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andrewo Member
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Talk about one step forward, two steps back. I solved the starter problem and the engine cranks, but does not fire. Since the gear on my distributor does not seem to have any marks, I used an ohmmeter to determine when the points were open and closed, and managed to get the timing set to the point where #1 is actually firing a couple of degrees before TDC, or at least I think it is. Using a timing light when running on the starter, this appears to be the case. Here are some relevant details: 1. The engine has been completely rebuilt. 2. The points, condenser, rotor, and cap are all new. 3. The carberetturs were not rebuilt. I bought them complete with intake off of someone who switched to Delortos and represented them as fine, so I shelved my set and just bolted them on. 4. The cam gears are lined up properly. How do I verify that the distributor pulley is in the right position? What else should I check? Are there any San Diego area folks who are good at troubleshooting and might want to take a look? Pizza, beer, etc., would be on me. Thanks - Andrew |
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Mark Rosenbaum Member 
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Carburetors. Strombergs are VERY reliable and the only things likely to go wrong with them are wear, damage caused by somebody jamming a screwdriver where it didn't belong, blocked passages due to rust from the fuel tank, and corrosion if there's lots of water in the fuel. For each carb, make sure you can lift the vacuum piston all the way to the top of the carb opening with force from a single finger, and that the piston when released will then glide all the way down by itself, within a couple of seconds at most. If not, you'll need to fix whatever's wrong inside the carb in question. Ignition. It's my understanding that the alignment marks for the gear that drives the distributor were for Lotus' convenience during engine assembly, to make sure the distributor would be installed correctly. In any event, if the ignition timing is right, the gear's orientation does not matter. If you are getting spark at what seems to be the right time, and if you have fuel in the carbs and have applied a little bit of 'choke', but the engine won't even cough, then possibly the plug wires are not in the correct order. You could have the wires in the distributor 180^ out so that the #1 cylinder is firing when the #4 should fire, etc. Fortunately, it is easy to check for that. Set the engine to #1 TDC making sure that the crank timing marks are aligned and the two cam gear marks point to each other. Pop the distributor cap, and note where the rotor is pointing. Line up the dist. cap to the distributor body and determine which plug wire turret the rotor points to. Manually trace the plug wire from that turret and ensure that it goes to the #1 (front) cylinder. If so, the next wire, moving COUNTER-clockwise while looking at the top (wire side) of the dist. cap, should go to the #3 cylinder, followed by the wires to the #4 and #2 cylinders. If this is the case, the spark plug wires are correctly installed. However, if the wire does NOT go to the #1 cylinder, disconnect all four plug wires from the dist. cap. Next, manually trace the wire from the #1 cylinder until you find the dist. end, then install that wire into the turret to which the dist. rotor is pointing. Moving COUNTER-clockwise while looking at the top (wire side) of the dist. cap, the next turret should go to the #3 plug wire, followed by the #4 plug wire, and finally the #2 plug wire. Reinstall the dist. cap and make sure the wire from the coil is still in place. Try to start the engine again. It should fire right up. You'll still need to set the timing with a timing light but this should not be a problem. |
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Dave Member
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Most often when I've had the problem that the engine does not fire at all - no cough, sputter, or other engine noise, it's something basic that I've overlooked. Pull the fuel line, put it into a jar and crank the engine making sure that you're getting gas flow to the carbs. Pull the plugs, put them on the engine block and crank making sure you're getting good spark to all the plugs and they're hitting in the right order. Make sure the main distributor wire is set in place tight. Are the wires really old and maybe shorting out due to dry rot or just losing too much amp on the way to the engine? Check the spark with a volt meter (that can handle the volts from the coil). Is your coil good? Try blasting the carbs with some carb cleaner just in case something is stuck from sitting too long after the PO replaced them with the dell's. If you've got gas and spark you should be getting some engine sounds, then it's just a matter of getting the RIGHT engine sounds:) Sorry if this is too basic, but I've missed this kind of stuff too often.... Good luck, Dave |
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andrewo Member
