| Sgstepp@yahoo.com | -- 09-21-2016 @ 5:30 PM |
|
My 47 Ford half ton pick up with flathead engine is experiencing a high rpm miss. It idles great but when the rpm is brought up to approx 800 rpm and higher it has a severe miss. This happens when cold or hot. I have replaced the plugs, points and condenser. The points only had about 100 miles on them since I changed them last but they showed some burned points so I replaced them. I adjusted them to .015 gap. The rotor and cap looked great and clean so I kept them. Could the plug wires be a culprit, especially since they are so close together inside the wiring tube. How much of a job is it to install new wires. Also what kind of connection is on the cap end of the plug wires. Do they simply pop out when disconnecting from the distributor cap. Should I install a new distributer cap at the same time or am I totally off base with these thoughts. I thought about the carburetor being the culprit but I can't wrap my head around that being the cause. I have compression on all cylinders between 80 and 90 lbs so sticky valves do not appear to be an issue. Does anyone have any thoughts that would help me out? Thanks for any feedback.
|
|
| ford38v8 | -- 09-21-2016 @ 6:43 PM |
|
I would leave the plug wires alone for now, and concentrate on fuel delivery as the possible cause. A restriction in the lines caused by rust debris, or within the fuel filter can reduce the flow to the carburetor, thereby starving the engine at higher rpms. The fuel pump can be the cause, for much the same quality of fuel issues. The carburetor may itself have an accumulation of debris in the bowl, preventing a full flow through the main jets. I suggest a simple test, run the engine up to the point of the heavy miss you describe, then shut it down. Remove the airhorn to discover the level of fuel in the carb, as well as any debris in the bottom of the bowl. If that test shows a low level of fuel, a second test can be done with the pump, by removing the line at the carb and directing it into a large container. With the ignition OFF, crank the engine over continuously to see the capability of the pump to deliver. It should be a strong pulsating stream. If not, look to the pump and filter next. You should have a glass sediment bowl on your fuel pump, which may show an excess of sediment, or air bubbles, which would indicate a dried up cork gasket. Here's hoping you won't need further ideas, and please get back to us with what you discover. Alan This message was edited by ford38v8 on 9-21-16 @ 6:47 PM
|
|
| TomO | -- 09-23-2016 @ 6:55 AM |
|
Check for a strong spark at all RPMs. Do a cylinder balance test, by shorting out one plug wire at a time with a screwdriver. The drop in RPMs should be the same with all cylinders. If one or more do not have an effect on the RPMs, concentrate on that cylinder. If you have a plugged fuel line, sometimes pulling out the choke will get enough gas to the carb to improve the running. Tom
|
|
| Sgstepp@yahoo.com | -- 09-25-2016 @ 2:27 PM |
|
Hello Alan, I finally got time to perform the tests that you described. After running the engine up to the point of noticing the miss, I held it there for about 10 seconds and then shut it down without changing the throttle position. I removed the air horn and looked into the float chamber to see the fuel chamber at half full. I saw no sediment in the chamber so I reassembled the air horn. Also the fuel pump is performing as expected it should. I did get a small burst of fuel from the carb fuel connection when I started to remove it from the carb showing some pressure in the line. After reassembling the air horn, I restarted the engine and it still has that dreaded miss. I took it for a short drive and took it up to 40 mph which is really quite fast for this setup and it had the miss all the way from approx 800 rpm to a very high rpm and it had the miss the entire time. What are your thoughts?
