Banjo

Hi Jeremy, Let me explain it another way. The primary & secondary resistances have really nothing to do with whether a spark generated by that coil is weak or strong. Yes coils can break down, but I'm not talking about used ignition coils; I'm referring to new coils. The coil with a primary resistance of 3.0 ohms can deliver the exact same energy as a coil with 1.5 ohms. It just takes longer for the coil to charge up. Yes, if you have a V8 doing 10,000 rpm, you have very little time between firings, to charge up the coil for the next firing, so may need a low primary ohm coil to make it charge quicker. We are talking here about a 4K engine with half as many cylinders, and half that sort of revs. It has plenty of time to charge up a coil with a 3.0 ohm primary. GT40, no ballast resistor… 14V / 3.4 ohms = 4.1 ampsGT40R 1.4 ohm with 1.6 ohm ballast resistor… 14V / 3 ohms = 4.6 amps As far as the secondary resistance goes, the voltage developed by the coil, is only as much as needed to jump across the spark plug gap. It you close the gap right up, a spark can jump it with probably 2-5K volts. In a working engine, under pressure more volts are needed to jump the gap, but any coil capable of around 20K volts will suffice for our humble Rollas. It's only extreme performance cars that may need potential voltages like 30K - 40K volts to fire a spark. I have a little spark gap here on the bench, you can buy on ebay for less than $ 5.00, that allows you to increase the gap until it won't spark. The rough scale on the side tells you what the voltage is to jump that gap. At 30K volts the gap is 20mm wide ! The indications of a good strong coil, is one that produces a spark that is bright blue/purple & white in colour. A weak coil, is one that produces a very yellowy spark colour. Yes, there are weak coils. One of the big dangers with coils is operating them without a spark gap, which can lead to breakdown inside on the secondary winding, which has a lot of turns of fairly fine wire. Don't forget there other things in the secondary of the ignition coil that can create weak sparks. The main culprit is bad HV dizzy leads. P.S. As a rule of thumb, a good coil should produce a clean sharp bright purple spark with an average dwell time (charging time) of about 3 milliseconds. If you are getting a weak spark, I'd be looking at other things in your system, than just the coils specs. Cheers Banjo

Hi Jeremy, I understand your frustration. Everything you read on the internet is not always "gospel" ! The term HEI (High Energy Ignition) is loosely used. I think it just "Sounds Good" to some people ! There is two (2) specifications regarding the primary of any given ignition coil, when you are charging it with an electronic ignitor, rather than the traditional points. One is is its primary resistance which purely determines the maximum number of amperes DC that can flow into the coil during the charging process. As I stated before, you can work out this "amps" figure by using Ohms Law calculation, as long as you know what the DC resistance is of the primary winding of the coil you have. Measuring this with a cheap multimeter is pretty hard & suspect, but a good quality multimeter should be able to read resistances down that low. You could just feed 12 volts to the coil., for a short time, & measure the DC amperes, using the DC current range on a multimeter, but most of the low to medium priced multimeters, only have max. 10A DC current ranges. Any ignition coil with a primary resistance lower than about 1.2 ohms, will draw more than 10A DC current, whilst charging. The second spec. you see for ignition coil primaries, is the "Inductance, usually specified in mH (Milli Henries). This inductance figure determines how long it takes to charge the coil up, before you can trigger it, to collapse & create a spark in the secondary circuit. The resistor in series with the primary winding of the ignition coil has an history story behind it. Yes it does reduce the current switched by the points in older dizzies. However, that is not the true reason for its introduction. The original ignition coils were designed for use at 12+ volts, which is what most coils run at, when the car is driving. However, in colder climatic parts of the world where great strain is put on batteries, during cold starts on a wintry morning, the battery volts would drop to say 9V, under starter motor high cranking current load. Just at the time when you want the car to start, the ignition coil is only fed with 9 volts, & hence provides its lowest output. I believe the first Rollas were provided with 12 volt coils like that. So some bright spark, decided to design & manufacture the coil to operate with full output at just 9 volts. Cars then starts, but when driving, the coil is subjected to 12+ volts & overheats. Solution; put a resistor is series with the 9V coil, such that it drops 3 volts across the resistor, when the car is driving, & everyone is happy. The resistor is short circuited whist turning over the starter motor, but is placed in circiuit, as soon as the car starts. 100s of thousands of cars were designed that way thereafter. Problem is there are lots of ignition coils around that have no markings on them, so you don't know whether they designed for 9V or 12 volt. Simply, a 9V coil requires an external resistor, whist a 12V coil doesn't. The popular GT40 coil, which many Rolla members use, is clearly marked. There is a model GT12, (12 volt) & a model GT12R (9V) which requires a resistor. This is clearly stamped on the coil body. However, many use the GT12R with the lower resistance, or other 9V coils, with electronic ignitors able to handle the extra current drawn by the lower resistance coil. This is fine, if you are using a "smart" ignitor, that is sensing the drawn current, & switches it off, as soon as the coil is saturated (fully charged), but not good, if you have a dumb ignitor. Those playing around with programmable ignition ECUs, often get into trouble when setting dwell periods too long. The dwell period, should never be set any longer that the time it takes for the coil to be charged. Lots of ignitors die an early death as result of not understanding the implications of matching the coil characteristics to the ignitors maximum design criteria & specs. I have been building my own ignitors for some time, using the original Bosch chip, (BIP373). These you can buy from Megasquirt (DIY AutoTune) for around $ 10.00. I've never lost one yet. They have thermal shutdown if they get too hot, & are almost indestructible. They can be driven from a 5V signal, & all you need to do, is mount them on a good heatsink. So there is a lttle bit more to putting coils & ignitors together than meets the eye, but with a bit of care, you can obtain all the advantages of precise electronic triggering & ignition, & still have the reliability. Cheers Banjo

