| hootomik | -- 08-01-2023 @ 1:53 AM |
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Hi, I am new to this forum, I live in the UK and have a 1949 Ford Custom sedan which I bought (restored) from the USA and have had running for a couple of years. In 2021 it was running OK to a point, but would not rev cleanly at higher revs. I replaced the points with electronic ignition but no significant improvement. Last year I had a series of problems due to dirt in the fuel; I replaced the fuel pump and stripped and cleaned the carb, then obtained a rebuilt carb - no improvement. I let the car stand outside over the Winter and made no attempt to start it. After 4 months I tried to start it but the engine was seized. I freed it with oil down the bores, and it started-up, but although we got it to idle OK it will not rev at all - lots of misfiring and backfires. My question: could the valve stems have corrosion which is causing them to stick open as the motor warms up or I attempt higher revs? I have been through all the ignition and fuel system and replaced everything but the distributor and nothing makes a difference. I am now back to points and a condenser; the distributor looks fine, the cam gear is aluminum and looks pretty new and the timing marks all line up. Any ideas or experience are most welcome! Thanks, Mike.
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| marko39 | -- 08-01-2023 @ 5:26 AM |
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i would start with checking engine vacuum and doing a compression test.
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| carcrazy | -- 08-01-2023 @ 12:35 PM |
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Some of the items that can cause lack of power at higher RPMs or loads are: a failing fuel pump, contaminants in fuel system or plugged tank vent obstruction in exhaust system or air cleaner point bounce due to weak spring
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| alanwoodieman | -- 08-01-2023 @ 3:01 PM |
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lousy gas is probably the culprit in your problems, In the states we use marvel mystery oil in the gas to help prevent valve stem problems also some in the engine oil. for now if it will run at all spray some of the mmo down the carb and see if this help. if you cannot get mmo some automatic trans fluid will also work, remeber it will smoke up the joint so put the car outside
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| TomO | -- 08-01-2023 @ 5:22 PM |
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Welcome to the Forum. We enjoy seeing photos of the cars. It sounds like you have a new problem or the old one has gotten worse. Start with the basics: Check your spark at idle with the engine warm. When you hold a plug wire near a head bol6t, you should have a nice blue spark about 1/2" long. If you do not have this, the problem could be either the coil or condenser. Change on or the other and retry the spark test. If you have good spark, check the compression. It should be within 5 PSI from the lowest to highest, but if you have a problem with rings or valves there will be a significant (20 pis or more) difference. If one or more cylinders are out of range, pour about 15ml into the cylinder(s) and repeat the test. If compression increases, the rings are the problem, if it stay about the same, the problem is more than likely valves burn or sticking. Come back here withe you compression readings for further guidance. Good luck and let us know how you make out. Tom
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| hootomik | -- 08-02-2023 @ 7:29 AM |
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Hi, thank you for your comments. I have just run some Redex solution through the carb (one litre of gas, 250ml of Redex) - no change. Idles OK, but as soon as you try and rev it backfires and stutters, and will not rev. Checked the spark - good and strong. In the last few weeks I have replaced the coil (high output fitted), plug leads, points, carb, fuel pump and associated pipes. I am running it off a can at the moment because I suspect that I have a separate problem of dirt in the tank. I am using low-ethanol gas (5%). I checked the compression last week: 100psi +/- 4psi across all cylinders. The car runs a twin exhaust system, and both sides seem to push out similar amounts of exhaust gas. I have had the assistance of a couple of friends who both have V8 experience, but not side-valves. We have covered all the bases we can think of, apart from stripping the engine and having a look at the valves. I am looking on this as a last resort and hoping that one of you may have an idea that would avoid it... I am not the best mechanic! This message was edited by hootomik on 8-2-23 @ 7:31 AM
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| carcrazy | -- 08-02-2023 @ 9:19 AM |
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If the engine backfires through the carburetor, chances are good that the fuel/air mixture is too lean or the ignition timing is off.
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| trjford8 | -- 08-02-2023 @ 9:49 AM |
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I would drop the gas tank and see what you have for crud in it. It's possible that there is some in the gas line and causing the car to starve for fuel.
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| mfirth | -- 08-03-2023 @ 5:19 AM |
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Hi Mike, be sure to make sure the vacuum advance diaphram on the didtributer is working properly. Also, there is a wire in the distributer under the plate that the points are mounted on that can temporarely go to ground if the insulation is compromised. Causes all kinds of problems. You can probably get a diagram of the distributer on line. Just another possiblity.
