More issues with datsun 521

[josh817]

Get an over flow bottle. This made a little difference for me. In my Z it made a huge difference. The radiator will puke itself empty if it has a chance. It dumps it all over the ground. By adding an overflow bottle it will puke into it, and then as the pressure drops it will suck it back in.

 

Do you have your crank case and valve cover vents hooked to your manifold/carb? Perhaps you have a lot of blow by through the rings that you're sucking in.

 

The hose that Wayno is talking about indeed plays the function he was saying but it also provides water to the pump while the thermostat isn't open so that the pump doesn't start to cavitation badly. There are other bypasses too that you should be aware of. If you are running a heater core, and the core is open, that is a bypass. There is also an internal bypass in the block (at least on Z's there are). If the front cover looked like this:

 

That top square thats filled in, was the bypass. It's filled in because this guy is running Bob Sharp Racing stuff and they didn't want to bypass the radiator, otherwise it runs hot. No, you do not need to do this, it is only a reference so you can see that there are many ways for water to recirculate and never go through the radiator. If you are not running a heater core, don't loop that line from the back of the head to the water pump inlet. That's too much hot water recirculating.

[.sunlover]

Damn man you're up late

 

hehe, yeah, I usually don't get off work until midnight, so 1am is my early evening :)

[d510addict]

Alrighty,

 

So I checked my thermostat today, the dongle was on the wrong side so I rotated it, the temp on the thermo was 180 deg I do not know if that is ideal or not. Then I warmed up my truck and checked the timing, we timed it right after install and had it set to 8 deg BTDC, the dizzy must have moved when we tightened the bolts because when I checked it today it was more like 5 deg. So I retarded the timing back to 10 deg BTDC. End result is it still smokes badly but I have a theory on that, still runs warm but I think that once I am able to find a fan cowel it will stay cooler (or electric fan). The radiator seems to be holding water and with the Ratsun style overflow tank I installed I think losing water will no longer be a concern. The truck still diesels not sure if there is anything I can do about that. I set the valves on the head before I installed the motor and now the valves are getting noisy but I think that is them just working themselves back in as the head sat for a long time and had some carbon build up left after the hot tank.

 

After checking all these things I think that my heat issue is due to the lack of a fuel return line, which on the larger motor is heating the fuel up higher than the L16, on top of no cowel (l16 ran fine without one + I dont know where to find one that will fit). I also think that the smoke is probably from too much fuel at Idle as it clears up at higher RPMS (at least I think so, been trying to watch it to see when it starts to drop off). I am going to try and install the weber copy this week (tips on the 32/36 with electric choke install would be sweet).

[Sealik]

Actually you advanced the timing from 5 to 10 degrees.

Your overheating is not from the absence of a fuel return line.

Still should utilize though

A hot engine could create vapor lock, hard starting....dieseling.....etc

What's your idle set at?

Smoke at idle could be from various issues.....

[banzai510(hainz)]

take photo of motor. left and right side.

[d510addict]

Oh I advanced it? Just so i understand this correctly stock setting for timing is around 12 right? Also why pics of the side of the motor all the stuff is hooked up properly. I dont have an tach so I do not know the idle speed. Sealik what are some ways to diagnose reasons for smoking?

[wayno]

Did YOU have it rebuilt, or did you buy it from someone that SAID it was rebuilt? My new engine never smoked at all, it even got really warm once or twice till I put the proper thermostat housing on the engine with that hose coming out of it. I am not saying I haven't had issues like water in the oil from the headbolt problem, and it took forever to finally get the engine and head from the machine shop, he wouldn't release it till he was sure it was right. The guy(AC the machine shop owner)said that the products sold today for rebuilds are of such good quality, that they are almost broke in when they put them together, and he told me to just drive it to break it in, no paticular way, just drive it. Now this may be just him and the products he buys, he told me that the head gasket that came in the kit was the best money could buy, and the kit also came with an oil pump:) , it had everything, except L head stuff of course. :lol: White smoke to me says steam:(, that means water is getting where it is not suppose to be, but I have poured oil into my engine before, and when I started it it blew white smoke for a while, so oil can make white smoke also, but that engine was old and wore out, I bought it used and put a fresh head on it and drove the shit out of it for 10 years.

[izzo]

Yes. He had it rebuilt.

 

I gave him a free L20 which, was good at one point. But was not usable as it sat outside for a couple days in the rain. So he had it rebuilt.

[.sunlover]

You let it sit in the rain for a couple days? Well there's yer problem raht there, lol, it's just boiling mad and blowing off some steam. :) How would you feel if someone made you sit in the rain for a couple days?!!

 

180 is correct for temp btw

[banzai510(hainz)]

couple days wont hurt it. It will run

[d510addict]

One of the pistons in it was cracked and I needed a solid motor so I had it rebuilt.

[banzai510(hainz)]

Photos????

Never know maybe the Crank case is plugged with a spark plug .

Vac adv hooked up wrong.

