Help this 510 stay on the road in this heat

[ratatat dat]

Hello everyone -

Survivor wagon here, still getting a lot of exercise.

 

But Norcal is 80-90 degrees and I am running hot.

 

I love night drives because my water temp stays at 185 max which feels right.

 

But in the hot midday I’m at a solid 195.

 

At this temperature, every time I shut off, my engine runs on, igniting without spark for as long as 1 minute. Then it sputters and farts out the intake manifold.

 

Sometimes I purposefully stall to stop this....

 

 

 

My radiator is an older copper one, same size as original, and it’s all topped up. Before I buy myself a bigger one, is there anything else I can do to get rid of heat?

 

 

 

I don’t have the first clue about the heater hose or how that can help me. But this is what that situation looks like.

 

 

Also, my valves are supposedly “too quiet for an L series engine,” I forget if I’m supposed to tighten them or loosen them but would that help me run cooler?

 

 

 

 

Thank you SO much for any advice, I hope I get to keep running around and making a few people happy!

[datzenmike]

 

Black hose. Where does the other end go to??? If to this...

 

 

Where the lower radiator hose enters the water pump, you need to stop the water flow. Drain the cooling system, cut the hose, insert a wooden dowel, or suitable size bolt or anything to plug the hoses and attach hose clamps. Coolant must not flow from the head into the water pump.

 

You can by pass the heater in the winter but never do this in the summer. (not you, probably a previous owner) that water is HOT and it's being returned to the engine without going through the radiator, effectively by passing it. This puts an increased load on the cooling system.

[DARIN 510]

Hoses look pretty worn. You can still get the heater hoses from the dealer. Or you can buy from these guys. Part numbers B7020-A0800 and B7021-A0800

https://datnissparts.com/heater-hoses-set-of-2-with-clamps-1968-1973-datsun-510-b7020-a0800-b7021-a0800/

[datzenmike]

The heater is likely disconnected because it's leaking.

[thisismatt]

195° is not too hot, perfectly normal.

[datzenmike]

NEVER let an engine diesel or 'run on' after the ignition is shut off. It's extremely rough on rod bearings and timing chain. RPMs are under 400 and oil pressure very low. Just don't do it.

 

 

My L20B has a 180F thermostat but the sensor for the fan is 190-195F so if not moving it's close to that. The problem with the L16 is it likely doesn't have the idle cut solenoid that would prevent 'run on'.

 

In that case select fourth gear hold brake on, let clutch up till engine struggles and turn ignition off. Simple and effective. If automatic just shut off in drive and when engine stops put in park.

 

Still... if the heater has been by passed, the water flow must be shut off.

[bananahamuck]

as said 195 is pretty normal ..

when I used to drive my 510 in winter ,, it’s cold up here in NW .. 195 is/was achieved by choking air flow through radiator a bit by using cardboard ..

   To warm inside car better. 
 

that said ,,

My brothers radiator gave up the ghost a couple years ago and it’s very costly to fix these days … I might add ,, he has  at least 6 radiators piled up in and behind my shed and not one of them holds water anymore .

. So he bit the bullet and installed a VW radiator ( dime quarterly write up ) and he says it works perfectly. 
 

look it up ,, I can’t link to it because on phone 

Edited August 24, 2023 by bananahamuck

[banzai510(hainz)]

Mine gets HOT even with a 3 core in stalled traffic But Im using the stock gauge.

 

 

I cant open your photo. so I dont know what is there or not there.Going my Mike you might not be running the heater hoses.

I would buy a set of heater hoses as spares cause in the 521 they are NLA an wish I had more as a drve that vehicle more and have pulled the motor a seversal times which I think is hard on the hoses at the fire wall streching and yanking on them.

 

I like the old copper rads myself but if you think its getting hot and worried then don drive it.

Otherwise get a GOOD I mean GOOD 3 core but 99% you have to use a spacer on the core support cause they not really a exact fit. Hits the lip on the upper edge of core support.

[datzenmike]

So on the highway where there is lots of cooling air it runs a needle width above half in the marked run range. Stop and go is 190 and that's about 3/4 up the run range and there is still room above that.   

[ratatat dat]

Thank you everyone for the input, I really do appreciate it.

 

I'm glad to hear 195 water temp is normal... but I only get there on a hot day/in traffic...

 

And shutting off at 195, I get run-on.

 

 

 

My logic is that run-on = engine too hot.

 

Is that a safe assumption?

 

 

 

 

I really don't know what the names of the things in my picture are, or where each hose is SUPPOSED to go...

 

Mike you said the heater is bypassed. That looks right because the nipple in the firewall has no hose going to it... shouldn't I be concerned with reconnecting it?

 

Won't connecting the heater help the engine lose some heat?

 

 

 

 

[datzenmike]

195F isn't normal but it's higher than optimal. See 1/ below

 

It's most likely disconnected because the heater leaks.

 

1/ See where than black hose goes. If it's looped to the lower radiator hose then it needs to be shut off. If the heater were connected in the summer it would be turned off and in the off position there is no coolant flow through it. Read my first post on what to do.

