Banjo

Hi Bill, On another thread here, I've been looking at the various water pumps, with their different inlet & outlet configurations; to find one suitable for a mod, I want to carry out for the return coolant circuit, from the back of the head. In that research, I came across several different K series pumps; & surprise, surprise, some of them had a different water pump pulley, with different (bigger) centre hole diameter, & a different spacing for the four attachment bolts. The pictures appear to indicate, that the pulley, is a lot flatter, than the standard "conical" one. Overall, the O.D. appears to be very similar. This lines up with your description, as my standard pump has a 16mm centre hole, whereas, yours is 24mm. Apparently, these were fitted primarily, to K engines that had the larger plastic fans, with a clutch in them. These apparently, were fitted, in the main, to 5K engines here in Australia, which Toyota used in commercial vehicles, like vans, & forklifts etc. I have managed to find one here in Brisbane, & I'm going to catch up with this guy this afternoon, so may soon have one in my hand, that I can photograph for you, & measure up accurately, to see if it suits your 4K application. Stay tuned ! Cheers Banjo

Hi Jeremy, Just remember, we are not just cooling the head. The coolant also flows around all four (4) cylinder walls, inside the block. Cylinder no: 4 walls, also are the hottest in the engine. There are many on this forum, like myself, that will atest, that if you are going to do a ring or rings in, 9 times out of 10, it will be no: 4 piston. You'll never get perfectly even temperatures across the coolant system, because at the intake point at the front of the block, the coolant will be at it's lowest temperature. When it exits the engine through the front of the head into the thermostat housing, the temperature of the coolant will be at it's maximum. What we presently have, (and I will prove with real readings), is that the water at the back of the head can be 10 + deg C higher than the water entering the thermostat. Introducing cooled coolant directly into the head, may sound good, but I think it would result in serious issues. All cooled coolant should enter the engine through the block. What I'm looking for is a simple solution, that anyone can do to their K Series engine, without great cost, or need for machining or fabrication. A two (2) way water tap/valve seems like a simple "doable" idea. It might not be perfect, but I'm confident, it will result in a much better coolant temperature differential across the whole engine/block. As I said earlier. We could theorise all day, but experimenting & measuring the results, is the only way to get to a reasonable compromise, without "re-engineering". P.S. I'm just about to hop on the net, and source a suitable mechanical water tap/valve. If any one has a suggestion, of an existing product, or one from another auto, please post your suggestion here, & have your say. Cheers Banjo

The plate on the back of the head was always going to play a crucial function, in correcting this design issue, of higher temperatures at the rear of the K Series engines. Industry's approach was to block the coolant transfer holes between block & head water jackets, in the front of the head gasket. This had the desired effect of forcing the water to flow to the back of the block and then up into the head, then back forward to the thermostat housing, at the front of the engine. This does improve the temperature differential from the front to back of the head, but not totally. However, it also reduces the flow rate of coolant in the system, by effectively throttling it, midstream, which is undesirable. The real problem is that the water pump forces "cooled" coolant into the front of the block, & the hot water exits the head, at the front of the head. The water will always take the path of least resistance, so flow to the back of the block & head is reduced considerably. There are lots of radical things we could do, like mounting an external water pump, that fed water into the centre, or rear of the block via a Welsh plug point, but initially, I have a few ideas I want to try. Many KE series Rolla's take hot water from the back of the head, for the cabin heater, which does improve flow, through the rear of the head. The return of the hot water heater coil, is usually through a pipe or hose, to a point on the water pump, as this water doesn't need to be cooled, as it has given it heat off in the cabin. If the ON/Off tap on the coolant line at the firewall, was replaced with 2 way water valve, then coolant would flow out the back of the head, even when the heater was off, (which is most of the time). My plan is to try this out with multiple temp readings taken before & after the mod, to see how well it works. It must improve it, as currently, there is no flow out of the back of the head, unless the heater is engaged. If there is still a differential, I believe we can equalise it, by restricting flow slightly out of the front of the head to the underside of the thermostat, which should result in increased flow to the rear. I would also reinstate a head gasket, without any blocked transfer coolant holes. The proof is always in the "eating of the pudding', so I'll see what eventuates. Changing the flow between head & thermostat housing at the front of the engine, is easily accomplished with a restrictor plate between the two. Cheers Banjo