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Thank you Dave and Mark for the suggestions. After checking everything that you mentioned, and some other tinkering, I am starting to think that maybe I am firing on the exhaust stroke. Since the crank turns twice for every turn of the distributor, I should be able to solve this by removing the timing belt, rotating the crank once, and replacing the belt. If I do this at low speed with a wrench, do I risk any damage to the valves? BTW, my impression seemed to be confirmed when, after checking everything else, I tried a little starter fluid, and it backfired through the carbs. |
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Mark Rosenbaum Member
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If you disconnect the timing belt and rotate the crank 180^, the pistons WILL hit any open valves and will almost certainly bend them. As Dave points out, it's awfully tempting to ignore the simple stuff simply because it is so basic. If the engine currently is firing on the exhaust stroke, that just means the distributor is 180^ out of phase -- i.e. the rotor points to the #4 spark plug turret when it should be pointing to the #1 turret. The easy fix is to move the spark plug wires as described in my post above. The hard fix is to slip the timing belt off the auxiliary shaft (distributor) gear, rotate the gear 180^, then put the belt back on. The 'easy' method is quicker and a bit safer as it does not involve disturbing the timing belt. |
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Brett Gibson JH5 20497 Member
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Andrew, listen to Mark, do not turn that crank shaft with the belt lose, line your crank timing mark up, make sure the cam marks line up with each other, pop #1 cylinder spark plug and make sure the piston is at the top, take the distributor cap off and guess what, your rotor will probably be pointing at #4 spark plug wire connections, just loosen the dizzy up so it comes out a bit and turn the rotor so it lines up with the #1 cylinder, push the dizzy back in engaging the slot and retighten, or as Mark writes, instead of moving the dizzy just move the spark plug wires around. It really sounds like your almost there to get it running, let us know. Brett. |
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andrewo Member
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Okay, clearly rotating the crank is a bad idea, but I am still puzzled. When I attach an inuductive timing light to #1 wire, it is firing as the timing mark on the crank pulley reaches TDC. If I move the plug wires, then won't a different cylinder be firing at TDC? What about the relationship (2:1) between crank rotation and distributor rotation? I think maybe I'm just obtuse, but it seems like moving wires would make the problem worse, not better. The more I think about it, the more confused I seem to get. |
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Mitch Ware Member 
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The 2:1 ratio between the distributor and the crank is exactly your problem. For each 360^ the crank turns, the dizzy turns 180^. This means that each time the crank timing mark is at TDC the rotor is either pointing at #1, or pointing 180^ away from #1. If you take off the cap when #1 is at TDC and all of the valves for #1 are closed and the rotor is pointing 180^ away from the #1 wire, then you simply move the #1 wire to where the rotor is pointing and put the other wires in the right holes relative to the new #1 position. Mitch Ware 1974 JH-5 #111119670 1971 TR-6 #CC66950LO |
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andrewo Member
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Okay, this is starting to penetrate, I think. If I understand this, what you are all saying is that there are actually two points in the timing cycle that the crank pully will indicate TDC. Once is really when the #1 plug should be firing, and once is when the third cylinder to fire will be firing (not actually #3 as I recall). So I have to rotate the engine, with the belt engaged, by 360 degrees, away from the point at which #1 currently fires, and that should result in a 180 degree revolution of the dizzy, which is where I really want #1 to fire. I then move the wires accordingly. Could someone verify that I understand what you are all saying, and that I have the procedure correct? |
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Brett Gibson JH5 20497 Member
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Andrew, if your at TDC on the crank pully and the cam marks lign up you should be firing on the #1 spark plug, anything else is WRONG. So shift your wires around till the rotor points at #1 spark plug wire. |
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Mark Rosenbaum Member