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| 40cpe | -- 08-03-2023 @ 11:10 AM |
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I believe your compression is too good to cause your symptoms. With those readings, I believe you are a long way off from tearing your engine down. I agree with mfirth above. Check the wire under the points plate in the distributor. Insulation rubs off and shorts the fire to the points or the ignitor as the plate moves when the ignition advances. You might want to disconnect the vacuum line to the distributor and see if it still has the same symptoms. It might give you some insight on distributor problems. I noticed your changed the points, but didn't mention the condenser. The condenser can also cause mis-firing. Good luck, I hope you find the problem soon. This message was edited by 40cpe on 8-3-23 @ 11:16 AM
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| TomO | -- 08-04-2023 @ 6:26 PM |
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You have good compression readings, so it is unlikely that you have worn rings or burnt valves. Another cause would be plugged jets, but you said that you replaced the carburetor. If the primary wire in the distributor is OK (remove it from the distributor and examine it closely). I would not tear down the engine until you prove that it needs to be done. The next step would be: Remove the windshield wiper vacuum hose from the manifold and plug the manifold vacuum port. Remove the vacuum advance vacuum line from the vacuum advance and plug the line. Now try and start it. If it runs OK connect the vacuum advance and retry. If the problem comes back the vacuum advance is bad, if it continues to run OK the vacuum hose to the windshield wipers is bad. If it does not run OK restore the vacuum lines and continue below. Check all of the spark plugs for condition and gap. It won't hurt to do it again. Clean and re-oil the air cleaner. Because you put in new wires and a high output coil, run the engine after dark and look for crossfire. If you have crossfire, order the 1950-1951 spark plug wire bracket P/N 0BA-12111. This will space the wires so any crossfire will have a minimal effect on performance. Sparks coming out of the wires to the intake manifold or heads need to be replaced. Connect a vacuum gauge to the windshield wiper port and check engine vacuum at idle and as you come off of idle. Use the chart on this site : https://www.onallcylinders.com/2016/03/31/vac-visual-quick-guide-vacuum-gauge-readings/ as a reference. If none of these suggestions help the problem, please post photos of the engine compartment showing the routing of the plug wires, closeup of left and right sides of the carburetor without the air cleaner and the wiring of the distributor cap. A photo of the vacuum gauge with the engine running would also be beneficial. Tom This message was edited by TomO on 8-4-23 @ 6:48 PM
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| hootomik | -- 08-06-2023 @ 10:28 AM |
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Thank you for your guidance - I will carry out some further experiments! All this help is much appreciated!
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| hootomik | -- 08-09-2023 @ 2:04 PM |
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OK guys, I have done the tests with the vacuum, blocking off both carb and inlet manifold (windshield wiper) ports and there was no improvement in running. I have run the motor in the dark, and there are no signs of any external sparking anywhere on the ignition system. I don't have a vacuum gauge (but I know a man who has) so I haven't been able to measure the vacuum yet. Having tried the 'paper test' putting a sheet of A4 over the tailpipes there is no sign of suction - the pipes just blow out gas - which I'm informed means the valves are not sticking. I will get some photos of the engine bay tomorrow and post them for further info. thanks for all the ideas - keep 'em coming please!
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| hootomik | -- 08-10-2023 @ 8:44 AM |
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I have some photos of the engine bay for your info. To head-off some questions: The car operates on the original 6v system, except the starter-motor which is powered by its own 12v battery. The carb is a Chinese copy of the original Type 94 unit. I recently fitted this - it made no difference to the running problem. The original carb has been rebuilt and cleaned and appears to be in good condition. The mechanical fuel pump is disconnected from the carb. I am feeding it from a can via an electric pump. The car is operating on points ignition currently, with a new set of points, coil and leads, but the condenser is a couple of years old. A new one is on order. Thanks, Mike.
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| TomO | -- 08-10-2023 @ 11:35 AM |
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Thanks for the photos. I cannot see anything unusual in them. I was betting on a vacuum leak and that is still my first choice. Over here I would just get a can of propane gas or carburetor cleaner to check the areas where the carb is mounted and the intake mounting. I don't know the air pollution restrictions in the UK, so I am reluctant to recommend this. I will wait for you to clean and check the spark plug and their gaps and hope that you get a vacuum gauge soon, to check the vacuum. Tom
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| carcrazy | -- 08-10-2023 @ 8:30 PM |
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Where is your coil mounted? Normally on third generation (1949 thru 1953) Flathead V-8s the coil mounting bracket is bolted directly to the passenger side (in the U.S.) cylinder head near the distributor. In this location there is no relative movement between the coil and the distributor. When the coil is mounted remotely from the engine there will be relative motion between the coil and the distributor which enhances the chances of intermittent continuity in both the primary and secondary circuits of the ignition system. Make sure the primary and secondary wires are sound and making good connections. The primary wires should be soldered to their terminals at both ends to insure reliable conductivity at all times .
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| alanwoodieman | -- 08-11-2023 @ 8:09 AM |
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the coil is mounted on or just above the right side exhaust header? if it is, get it out of there it is probably failing due to heat from the exhaust.