We just catch little things with photos that turn out to be big things when it comes to running.

[wayno]

Who put it together, I have be told some weird ways to put rings on pistons by people in the past, beleave it or not, one guy told me the ring gaps were supposed to be all lined up.:blink: Nothing has been forgotten, like valve stem seals?

 

 

[.sunlover]

couple days wont hurt it. It will run

 

Just seems rude is all... Leave it in the rain for a couple days, and then ask it to take you 300,000 miles or so. I know, I know, you are all trying to be serious and problem solve, but it's a seriously modified l20b that isn't overheating, just blowing what is probably fuel smoke from a mismatched carb, and best guess jetting setup. A little jetting, that's it, and here's a 521 that left the road for what? a ,few days and is back, better and stronger.. This should be a happy time imho. Those guys at DIP by your house, Derrick know their shit about the 32 36 dgv webbs, and although it's different, I bet they'll be able to get you down the road faster using less gas then you are now. Less than 5 bucks a jet and if you need to change your emulsion, and that's I think about 20. And correct me if i'm wrong, but don't you need to change your radiator cap to get it to suck coolant back in when it cools? I thought the old ones were a 1 way. (Exit only)

[d510addict]

Photos????

Never know maybe the Crank case is plugged with a spark plug .

Vac adv hooked up wrong.

We just catch little things with photos that turn out to be big things when it comes to running.

 

The VAC advance tube can only go one way with this carb and the crank case breather is hooked up to the PCV (PVC?) Valve on the intake mani.

 

@Wayno - my Father and I put it together, the rings came with directions on how the gaps should be in relation to each other and we followed that.

[d510addict]

Just seems rude is all... Leave it in the rain for a couple days, and then ask it to take you 300,000 miles or so. I know, I know, you are all trying to be serious and problem solve, but it's a seriously modified l20b that isn't overheating, just blowing what is probably fuel smoke from a mismatched carb, and best guess jetting setup. A little jetting, that's it, and here's a 521 that left the road for what? a ,few days and is back, better and stronger.. This should be a happy time imho. Those guys at DIP by your house, Derrick know their shit about the 32 36 dgv webbs, and although it's different, I bet they'll be able to get you down the road faster using less gas then you are now. Less than 5 bucks a jet and if you need to change your emulsion, and that's I think about 20. And correct me if i'm wrong, but don't you need to change your radiator cap to get it to suck coolant back in when it cools? I thought the old ones were a 1 way. (Exit only)

 

Its not a stock radiator, I have no idea what its from actually, its just what came with the truck.

[banzai510(hainz)]

Vac adv hooked up wrong.

 

 

yeah I know but I have caught 3 people with them hook up to the manifold instead of the carb when they showed my photos.

 

L motors are EZ. Its a simple fix.

[racerx]

I always hook up vacuum to carb and never in intake manifold but I never knew why..so maybe someone can answer that.

[d510addict]

Installed the Holley 5200 (weber copy), as I was taking the old carb off i noticed the carb was not tightly attached to the manifold. So I made sure all was well once the other carb was on. End result is the thing still smokes to high heaven while idling and on takeoff. The smoke is still light in color and seems to clear up a bit while driving at speed. So far the truck doesnt seem to be losing water and when I drained it the water looked clear with no oil in it.

[wayno]

Is it smoking more than this? Is it the same color?

Wish I knew how to help you, i can't imagine there are a lot of ways to make a new engine smoke really bad, I can make it smoke black(rich) by pulling the choke on, my old engine would smoke white when I added a bunch of oil, I suspect that was old valve seals and maybe guides, because it would quit smoking after a minute or so. Can you see the valve seals in there?

[d510addict]

Smoke looks just like that and about as thick when I take off, but not as bad when just idling. Talked with my neighbor today and he thought it may be valve seals. I guess it makes since as the head was sitting in my carport for 10 years or so, if not longer. Got new seals with my gasket kit so when I get some time on Sunday i'll tear into the head and replace them.

[wayno]

You didn't have the head rebuilt? I have been thinking the whole thing was rebuilt all along. It's probably dried out cracked valve seals and possibly bad/worn guides. You know that a fresh rebuilt block with good rings will pull oil threw old valve seals and guides, it will smoke real bad sometimes.

[banzai510(hainz)]

Does it smell like antifreeze?????????? if water passage head water can get sucked in.Are you loosing water.

 

tighten lower intake bolts or see if dripping from there

[d510addict]

Intake bolts are tight I haven't been losing water, I think when my radiator puked water that was the only time water level went down. The head i did not have rebuilt as it was done then didnt get many miles on it, but I did have pressure tested at Ricks cylinder head and he said it was good.

[Sealik]

Could be the seals...it also could be leaking coolant into the intake valves from the intake manifold.

Does your head have the coolant passages that match ones in the intake????

If not....You could remove that coolant plug from the IM...suck out all the coolant and see if still smokes.

Might take a while to burn off the residual.

Mine was leaking....so I removed that fitting