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Andrew, your understanding is basically correct, though most folks find it easiest to set the engine so the crank timing marks indicate TDC and the cam marks are aligned, then make the spark plug wires match up with whatever the distributor happens to be doing. The trick to understanding a four-stroke car engine is to recall that each piston does four things, each thing taking a half turn of the crankshaft. This means that the crank makes two full rotations in the course of one complete engine cycle. Meanwhile, the distributor and camshafts make one full rotation. This is why it's the camshaft position, not the crankshaft position, that determines where in its cycle an engine happens to be. Of course all the bits have to be properly synchronized if the engine is to run. It may help to make a simple table showing the state of the engine at the start of each 180^ rotation of the crank. In this table, P = power, E = exhaust, I = intake, and C = compression. Rotation #1 #3 #4 #2 0/4 P C I E 1/4 E P C I 2/4 I E P C 3/4 C I E P For simplicity you can assume that ignition occurs at the start of the power stroke and that the intake and exhaust valves snap open at the start of their cycles, and snap shut at the end. It's then easy to see that if you get a spark in the #1 cylinder when the #4 is at the start of its power stroke, you'll get backfiring through the intake. Hope this clarifies things. |
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Dan Collier Member 
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Couldn't help it. Had to post this.  Dan Collier JH74 14381 2.2L Jensen-Healey Preservation Photo Gallery Last edited on 08-04-2005 03:59 am by Dan Collier |
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andrewo Member
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Thank you all for your help. I finally understood what you were trying to explain, and the engine fires. |
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Panini Member 
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andrewo. Tune in the carbs and head over to Tx. and help me do it. |
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colinw59 Member 
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Hi Mark, maybe you can help me here? I'm restoring #15851 and she ran on the second turn of the key, albeit rough and lumpy (rebuilt carbs not set or balanced probably being the cause). The car has engine # b74.02.6163 with new:- plugs (set to 0.035"), leads, rotor arm, distibutor cap, Petronix ignitor, Petronix flamethrower coil. Timing is set to 8 deg BTDC. With the engine runnng and good oil pressure, an oil leak resulted which forced me to replace the front cover gasket & oil seal. This was the perfect time to replace the timing belt and the tensioner bearings. The belt was tensioned with cylinder #1 at TDC and cam sprocket marks in line at 110 IN and 110 EX, with the rotor arm pointing at the distributor contact for plug #1, which I'm sure is correct for this engine number. I cranked over the engine manualy first to make sure I wasn't going to bend a valve, all was ok. Now she won't run. In fact I have an intermittent spark at #1, then no spark. I checked this with the timing light across each plug lead and the high tension lead, no flashing light! I also checked the voltage across the coil (with a jumper wire ran from earth to the earth terminal on the coil) and there was 8 volts across the coil, which is what I think it should be. I have continuety from the earth lead from the ignitor to earth and all the other electrical conections in the spark/run circuit are good. I also tried a coil from an 74 MGB that I know to be good, this made no difference. I've narrowed it down to 2 things, either the Petronix ignitor is bad (but I don't see how something that works of off magnetic pulses or by producing an EMF can be intermitent) which would just so happened to coincide with changing the timing belt. Or I've selected the incorrect marks on the cam spockets a direct result of changing this belt. Am I missing something Mark? http://jhppg.com/gallery/74-Jensen-Healey-15851 |
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Rory Clark Member
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My best guess is that you let the Distributer sprocket turn on you when you replaced the belt. (I know I did it) Therefore your timing is off. |
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Mitch Ware Member
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Are you sure you got the distributor all the way in? It can be a real pain to get it seated all the way. With the cap off, have someone turn the engine over and see if the rotor is spinning. Mitch Ware |
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colinw59 Member
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Hi Rory I thought of that, so I checked it. With #1 at TDC and the cam sprockets lining up, the rotor is pointing to the correct contact within the distributor. Thanks |
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colinw59 Member
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Hi Mitch That happened the first time I put the distributor back on. The second time I made sure it was seated correctly and the rotor turned when we cranked the engine. Thanks |
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Mark Rosenbaum Member