Hi Dave, Not into Ardinuo as yet. Love my PICAXEs. Hardware is so simple, & chips are so cheap, & the code only takes a few minutes to put together, for simple applications like a thermofan with multiple sensors, & run on timer etc. I'll give you a look, once I get to that stage. Stage 1, is grab this fan next week, & get it fitted to a KE radiator, then the fun begins. Cheers Banjo

Hi Dave, I'm aware you can get two (2) switches in one housing, but they are pre-set fixed switching temperature points, & I want to be able to adjust these switching points slightly, so I can achieve an ideal solution, once I've logged it all, at multiple points in the coolant sysytem, over different driving scenarios, & see how it all pans out. Thanks ! Cheers Banjo

That's exactly what I plan on doing. Instead of using commercial sensor/s with the switch built in, where the switching temperature is fixed, I was thinking of a single sensor only, (no switch), fed to a PICAXE programable uP, so that I can assign any control regime or system I wish, with adjustable temp switching points. The PICAXE output, would, just switch an auto relay, to turn the fan on & off. Could be fun, & allow ability to experiment, & get a result as good as possible. Cheers Banjo

Hi Jeremy, It was in a post called A Bit of Lateral Thinking. https://www.rollaclub.com/board/topic/73209-a-bit-of-lateral-thinking/?tab=comments#comment-708383 Unfortunately, there aren't any points on the block that you could easily fit engine mounts to to make an East/West engine, fit a RWD Rolla. Mating a RWD gearbox, would also require a purpose made adaptor plate. Cheers Banjo

Great Viterbo ! I'm pretty sure I've got one in my shed somewhere, but I couldn't find it a couple of weeks ago. If I can't find it, I'll grab one off ebay, or see if I can find a Starlet at a wreckers here in Brissy. Is that on your engine. If so, what thermo-fan did you use ? Cheers Banjo

Thanks Mate ! That solves that riddle. Might get one, as I bought a Echo radiator & fan assembly on Gumtree yesterday, here in Brisbane, & will pick up this coming week, & fit to the KE30, so that it has a thermofan, doing away with the plastic noisy water pump fan. All the existing "spare" temperature pick up points on the thermostat housing, are physically, behind the thermostat, so the point on the top of the thermostat outlet spout, is basically the temperature at the top of the radiator. Cheers Banjo

Hi Pete, I liked the bug eye Sprite, as when you remove the whole front grill/guards/bonnet piece, you have easy access to the engine bay. Cheers Banjo

Hi Bill, Have compared the pics of your water pump & mounting boss, with my posted ones, & they appear to be different. The water pump shaft on our water pump is 16mm in dia., as is the centre hole of the pulley. The four (4) mounting holes for the pulley are each 31mm apart. C/P to C/P. The distance between the front face of the mounting boss & the centre line of the fan belt is 36.5mm. The pulley, weighs 500g, so packed would be about 1kg. If it it is suitable, let me know, give me your full name & address details, & I will post it over. Cheers Banjo

I totally agree with Big G. Take out all four spark plugs & compare colour, and you will probably find one is very clean & white. That will confirm, its time for the head to come off. Cheers Banjo

OK, the gearbox measurement mentioned above is 55cm or 21.5 inches. the water pump snout looks pretty much the same. Here are a few pics. The measurement of the gearbox, mentioned above, on our 4 speed is 55cm, or 21.5 inches approx. Cheers Banjo

Hi Bill, Thanks for the pics. Gives us a clear idea. The letter after the 4K, never appears in the engine S/N on the block. It is usually on a sticker attached to the side of the rocker cover, just above no: 4 spark plug. From your pics, looks like that sticker has long since gone. I don't know if it is an optical illusion, but it appears that the point the gear stick comes out of the gearbox rear extension, is much further back than normal, for a 4 speed. Have you worked out where it will "appear" on the Healey's floor tunnel ? What is the measurement between the centre point of the gear stick pivot ball, to the front edge of the bell housing mating point to the block ? I'll go & measure a 4 speed box I've got on the garage floor, & post it here. Our 5 speed gearboxes, had the gear stick further back. The water pump pulley I have will fit your pump OK. I'll go & take a pic, & post here with hole dimensions. Can't imagine they would be different in the USA, but you never know. Cheers Banjo .