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| hootomik | -- 08-13-2023 @ 11:36 AM |
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HI, the coil is mounted in a bracket which is attached to the passenger side cylinder head (see photo). The connecting wires are crimp-terminated.
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| hootomik | -- 08-17-2023 @ 3:23 AM |
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Hi, I have borrowed a vacuum gauge, and connected it to the windshield wiper take-off point. The reading was steady, in the 'normal' range at 19psi (see photo). I have also replaced the distributor-cap and the condenser - neither change made any difference to the running. Idles OK, but when asked to rev it bangs and stutters and pops. This message was edited by hootomik on 8-17-23 @ 3:27 AM
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| carcrazy | -- 08-17-2023 @ 8:05 AM |
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Your vacuum reading looks good. I would check for something shorting out your primary ignition circuit when you accelerate the engine. Check inside your distributor for wires being shorted out or causing an open circuit. If you have a spare distributor, try substituting it for the current one to see if the problem goes away.
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| RAK402 | -- 08-17-2023 @ 9:13 AM |
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hootomik, Is there any chance that there are any plug wires reversed. I vaguely remember having a similar situation on my '40 when I first got it-it would idle pretty well, but would not run right on the road. Two of the plug wires were reversed in one of the distributor caps. Once we got that sorted, it ran fine.
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| MG | -- 08-18-2023 @ 9:11 AM |
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RAK402's suggestion above is well worth pursuing. Several years ago, with symptoms similar to yours, I found two spark plug wires in my '37 that were reversed in a distributor cap. It had me stymied for months...
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| hootomik | -- 08-19-2023 @ 2:28 AM |
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The distributer cap is a 'modern' type, with the leads plugging into holes on the top of the cap above each contact. Starting at No.1 going clockwise the order is 1-5-4-8-6-3-7-2 and I have confirmed that the correct leads go to the appropriate plug. I have ordered a second-hand (refurbished) distributor from the US, and am awaiting its arrival to enable me to try a final throw of the dice...
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| 40cpe | -- 08-19-2023 @ 9:10 AM |
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Can you move that distributor cap hold-down clip and take a clear, close up picture of the connection at the points?
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| hootomik | -- 08-20-2023 @ 7:24 AM |
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Distributor today: new condenser (didn't make any difference).
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| 40cpe | -- 08-20-2023 @ 6:55 PM |
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I am grabbing for straws, now. The original wire that feeds the points from the coil was a very flexible, fine stranded wire. That red wire might bear checking out. Also, I don't remember reading that the bushing for the distributor shaft being checked. A loose shaft allows point setting to vary, sometimes enough to prevent the points from opening. Grab the shaft where the rotor mounts and try to move the shaft from side to side. I don't remember the spec, but movement more that 4-5 thousandths would concern me.
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| TomO | -- 08-20-2023 @ 7:27 PM |
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What did your vacuum gauge show when you revved up the engine? Did you recheck your spark plugs for condition and gap (.029-.032)? Can you show a photo of the rotor? Also the contact side of the distributor cap? Do you get a good, steady spark when you increase the RPM? Do you have a timing light? If so have you check the timing with it? Tom
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| hootomik | -- 08-21-2023 @ 11:13 AM |
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Hi Tom, to the best of my recollection the gauge reading flickered a little towards 20 when the engine was revved, but I would have to do it again to check properly - and also to tell you about the spark strength / frequency. The plugs were checked and gap at .030". All dry but sooty. The photos show the inside of the distributor cap and the rotor arm I am currently using. I swapped these over with other barely-used items I have last week and there was no difference in the running. I have today received a new condenser (correct for the car) from USA which I will fit tomorrow (weather permitting), but as I have just fitted a different new unit and it made no difference I am not holding my breath...
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| carcrazy | -- 08-21-2023 @ 1:01 PM |
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One thing you can try is using a set of points that is not so plastic intensive. It looks like you are using the 7RA-12171 type of points. My suggestion would be to use the FAA-12171 type of points which are more traditional looking and employ steel instead of plastic for the main components. These points are available from vanpeltsales.com. They are listed on one of the links shown on this website under "Friends". Hope you find the solution to your problem.
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| RAK402 | -- 08-21-2023 @ 7:22 PM |
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I am really curious as to what the issue finally turns out to be.
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| hootomik | -- 08-22-2023 @ 6:18 AM |
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Not as curious as me RAK402! I fitted the correct condenser today, then hooked-up a vacuum gauge to the wiper port. At idle, the reading is 19. Increasing the revs drops it progressively to 10, and down to 5 when the throttle is properly 'blipped' (at which point it is backfiring through the carb). My perception is that the car is revving a bit more freely now... but still popping and banging as the revs rise. What does this all mean?
