The T piece is copper & brass combo type.  The bottom of the "T", that  is silver soldered to the plate, is very thick brass.  It is very solid & strong.

It is very tight down there between the back of the head & the firewall.  No room for a 2 way valve. The pipes coming out sideways, is so that any movement, will be absorbed by the hoses.

This way, the existing heater tap, on the rear of the firewall, will still be used to turn on the heater. The return to the front of the engine, of coolant from the back of the head, will flow all of the time.

P.S.  I did have a look at 2 way valves on the net, but they are all four port, & it would result in it being a plumbers nightmare down there, & very messy.

 

I'm using the K.I.S.S. principal.

(Keep It Super Simple)

Cheers Banjo

 

  

https://www.ebay.com.au/itm/ELECTRIC-BYPASS-HEATER-VALVE-KIT-Heat-Buick-Cadillac-Chevy-Ford-Dodge-NEW-D83/401022119552?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

 

On sale right now Banjo.

Well, finally got a couple of hours over the Christmas break, to complete the 12mm dia. return coolant line from the back of the engine, to the thermostat housing, from the little "Tee" adaptor I fitted to the head rear access plate.

Normally the heater return coolant line runs down the distributor side of the K series engine..  With the COP conversion, I am doing on this 5K, I wanted to keep the distributor side of the engine as clean looking as possible.  

I decided to run the return line down the manifold side of the engine, as there are a couple of unused mounting points, provided on the aluminium inlet manifold casting.

It turned out perfectly, so am very pleased with the end result.

I was originally considering fitting two (2) off return coolant lines; one for the head only, & the other for the heater, when in operation.  That's how I did it on my 4K-U in my daily drive. However, as the heater is used so infrequently, here in "sunny" Queensland, I have decided to let the one return line carry both return coolant circuits.  This results in a lot less complication, & a cleaner uncluttered look.

Parts Required:

1 meter length of 12mm copper pipe from Bunnings.

2 off the shelf metal brackets, which I cut down to suit, from Bunnings.

2 off 1/2" pipe saddle mounts.

4 off 5mm bolts, nuts & washers.

2 off 6mm x 25mm bolts, for brackets to manifold.

6 - 8 off 11-22mm screw type hose clamps.

1/2" hoses off a Commodore or Hi-Lux.

1 off SpeedFlow 16 x 1.5M 1/2" hose adaptor, to plumb line into thermostat housing.

Bit of hi temp silver paint

This is surely one of the easiest & best mods you can do to your K Series engine, to overcome the inherent issue of the rear cylinder no: 4 running hotter than the forward cylinders.

P.S.   Although I advised it is an easy job, it is best carried out, when you happen to have the engine out of the car, or the head off. Undoing the four (4) off bolts that hold the little access plate can be fraught with difficulties, if they are corrosion welded to the aluminium head, as it is virtually impossible to drill & tap new threads with the engine in the car & the head on, as the distance between the rear of the head & the firewall, is so limited.

Cheers Banjo

 

 

 

 

 

 

Edited December 28, 20187 yr by Banjo

Stellar findings, and applied theory Banjo.  Threads like this are why I joined rollaclub, even though I don't have a 'rolla.  

Bringing this back, because after reading through completely and considering my 5K application in a van (between the seats), some comments / questions come to mind. 

 

1.  Have Toyota forklifts been considered as a source for alternate configurations of cooling systems / parts?  Did a quick look around, but seems like without a known part number it is difficult to look anything up on the forklifts. 

2.  What is the recommended cleaning or de-rusting method for a vehicle that has been running straight water for an unknown period of time?  I have recently upgraded to a 3-core radiator, and a new water pump was going to be next on my list.  Anything that can be checked or flushed with the engine in the vehicle, I am game.  Any recommendations when shopping for a water pump?  

3.  Regarding radiator caps and bleeding the system, it may interest some of you Rolla owners to know there is a 5K/4K water neck available with a filler cap right on the top.  Toyota part number 16304-13050, as configured for a Liteace / Townace.  

4. Regarding electric fans vs. clutch fans, there is a lot of interest in this subject over on Toyotavantech.com.  Since the vans are presumably heavier, with the radiator buried underneath, you can imagine the problems that ensue.  Some very thoughtful research and experimentation there has shown that nothing beats the raw cooling power of the mechanical clutch fan.  Albeit, with a penalty of horsepower loss.  My plan is to keep the clutch fan but run electric fan(s) on the AC condenser, on a thermo switch, once I source a custom AC system.  No doubt in a lighter corolla, with the radiator in front, the fans are only needed at stoplights as your data seems to show.  

5.  Glad to see the fan shroud made minimal difference in your application.  Bonus points for freeing up wasted water bottle space!

6.  In Philippines, these cars never even had a heater installed.  But I never knew the importance of the bypass hose, thank you for that.  

7.  Do you see any value in monitoring the head temperature or exhaust temperature?  From my air-cooled days, this has always been something that stuck with me, as the ultimate thing to keep an eye on (along with oil pressure).  Appreciate any insights you want to share about 'essential' gauges when it comes to the K-series engine.