Hi Graeme, Always harder when the engine is the car. When it is out of the car, you can always jam or lock the flywheel. I swift hit with a mallet has always worked for me, but it needs support of the extension shaft with the socket on it, at the opposite end to the socket. The starter motor option, does apparently work, as there are several utube vids showing this. Haven't tried it myself. Certainly would not be risking Jeremy's second suggestion jamming pistons 2 & 3. Worst case, you might have to remove the radiator, to give yourself some more room. Cheers Banjo

Hi Jeremy, I'd be more concerned with the primary resistance/impedance, than the secondary resistance. The secondary resistance basically only controls the maximum Kilo Volts you get out of the coil. The very low primary resistance of 0.5 ohms, is known as a High Energy or HEI type coil. These low impedance coils are not suitable for use with a 4K electronic dizzy with an internal ignitor. It might work initially, but will eventually burn the ignitor out. The Toyota Yellow Bible gives specs. for the coil primary for use with a 4K dizzy with internal ignitor as minimum 1.3 to 1.6 ohms. A coil with 0.5 ohm will eventually kill it. A fellow RollaClub member had this problem, just 2 weeks ago, which I had a look at. Brand new 4K electronic dizzy from ebay & a HEI coil. Ran for several months then, "no start". Diagnosed ignitor stuffed. Saved dizzy, by removing internal ignitor, & connected the reluctor pickup to the original ignitor wires out to the coil. Fitted a genuine external Bosch BIM-024 ignotor, and back in business. However, to be on the safe side, replaced coil with a GT40 which has a higher primary resistance than the HEI coil that killed the ignitor. I have intended to write a piece for the forum about the importance of matching coil specs to ignitor specs. There are a lot of people out there, that don't fully understand how important this is, is you want outright reliability. Basically the coil primary resistance determines the maximum current that can flow into the coil, whilst it is charging. So Ohms Law says I = E/R If the Volts are 13.5 & the resistance of the coil is 0.5 ohm, then I = 13.5/0.5 = 27 amperes. Ignitors come in various specs, one of which is the maximum DC amperes it can switch. I've seen various ignitor specs ranging from, 3A, 6A, 10A, 16A, & 19A max. Switching those sorts of current generates heat in the ignitor, so cooling them and having good airflow over them, is important for long term reliability. Heatsinks are important. I don't know specifically what the max. amperes the 4K dizzy with internal ignitor can handle. Its not in the manual, & doesn't appear on any website I have come across. They just provide a resistance range for the associated coil primary. So if we assume 1.3 ohms as spec'd, & assume a nominal voltage of 12 volts, then R = 12/1.3 = 9.0 amperes. Be very careful with this one, as it is so easy to lose an ignitor. There are "smart" ignitors, that prevent the ignitor from charging the coil, once the coil has reached saturation. I'm playing with some "smart" Toyota COPs at present, which do just that, but I can assure you the ignitor in the olde 4K electronic dizzy, has no such feature, like that. Cheers Banjo

