TinKanTosser

Very nice truck, same era as mine but much nicer. The hood having metal vents instead of the later awkward plastic vents I have is interesting, I never knew they existed. These trucks being easy to work on removes a lot of anxiety about their age and the bucket list of things you have to do on them. You can mostly just get it running easily and drive it hard unlike a Porsche or my Triumph.

I've been running 20w-50 high mileage and the smoking has somewhat decreased. Still seems to be entirely up to the mood of the engine and has little to do with temperature. I had a new muffler put on so the smoke at least comes out the tailpipe and not up the back of the cab. I got a 4x4 instrument cluster for the tach, and it also has a trip odometer which mine doesn't. The new odometer is at 87k miles so I'm going to keep using my old one until I get up to that mileage, then I'll swap that in too. I think I've located the signal wire that goes to the coil and I just need to get to RadioShack and see if I can get a 2.2k ohm resistor from them, else I'll have to wait on it to come in the mail. I got my tractor paint but haven't had any time to start prepping; all my days off are scattered around the week so I never even have two days in a row to get any work done. Still have not changed ball joints. My windshield leaks so I feel like I need to try to remove it and change the gasket when I paint the cab. Rain seems to come in the upper driver side corner from a lifted lip, and it runs to the inside in the upper driver corner and down below, where it runs down to the area below the speaker. Also have heavy leakage in the passenger floorboard. Not sure if heater core or windshield. Rust will be gnarly.

A few years ago I got a Walker Quietflow SS from Amazon on clearance for $17, it was for a Ford Ranger and I knew I'd eventually have another small truck that needed a muffler. I had it put on my Datsun two days ago and now it's almost completely silent and sounds like a 2015 model. All the sound I have is valves clacking and vibration resonance through the cab, also I can hear the Weber sucking air from inside the truck. Kind of regret getting it this quiet... but it's nice going through neighborhoods at 3 in the morning and knowing I'm not being heard by anyone at all.

Everyone I've talked to thinks swapping engines would be a gross overreaction when it runs this well, not to mention I don't actually have the equipment to pull an engine, nor a fresh engine. Where could I get a good condition Z motor for less than $500 that I could just drop in with no other work to do? Not to mention the truck is full of holes so if I consider the engine a writeoff then the whole thing is too. That's not right. If I wanted to throw it all away and make all my problems go away I'd get a hardbody. I've been considering that possibility and planning to check for it, it just seems like the machine shop would have noticed. The odometer is still below 60,000 miles and it works. Considering the truck is all rot and no wear, I'd expect gummed up rings, dried out seals, and improper installation of new seals. Just what seems likely to me. This truck was tampered with before I got it but it had not driven since it was almost new, I strongly believe that.

Now that the weather is proper hot I officially agree with those of you in the thread who said my oil burning is from valve seals. During engine braking, the hot oil is pouring into the cylinders so fast it's popping and pouring smoke. I also do have an instant cloud of smoke immediately as the engine starts up. I'm now running some 20w-50 high mileage and it's given some relief, but at this point I'm reaching idle-killing levels of oil soot in the cylinders on a hot day. I had a valve job done at a reputable machine shop, which also happens to be the only serious machine shop in this part of the state, and the old man put on all new valve seals; they're bright blue. How do I go about this? What could the shop have gotten wrong and how can I check for it? Is it possible to clear the oil return hole without pulling the head again? I plan to go back to the shop and bitch about it but I don't want to pull the head when I have perfectly even compression. I accept that I'll probably have to get a spring compressor and do the job myself but I don't want to do it until I know what to look for, given that this is my daily driver. Also keep in mind that it smoked worse than this before the valve job, and it smoked worse than this on the first startup after the valve job. It's better than it was, but then it stopped getting better and is worse now due to heat.

I took the bumper off my dad's 84 a couple days ago, it's made just for a 720 because the brackets that bolt to the frame are angled so as to dip below the taillights. It's stamped SERRA DATSUN BIRMINGHAM AL. It's beat to hell and at some point got slammed so hard it bent the brackets so it sits at one side, but it does good. It's not as heavy as the 620 bumper I was gonna put on but still just having a bumper on the back makes me feel like I'm pulling a trailer. At least it gives me more traction and a smoother ride. Still planning to take the 84's rear end for my truck, I think it will save me a lot of engine and transmission wear. Will make it more viable to use 4th gear and probably give me a crap ton more gas mileage. Just have to get the 84 raised up enough to work under it when I get the free time. I finally got my left front turn signal working recently, the problem was the ground wire to the socket is not making contact at the socket, and the piece of junk is fully encased in plastic so I can't get to where the metal makes contact to clean and reattach. My very effective bandaid fix was to cut a piece of wire, bolt it to the body, and stick it in the light socket so it's grounded. Works like a charm until I need to change the bulb. The big to-do that I dread is changing my tie rod ends, I never have luck getting them loose. It's honestly easier on front wheel drives where there's only one on each side and the mounting points are straight and even; rear wheel drive trucks seem to have balljoints everywhere and half of them sit crooked where my puller won't go straight on. I wish shops didn't charge so much for crap that they have the tools to do in 15 minutes.

