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After cleaning the distributor, changing the condenser and points, my Windsor is running a tick worse than before. It now gets up to about 45 mph and just cuts out, starts chugging as if it's hitting a rev limiter. My assumption is that he timing is off and/or my points aren't adjusted right after reinstallation. I changed those parts to try and fix a slight miss I'm getting at idle, which is still there. I also invested in a compression gauge and this is what I found:

1 - 105psi

2 - 105

3 - 100-105

4 - 110

5 - 85

6 -105

The readings are all fairly consistent besides number 5. The engine has 78,000 miles and being a 1949 I'd say the readings are what I expected. Would anyone suggest that perhaps my number 5 cylinder could be a valve issue, and causing the miss I've had before and after the distributor adjusting?

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Whilst the low compression in 5 is not helping the cause its unlikely to be the main problem here (however the valves are high on the list for compression loss). Given that you have done some ignition work l would be working my way through the fuel system, starting with the carb, pump and lines from the tank.

Having said that, if you dont cure the problem via fuel supply you might look a little closer in the ignition system by replacing plugs, wires, rotor, cap etc. After that it could be in the distributor itself with worn drive shaft bushes.

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Make sure that the points are installed correctly. I found where a guy had the spring that pulls the points closed positioned wrong and with reduced closing pressure it acted like you are describing.

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You have plenty of compression to be going along with in spite of low #5. That leaves ignition and carburetor.

If you have a good hot spark, at the right time, on all cylinders that leaves the fuel system. Your description sounds like a clogged fuel filter or faulty fuel pump. As if you are getting enough gas to go 45 but no faster. And as soon as you try to go faster you run out of gas.

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I can rev the car as high as I comfortably want it to in the driveway, but under load in gear it cuts out. Visually the points are correct, but I'll go ahead and pull the distributor just to verify the gap again; easier off the car for me. When I first got everything back together on the car I did get a backfire, but nothing since. All the plug wires are correct and both the wires and plugs are all two years old. Could the backfire have forced crud back through the carb and/or fuel lines?

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Revving the engine in the drive is not the same as driving with the engine under load, so dont think you have eliminated the fuel supply factor. When you are on the road your fuel consumption is much greater than revving in the driveway, additionally there are a number of different fuel flow circuits at play within the carb, so you would be well advised to check the carb out a little further as well as the pump and fuel lines.

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Even on the road, you can burn gas faster than it fills the carburetor until you drain the float bowl. This might take half a minute. Gunning the engine in the driveway, and having it rev faster than it will on the road, is typical of a weak fuel pump or clogged filter. Could also be a weak spark. The difference is with a weak spark the engine will usually sputter and misfire, out of gas and it just cuts out .

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How will that fix a bad fuel pump? Suggest you disconnect the carb and feed the fuel line into a juice can or 2 liter pop bottle, while someone turns the engine over. You should get a healthy shot of gas every time the engine turns over. Or, you can test the pressure with your vacuum gauge/fuel pressure gauge.

In reality the problem could be anywhere from the gas tank to the carburetor. That is, if the running out of gas theory is correct.

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Guest JohnArthurSpinks

Maybe the breather on the gas tank is blocked.

Try running it down the road without the gas cap.

Have a look at the glass bowl on the fuel pump when the engine is running and the gas level should be steady and solid gas with no bubbles or surging.

if you see bubbles you have a vacuum leak somewhere.

Cheers

John Spinks

Aussie C9 Airflow Coupe

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  • 2 weeks later...

Put a rebuild kit in the fuel pump and a low pressure blast through the fuel line back to the tank. While putting the fuel pump to carb line back on I cockeyed the threads on the brass fuel pump outlet, which created a fuel leak at that brass outlet. Can those be found at parts stores or is there a good place to find those online?

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Now trying to adjust valves. I've used a feeler gauge and I believe all of them are a bit tight as none will accept anything more than a .08 inch gauge, and even most of those have heavy drag when pulling the gauge out. I've got the wheel and inner fender cover off, and obviously the valve spring covers, but I'm having troubles confidently determining which valves are exhaust and which are intake. Anyone have a schematic/diagram showing the front to rear layout of the valves on a 251 six? My Chrysler shop manual doesn't do that great of a job specifically showing which valves are which. Thanks.

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Simply look at your manifolds. The exhaust ports line up with the exhaust valves and the same for the intakes. Remember that two of the exhaust ports are in common ports of the manifold. I believe you are looking at .008 for the clearances on the valve stems. Too tight will burn the valves, are you setting them running (ass suggested and darn near impossible to do) or setting them cold. Cold, typically add .001 to the recommended clearances. Hope this helps. I normally take a piece of masking tape or cardboard and mark my valve positions so I don't have to think about it under the car.

Rob

Hattie's Garage

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Miss at idle appears to be gone. All valves were tighter than spec, especially the intake on cylinder 5. Letting the car idle for roughly an hour did push it up to roughly 200-205 degrees. Never seen it get that hot but it is idling in the garage with the doors open. I'm doubting they've ever been adjusted.

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Tight valves can definitely affect performance. Luckily, it seems you adjusted them before any damage was done. Valve adjustment should be the first step in any tuneup. The rule is valves first, then ignition, finally carburetor because the other 2 affect carburetor adjustments.

