The Ford Barn

Ken Canada · 09-02-2013, 07:42 PM

Hi, due to a bad radiator I overheated my engine. Since then the engine does not idle properly, when I remove the lead to either spark 3 or 4 it doesn't seems to make a difference in the engine idle. Below is what has been done
- no cracks found on block or head
- valves appear to seat properly, open and close properly
- new head gasket (60lbs across all cylinders)
- swapped out distributor with a known good one (off my other A)
- checked for any intake leaks (I sprayed ether around intake no change)
- swapped carburetor from the other model A
- changed plugs
- double checked propre gap on points and new plugs
- changed coil, even though we had good spark

The engine runs strong and does not seems to be missing when driving at any speed. Just when you go for a stop the idle seems to be missing. I assume on 3&4 because of the test of pulling the leads on those 2.

Today I pulled the head off again to check for cracks or anything, but I think I'm at a point were I'm going in a circle and maybe some fresh in-site or comments may help.

Thanks in advance for any help in solving this puzzle.

Ken

spdway1 · 09-02-2013, 07:46 PM

Condenser, just ask CTVPA !

blgitn · 09-02-2013, 08:03 PM

Maybe intake manifold gasket leaking; you can try spraying a little carb cleaner at the block/manifold gasket joint while it's idling to see if you notice a difference.

noboD · 09-02-2013, 08:14 PM

How hot was it?

Tom Endy · 09-02-2013, 08:34 PM

You state that you swapped out the distributor. Did you replace the top section of the distributor, the bake-a-lite portion. It could be open or shorted internally.

Tom Endy

Mitch//pa · 09-02-2013, 08:43 PM

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a few things come to mind to try but unfortunately with the head on. spdway mentions condenser but i an assuming since you swapped the dist out that was changed also. blgitn mentions spray around for a vacuum leak but i see in your original description you already tried that.

even tho you did spray around the gaskets ,,when running try richening by spraying a tiny amount of 2+2 into the intake at the wiper port to see if that smooths it out.

even tho you have good compression do a leak down test anyway with the other plugs out and the rad cap off for possible air going into the cooling system. do the 3-4 pistons look clean from possible water? also make sure 3 is not leaking into 4 from a warpage but that should have lowered compression to a more noticeable reading.

run the car with inline spark testers to all the cylinders and ck for any visual variations leading to a cap distribution problem ( cracked cap).

make sure you have good fuel and not a bad load

make sure your valves are opening and closing

use a spray bottle with h2o and squirt each cylinder on the exhaust manifold near the head and a non or low firing cylinder wont sizzle off as fast

these are just some thoughts i would have tried

markyb · 09-02-2013, 09:41 PM

Was your "60 pounds across all cylinders" referencing your torque setting on the head bolts or the compression for each cylinder? I'd be curious what a vacuum gauge shows if you can rig one up too. That might give you an indication of valve problems or vacuum leaks

http://www.classictruckshop.com/club...ts/vac/uum.htm

http://www.myclassiccar.com/pdf/howt...ssiongauge.pdf

some info that might help

PC/SR · 09-02-2013, 10:55 PM

My initial thought was a warped manifold or gasket leak, but with your tests being negative, I am starting to think of warped valves/seats. A very small leak can show up at idle but engine speed can mask a leak at higher RPMs, those being the symptoms you describe. Do you have inserted valve seats?
A compression test for starters, a leak down test is better, compare to 1 & 2. With the head off I would try Prussian blue on the valves to see if they seat well with good uniform contact all around before putting it back on. I don't know the condition of your engine but if it has been run for a long while a little valve lapping may do it some good anyway although I do not normally recommend lapping as a fix.

Patrick L. · 09-03-2013, 05:15 AM

If all 4 cylinders have 60 # compression, the engine itself seems fine. When you checked for cracks, how was that done ? Did you just look at it or did you use a torch ? If you really don't have any cracks, then it seems you have an intake leak even though you said you ether'ed it. But, it could very well be an ignition leak, such as bad cap. Look for carbon tracking or a crack in either distributor cap.