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I'm assuming from the exchange above that colin59's car still has its problem. The mechanical cam timing sounds correct, as does the stated static ignition timing. And while problems in these areas might prevent an engine from running, they would not prevent the ignition system from working. The stated 0.035" spark plug gap is too big. And while a good ignition system will often give a spark across such a large gap, the time to experiment is after everything else is working fine. Initially, at least, the correct gap is 0.025" with Strombergs and 0.023" with Dellortos. Installation of a new Pertronix coil was mentioned. If this is the type of coil that requires an external ballast, then it is hooked up exactly as is the stock coil, with the ballast resistor being connected between coil and ignition switch and the ballast bypass wiring (from the starter solenoid) also connected. Note that a coil that requires an external ballast, if run without one, WILL overheat and may fail in a very short period of time, giving precisely the symptoms mentioned. However, the substitute coil speaks against this as the problem. However, with sufficient bad luck, the current through the coil could have been so high that the switching transistor inside the Pertronix module was destroyed. On the other hand, if the coil contains an internal ballast, then the wire from the ignition switch connects directly to coil (+) and the ballast and the ballast bypass wiring from the starter solenoid are ignored. A coil with an internal ballast, that is wired up with an external ballast as well, may not produce enough high voltage to create a spark across a wide spark plug gap. Deal with the issues above and see if the car runs. If not, then the problem sounds like the basic 'No Spark'. When that occurs, I usually suggest the following: 1. Manually rotate the engine so that the distributor rotor aligns with one of the spark plug turrets on the distributor cap. Do not guess, do not assume, pop the cap, take a look, and make SURE. Check a second time as you put the distributor cap back on. This is particularly important in a JH as many if not most of its ignition problems involve incorrect ignition timing of one form or another. 2. Trace the high voltage wire from the turret to which the rotor points, to the associated spark plug. Disconnect this high voltage wire from this spark plug, and connect it instead to a test spark plug having the correct gap. Ensure that the body of the spark plug is in firm contact with the engine block, and that it is possible to see the spark plug electrodes. 3. Unplug the wire attached to the coil (-) terminal. Place the ignition switch to the RUN position and verify the presence of +12 volts on the coil (+) terminal. 4. Repeatedly make and unmake a connection between the coil (-) terminal and chassis ground using a test wire, screwdriver blade, etc. Each time the connection is unmade, there should be a bright blue spark between the electrodes of the test spark plug. 4a. If so, then the basic problem is either incorrect ignition timing, some sort of mechanical problem in the distributor or its drive, defective points / condenser / Pertronix, or (very rarely) a coil whose high voltage output is so low that it can make a spark in air but not in a cylinder under compression. 4b. If not, the problem is a defective coil, a defective high voltage wire between coil and distributor or between distributor and spark plug, or a defective distributor cap or rotor. 4c. In either case, you'll have a direction in which to proceed. To verify Pertronix operation, connect the coil wiring as appropriate, then rotate the engine and verify that the voltage on the coil (-) terminal goes from zero volts to +12 volts and back to zero twice per engine revolution, just as it would if points were installed and were opening and closing. If not, either there is something wrong with the Pertronix or the distributor shaft isn't turning. |
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Esprit2 Member
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colinw59 wrote: Hi Rory I thought of that, so I checked it. With #1 at TDC and the cam sprockets lining up, the rotor is pointing to the correct contact within the distributor. Thanks Colin, This is long. Sorry if I lose you with the length. With the crank at TDC and the cam pulley timing dots properly aligned, #1 cyl is at TDC. Good. With the engine in that position... Normally the ignition fires as the rotor arm is just overlapping the terminal on the distributor... not on-center with it. That's to maximize the rotor/terminal proximity duration as the rotor sweeps by so the spark can jump over a time period at high rpm (the spark isn't instantaneous). If you have the rotor aligned straight-on with the terminal at TDC, then the ignition timing is probably actually after TDC. You want 8 - 14 degrees before TDC. With #1 at TDC, all you should be looking for is which terminal (+/_) is the rotor pointing toward (not timing). That's the #1 terminal, so make sure the #1 spark plug wire attaches there. Then install the rest of the wires in 1-3-4-2 order, counter-clockwise around the distributor as you look at the top of the cap. "IF" #1 is pointing straight up, #3 will point at the engine block, #4 straight down and #2 at the oil filter. Now turn the crank through one more