Hi Bill, Welcome aboard ! Do you have the plastic fan blades already ? Can you post a pic of this "water pump with the wider snout" , so we are not crossing paths here. Plenty of pulleys here, but would hate to send you one & then find it doesn't suit. Do you know what type of 4K engine you have. I'm presuming that it is a 4K-C, where C stands for "California". Lots of 4K-Cs here in Australia, as we adopted the same emissions regulations at the time. Is the transplant very complicated ? Have you got some pics of the 4K sitting in the engine bay ? What gearbox, have you got behind it ? I Googled it, but couldn't find anyone previously on the net that had done a 4K swap. Found someone who did a Toyota 20R motor swap, so I presume if it fits, then the 4K would also. http://autoweek.com/article/car-life/toyota-engined-austin-healey-sprite-will-haunt-me-forever Cheers Banjo

Hi Keith, Did a bit of research, on suitable fan sizes that would suit the standard KE radiator, but the answer was right under my nose. I bought my daughter a 2004 Echo last year, & I went out and measured it's radiator & fan up this morning, & it is almost perfect. It's outside frame couling/shroud, is within a cm of the KE radiator core dimensions, in both directions. If anyone has utilised an Echo fan on a KE sucessfully, please give me a yell. I will get hold of one, & adapt it, using a spare radiator I have in the shed, then pop it in one weekend. On paper, it should be an easy & clean swap. I'll post a pic on here, when it is done, after which I'll do some temperature data logging exercises, with multiple temp points, to see exactly how well it performs. Cheers Banjo

Strangely enough, when I was digging around in all my bits & pieces the other day, looking for the box of old thermostats, I came across an old 3K thermostat cover/spout/outlet thingy, that actually had a hole right in the top of the housing. It was OEM, as the hole had a land around it, not just previously drilled out & threaded, by some enterprising individual. Just went out, & looked for it in the shed, so I could take a pic of it, but it is almost 40 deg C, so retreated to my office. Looked up the net & low & behold, someone in Thailand, is selling aftermarket ones. https://www.ebay.com/itm/THERMOSTAT-HOUSING-FOR-3K-ENGINE-TOYOTA-COROLLA-KE20-KE25-KE26-KE30-KE36-KE38/152473006588?hash=item23801971fc:g:cmoAAOSwax5YyQiY&vxp=mtr Have no idea what was fitted into this hole originally. Probable a temp sensor of some kind. There you are Jeremy. Get one, & fit a little tap or cock to it, & you've got a coolant bleeder, & you won't have to remove & reinstall the thermostat cover ever again. Cheers Banjo

Hi Jeremy, There should not be a necessity to do this, if everything is OK. Imagine if the Toyota manual used that instruction, you describe. It would indicate a design fault. Based on the picture of your head that you posted, & what the quality of your local water did, in terms of corrosion, I have a gut feeling, that there is something very wrong inside the coolant system of your engine. You are correct, that the water pump is needed to produce flow in a closed circular coolant system. Based on your statements, my first suspect would be the water pump itself. Have you had it off lately, & had a look inside. I wouldn't be surprised if the vanes on the impellor are all corroded away, & doing little more than cavitating the water in the local area. As you presently have the head off, I'd be removing some whelsh plugs on the block & having a look inside. You might be shocked. With the head off, it would also be a good idea to remove the plate on the very back of the head, which gives access to the head's water jacket. Again, you might be shocked. Cheers Banjo

Hi Keith, Will definitely be placing a probe in the back of the head area, as I know from previous tests, a couple of years ago, that water in the very back of the head suffers from poor circulation, & elevated temperatures. With the water pump at the front & the discharge of water through the front, its a case of the water flow taking the "path of least resistance". Cheers Banjo

Good One ! Did the threads indicate whether any of the penetration oil got through, or was it complete rusted on ? Cheers Banjo