09-02-2013, 07:42 PM	#1
Ken Canada Junior Member Join Date: Sep 2013 Posts: 1	Missing on 3&4 Hi, due to a bad radiator I overheated my engine. Since then the engine does not idle properly, when I remove the lead to either spark 3 or 4 it doesn't seems to make a difference in the engine idle. Below is what has been done - no cracks found on block or head - valves appear to seat properly, open and close properly - new head gasket (60lbs across all cylinders) - swapped out distributor with a known good one (off my other A) - checked for any intake leaks (I sprayed ether around intake no change) - swapped carburetor from the other model A - changed plugs - double checked propre gap on points and new plugs - changed coil, even though we had good spark The engine runs strong and does not seems to be missing when driving at any speed. Just when you go for a stop the idle seems to be missing. I assume on 3&4 because of the test of pulling the leads on those 2. Today I pulled the head off again to check for cracks or anything, but I think I'm at a point were I'm going in a circle and maybe some fresh in-site or comments may help. Thanks in advance for any help in solving this puzzle. Ken

09-02-2013, 07:46 PM	#2
spdway1 Senior Member Join Date: Feb 2011 Location: Chicopee, MA Posts: 1,402	Re: Missing on 3&4 Condenser, just ask CTVPA !

09-02-2013, 08:03 PM	#3
blgitn Senior Member Join Date: Jun 2011 Location: West Point, VA 23181 Posts: 373	Re: Missing on 3&4 Maybe intake manifold gasket leaking; you can try spraying a little carb cleaner at the block/manifold gasket joint while it's idling to see if you notice a difference.

09-02-2013, 08:14 PM	#4
noboD Senior Member Join Date: May 2010 Posts: 319	Re: Missing on 3&4 How hot was it?

09-02-2013, 08:34 PM	#5
Tom Endy Senior Member Join Date: May 2010 Location: Southern California Posts: 3,131	Re: Missing on 3&4 You state that you swapped out the distributor. Did you replace the top section of the distributor, the bake-a-lite portion. It could be open or shorted internally. Tom Endy

09-02-2013, 08:43 PM	#6
Mitch//pa BANNED Join Date: May 2010 Location: Bucks County, PA Posts: 11,454	Re: Missing on 3&4 Sponsored Links (Register now to hide all advertisements) a few things come to mind to try but unfortunately with the head on. spdway mentions condenser but i an assuming since you swapped the dist out that was changed also. blgitn mentions spray around for a vacuum leak but i see in your original description you already tried that. even tho you did spray around the gaskets ,,when running try richening by spraying a tiny amount of 2+2 into the intake at the wiper port to see if that smooths it out. even tho you have good compression do a leak down test anyway with the other plugs out and the rad cap off for possible air going into the cooling system. do the 3-4 pistons look clean from possible water? also make sure 3 is not leaking into 4 from a warpage but that should have lowered compression to a more noticeable reading. run the car with inline spark testers to all the cylinders and ck for any visual variations leading to a cap distribution problem ( cracked cap). make sure you have good fuel and not a bad load make sure your valves are opening and closing use a spray bottle with h2o and squirt each cylinder on the exhaust manifold near the head and a non or low firing cylinder wont sizzle off as fast these are just some thoughts i would have tried Last edited by Mitch//pa; 09-02-2013 at 09:49 PM.

09-02-2013, 09:41 PM	#7
markyb Senior Member Join Date: Apr 2012 Location: Rochester, Michigan Posts: 112	Re: Missing on 3&4 Was your "60 pounds across all cylinders" referencing your torque setting on the head bolts or the compression for each cylinder? I'd be curious what a vacuum gauge shows if you can rig one up too. That might give you an indication of valve problems or vacuum leaks http://www.classictruckshop.com/club...ts/vac/uum.htm http://www.myclassiccar.com/pdf/howt...ssiongauge.pdf some info that might help

09-02-2013, 10:55 PM	#8
PC/SR Senior Member Join Date: May 2010 Location: Santa Rosa, CA Posts: 1,279	Re: Missing on 3&4 My initial thought was a warped manifold or gasket leak, but with your tests being negative, I am starting to think of warped valves/seats. A very small leak can show up at idle but engine speed can mask a leak at higher RPMs, those being the symptoms you describe. Do you have inserted valve seats? A compression test for starters, a leak down test is better, compare to 1 & 2. With the head off I would try Prussian blue on the valves to see if they seat well with good uniform contact all around before putting it back on. I don't know the condition of your engine but if it has been run for a long while a little valve lapping may do it some good anyway although I do not normally recommend lapping as a fix.

09-03-2013, 05:15 AM	#9
Patrick L. Senior Member Join Date: May 2010 Location: Largo Florida Posts: 7,225	Re: Missing on 3&4 If all 4 cylinders have 60 # compression, the engine itself seems fine. When you checked for cracks, how was that done ? Did you just look at it or did you use a torch ? If you really don't have any cracks, then it seems you have an intake leak even though you said you ether'ed it. But, it could very well be an ignition leak, such as bad cap. Look for carbon tracking or a crack in either distributor cap.