Hi Guys, i note that Rare Spares have a new website, where it is easier to find bits they have, for our Corollas. There are several pages thereof. https://www.rarespares.net.au/beta/rarespares/search?q=corolla&page=0 Cheers Banjo

Hi Madelaine, There is nothing like a good long country run, to allow any gremlins to surface, in an olde engine. You said, "she only overheated twice". What were the driving conditions during when there was these two occurrences ? Going up over a range or mountain ? Stuck behind a big truck ? Forced to drive in a lower gear ? The circumstances might give us an idea of what it might be going on. As she ran fine most of the time, I would tend to discount the horrible head scenario. Inspection of spark plugs directly after a run, will usually indicate whether water has entered a cylinder, with a very clean plug, in the offending cylinder. If it was me, I'd be removing the thermostat for the day, & see if that makes a difference. If it was a 35 deg C day, it should not make any difference, as I would expect the thermostat to be open most of the time under those conditions. Removal of thermostat is an easy 10 min. job. Just check the specs of the radiator cap, usually stamped into the metal, on top. Even relatively new thermostats have been known to fail. My guess is the run has loosened some crapp inside the engine, & it has created a blockage somewhere, "throttling" the flow of coolant. My other best guess, is a partially blocked radiator, that has enough flow to run under normal conditions, but not enough to handle an extreme day. Maybe just take the bottom hose off, and put a hose in the top spout. Turn the tap on full, and check the radiator gets it all through to the bottom. If the radiator overflows at the intake at top, it may indicate a reduced flow, due to partial blockage, or build up internally. Cleaner, run, then flush, could fix it, but the safer bet is to get a radiator shop to check & flush, or give it a core clean. Lets know what you find. P.S. I assume, you have checked the fan belt tension. Does your dash temp guage work OK ? Was it running hi all day, without going into the red zone, when she was running fine ? Cheers Banjo

Found this wiring diagram on the net. It is for AE71 lamps only. https://rollaclub.nyc3.digitaloceanspaces.com/monthly_08_2014/post-7544-0-45827600-1407715211.jpg Here is the "legend" for the wiring diagram. Cheers Banjo

They are brushes, not bushes. A bush is a bearing in an alternator context, where a brush is something that "brushes" as it slides/rubs on the slip ring. If you tell your auto sparkie you need new bushes, he'll quote you quite differently, than for fitting new brushes. Brush change/replacement is easy, as long as the slip rings are in good nick & haven't gone slightly oval. Cheers Banjo

Aftermarket extractors have an advantage that they are separate from the inlet manifold, & pull up to the head independently. However, the flange tips of the inlet manifold & extractors can be different depths, making it difficult to get a thick washer to pull down firmly, & parallel to the head. You could probably grind down the thicker flange tip on the outside to match. If you have a standard setup, then the inlet & exhaust manifolds are bolted together, with 4 off bolts. If you can loosen these slightly (good luck), then pull the manifolds up to the head, (without gasket) then tighten the 4 off bolts holding the manifolds together. Remove the manifolds from the head, & they should now be in the same plane, across the mounting faces. The problem with this suggestion is that the 4 off bolts will be so tight in the threaded section, (which is in the exhaust manifold), that they will break off, whilst trying to undo them, & then you have the need to drill them out & retap them. Cheers Banjo

