Can you block off heater fitting on L series head

[hsepwr]

On my L18 the 90 deg heater fitting that screws into the spark plug side of the head at the back points forward to the water housing at front of engine. I have been running a hose along the side of the head to the front housing but ideally would like to get rid of it and i want to bung the port up at the back of the head but dont want to starve an area of water and wreck something.

has anyone done this if so any info would be great.

Cheers
Craig

[DJZ]

If you block off the outlet from the head and the lower radiator hose inlet from the heater you'll be sweet. Looping it is apparently a bad idea.

[classicdat]

I noted on Ricks 240 that he has added an external water gallery to prevent hot spots in the head that must have been causing issues, what motivates you to remove it? Rick fitted his on the inlet side, it is pictured on here somewhere.
Found it: http://www.nzdatsun.com/forums/viewtopic.php?t=3170" onclick="window.open(this.href);return false;

[hsepwr]

If you block off the outlet from the head and the lower radiator hose inlet from the heater you'll be sweet. Looping it is apparently a bad idea.

when you mean looping do you mean running a hose from outlet on head to the rad hose inlet which is what i was doing but now i think of it i had a solid piece of steel rod rammed up the hose which was effectivley blocking it off anyway.

[DJZ]

That's fine as long as it's completely blocked off, removing the hoses altogether would look heaps nicer if you don't need a heater.

[nzdatman]

I have heard the hot spot rumours too (when blocking it off) but whats the difference between blocking it off and having the heater turned down to cold which would block the water flow through there by closing the heater valve anyway?

[DJZ]

Nothing, the hot spots aren't related to the heater bits and pieces.

[nzdatman]

I've heard people say that blocking off that fitting can cause a hot spot at the back off the head. I don't see how.
Nothing to do with what Ricky has done with his 240z, I was just referring to the heater fitting that Craig is asking about.

[DJZ]

Tony D who considers himself some sort of God amongst Z owners in the States (but take this with a grain of salt) said this on Zcar.com:

1) To PROPERLY bypass your heater core, you take the hose off the head, and plug it with something---like a spark plug. I say off the head, but in reality it can be off the heater core barb---the idea is you stop the flow of hot water into the heater core, or valve.

2) You remove the hose at the firewall that goes back to the lower radiator hose inlet casting, and plug it as well. I prefer to use pipe plugs in the head, and a spark plug at the lower radiator hose with a stub of hose so the side of the block is cleaned up.

3) run the car and enjoy no heat.

************************************************** *****************

DO NOT SIMPLY INSTALL A U-HOSE BETWEEN THE TWO FITTINGS ON THE BACK OF THE BLOCK!!!

By doing this, you allow a 15mm DIRECT SHUNT from the hottest part of the engine to the inlet---which is designed to only have 2 8mm hoses permanently bypassing to that area. The heater core will COOL the water as it goes through it same as the radiator, so reintroducing it after the core is fine...but LOOPING the hose without cooling it can lead to severe overheating issues.

For those who say it's wrong to plug it---what exactly happens when the heater valve is closed?????? There is NO PERMANENT PATH there! And on ZX's there is a poppet valve that pops at a given pressure if someone is revving the piss out of the engine before the thermostat is open---this poppet opens before the spring on the thermostat is overwhelmed in it's safety feature, so it promotes rapid warm up under these circumstances.

People who simply loop the hose have no real idea what they are doing to the cooling system of the vehicle. Sure, it's winter and it's cold out, so likely there won't be a problem---in fact the engine MAY indeed warm up QUICKER in extreme cold because of the increased bypass flow (hmmm, curious, and supportive of the overheating problem later in the year...)---but when it warms up you can have issues especially if you have a marginal cooling system.

Plugging it completely is 1000% better than doing the 'dreaded loop'!

Take that loop out, and plug it at the firewall in the engine bay using 15mm plugs or caps. You don't want that loop in there!

[hsepwr]

Thanks heaps for that info it make sense. I've always thought it seems a bit odd to loop it and throw water back into the engine that hasn't been through the radiator. It's a 3/8 npt fitting and I have some alloy Allen head plug bungs at work which will do the trick nicely and might get the other end welded up, I'm not that keen on more hose clamps and bungs that could work loose.