I re-positioned the ENGINE at TDC and put Plug #1 at the Rotor position. The car wont fire up even with Starting fluid so I am assuming my timing or the plugs is off although I switched the plug wires to be 180 off and still no start.
 
I assumed you meant 'Counter-Clockwise' on the plug wire count, as seen in most other places on Ratsun. 1,3,4,2
 
The Dizzy has two sets of points and I had to gap the second set to make it spark but it sparks on both sets of point now. Is that not needed?
 

[banzai510(hainz)]

dude this isnt that hard

 

https://vimeo.com/19077890

 

the main set of points is the bigger capacitor(condensor side)

the 2nd set of points dont work untell 3rd gear. this is the small capacitor

 

main wire is the blk/red wire I believe for this

 

use the stock coil and the ballast otherwise points will burn up.

 

I cant tell which EI distributor you have on hthis motor. old datsuns .com in the tech section has all the infor and on here in the HOW TO section of electrical ignition conversions. How to hook up.  If this DOES NOT have the blk box on the side then you have the 1st gen EI nissan distributor and need the elelctrical box to power up the distributor.

 

put on TDC then Counterclockwise and it will fire off if you have gas and compression(means adjust the valves to make sure its closed)

 

if gas i carb one never needs starting fluid/ I never have used it.

 

 

have a feeling your last motor was fine

 

I would have threw away all the intake and exhaust crap and use the 521 stuff. the intake and the 521 exahust manifold( i cant see it but assume you used the one that came with this motor) so now you need to rig the exhaust Y pipe . mean strip the motor down then use the 521 stuff and just bolt it on. and everything hook back up.

 

dont need a fuel return line. throw all that way. this water pump is good what you have if still good. but the other one is fine also.

[biggaryT78]

Thank you! I know its not that hard that's why I feel pretty lost and a little dumb. From your video it appears my dual points Distributor is on backwards.

 

The exhaust manifold seemed to be bigger than the L18's but it would have been nice to get all the smog stuff off that's for sure do you think that is my issue here?

 

The L18 that was in it had really low compression on 3 out of 4 cylinders and was running... but on two cylinders. I do not think it was fine but maybe you are right and I didn't need all this work but this swap was easy until I tried to start the thing. I will be putting the Dizzy in again tonight and also switching the Coil back to the old coil which might be my issue here too now that I am back to using the ballast resistor.

 

Cheers!

[biggaryT78]

I definitely had the dizzy on backwards. For dual point early model Distrubutors put the adjustment screw to the rear of the engine and the vacuum advance to the Lower side.  

 

I then flipped the firing order over (since dizzy is flipped now) using TDC starting 1,3,4,2 Counter-Clockwise, but it wouldn't start, but almost started, on what appeared to be ONE cylinder.  At this point I knew I was very close and then it hit me!! Switch the plugs you idiot! this is old Coil, points and dizzy!!

 

I pulled the L20B plugs and replaced them with the L18's and BRAAAAP!! it fired right up and sounds great!  I only let it run for 1 minute.

 

Adjustments and a timing light needed, but runs well right off the bat, and once the exhaust is on there I can feel the LOVE from this engine already!

I will have to get a fan to use with this water pump or use the 4 blade one and the water pump from the L18 as L_MotorGod suggests. 

 

This truck is almost back on the road. Right before the snow fly's here!

[banzai510(hainz)]

you can put the dizzy 180 out just swap the wires 180 also.

[biggaryT78]

Yes I think it would have started had I done the plugs first!

 

Cannot wait to get this thing out for some pictures in the sun.

 

stay tuned.

[biggaryT78]

Adjusted the carb. and the timing and it is running very well, slightly rich, I may need to mess with the float position to get it dialed in.

 

UNFORTUNATELY I think I messed something up. :(

 

Haven't had time to check it out closely with the Slave adjustment screw but my clutch does not engage!! :( pedal feels strong all the way through even at the starting point, so I assume it is resting against the fingers of the pressure plate slightly. I hope it has some room for adjustment but something tells me it doesn't, I used the wrong collar or sleeve or clutch as Mike said originally. This sucks I may have to pull the engine or transmission and install a different clutch setup which will slow me way down but make me better at taking this thing apart.