|
|
| ford38v8 | -- 09-25-2016 @ 3:04 PM |
|
I think TomO's advice is good, and does appear to be better than mine considering the outcome of your tests so far. Always do the simple tests before progressing to the more complicated and expensive ones, by the way! In rereading your first post, you say the points were burnt after only 100 miles, which I should have caught at the previous reading! With ignition, my first guess would be that your new condenser may be at fault, as even new ones may fail in short order. Check the mounting first, as it must have a good solid connection to ground. Tell us about your ignition setup: Is it as original to your year 1947, and the coil you are running? With or without the original resistor mounted on the coil bracket? Have you converted to 12 volt? I think these are some of the questions TomO would ask, as he is more into ignition issues than I am. Alan
|
|
| ken ct. | -- 09-25-2016 @ 3:54 PM |
|
If you have more than normal pressure at the gas line when you removed the line,check and run car W/O the gas cap your vent may be blocked or wrong cap,you may need a VENTED cap on there. Ive seen it happen before. ken ct.
|
|
| Sgstepp@yahoo.com | -- 09-28-2016 @ 4:34 PM |
|
I failed to mention before that I have replaced the condenser on the distributor at the same time as the points. The elec system is the original 6 volt system with positive ground. The coil has been changed once with a six volt coil from the parts store after the original gave up when it got hot. The plugs are new. I cannot see a resistor on the coil bracket. It must be located elsewhere. I did the old trick of pulling a single plug wire and listening to the engine idle. The right bank tested good with definite engine rpm drop when each wire was pulled. The left bank was different. The front cylinder had no engine drop, the second cylinder had no drop, the third and fourth cylinder had about 50% engine rpm drop. Does this explanation or test help to diagnose the engine miss? The only other thing that I ran into this weekend is a notice on a gas pump to use non-oxygenated regular gas in all collector vehicles. I have regular gas in this pick up. Also I must use the choke to start the engine when cold, not so much when warm. I hope this information helps.
|
|
| cliftford | -- 09-28-2016 @ 9:05 PM |
|
Do a compression check and see how they compare. The cylinders should be within a 20 lb. range. If not, you have some serious problems, probably rings and/or valves.
|
|
| ford38v8 | -- 09-28-2016 @ 9:30 PM |
|
As you pulled the plug wires to test the individual cylinders, did you also check the spark itself at the plugs? Hold the plug wires near a head bolt to check color and strength? And have you inspected the condition of the spark plugs? Pay particular attention to differences between plugs and spark at the good firing cylinders as opposed to the poor firing cylinders. The lack of a resistor at the coil may also offer a clue. Some coils have internal resistors, and would be identified as such on the packaging. Also, your year Ford is very close to the point at which the location of the resistor changed from earlier models above the steering column under the dash, to the location at the coil mount on the engine. I'm not positive one way or the other, but there must be a resistor in the circuit somewhere. Your burned points are another clue that either you have no resistor in the circuit, or that your condenser is faulty. Condensers do sometimes go bad right out of the box, and must also be connected solidly to ground to work correctly. Alan This message was edited by ford38v8 on 9-28-16 @ 9:32 PM
|
|
| ken ct. | -- 09-28-2016 @ 10:47 PM |
|
Use a NAPA cond. # ( IH-200 ) these are very reliable. Been using these in rebuilding for yrs. ken ct omo
|
|
| TomO | -- 09-29-2016 @ 7:57 AM |
|
If you are using a round coil for a 49-55 Ford, it should have an internal resister. Other round coils may not have the resister and may not be for POS ground. Make sure that the terminal marked + is going to the distributor. Follow Alan's advice about checking spark. Weak or no spark can be caused by the wires not properly seated in the distributor cap, bad distributor cap or bad rotor. If the spark is good, check your plugs. They must have the correct gap and not leaking compression. Some of the Champion H10C plugs do not work very well in the automotive engines. They are designed to be used in lawnmower and other small engines. Tom
|
|
| Sgstepp@yahoo.com | -- 10-01-2016 @ 1:24 PM |
|
I finally am getting back on the latest test to help determine this miss. I now believe that the miss is happening at all times at any rpm. I took all of the plugs out and plugged them into the plug wires. Then I grounded each one to a head bolt to determine the spark on each plug. Keep in mind that my compression test showed 80-90 lbs on all cylinders. The right bank showed a small blue spark. Not overly strong but still showed blue. The left bank showed very little spark on the rear cylinder and no spark on the other three. Keep in mind that these are new plugs with proper gap. The only thing I have not replaced is the rotor, dist. cap, and plug wires. When I reinstalled the plugs and wires it starts but the left bank shows more rpm drop then the right bank when I pull the wires off of the plugs, one at a time. Any thoughts, thanks to everyone for your assistance, it is appreciated.