You may notice higher compression and better performance now.

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After replacing my brake lines I finally got the car back out on the road. Thing still wants to stutter and bog down at 50 mph; I have to be running too rich. I leaned out the fuel mixture with the screw on the side of the carburetor and it doesn't seem to do much of anything. The carburetor was completely cleaned and a new kit installed late last year.

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I did blow some air pressure back through the fuel line into the tank. I really doubting it's anything to do with the fuel tank or the lines, but ill pick up a vacuum gauge tomorrow and check the fuel pressure out of the fuel pump. Rebuilt the fuel pump a couple weeks back so hopefully that's no issue. Noticed the exhaust has a good amount of black smoke coming out, so it's definitely burning off plenty of fuel.

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Your carburetor is definitely faulty if you see black smoke. If it was rebuilt correctly, and all adjustments to factory spec, I would suspect a leaking float.

The only other possibility is a completely choked air filter. Do you know how to clean and service the air filter?

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The car ran great up until changing the points and condensor a few weeks back. That's when it did backfire once. I haven't ever seen the air filter, and I wasn't aware it had one from the looks of it. I'm guessing you may be referring to the oil lined can above the carburetor? It's been a year or so since I've drained and refilled that with fresh oil.

Edited by chrysler49 (see edit history)
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Oil lined can = permanent air filter. You need to take the top part off, and soak it in a pan of Varsol, kerosene or cleaning solvent. Swish it around and let it drip dry, do not blow with compressed air.

The bottom part needs to be filled to the line with 50 motor oil.

This only needs to be done once a year or less. As long as the base is no more than half full of dirt and the oil is to the line (check at each oil change). If you drive on paved roads, it will be good for years.

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3 checks for fuel pump.

1-pressure

2-vacuum

3-volume.

Automatically change all rubber lines and check for restrictions in the steel lines.

I'm going to be putting a dist machine and a scope on line. That will take a lot of guess work out of the equation.

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Soaked air cleaner in kerosene most of the day. Did make a difference; car seems a bit more peppy, but up around 45-50 it still is stalling.

Grabbed a fuel pressure gauge today, and then realized my hard fuel lines can't really be spliced into, and I don't have the additional hardware to fabricate a junction. I guess from here I'll have to take the carb off and check it out. Other than the carb it really can only be something within the ignition system I didn't get set just right.

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Soaked air cleaner in kerosene most of the day. Did make a difference; car seems a bit more peppy, but up around 45-50 it still is stalling.

Grabbed a fuel pressure gauge today, and then realized my hard fuel lines can't really be spliced into, and I don't have the additional hardware to fabricate a junction. I guess from here I'll have to take the carb off and check it out. Other than the carb it really can only be something within the ignition system I didn't get set just right.

Have you driven at high speed with the air cleaner removed ? This might tell you if the air cleaner is at fault, and when it bogs down you might also consider pulling over smartly, shutting off the engine and removing a couple of spark plugs; if its running rich they may well be sooted up confirming that there is a mixture problem.

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  • 2 weeks later...

You might try gravity feeding the carb from a lawnmover tank thus eliminating any fuel line and pump issues.

Did you successfully bring the car above 50mph before the tune-up? If so, your distributor work would be prime suspect. By rebuilding the carb you might have introduced another problem.

Tom

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I just removed, examined, readjusted and reinstalled the distributor and I'm still getting the chugging at 50mph. I did notice the "minor timing gauge" on the distributor bolt down plate, and didn't notice it before. Would that have enough of an effect slightly moving the distributor clockwise or counter clockwise according to the little gauge? Gonna go ahead and remove the carb, reclean and examine the float, and if that isn't it it's gotta be something in the ignition system.

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Soaked filter in kerosene and it's good to go. Recleaned carb earlier and checked float. No difference.

Car did backfire awhile back after updating the ignition components and it seems since then it's had this issue. Could there be an exhaust blockage or issue since then?

Edited by chrysler49 (see edit history)
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Gets to a certain rpm, whether 30 mph in low gear or 50-55 in high gear, and it won't go any faster. Thing chugs and has nothing left. Definitely tied in with the black sooty plugs and black exhaust. I cannot imagine my timing would be that far off after replacing ignition components that it runs great until higher rpms.

Edit: did completely unhook the choke and the car now bogs down around 20-25 mph in low, and 45-50 mph in high. A bit lower in the rpm range than before.

Edited by chrysler49 (see edit history)
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Gets to a certain rpm, whether 30 mph in low gear or 50-55 in high gear, and it won't go any faster. Thing chugs and has nothing left. Definitely tied in with the black sooty plugs and black exhaust. I cannot imagine my timing would be that far off after replacing ignition components that it runs great until higher rpms.

Edit: did completely unhook the choke and the car now bogs down around 20-25 mph in low, and 45-50 mph in high. A bit lower in the rpm range than before.

What carb is fitted ?

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You need to look at both the 6V feed wire and ground cloth covered wires in the distributor. The wires are a very fine strand flexable wire so they don't break because of the constant flexing caused by the breaker plate movement.

Bob

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