revolution, stopping when the pulley hash mark aligns with whatever static timing you want, stop there. You don't have to go around two revolutions and back to approaching #1 TDC. After you have determined the #1 terminal and installed the wires properly, it's enough to just go around once. The distributor will fire each time the crank approaches TDC. For "ignition" timing purposes, it doesn't matter if it's #1 that's firing, or #4. They'll both fire with the same advance. Connect a continuity light between ground and either of the 12v terminals on the ignition coil. With the ignition on, the test light will be off or dim when the coil is charging (OEM breaker points would be closed). The light will turn on or become bright when the points open to fire the coil. Off-dim and on-bright depend upon the current rating of the test lamp and how much current it is drawing. "Off" is just a special case of "dim"... etc. With the crank's timing hashmark set to desired static timing, test light connected and the ignition "on"... Loosen the distributor clamp so you can rotate the body (apply inward hand pressure to the distributor to hold it into the housing against the spring pressure "before" loosening the clamp). Rotate the distributor back and forth a bit to find where it switches from off/dim to on/bright. If you have followed instructions, started at #1 TDC, and went to your static timing point (8 BTDC ?), then you will find the on-off point a little clockwise from your starting point. "Clockwise" as you look at the open end of the distributor body/ top of the cap... ie, turn toward the oil filter. Find the on-off point, then rotate back and forth a few times watching the light go on-off to get a feel for where the on-off point is. From the on-off point, rotate the distributor body counter-clockwise toward the engine block until the light goes off... then a bit more. Then reverse, and rotate the distributor body clock-wise back toward the oil filter until the light "just" comes on or gets bright. Stop immediately without over-shooting. If you miss it, back up and try again. When you're comfortable that you nailed it to your satisfaction, tighten the distributor clamp. Do not release the inward hand pressure upon the distributor until after the clamp is tight... or you'll be re-installing the distributor. Now the ignition is static timed. Turn the Ignition off as soon as you're done (important... don't leave it on). Disconnect continuity test light. If the light doesn't change at all when you rotate the distributor body, then something is wrong in the distributor/coil circuit. If there's voltage at the coil (+) and (-) terminals, then follow the white wire from the coil's (-) terminal to the distributor and check for voltage there. If no voltage, the wire is bad, fix it. If there is voltage at the distributor end, but the test light doesn't change (off or dim to on or bright), then there's a problem with the Pertronix unit or it's installation. Early PERTRONIX FRAILTY: When the ignition is "On", current may or may not be flowing through the coil depending upon the position of the distributor. If the distributor is in one of the four positions where the coil/spark has just fired, then the 12v to the coil-charging current is off and not flowing through the Pertronix amp. However, at all other times, coil-charging current is flowing through the Pertronix amp full time whenever the ignition is "On" and the distributor isn't turning. That puts the amp in a 100% duty cycle condition it was not designed for... originally. In that case, early Mk 1 Pertronix amps will overheat and fry fairly quickly... a few minutes. The damage is permanent and the cure is a new unit. When working on the engine/ ignition, do not turn the ignition "On" and leave it on. Switch "On", do your task, switch "Off". Later Mk II Pertronix units have a heavier duty amp that can withstand prolonged current... but it's still best not to push your luck. Also, both Pertronix units are polarity sensitive and intolerant of reversed bias. Do not apply reverse polarity for even an instant or you'll be replacing it. I guess what I'm saying is that your Pertronix unit may have died even though you "didn't do anything to it"... intentionally. SPARK CHECK: Voltage gets to the coil via two paths. One wire goes to the ballast resistor which drops nominal system voltage down to 7-8 volts. That's for normal running. A second wire coming from the terminal on the starter solenoid, bypasses the resistor and feeds 12v directly to the coil during starting. 