Are Timaru ! In another life, I once owned a Triumph 2500PI (Petrol Injection). Great car ! I can still remember the first time I ever visited N.Z. Just couldn't get over the number of British Cars ! Now, it Japanese second hand imports. P.S. ebay link for 1 piece composite K series manifold gaskets. https://www.ebay.com.au/itm/1974-1978-For-Toyota-Corolla-KE30-3K-3K-H-Extractor-Manifold-Gasket-/201510257673?hash=item2eeaf28409 From the Rollaclub Tech Pages: Exhaust Manifold The stock exhaust manifold is alright if you're just playing around trying to get your car running nicely. There are two types of stock manifold, one has just one outlet pipe, the other has two pipes and is similar to tri-y (4-2-1) extractors. Generally, as you add a larger cam, you need to have tuned length extractors and a larger exhaust in place, or all the extra air your engine is now moving is too much for the stock manifold to hold, and the exhaust gases pulse back up against the inlet charge and fuel comes back in a fine mist out of the carburettor. Any extractors will do, new ones are about $280. You can pick second hand ones up for $50-$100, or sometimes even free if you're lucky like me. Second hand extractors tend to be a pest, in that either the middle pipe has bent out and doesn't like to seal, or the end pipe (usually the rear) is bent from a poorly hung exhaust pulling on it for so many years, and is hard to line up with the head. I've always used second hand extractors which I got for free, and by far the best thing you can do to make the manifold easy to locate and seal is use studs and nuts instead of bolts. This also puts a more even force over the threads of the head, so you're less likely to strip a thread. The normal two-piece manifold gasket can also cause sealing problems if the middle pipe is bent, but an exhaust shop should be able to sell you a one-piece extractor gasket which is much better. You can get metal ones which are alright, but I like the floppy asbestos type gaskets which are difficult to get these days. If your manifold gasket just won't seal, there's a chance the flanges of the inlet manifold and exhaust manifold (or extractors if you're using them) are different thicknesses. Any engine builder or machine shop should be able to grind the faces of the manifolds together for you, to ensure they're flat and sealing properly. This should cost you between $40 and $80. _____________________________________________________________________________________________________________________________________________________________] PERASEAL do a one piece gasket, which has the P/N EM30, available through Bursons here in Australia. I've used them on all my Rollas, & have never had a manifold issue since. Cheers Banjo

Your alternator is one with an inbuilt regulator. (that grey plastic bit on the back of the alternator). Only 2 screws to remove to take it off, after disconnecting the battery. Brush assembly & regulator are all one piece. Easy to remove & inspect. Brushes are easy to replace. With the regulator removed, have a look inside the hole, if possible, & take a look at the condition of the slip rings. A quick turn with a bit of 400 wet & dry emery paper will usually have them shiny again. P.S. I did it once on the side of the road. Brushes were worn. Stretched the springs a bit & put it back together again. Got me home OK. Cheers Banjo

If you've got bolts holding your manifolds to the head, it is a good idea to replace them with studs & nuts. whilst doing that, also get a one piece manifold gasket. That will get rid of any manifold issues for a long while. P.S. Timaru NZ; nice place, I've been there once. Cheers Banjo

.Most likely the brushes on the slip rings have got to the end of their life and are not making constsnt contact with the slip rings occssionally. Easy fix. Cheers Banjo

Hi Jeremy, You might want to look at something like this, if you've got a good flat straight road nearby. http://www.ddisoftware.com/ttdyno/ Cheers Banjo

Hi Jeremy, I'll dig some stuff out, in the next day or so, that has worked for me, on my KE30 2 door, with a relatively stock 4K-U engine. Cheers Banjo

http:// 4 cylinder cars have famously un balaced motors with resonant vibration problems, so hence the term buzz box My kids when they were small, got driven to school and back each day, by my wife in her KE55 Coupe. The kids nick-name for the KE-55 was "BUZZIE" ! Say no more. Cheers Banjo

Yikes ! Sounds like Cavite could be a good holiday destination for serious Rollaclub members next year. Take 2 empty suitcases & fill them up. Found 7 things to do whilst in Cavite. https://trip101.com/article/things-to-do-cavite-city-philippines Maybe they should add an 8th thing to do. 8. Pick up some cheap 4K parts for your Rolla back in Ozz ! SPOT THE 4K & WIN A FREE TRIP TO CAVITE FOR CHRISTMAS ! Love it. Cheers Banjo

Hi Jeremy, Just checked out your video of the Jeep. I can see your problem right away. You forgot to put your suitcase in the second boot / trunk there in front of the radiator. What the Hell ! Do they put straight 6 cylinder engines in these "jeeps" also ? Cheers Banjo

That's insane ! I've never heard anything like that in all my Rollas over many years. My Jacuzzi with a party going on, doesn't even make that much noise. There is something seriously wrong inside that engine. Can't believe all that noise, is caused by a a 0.5 liter of air trapped somewhere inside the block. That's serious cavitation, like when a outboard motor propellor is lifted part way out of the water. Cheers Banjo

Hi Jeremy, Nice thongs ! We should probably point out to others looking at your post pics, that the long reach plug is only suitable for the 4K-U engine, & not other 4K variations like the common 4K-C. The long reach plug is only used where dished pistons are utilised. How about a few pics of your "jeep". Cheers Banjo

Chassis earths are such a pain in our old Rollas. A good hour taking all the earth lugs off, cleaning them up, & then reconnecting can pick up some lost volts very easily. Pay special attention to the big ones between engine & chassis.

