Engine Head Plug Sizes

[Blue_streak]

What size plugs do i use to plug the cylinder head outlet to heater core and heater core to water pump inlet? Im bypassing my heater core and cant seem to find the sizes in any thread.

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[siteunseen]

I connected the heater hoses together with a 3/4" PEX coupling and put a bolt in a piece of hose for the cylinder head until I  can get my heater core's valve fixed.

 

[Zed Head]

If you have extra engine blocks, the block drain plug (under the intake manifold) is the same size as the head elbow.

 

Here's another possibility, depending on why you're blocking it - the vacuum water **** (rooster) blocks water flow.  You can leave the head hose connected and disconnect the vacuum supply.  That's one, the return line still needs a solution.  But you could loop the heater hose return line around under the dash, both sides to the vacuum water **** (rooster), which is closed.  Just getting creative, only works if you have the water **** (rooster).

 

Watercokc, watercock, water ****.

Edited March 27, 2015 by Zed Head

[Zed Head]

Might be available - http://www.courtesyparts.com/plug-p-237513.html

 

http://www.carpartsmanual.com/datsuns30/DatsunZIndex/Engine280Z/CylinderBlock/tabid/1598/Default.aspx (17)

[siteunseen]

Water-rooster. LMFAO!

[Blue_streak]

Im blocking it because my heater core is leaky, my valve is leaky, my transfer between engine bay and behind dash is leaky and i just do not feel like dealing with it when there are more important things to do to get it on the road.

I went to homedepot this morning and bought 2 1/2 pipe plugs ill plug up the two areas in the pic and hopefully it eill work.

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[Zed Head]

Not sure what you plan to do with 1/2" but the threads are metric.  You can also connect the return hose to the supply line and put a kink in it, or clamp it.  It doesn't need to be completely blocked, just mostly.

[Blue_streak]

Threads right in to the spot. Found this after some googling.

http://forums.hybridz.org/topic/113647-deleted-heater-core-how-to-plug-cooling-system/

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[Zed Head]

Just one of those lucky cases where thread sizes overlap.  Be careful, since you're not getting full, proper, thread contact.  You could damage the aluminum head.

 

Actually, those threads may not be metric.  But they would still be British.  McMaster Carr has BSPT.  1/2" pipe plugs too.

 

http://www.mcmaster.com/#aluminum-british-standard-thread-pipe-fittings/=whyvyg

Edited March 28, 2015 by Zed Head

[Blue_streak]

The next challenge is figuring the water pump inlet. It has the barb that goes to it the. A smaller one comes off it and snakes its way to the intake manifold before finally ending up at the thermostat.

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[Blue_streak]

http://m.homedepot.com/p/Watts-1-2-in-Lead-Free-Brass-Square-Head-Plug-LF-A823/202254950/

This is the pipe plug i picked up, for sone reason looks like no link but its there.

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Edited March 28, 2015 by Blue_streak

[Stanley]

On my 240z the outlet on the head (for the hose to the heater) is 3/8" BSPT, and the one on the bottom of the thermostat housing is 1/4" BSPT. BSPT fasteners screw into BSPT holes way nicer than NPT or metric. NPT sort of works except for threaded BSPT fuel fittings, where they don't work at all.

Interesting that the 280z has a threaded hose barb on the main water inlet, and there's a pipe that goes around the front of the engine, through the intake and over to the thermostat housing. Didn't know any of that. Is there a thermostat in that line? The 240z manifold heater goes around the back of the engine. Maybe you should keep that part hooked up per some of the HybridZ posts.

I used tapered rubber plugs from ACE hardware with silicon caps from M-C clamped over them to bypass the heater. Never use Dorman rubber caps, they fall apart from the heat.

Water Rooster!