12v for starting, 7-8v for normal running after the starter is released. Check that both circuits are working. After confirming that the coil is getting voltage, trigger it manually and watch for a spark. To trigger the coil, remove the wires from both the (+) and (-) coil terminals. Make a jumper wire to connect the (-) terminal directly to ground. Make a second jumper and connect it to the (+) terminal and have it long enough to reach the battery'e (+) terminal. Pull the high tension coil wire off the distributor cap and make sure the other end is firmly seated in the top of the coil. Pull the boot back on the free end to expose the terminal, then hold it near a good ground... like the engine block (not the carbs/ intake manifold). Grip the wire well back from the terminal to avoid a shock. Hold the coil's high tension wire near a good ground but not touching (gotta see the spark jump). Touch the free end of the (+) jumper wire to the battery's (+) terminal briefly, then lift if off. Everytime the batterry connection is broken, the coil will fire and you should see a spark jump from the coil HT wire to the ground point. If a spark jumps, the coil and high tension lead are both good. If no spark, then one or both are bad. Replace the coil HT lead with a known good one and repeat the test. Still no spark?... the coil is bad. Replace it. With a confirmed good coil and HT wire, a spark will jump every time you lift the jumper wire off the battery (+) terminal. When you get to that situation, put all the wires back in their proper places on the coil. Now, test for spark using the Pertronix to trigger the coil. Coil 12v wires installed, coil HT lead still disconnected and held near a good round, transmission in neutral, key the starter to turn the engine over. If no spark occurs, then the problem is either in the Pertronix unit, or in the small, white 12v wire from the coil's (-) terminal to the distributor/ Pertronix unit. Test for voltage at the Pertronix end of the wire. If you have primary voltage there, then the wire/ circuit is good and the problem is in the Pertronix or it's installation. No jab intended... but are you familiar with starting a carb'd engine? In this day of fuel injected engines, that's a fair question. With fuel injection you aren't supposed to do anything other than key the starter. With carbs you need to be an active participant. You won't have much success if you don't do your part. Good luck Tim Engel |
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colinw59 Member
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Thank you both very much John & Tim for your very thorough replies. When I initialy got the car running, I did so with the plugs gapped at 0.025". On reading John Kimbrough's article on installing his Petronix system I regapped them to .035". After this the car ran about the same. She's not fully roadworthy yet so this was based solely upon how she sounded statically. My assumption has been that power for the spark was not being generated, or being generated irratically and not that the spark circuit was incomplete. Wrong! I pulled the new plugs last night. They were carboned up (too rich a mixture I hope, as the carbs have yet to be set, or balanced). I replaced a plug at a time and cranked the engine, better. Replaced another, better still. I replaced all four plugs and she's now runnin' fine. I'm hoping that the larger gap combined with a nice coating of carbon was the root cause of the problem, that just so happened to coincide with changing the timing belt. We have a word for this in English, coincidence! This one sent me on a fools errand for many hours! I'll road test after setting & balancing the carbs and if she exhibits the lack of spark that John Kimborough experienced, I'll trying gapping the plugs to 0.035"- 0.045". Fingers crossed. Thanks again gentlemen. |
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Esprit2 Member
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colinw59 wrote: I'll trying gapping the plugs to 0.035"- 0.045" Colin, It takes a higher voltage spark to jump a larger gap. The appropriate gap for the OEM coil was 0.023" For the Pertronix Flamethrower you can go to .035". However, I'd be cautious about going further than that. If you go to far with either high voltage or large plug gaps, you may start to have issues with the spark cross-talking between the closely spaced terminals in the distributor cap. Look at late model distributors designed for high energy coils and you'll see that the caps are very large. Sometimes the size is necessary to enclose more stuff crammed inside; but more often than not the size is also a design requirement to keep the terminals far enough apart to permit the use of the really high voltages. The Lucas distributor has a tiny cap, and the terminals are very close together. A gap of 0.035" shouldn't be a problem, but I wouldn't go with more. Don't go nutz. Tim Engel |
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John Kimbrough Member
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Colin, Tim is probably right. I gapped at .045 to get it running and then began working backwards. I didn't have a problem with cut out at the higher gap, but it didn't seem necessary to keep it that wide. With the stock gap I had the same problem with carbon buildup you had and when I cleaned the plugs it ran better until the carbon built up again because the "real" spark was only intermittent. I know it sounds wierd, but the spark plug with the small gap was acting as a dead short. With the gap substantially wider, the fully developed spark ingited fine. Since I got it adjusted I have had absolutely no problems. I, too thought it was all kinds of complicated things, and practically went nuts, but it was really very simple. Good luck. John. |
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