I got my dream pickup, a 1981 720.

[toshts]

6 hours ago, TinKanTosser said:

The idea is to dump it back in. I'm losing a quart of oil every couple days, it's not feasible to keep dumping in good new oil and I don't want to put poor quality oil in it.

But you were right, the PCV turned out not to be the main issue. When I pulled the suction hose off it was soaking wet with oil, but when driven that way it smoked about two times as bad. So while the PCV is sucking oil from the bottom, it's not the singular cause of the smoke. And it seems like the PCV is helping the ring seal just enough to mitigate some of the smoke.

 

I don't have time to have it down for full rebuild right now especially not on a truck that's leaking rainwater in through the doors, windshield and floor (I keep finding new leaks) but it did dawn on me yesterday that I have all the donors I'd need to build an LZ23. I have a bad-condition Z24 from my dad's truck, and presumably an L20B in a king cab 620. I know our older 620 has been sitting out with the valve cover off for 30 years though, so if the L20B has been too then it's a no-go I guess. Unless I could get a new cam for the head.

 

I don't have the area or equipment to pull the Z24, especially not with it out in the woods, but if I could do it and get the parts together I could build the LZ23 on a stand at my own pace, then drop it into the truck when it's ready. Seems like a good idea considering I have a low mileage gearbox and diff; a new motor would solve everything but the rust.

If you wanna keep the low mileage trans you'll need to swap the front casing from the l20b trans onto it. If you took a z22 and either shoved the z24 crank in (clearancing required) or bored out to fit ka pistons you'd be looking at an lz23. An lz24 isn't as common as you need to extend the timing cover and chain from the l20b along with the frequent coolant jacket cracks in the z24 block. I'm quite happy with the performance from the lz22 which is the easiest (granted you've got a good z22 block) but it'll probably be more involved than just swapping the motor in when it's time. 

 

I've got a high mileage Toyota 3tc that has pretty worn cylinder walls and rings that was burning quite a bit of oil (1/4 quart every 300 miles). Did a warm piston soak with berrymans to help unstick the rings and it got rid of the blue smoke on startup and the it hasn't lost any oil in the 500 miles since (at least noticable on the dipstick). While I'm sure it's still burning with how washed the cylinder walls are it greatly decreased the amount though if the rings aren't stuck it probably won't make a difference.

 

 

[TinKanTosser]

2 hours ago, datzenmike said:

An L20B and a Z24? You can't make an LZ23 out of those two.  For that you need a Z22 or L20B block bored to 89mm, a Z22 crankshaft, Z22 or L20B rods and KA24E pistons.

 

If you fit the L20B head on the Z24 block you would have an LZ24 with 9.47 compression. 

I was completely mistaken on what an LZ23 is, sorry about that. So when the time comes the path of least resistance for me will be to just take the head off again and change the rings with the motor in place.

 

In the mean time I'll keep driving it and hopefully find the time to do the body work.

My plan is to take off the fenders and doors, spray the insides of them with canned primer, and paint the outsides of the truck with epoxy tractor paint. I was inspired by this video:

 

In the one-year update he shows that the car got wrecked and the paint completely held on, didn't scratch or chip. If I coat my truck evenly it should be polishable but still hold up well against chipping. My plan is Ford Blue with white lettering on all the Datsun emblems.

[NC85ST]

12 hours ago, TinKanTosser said:

take the head off again

And the oil pan, to get to the rod bolts.

[datzenmike]

After priming cover with paint, anything at all: no one will see it. Primer won't do squat for rust protection, even attracting water and making it worse.

[bottomwatcher]

On 6/2/2026 at 1:49 AM, TinKanTosser said:

I was completely mistaken on what an LZ23 is, sorry about that. So when the time comes the path of least resistance for me will be to just take the head off again and change the rings with the motor in place.

 

In the mean time I'll keep driving it and hopefully find the time to do the body work.

My plan is to take off the fenders and doors, spray the insides of them with canned primer, and paint the outsides of the truck with epoxy tractor paint. I was inspired by this video:

 

In the one-year update he shows that the car got wrecked and the paint completely held on, didn't scratch or chip. If I coat my truck evenly it should be polishable but still hold up well against chipping. My plan is Ford Blue with white lettering on all the Datsun emblems.

White on blue!

[TinKanTosser]

I was laying down in my truck at work and a Mennonite farmer from Pennsylvania did a hit and run on my truck, scraped both corners hard and shook it around. I jumped out, yelled and blew the horn, and when he kept going I jumped in and chased him to where he'd parked. He got out and looked at it and seemed very dismissive. "Well sorry" I wasn't gonna shake him down for insurance or money but his attitude pissed me off. His wife was in the truck too and supposedly neither of them noticed the trailer dragging against a parked vehicle. He should have his CDL revoked considering the length of his trailer and where he was but I'll let someone else go after him. I find it amusing that literally any pickup made after 83 would have lost both taillights from this

 

[NC85ST]

I would definitely go after him for damage like that, especially with the attitude you described.

[Thomas Perkins]

If he did that where I worked.He would of got fired.Someone has before.With all the cars in our parking lot.There is always some people in there vehicles taking a break in them.I get 3 breaks a day at work and I sit in my truck and call my wife..Also

 

 

other people sit in them instead of going in the break room.But they cant make that person pay for damage.