Datsun problems (510 wagon)

I used to own a 78 Datsun 510 wagon which, due to being a giant pile of crap, i sold. Not one to pass up a nightmare, my dad bought it from me and got it running. Flash forward a couple years and my brother is now driving the car.

Well a couple days ago he was driving it and (his description) it started chugging, losing power, and backfiring. He had it towed to my house so we could attempt to troubleshoot it, but having a 4 month old and full time job means my troubleshooting hours are limited.

I tried starting it a couple days in a row and it just cranked, wouldn't even pretend to fire. Today it starts and runs like nothing happened. Compression checks good on all cylinders, fuel filter in the engine compartment seems clean, and the distributor is reasonably new. Plugs and wires also seem ok.

I suck with carberated (sp?) cars and don't have a lot of spare time so any ideas as to what else to check would be appreciated.

thanks!

Jacques

Problems that fix themselves can be hard to track down. My first guess was going to a timing issue, but I don't see how that would be intermittent. I would check the timing anyway as my first step. Here is my wild ass guess - you have a loose spade connector on the (-) terminal of your coil.

The good news is that there should be plenty of Datsun experience here to answer this one.

I used to have water and distributor cap problems with my first Datsun.

A combination of a little rain, a crappy knockoff brand distributor cap and taadaa.......engine dies, won't fire.

I finally stuck to the official Datsun distributor caps and rotors and life would be fine......

cap/rotor problems are relatively easy to diagnose if that's what it is and it's intermittent. Next time it doesn't fire, try spraying some WD-40 in the cap (take it off) and crank it some more.

-Brian

loose distributor hold down bolt? Oddly enough, pretty common.

Or just skip it,and by my 78 510 coupe. Not such a pile of crap.

I had a '78 datsun 620 pick up with the L20B engine that is probably the same one that you have, I had an intermitant problem when it got hot similar to what you described, and it would some times completly disapear when the engine was completly cooled down. It turned out to be a valve seat that was coming loose in the head. I pulled the head off and had a machine shop install all new valve seats, the machinist was an old timer and mentioned that he remembered seeing this problem frequently on datsuns of the seventies and early eighties. Also later on after the engine was fixed it had a coil tower failure that would only act up when it was raining or very humid. One last bit of advice, if the carb is shot, don't waste your money rebuilding it, get a weber upgrade carb kit.