 

Blocking the flow will likely drop the temperature to normal 180F and stop the run on.

[thisismatt]

Mike, if you look up normal (ideal) operating temperatures you'll find 195 is the low end of normal.

 

Weren't you posting this on facebook?  Chances are you're running rich and have carbon deposits on the head causing the dieseling.  Hotter engine temp = hotter deposits.

[ratatat dat]

Oooh this is starting to make sense.

 

I honestly didn't know the heater works by getting water from the cooling system.

 

I cannot see where the black hose goes, lots of stuff in the way... I will check again in a few minutes here...

 

 

Now it makes sense why there are two nipples in the firewall, one for heater inlet and outlet...

 

 

 

 

 

I guess I will take the heater out and see if I can find a leak and repair...

 

 

 

 

I bet I do have carbon deposits. I've been fiddling with my carb a ton and have more than likely done a good amount of driving too rich.

 

 

For carbon deposits shall I pour a trickle of water down the carb while the engine is hot and running? I saw some guys do that in a video, they said it was an old school trick, "steam cleaning."

 

 

Also my exhaust has always been very noxious, you do not want to stand behind my car... maybe that's a result of carbon deposits too?

 

[thisismatt]

It's going to be even if it were running well because there is no catalytic converter and no engine burns the gasoline 100%, but running rich will certainly make it worse.

 

I've never done water, but I have done seafoam...not really sure which is better.  I know water/steam can wash the cylinder walls of lubricating oil, which isn't great.

 

How it the idle? RPM?

[datzenmike]

49 minutes ago, thisismatt said:

Mike, if you look up normal (ideal) operating temperatures you'll find 195 is the low end of normal.

 

 

 

Today's cars do, and even higher, but the L series was from the mid '60s and this L16 running at 195F obviously isn't intended to and why it runs on. L20Bs even with 180F thermostats will run on if not for the idle cut solenoid. 

 

You can run at 195 but performance will suffer. Might even ping under load from the heat. 

[ratatat dat]

I think I have my idle set at 800-1000, fast I know... it's actually hard to get it down to 700 without feeling like it might die

 

 

Idle always fluctuates a little

 

 

I can hear it idling faster in the middle of the day than during a night drive. (Because engine is 10 degrees hotter)

 

 

[datzenmike]

The air filter has an idle compensator. Under extreme under hood temperatures the idle goes rich. This compensator bleeds outside air into the intake to lower it. Seems like the idle would go up some.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

d go some.  

[thisismatt]

You can't get it down even after warming up?

[yenpit]

16 hours ago, ratatat dat said:

Oooh this is starting to make sense.

 

I honestly didn't know the heater works by getting water from the cooling system.

 

I cannot see where the black hose goes, lots of stuff in the way... I will check again in a few minutes here...

 

 

Now it makes sense why there are two nipples in the firewall, one for heater inlet and outlet...

 

 

 

 

 

I guess I will take the heater out and see if I can find a leak and repair...

 

 

 

 

I bet I do have carbon deposits. I've been fiddling with my carb a ton and have more than likely done a good amount of driving too rich.

 

 

For carbon deposits shall I pour a trickle of water down the carb while the engine is hot and running? I saw some guys do that in a video, they said it was an old school trick, "steam cleaning."

 

 

Also my exhaust has always been very noxious, you do not want to stand behind my car... maybe that's a result of carbon deposits too?

 

 

The heater CORE can be bad & leak, but it is more often the heater VALVE that leaks, which is on the drivers side, inside the car, under the dash, near the accelerator pedal.  If you see green goo around the valve, that is old congealed coolant..........in other words it was leaking, thus disconnected.  The 510 valves are long discontinued, but you can buy a 240Z valve & "rebuild" your 510 valve, using all of the internal parts from the 240Z valve.  OR figure out a cheap universal in-line heater valve available at just about any auto parts store.  I have used universal valves, but only when installing a CA18 KA or SR................these swaps sit too far back against the firewall to utilize the factory heater inlet & outlet, so I have always rerouted/custom made the heater hoses & installed a cable operated universal in-line heater valve.

 

You can pull the complete heater box assembly out from under the dash & pull the heater core for testing, but it is a relatively big job.  Since your heater is currently disconnected, it should not disable your car by pulling the assembly.

[banzai510(hainz)]

Rat ta tat

If your Datsun has a Weber without the cut off selinoid its going to diesel with a Open chamber head. Most like a U60 U67  maybe a open designed chamber A87 head.  This is a normal ocurrance whe a Weber is installed cause after like 1973 or so the stock Hitachi carbs had this just for that reason cause it it didnt have the cutoff the stock carb would do it also.  Less octane gas ectt timing .....

 

one can mitigate this . By getting a different weber the IC version that has the cut off or time your vehicle maybe better , 93 octane. retard the timing. then adjust the mixture again till you get it better but most like will still have this issue

 

I periodically run the motor on a hot day and trickle in water in the carb to maybe steam clean the valves and piston tops. Does it help. Maybe I dont know makes me feel better.

 

 

My 521 is a L16 with a L20 head and it has run on like a MOFO when I run 87. and that still 5$ a gal here.