|
|
| Sgstepp@yahoo.com | -- 10-01-2016 @ 1:36 PM |
|
After rereading some posts I thought I would add that I am using Autolite 126 plugs. Also the plug wires are the original wires as far as I can tell still strung inside the plug wiring tube. Does it make sense that wires that old would possibly be leaking into the plug wiring tube? Thanks again.
|
|
| ford38v8 | -- 10-01-2016 @ 6:09 PM |
|
That's not really the best way to test spark. Hold the plug wire near a headbolt without the plug attached, while the engine is running. Do this individually with all plug wires. TomO advised about rotor and cap, but you haven't checked or changed those? Have you checked the plug wire's seating within the cap? Your points showed quite a lot of metal transfer, but you stay with the same condenser because you replaced it once? Do you know the incoming voltage to your coil, and have you determined that the coil has it's own resistor? I'm not trying to be a smart ass, I'm just trying to get you to try the suggestions you've been given before you go on to more expensive ideas. Alan
|
|
| Sgstepp@yahoo.com | -- 10-02-2016 @ 7:58 AM |
|
I just did a test of the plug wire spark with the engine running at idle. I found that the right bank had a gold color up to 1/8" long. The left bank was a little weaker with a small blue/white spark up to about 3/32" long. I noticed more of an engine rpm drop when I pulled the right bank plug wires than the left bank. None of the plug wire sparks seemed as strong as it should be. It is not a strong snap when it fires. I did find the resistor under the dash up high on the drivers side. Nice shiny coils like it had been replaced lately. No burned out look to it. A voltage test on the coil showed 6.4 volts coming in and 3.4 volts coming out. I have a 8 volt battery in the truck. I have not changed the cap or rotor as they looked good And clean when I had it apart and everyone seem to give me the idea that I should do more testing before throwing a bunch of money at it. That is what I am doing now is following the suggestion given to me. I appreciate everyone input.
|
|
| ford38v8 | -- 10-02-2016 @ 8:22 AM |
|
OK, good test there, and good information. Do this please: Engine off, ignition on, voltmeter on the incoming coil terminal, and record the reading. Then bump the engine over without starting it, and record the reading at the same place. The two readings will be different, and will provide more clues for us. Determine whether your coil has an internal resistor or not. It may not indicate on the coil itself, b ut trace down the part number for this answer. Alan
|
|
| ken ct. | -- 10-02-2016 @ 8:26 AM |
|
Get rid of the 8 V battery first of all use a 6 V one. I would change the wires for new SS or copper core ones. You should have better blue spark at the plugs. OMO. ken ct. and change the cond. to a NAPA IH-200 these are reliable out of the box.
|
|
| ford38v8 | -- 10-02-2016 @ 8:40 AM |
|
Ken, I fully agree, but let's get him running first before rebuilding his car. Alan
|
|
| trjford8 | -- 10-02-2016 @ 8:59 AM |
|
If the plug wires are original they are 70 years old. Put in new ones. You have no idea if the insulation has gone bad due to them being hidden in the metal tube. By now the wire core has also corroded setting up a lot of resistance.
|
|
| Sgstepp@yahoo.com | -- 10-02-2016 @ 11:26 AM |
|
I got the readings for the coil, I started by taking a reading prior to bumping the engine over, 4.6volts, after the first bump I got 4.1 volts, the second bump I got 3.9 volts, then 3.8 volts. I also checked the coil part number and it does not have a resister. Coil pn niehoff FF-170. I hope this helps and thanks for all of the quick responses.