That's exactly what I've always believed the little tear drop valve in the thermostat plate was designed to perform. Very well described, & a thoughtful explanation ! I pulled out a couple of old thermostats in a box on my shelf, from engines I have scavenged on. Here is an old brass one, where you can see the rivet shaped tag hanging through a hole in the valve plate. I don't really understand what the tag thing hanging there does, other than to wiggle around & keep the hole free of debri & build up. It can only function, or do anything, when the coolant is below operating temperature, as normally the valve would be opened either partially or fully. I have always assumed it was to bleed away air bubbles at the top of the head during filling, or allow the water coolant pressures either side of the thermostat to equalise, whist the thermostat is closed. There was another old thermostat in my box, that didn't have the tear drop thing in the hole in the valve plate, at all. As you can see, some enterprising person, has created there own bypass holes around the edge. If I have completely drained my cooling system, & refilled, I always let the car idle for 20 minutes with the radiator cap off, until any air is out of the system, then put the cap on, as the coolant starts to flow over the top of the cap neck. If you want to be really pandantic, you can run the front wheels up on some ramps, to ensure the radiator cap & front of the engine are at their highest. The biggest problem I have seen on Rollas, is leaks or cracks in the rubber or plastic pipe, between the top of the radiator, & the coolant over flow bottle. What happens then, is that the excess expanded coolant is forced into the overflow bottle OK, but when the engine cools overnight, the coolant in the overflow bottle does not all get sucked back into the radiator, as there are air leaks in the hose or connections between radiator & overflow bottle. If you look in your overflow bottle when the engine is cold, & find the coolant level higher than normal, then that is probably the cause. Thanks for the suggestions regarding suitable thermofans. I agree that the ideal situation, is to use the thermostat, to do it's job, of getting the engine temperature up to design levels, as quickly as possible, & set the thermofan switch a bit higher than the thermostat point, below which it starts to close. eg: If thermostat starting opening & closing temps are 80 & 90 deg C, then the thermofan switch should be set 5-8 deg C higher, at something like 95 deg C. Once I get it set up, a couple of weeks with the multi-channel temperature data logger probes at various points, should allow me to fine tune it perfectly. I'll put the results up here, for anyone who has an interest in this subject. Cheers Banjo

Hi Keith, So not wanting to "reinvent the wheel", what aftermarket, or other vehicle's thermofans, are suitable for bolting onto the back of a standard KE3X - KE5X radiator, with a stroud ? I don't really mind whether it is one big one, or two smaller ones side by side. Had a quick look on here, & generally Googling the net, but couldn't find any images of a conversion on a Rolla. Once you take the plastic fan blades off the water pump pulley, there is a heap of room, between the back of the radiator core & the front of the engine. Alternatively, it will be off to the wreckers, with a tape measure, to see what fits the best. Any suggestions, greatly appreciated. Cheers Banjo P.S. Just after posting this, I came across your thread, using a Mazda 121 thermofan. https://www.rollaclub.com/board/topic/68673-how-to-fit-an-electric-fan/ Would you still recommend that one ? As I've already got a solid metal stroud that bolts onto the radiator frame, I was thinking of just getting an electric fan with same diameter as the stroud opening round hole, & adapt the mountings to the metal stroud, which should be strong enough. What do you think ?

Hi James, Interested to know whether you were able to get that "pesky" broken front head bolt out, & how you did it. Cheers Banjo

I blew the picture of the head up, & rotated it 180 deg. The first number is definitely a 1. The second number is much harder to deduce, but 8 is probably a good guess. Yes, so maybe it is a no: 18 head. There is a no: 16 listed in the WiKi, but not an 18. Maybe it is a 16 ?

Hi Jeremy, I can assure you the probes were calibrated at 100 deg C, and are accurate. I can assure you the thermostat is within spec. & opens between 80-85 deg C. The "wiggly" temp line around 70 deg C, for 30 minutes, is not the thermostat opening & closing. This sort of test, is best done on a long hard run, in the country. This particular 1 hour trip was in the city & suburbs. That means, you are constantly stopping & starting at traffic lights. Every time you stop, the ram effect of air through the radiator stops, & you are left with the air drawn through by the fan only. The temperature always rises, then drops again, after you get moving again. That's what is causing the wiggly line. I've previously used an external O/S sensor in front of the grill, to clearly show, when the car has stopped, & it always aligns, as I describe. The problem with fixed fans like our Rollas, is that the fan is going all the time the engine is running, whether it is needed or not. A thermofan, only switches on, when needed, & would result in the temperature getting to optimum operating temperature more quickly, & stop sapping of power unnecessarily from the engine. That's the way I'm going ! Cheers Banjo