L20B into a 1980 510

Problems, ideas and comments specific to engine swaps.
CesarRubio
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Location: Seattle, Washington

L20B into a 1980 510

Postby CesarRubio » 04 Oct 2014 00:33

Hello, I have a question regarding my current project.
I bought a 1980 510 from a guy on Craiglist for dirt cheap, but the crank and the actual engine block dented/bent when the rod cap from cylinder 2 broke off. The rod did major internal damage.
Anyway, I went down the the local Pick N Pull and picked up an L20B from a 1986 King Cab. The Z20 engine that was in the 510 was one of the ones with 8 plugs, and therefore had 2 igniton coils. Now that I've put the L20B in, does it matter which coil I use? If I take off one coil and cut the extra leads, would it matter? Also, the 510 had electronic ignition, the L20B doesn't. For the new distributor, which lead should I connect to the distributor?
There was a yellow lead on the truck, that I took the L20B from, going to a what seems to be a sensor in the exhaust manifold, under the upper radiator hose. What lead goes here?
Thanks for reading.
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okayfine
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Re: L20B into a 1980 510

Postby okayfine » 04 Oct 2014 08:26

Do you have a wiring diagram for your Z20 510? The dual coils are wired as a primary and a secondary, you're going to want the primary coil (secondary is slighty retarded, IIRC). IF Datsun kept the wiring colors consistent (and there's no reason to bank on it), the lower coil with the black/white wire to the positive side is your primary coil.

If you're wiring up a points distributor, the negative side of the coil goes to the connector on the distributor.

I'm sure datzenMike will be here soon to set me straight.
Because when you spend a silly amount of money on a silly, trivial thing that will help you not one jot, you are demonstrating that you have a soul and a heart and that you are the sort of person who has no time for Which? magazine. – Jeremy Clarkson

datzenmike
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Re: L20B into a 1980 510

Postby datzenmike » 04 Oct 2014 08:40

Because the L and the Z series engines sit at about 18-20 degrees different to each other, how on earth did you get it to bolt to the transmission? If you used the Z series engine mounts on the L series engine it will be sitting with the intake almost into the driver's strut tower.


Both Z series intake and exhaust side coils fire together, there is no advanced or retard side.

The last year for the L20B was the 1980 720 truck so not '86... (maybe you mean the '76 620?). If from a 720 it should have electronic ignition (EI) as all were EI after '77. Take the cap off the L20B and confirm you have points and not a similar looking remote igniter EI dizzy. This is important as the Z series coils won't work properly with a points dizzy. We need to know what distributor you have first.

The sensor on the thermostat housing (not the exhaust manifold) is the water temperature gauge sender. Your Z20 sender is on the intake just below the thermostat under the top rad hose. Just move the wire over to the new location.

Image
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs

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okayfine
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Re: L20B into a 1980 510

Postby okayfine » 04 Oct 2014 09:04

See?
Because when you spend a silly amount of money on a silly, trivial thing that will help you not one jot, you are demonstrating that you have a soul and a heart and that you are the sort of person who has no time for Which? magazine. – Jeremy Clarkson

CesarRubio
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Joined: 21 Sep 2014 20:53
Location: Seattle, Washington

Re: L20B into a 1980 510

Postby CesarRubio » 04 Oct 2014 13:45

Sorry, I wrote this late at night...
I haven't bolted on the transmission yet, I just want to test the engine before the 30 day return period. DatzenMike gave me some suggestions on what to do at that point on my post on the introduction thread. Thanks Mike.
Yes, the L20B came from a '76 620. The distributor uses points, it is not electronic. So, I basically have to buy a new distributor for this distributor. Is that correct?
Thanks for the help.

datzenmike
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Re: L20B into a 1980 510

Postby datzenmike » 04 Oct 2014 17:02

No, the points distributor will work, but you need a points coil and a ballast resister for it.

Or just get a matchbox distributor and use one of those coils from the Z20. Here's an idea... put the Z20 distributor in and remove four of the eight wires. Costs nothing to try and you already have a coil for it. If you look on the underside of the dizzy cap and the rotor you can soon figure out which coil lead goes to which rotor tip and goes to which four wires.

Yeah twisting the engine to the right and the transmission to the left to get them to line up so they bolt together isn't going to work well. The rubber mounts on both are not going to stretch that far. Any chance of getting that '76's transmission?
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs

Paul J
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Re: L20B into a 1980 510

Postby Paul J » 12 Oct 2014 10:44

Oh boy, this thread gave me flashbacks. In college I had an 81 200SX with the Z20 engine. I broke the trans coming back home over break and went to the local salvage yard and pulled a dogleg box out of a L20B powered car. We cleaned it and put in some bearings and seals and it wasn't until I got it bolted up to the engine. It seemed weird that the shifter was over in the tunnel, and the trans mount couldn't fit. We ended up taking the trans back and he flipped another car on its side and we ripped the trans out, in the snow, and went back to the shop. We drained the old gear oil and threw it in the car so I could get on the road back to school. Ah the memories.
I agree with Mike,you probably need the trans to go with the engine. I hate to have you go through all that work and it will not fit in the engine bay. It's a bummer because the bolt pattern is the same.

datzenmike
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Re: L20B into a 1980 510

Postby datzenmike » 12 Oct 2014 11:39

Using the Z20 oil pan on an L20B will be a problem because of the engine tilt to the right and it will be low on the right side under the car. The oil will be sitting in the pan as if you are driving off road on a 20 degree side hill at all times. I suppose you could try the Z20 engine brackets and place the L20B in the Z20 position... at least the transmission would then sit properly, but the carb and intake will be rotated to the left and into the driver's strut tower? The carb will then be at a 20 degree tilt but still work?

The exhaust down pipe will be different, Z20 to L20B manifolds.

The earlier L20B 4 speed from the A10 or the 710 are the same and even the '73 610 and the PL510 should be a good fit in the A10 if you decide to run the L20B in it's proper orientation.
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs


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