|
|
| ford38v8 | -- 10-02-2016 @ 12:23 PM |
|
OK, now I'm in over my head. I can't find info on your coil, and those voltage readings are nowhere near what I expected to see. I'm thinking your engine bumping began with points open, and each bump thereafter returned to points open also. The slightly declining values each time may be showing your resister getting hotter, thereby reducing voltage output. I don't think you got a reading with points closed. Because I couldn't find your coil info, I can't confirm it to be 6v. Your points being in poor condition, and the 8v battery all contributes to frying my old brain! Alan
|
|
| ken ct. | -- 10-02-2016 @ 12:52 PM |
|
I wasn't recommending him rebuild his car. Only suggested going back to 6V and installing new wires and condenser fairly easy job. OMO ken ct We will get him going. Leaving for Hershey early Tues. morn. "GDF 4,5,+6 " spaces green field. Praying for NO Hurricane.
|
|
| Sgstepp@yahoo.com | -- 10-02-2016 @ 1:32 PM |
|
It has a label right on the coil that it is a six volt coil. I also called the local parts store to confirm that there is no resister in the coil. I think there has been a lot of great input to try and help me out. The suggestion of replacing the plug wires makes good sense. 70 years old is a long time for the rubber coating to stand up. Do the wires simply slip out of the dist cap? Also I read that I should put a drop of solder on the end of the plug wires, is that a good idea? Being that I will have to remove the dist cap, should I replace those two items. Lastly where is a good place to purchase these parts, the local oreillys store doesn't have any listings for these wires. Thanks again.
|
|
| ken ct. | -- 10-02-2016 @ 4:10 PM |
|
Hate to say it but Mac's has the inner contact plates ,but ask for the BRASS contact ones only. They also have the wires . ken ct. Oh just noticed its a 47 are you running a rabbit eared dist or a crab type. These have diff cap and rotor differences and clips. ken ct.
|
|
| Sgstepp@yahoo.com | -- 10-02-2016 @ 4:44 PM |
|
It is the rabbit ear style. To be sure, I should get the rotor, inner and outer cap, gaskets, wires with brass connects and a new condenser, dist cap rubber boots and a new dist cap clip. I am looking at the Macs book also. I really don't care for Mac's that much but they do carry a lot of items. I returned some items about six weeks ago and haven't received a refund yet. Maybe now I can get it in parts???? Thanks for all of the feedback. Being that winter is getting close I will likely save this project for spring although I hate putting something away that is not repaired properly. I will let you know how things turn out.
|
|
| ken ct. | -- 10-02-2016 @ 4:56 PM |
|
No make sure the inner cap has the brass contacts not aluminum. The end of the color coded wires should be soldered to the wire. You can use your old outer cap as they really do nothing. These dist do NOT use a clip but use a large wire bale which holds both caps on. There are 2 gaskets 1 for each cap. ken ct. Use USA made points and short rotor. True crab dist. uses a longer (wider) rotor (42) only. Good luck. ken ct.
|
|
| TomO | -- 10-03-2016 @ 10:00 AM |
|
Just as a quick check, take a piece of high tension wire with ends on it to fit into the coil and remove the high tension wire going from the coil to the distributor at the coil end and replace it with the new wire. Take the other end and hold it near a ground while cranking the engine. This will show how much spark the coil and condenser are providing. If it is weak, you can use a NAPA coil for a 49-55 Ford and bypass the ignition resistor, or have an original Ford script coil rebuilt by Skip Haney. I believe that the FF-170 was made in the last century as it is Niehoff's old numbering system and I seem to remember them closing their plant in the late 1980's. I was disappointed to hear the news at the time, as I was a big fan of their parts. A coil that old is questionable and should be checked out before replacing other parts. Tom
|
|
| ford38v8 | -- 10-03-2016 @ 12:19 PM |
|
Tom, what about his 8v battery with the Napa coil & bypass resister? Or with skip's rebuilt coil? I'd want to start fresh with a good 6v, but he may not. Sgstepp, whoever put an 8v battery in your Ford likely was having hard starting issues or dim lights. If you replace it with a good 6v battery, we're helping your ignition issues now, and can help your lighting issues after that. Alan
|
|
| ken ct. | -- 10-03-2016 @ 12:53 PM |
|
Using an 8V battery to operate a 6V coil isn't the smartest thing to do. Get rid of the battery.Your PO was NOT too BRITE, omo ken ct. Keep us updated.