 

I am asking this question... beyond adjusting the screw way back on the slave is there anything I should try before taking it out of the truck again?

[banzai510(hainz)]

the slave has the jam nut and the half ball that's threads on there and you move this till the fork arm has about 1/8  1/1in slack in it. that's about it.  That's if this is the fork with the hole in it for the threaded slave rod to pass thru.

 

 

I saw this in your earlier post but didn't say anything as Mike should have caught it also

 OEM '78 200sx 225 24tooth Clutch kit. $100. 

 

200sx are all 200mm clutches even if L20. as 200mm were for the cars

the trucks are 225mm and use the T/O bearing which is bigger and a different sleeve. that's im positive.

 

I think partstrain.com sell the T/O bearing ans sleeve as a kit if you look up 620 L20 say 1979.

 

 

 

Now  what really you ordered?????????????

 

the L18 set up is 99% 521/510 200mm with a stock clutch.

 

 

 

do simple shit 1st bleed the slave cylinder

 

 

if fingers are engaed then the clutch sould disengage when you press on it as its already partially pressed right? unless Im  mistaken on this one

 

so now you have a 225mm pessureplate which will be obvious compared to the 200 mm s the bolt holes are farther out.

[biggaryT78]

Banzi,
Yeah I mean on both! I mean it wouldn't disengage. I was able to adjust the Slave to fork bolt "shorter" and the clutch is now working great! i had to move all the way back to get 1/8th inch play. And the clutch now works properly and feels great! I shouldn't have been that worried.



You are right! I didn't buy a 200SX clutch, what I bought was a '78 620 clutch-kit and Recond. lightened flywheel. The kit came with all the fixings to match. Now that it works I like my decision but I had no idea it MIGHT NOT FIT! as Mike suggested for clearance. I came to that decision by reading the many many posts on Ratsun.com that say the 225mm went on trucks, must have missed that they come on newer trucks that are not 521's. and NOT 4speeds usually. It was a little tough to sift through all the clutch related info on Ratsun.

I finally jacked up the truck on all for stands and rolled around under it... WOW USELESS Exhaust! I am now glad I kept the Manifold on the L20B. The stock pipe was cut off about half way down the truck and someone had just loosely stuck an old Borla Muffler onto the end and hung it up to the frame. NO clamp on the pipe! it was just shuved in there like IDGAF! I took the entire thing off and will have one made this weekend.

PARTS NEEDED:

^^need a fan^^

NOBODY makes a new cooling fan to fit this setup and nobody carries this in Denver!? Are they HIGH? I called around and nobody has or can even order this fan. I hate Ebay! been burned before with that place. Does anybody on here have a Fan for the smaller version of a FanClutch Type waterpump setup? A part number would be nice too which I cannot find the RIGHT one. 

PROBLEMS FOUND:
Still running a little rough after the timing light went on it, 13 Degrees BTDC seems to run best but the revs dont keep up! I think it is the Vacuum Advance. New plugs, wires, Rotor and cap are on the list anyway which might help. It could be carb. related but more tuning needed before a Weber is ordered.

There is a small oil leak from the oil pressure sensor. I will replace with L18's should be good to go.

The ignition light stays on when the truck is running. Not sure how it is supposed to function, is that normal?

[DanielC]

If you are using a externally regulated Nissan alternator, and a Nissan OEM regulator, the IGN light should go off when the engine starts.

There are two letters by the small "T" connector on the alternator.  "F" and "N" is an externally regulated alternator.  "S" and "L" is a Internally regulated alternator.   You can eliminate the external voltage regulator, and use a "S" and "L" alternator, but you must keep the black ground wire that goes between the alternator frame, and one of the voltage regulator bolts.  this wire grounds the cab sheet metal to the engine.  If this ground wire is missing, or goes bad, the cab grounds through the throttle cable, and melts it.