4g32 twin down carby issue.

[shuggy]

Anybody that has a 4g32 and stock twin down carbies, I need help with my coolant hoses. I'm overheating even with a hq alloy rad which only leaves a couple of options. I'm not sure if I have my hoses the right way.
Any help would be awesome

[81GL]

Take a photo and post it up Shuggy.

This is an on going issue for you isn't it?
& is this on the engine you've had rebuilt? (would assume new water pump & Thermo stat?)

[75wagon]

The hoses attach as follows:
The pipe that goes around the back of the motor to a splitter pipe.
The splitter pipe then feeds to the base of each carb.

Here's a pic of the hoses coming from the splitter pipe to each carb base on my wagon.


More pics and info here

[shuggy]

Thanks Dave. From the pipe that wraps around the engine, one goes to the heater core and then to the pipe that comes out the back of the head, and the other i have split and fed to each carby water inlet. Is this correct?

If so then I will check the thermostat, and then I will have to just try and build a front shroud for the radiators. I feel that I am not getting any air flow through the a/c rad and then the coolant rad. Like the A/c rad is deflecting all the air.

[75wagon]

From the pipe that wraps around the engine, one goes to the heater core and then to the pipe that comes out the back of the head, and the other i have split and fed to each carby water inlet. Is this correct?

It sounds right to me.

Years ago I fitted a 1400 motor to my Datsun 1200 coupe, and left the stock radiator in place. It ran just a bit on the hot side. I checked everything and it was all working fine. I tried removing the thermostat, but it didn't get to running temp, so I ended up drilling holes in the skirt around the thermostat. It worked perfect, it increased flow just enough to not overheat, but still got up to running temp just as quickly as it did when it had the 1200 motor in it.
My point: Try it without the thermostat in it. If it's still gets hot, then the cooling system is not adequate for the car. If it doesn't get up to temp, your thermostat isn't opening or opening enough. If this is the case, then you could increase coolant flow by drilling some holes in the skirt around the thermostat.

Dave...

[davetrees]

Very unlikely the carb hoses could cause ANY overheating issue ... they aren't part of the coolant flow circuit, just a "dead end" that heats the manifold. Likewise, unlikely to be a thermostat issue .. they either work or they don't .. and easy enough to test by taking the radiator cap off & seeing if the water is flowing.

What temp is it running at ? (ie. are you running a proper temp gauge marked in degrees, or just the meaningless/uncalibrated stock one that really don't tell you anything particularly useful .... )

My guess is either lack of airflow through radiator, or radiator core (or elsewhere in water galleries/block) blocked with crud. If you have put an A/C radiator in front of the main radiator, that would be my guess as to where the problem is, assuming the non standarsd radiator is new ? Remove the A/C rad & see if it fixes the overheating problem.

Like anything else, only change one thing at a time, otherwise you will never diagnose the cause !

[shuggy]

My guess is yes, airflow.

Idle it does not overheat as the davies craig is just sucking air. But on the freeway with the a/c on it slowly cooks. Even hot days with a/c off on the freeway it gets hot.

The engine is freshly rebuild and acid dipped with new welsh all round, the rad is a HQ V8 alloy 56mm tripple core brand new and it holds close to 7 liters. Its not the rad.

The a/c rad is my problem im fairly sure. Im going to do the thermostat trick first though to see.

my question is. Any ideas to increase the airflow to the rad? Should i reinstall the original fan so there is high suction at high rpm?

Dave when you said drill, do you mean like 6mm holes?

Thanks for your time gents

[75wagon]

Dave when you said drill, do you mean like 6mm holes?

Way too long ago to remember, but look at it this way, if you start small, you can always go bigger, but if you start big? I think you get the idea.

Dave...

[bruggz351]

My guess is yes, airflow.

Idle it does not overheat as the davies craig is just sucking air. But on the freeway with the a/c on it slowly cooks. Even hot days with a/c off on the freeway it gets hot.

The engine is freshly rebuild and acid dipped with new welsh all round, the rad is a HQ V8 alloy 56mm tripple core brand new and it holds close to 7 liters. Its not the rad.

The a/c rad is my problem im fairly sure. Im going to do the thermostat trick first though to see.

my question is. Any ideas to increase the airflow to the rad? Should i reinstall the original fan so there is high suction at high rpm?

Dave when you said drill, do you mean like 6mm holes?

Thanks for your time gents

This sounds like a coolant flow problem to me. Was it properly "burped"? Is the pump known good?
Do the fins on the condenser look straight and clear? ie, would it let air through? If you can see clearly through the condenser I doubt it's your problem. Is it tuned right, not running lean?

Finally, I know you don't wanna hear this, but it could be a head gasket. As a last resort, test for a blown head gasket. I know you said it's a fresh motor but I have had 2 blown head gaskets within as many months. Very frustrating!!

A fan isn't really going to help you on the freeway, only slow, stop start type driving and stopped.

Overheating on the freeway is coolant flow or air flow. My guess is coolant flow.

cheers

[shuggy]

Not what i wanted to hear.

Thanks brugs.

It is running lean though. Pings under load below 3k

I will check coolant flow..

[shuggy]

by burped, usrely if it has heated and contracted a few times all the air would be gone?

The water pump was brand new

[77GDWAGON]

Not what i wanted to hear.

Thanks brugs.

It is running lean though. Pings under load below 3k

I will check coolant flow..

Retard the timing a bit, if running lean and pininig you are creating extra heat and also destroying your rings and will eventually do the head gasket or crack a piston and destroy your motor.

[bruggz351]

Retard the timing a bit, if running lean and pininig you are creating extra heat and also destroying your rings and will eventually do the head gasket or crack a piston and destroy your motor.

[shuggy]

Yes i know that. The dizzy needs to be recurved. Cant get it to work with the stage 5 very well its a pain in the ass. Wont idle at low rpm with the timing retarded and then pings when advanced. Its shit

[75wagon]

The dizzy needs to be recurved. Cant get it to work with the stage 5 very well its a pain in the ass. Wont idle at low rpm with the timing retarded and then pings when advanced. Its shit

Are you sure the carbs are set up right?
Mine runs as sweet as with the No.5 and a stock distributor. I'm run between 8 and 10 degs advanced with no problems.

The carbs need to be tuned to each other, if they aren't they fight each other (well, they make the front and rear cylinders fight each other) and don't run well at all.

[81GL]

As above, do you have an after market temp gauge?
-Be good to know some numbers

Also, what fans are fitted at the moment? If your only running an electric fan at the front, is the radiator & a/c unit ducted around the edges? to help duct the air through the radiator?
-If you have the standard fan to pop back on, would be worth trying it!

[shuggy]

what rpm do you idle at dave? do you know what jets you have in?

My carbs were freshly rebuilt and all stock jets

I have davies craig suck through, but is not ducted between ac and normal rad.

The temp has reached 100 as the electric switch is a 60-100 actutor and i once cranked it to 100 and i didnt turn off!

im going to have a play. maybe thermostat is stuck or something