|
|
| Sgstepp@yahoo.com | -- 02-22-2017 @ 5:55 PM |
|
Hello all, We had a break in the weather with highs in the sixties and I got the bug to try getting the 47 back on her feet. I re-read the posts and decided to replace the plug wires, points, condenser, cap, and rotor. Replacing the wires was the biggest task, but got it done. Tried starting the old girl and had no luck. I reran the basic tests and I had the same results. After rereading the great posts that everyone gave me I got to thinking about the 8 volt battery and the comments about the coil. That's right the coil. I replaced both, I put a new strong 6 volt battery and the recommended replacement coil. hurrah it started and ran almost perfectly. I had to take it for a ride and had good results. The idle is a little high but that is a easy fix. Now the weather is calling for a foot of snow so I parked the old girl with a good feeling, finally. A big thanks for all of the great input to help me out. I really appreciate everyones input. FYI the new recommended coil has a resister in it.???
|
|
| TomO | -- 02-23-2017 @ 9:17 AM |
|
I am glad that you are back on 6 volts and that the new coil got you running. Before you run the engine any more, you should check to see if the voltage regulator was adjusted to supply more than 7.4 volts. If it was, you will have to have it reset to original specs by a generator repair shop or replace it. I prefer the reset as your regulator is probably better than the new ones available. To check, connect your voltmeter to the BAT terminal of the regulator, start the engine and slowly raise the rpm until the voltage reading stabilizes. It should read 7.2 -7.4 volts. If it does not read in that range, have it adjusted. You may experience light bulbs burning out because of their exposure to more than the rated voltage, so check them out every time you are going to drive your car. Tom
|
|
| supereal | -- 02-25-2017 @ 1:50 PM |
|
If it is a stock coil, it will need the resistor. If it is a round coil, it usually has a built in resistor. Using an 8 volt battery usually will mean problems unless you have the coil rebuilt. If your problem reoccurs, find a shop with a distributor machine. Our Sun machine strobes the distributor so we can check for point bounce. Many of the point sets sold today have weak springs and no brass in the pivot hole. Good point sets will cost about $30. Anything less means they are overseas parts. Condensers are also suspect. If the vehicle was running well before you installed the points, you should consider using the old condenser. A weak condenser will cause the problems you mention.
|
|
| Sgstepp@yahoo.com | -- 02-27-2017 @ 3:22 PM |
|
Hello TomO, I did the voltage test as you described and received a steady voltage reading of 7.0 volts. Should this be adjusted up to a mininum of 7.2 as you described in your last reply? If so, is this an adjustment that I can make or should I have an electrical tech tackle this job. Thanks also for explaining how to check the voltage output on the bat terminal of the regulator.
|
|
| sarahcecelia | -- 02-28-2017 @ 4:53 PM |
|
An engine miss is most always cause by the ignition. The hight tension leads could be breaking down, Point flutter( caused by improper tension on them) I suggest running the motor in the dark and watching for spark jumping to ground.
|
|
| TomO | -- 02-28-2017 @ 7:49 PM |
|
You will probably be OK at 7.0 volts. If your battery doesn't charge fully, have the regulator adjusted. You should take it to a generator repair facility to have it adjusted. The reading could be low due to voltage regulator temperature or circuitry in your voltmeter. Tom
|
|
| EFV-8 Club Forum : | https://www.earlyfordv8.org/forum |
| Topic: | https://www.earlyfordv8.org/forum/viewmessages.cfm?Forum=18&Topic=10099 |