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| Drbrown | -- 08-22-2023 @ 7:40 AM |
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A steady vacuum reading of 19 at idle is good. My '47 reads 17 at idle and runs great. Vacuum naturally drops as engine RPM's increase. A bad timing gear would show up at all RPM's. Back firing is basically an ignition problem but has also been known to be caused by carbon build-up.
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| TomO | -- 08-22-2023 @ 12:01 PM |
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Your cap and rotor look OK from the photos. The set of points you have look like a poor quality as the rubbing block looks worn in the last photo. Your problem could be the mis-alignment of the contact points. I did not notice it in the previous photos, but your last photo clearly shows that the alignment is way off. The points must meet so the the faces meet squarely and are aligned top to bottom and front to back. Make sure the alignment is correct before setting the gap. The vacuum readings also suggest that the spark timing may be incorrect. Can you get access to a timing light and a dwell meter? If so I would set the points with the dwell meter and then time the spark. https://constructionmanuals.tpub.com/14273/css/Figure-2-52-Contact-point-alignment-71.htm Here is a link to a set of points closer to you than Van Pelt. https://www.ebay.co.uk/itm/284576145836?hash=item42420f61ac:g:bfQAAOSw5oFhwKYZ&amdata=enc%3AAQAIAAAA4OH5wq5LpLIGiF%2BaUIoQKOC%2Bi4kLMjzuLKDfuJXX7w%2F1fS%2BKWbqTAYVAlXyaZKr8Is1EllCbV2MN8Igg0X1RXS7cpU77PNLOzTz0A%2BpKhAZU%2BmYwdCJ3JD3Vkw7Ja6vqznVGH0ZilqirCozfiqWDWJPonRatt4i8vON5cH8Vbe3gGrVTRqDrg%2FfPrpv9GVVIgAhYklQogER%2BzH4urNUq2eRPU4DBn%2B0TylzLMI%2FHKX0pcJhjI5bfSdlV%2BEr7jZNzujnEu3QgmAb55RgBktWcobcBIxv%2BD6kXRs7hYqYTUgYC%7Ctkp%3ABk9SR-im8OjDYg Tom
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| hootomik | -- 08-22-2023 @ 2:47 PM |
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A further update: Tom - thanks for the ebay link to the points - I've ordered them. My friend came over today with his vacuum pump and tester. The baseplate of the distributor moves under vacuum, but does not seem to move far enough. Also it appears to move back slowly when the vac is removed; is the baseplate not moving freely enough? Or could it be the vac advance unit (new last year)? We disconnected the vacuum at the carb and connected the vac pump to the line to the distributor instead. It held vacuum, so no leaks downstream, but also when pulling a vacuum via the pump, the timing advanced correctly and the engine revved smooth-ish with no pops and bangs. Switched the vac line back to the carb, and the running was as lumpy, poppy and bangy as before. I reckon the distributor is the culprit, so I await the delivery of my alternative (late next week maybe) with eager anticipation.
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| pauls39coupe | -- 08-22-2023 @ 6:46 PM |
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Check the exhaust. Mice in the Muffler? Drop the head pipe to see if that help. Mufflers are a great place for critters to hide their winter food supply, and rust can cause the interior baffles to plug up. A vacuum reading of 19 at idle is OK, but falling off may indicate a plugged exhaust.
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| hootomik | -- 08-23-2023 @ 1:31 AM |
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Mufflers were new last year, and there is plenty of exhaust gas blasting out of both pipe, so I don't think there is a blockage.
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| hootomik | -- 08-25-2023 @ 11:16 AM |
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Update: I lubricated the distributor baseplate with silicone spray, and it seems to move more freely. I also retightened the vac take-off from the carb. The upshot is that the engine is running and revving much better now, so I guess it was either leaking vacuum at the carb take-off, or a stiff baseplate, or a combination of both. Thank you all for your suggestions, and special mentions for all the guys who suggested vacuum was the culprit! Now I have another issue: the fuel tank that I had filled with 15 gallons of gas last September has a leak, and is empty (which caused a few false turns during my investigation...). I have tried a couple of suppliers in the US for a new replacement stock tank, but they won't ship to the UK. Can you suggest anyone who will ship, at a reasonable cost? (I've tried Gear Head World and Tanks Inc. without success).
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| RAK402 | -- 08-26-2023 @ 3:35 PM |
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Glad you got is resolved and thank you for posting the cause. That information will probably help many other people going forward.
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| TomO | -- 09-05-2023 @ 5:42 PM |
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Bob Drake shows a reproduction tank for the 49 Ford. You might consider taking the tank to a radiator shop and have them boil it out solder the leak and then you can coat the inside with a good tank sealer like Bill Hirsh sells. Follow directions completely, especially when it comes to adding a second coat. If you don't follow the directions, the coating will be too thick and will start to peel eventually. I just use 1 coat when I do it. Tom
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