Good advice from Altezzaclub there Max. I've saved a few senders by taking it out of the tank & bending the arms a bit. When they get that olde, and have been up & down so many times between empty & full, the pivots also wear, but nothing much you can do about that. As for not reading Full, then read my post regarding that exact issue. https://www.rollaclub.com/board/topic/73224-that-pesky-little-guage-voltage-regulator/ Cheers Banjo

Thanks Ian, Fixed that above. Got them around the wrong way ! I just went & checked my original post, where I got it around the right way. Cheers Banjo

I thought we had finished with this one, but there is the risk, that talking about coolants, & their effects on different engines, from different eras, with different evolutions of the automotive engine cooling system, we could well confuse some readers or researchers, in relation to the K series engine. Strangely enough, the Toyota Yellow bible 2K - 5K manual, only has 8 pages on the cooling system, & 2 off them on electric radiator fans. I'll go through the manual & pick out pieces of information/specs, at the back of the bible, that are relevant to the cooling system & put them up here for future reference, so watch this space. We can describe info & experiences, regarding the cooling system, that only relates to the K Series engine. The K Series, having a cast iron block & an aluminium head, can suffer seriously, if there is any acidity in the coolant fluid. Two different metals, & an acidic fluid between them (electrolyte) creates a battery; currents flow & metal moves . . . you get the picture. On my daily drive KE30, & on my test bed engine, I have a temperature sensor adaptor hooked into the bottom radiator hose. Isolated from the engine like this, via the rubber hose, it is fast reacting, as there is little "heat sink" effect. I have a temperature data logger, where I can record the temperature of both the sensor shown above & the engine temp sensor up on the side of the thermostat housing. The results of these two sensors, graphed together over a drive, show clearly the operation of the cooling system, and whether it is working as it should. I once added a third sensor in front of the grilled which indicated so clearly when the car was moving & when it was stopped at the lights etc. An ambient sensor in the data logger itself, helps relate all the stored readings to outside temperature, & lets you see its effect on the cooling. I'll see if I can't dig out my graphs & pop them up here later. In the meantime, here is a very interesting promotional video, from someone you will recognise, which touches on many of the things "cooling/coolant" that have been discussed here in this post in the past day or so. https://www.youtube.com/watch?v=t7PykrgzWPQ Cheers Banjo

Actually, I accidentally came across a site yesterday, which lists the history of Toyota engines in Russia; and basically says, that even the poorest Toyota designed engine, was better than any of the home grown local Russia offerings. http://toyota-club.net/files/faq/03-08-16_engine_eng.htm I was tickled to read what the article had to say about the K series engine. I was also staggered to read that K Series engines were used in Russia right up to 2013, which is only 4 years ago. I then quickly realised that they were talking about the 5K & 7K engines, which were apparently used in commercial Toyotas like the LiteAce & TownAce. Maybe "Clapped Out" would like a holiday in Russia, & could bring back a couple of 5Ks, as excess baggage ! I love the line "Extremely reliable & archaic design". To my knowledge, & from what I have read, the 5K was still used by Toyota, here in Australia, for their petrol forklifts, up until about the year 2000. Someone who works for Toyota may be able to verify this; but I was told recently, you can still buy a 5K short engine from Toyota here in Australia, off the shelf, as a replacement spare part. I recently posted my interest in the 2NZ-FE series, fitted to the Starlets/Echo/Yaris Toyotas. This engine is amazing. Great design, light, reliable, economical, long life etc. etc. I was looking at it, as a possible replacement to the K Series, when they are gone or banned, by legislation. They are the same 1.3L as the 4K, but pump out twice the HP, in standard form. The 1NZ-FE fitted to the Sportivo models, is a 1.5 litre in same basic block. Unfortunately, it is an east west engine, & could be a pain to mount into a KE Series Rolla. However, I'm prepared to look at it, so if any one knows of a cheap, wrecked, or broken 1NZ-FE engine floating around in Brisbane, or nearby, I'm interested. P.S. My daughter's 2004 Echo has the 2NZ-FE in it, but I don't think she would be too happy about me whipping it out for a week or so, so I can strip & see if it is possible to add different engine mounts to it somehow. Cheers Banjo