Hope this helps: Don't be alarmed about the oil around the diff plugs, I coated them with Fluid Film to keep the plug threads from rusting again.

It's damp out so I'll do it tomorrow in the daylight. If there are any spots where there should be a stamping on it I can try to clean them and find it.

One of these days I'll have a few coats of paint on the bed and won't want to do this again except in a trailer, but for right now, not having to maneuver a trailer, showing off the same way my dad did, and using the gravel as an abrasive to scrape off the deep rust and paint on the bed floor is my priority. I can pull a trailer with a V8 truck but being able to dart around and fill spots is great. KM720 on the top. I hadn't seen anything online about "HD46" so I really don't know what axle I have or if it's uncommon. Would appreciate knowing if anything about my truck is rare.

I needed a load of gravel on short notice so I had some dumped in the bed, it was a fun haul. I've been planning to add helper springs and now I'm definitely going to fast-track that. They didn't want to give me the whole scoop so they poured it slow and I had them stop when I got spooked enough, turned out to be about half a scoop of very wet crusher run, maybe half a ton? The stuff was dense and fine like concrete. It pulled and rode very well. The only problems I had were around curves and with gusts of wind on straight roads, the rear end would gently and slowly sway side to side, very threatening feeling like the weight was about to push the frame off the axle. I figure it was either the bushings or the bump stops, though it didn't feel bottomed-out to me, maybe just the bump stops being rotten to the point of total softness. I've ordered a set of poly bushings and a helper spring kit. My clutch also felt slippy when starting off, like I could let the clutch totally out without bogging the engine because it slipped enough to smooth it out. Brakes were just slightly scary and I near-ran a couple red lights accordingly. The big thing that concerns me now is that this truck is geared WAY too low. I see Mike saying to use fifth gear only for light cruising, but this truck goes into fifth at 30mph even with oversized tires. Even hauling half a ton I found out that I do not need gearing this low under any circumstances, I need it more oriented towards highway cruising. The plate on my right fender says the rear end is an HD46 if I read it right. My dad has a 1984 720, I want to take its rear end. It was geared much higher and brake parts for it should be more common. Its fender plate is gone so no idea what the exact gearing is. Thoughts?

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

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.

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.

There's no oil coming up through the valve cover PCV line at all, every time I pull off the air cleaner lid it's clean. When I pull the oil cap off while it's running it absolutely sprays me with oil droplets, coats everything under the hood, but like I said it's got more manifold suction than blowby pressure, and evidently when I'm driving it hard the blowby still isn't forcing oil up the valve cover hose. Rather than spend any time trying to diagnose, since I'm gonna drive the heck out of it anyway, I remembered I have a catch can I never really used before, so I'm trying to figure out how to mount it on here, and if blowby is pushing oil up the PCV suction hose then I can just catch it all and dump it back in. I get the impression this antiquated PCV design with the suction hose down on the block has caused a lot of worn-but-still-good engines to smoke like a freight train. I wonder if the mid-80s Mazda pickups had this same design? Because my dad had one that fit the description of mine, where it ran perfectly but would fill the pasture with smoke.

I believe my oil burning issue is not the rings nor valves, but the PCV. The biggest concentration of smoke comes when I've idled for a while and then punch it, like the vacuum of the closed throttle plate is pulling a bunch of oil up into the suction hose, then revving it gives it positive crankcase pressure that pushes the oil into the manifold. I drove on the interstate at a steady 80 MPH for a total of an hour (the faster this thing goes, the smoother it gets!!) and burned less than 1/4th of a quart, no smoke visible until I stop and then rev up. That consumption doubles or triples in city driving with stopping and going, and the smoke is frequent and pronounced. This makes sense considering the PCV suction hose connects to the lower crankcase, near the oil pan on this old Z motor. A lot more oil seems to make its way up the hose. But the only thing NOT original about my PCV setup is that the passive hose connected to the valve cover does not have the filter that would go in the air cleaner, since I'm using a Weber air cleaner. When I put my finger over this upper hose at idle I feel a steady suck then blow each stroke, with more suction than blowing. Perhaps that filter is needed to restrict the upper hose, and prevent the lower crankcase -> manifold hose from pulling so much air in. With the upper hose restricted somewhat as it was from the factory, the lower hose would hit a limit in the volume of air it could pull through the crankcase at idle. Just my theory. In the attached picture, the #2 filter is the one I'm talking about. It's like a piece of cotton or steel wool jammed into a pocket inside the housing. Maybe I could achieve something similar by stretching a thick piece of cloth over the hose nipple on my Weber air cleaner.