The Ford Barn

old31 · 06-18-2022, 06:08 PM

What would cause this?

With the car running i pulled the spark plug lead from the top of each spark plug about 1-2 inches and got a good spark at each plug.

But, when I totally removed the wire from plugs 1 and 2 the car made no change in running or sound or rpms. 3 and 4 when the plug wire was removed the car immediately dropped rpms and sounded different.

The dist body, rotor and cap are new within 100 miles. The plugs are new within 300 miles.

Ruth · 06-18-2022, 07:02 PM

Sounds like #1 & 2 are weak. What is your compression?

rotorwrench · 06-18-2022, 07:41 PM

The high tension will jump a pretty fair gap when everything is working as it should. If it's only running on two cylinders then it needs to have a compression test. Plugs could be fouled but a good inspection of them is in order anyway.

Ernie Vitucci · 06-18-2022, 07:52 PM

Good evening...you might consider checking your distributor body and rotor. There should be 25 thousands between the tip of the rotor and the four studs in the body. Occasionally a body becomes bent out of shape or it cracks and the spark excapes through the crack and does not get entirely to the plugs...just a thought...I found this out by experiencing it in the garage at night...or I would not have seen the spark jump out of the crack...made me say bad words...Ernie in Arizona

noboD · 06-18-2022, 08:17 PM

Also check continuity with an ohm meter to make sure the plug is grounded. If threads are dirty or rusty the plug MAY not be grounded.

old31 · 06-19-2022, 11:17 AM

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Follow up:

Plugs to ground, OK

Rotor to dist body .030. With electronic ignition that should be ok, but changed to .025

Compression with 4.2 head
WET
1 49 49
2 39 50
3 59 59
4 58 60

WHN · 06-19-2022, 11:42 AM

How many miles on your engine?

I would be worried about your compression, especially on your #1 and #2 cylinders.

If you testing is correct? Two of your cylinders, #3 and #4 are doing most of the work.

I would have liked to have seen your compression in the mid 60’s.

Good luck.

old31 · 06-19-2022, 12:07 PM

No clue on the mileage.

I redid the test with another distributor body and I got the same result. although I am getting spark to all 4 plugs the car only runs on 3 and 4. When I take off the plug wires on 1 and 2 it makes no difference.

i have also mixed up the plugs so what was in 1 is in 4 now.

I don't get it, what would cause this?

shew01 · 06-19-2022, 01:06 PM

Do you or a friend have a spare distributor body to swap out for testing?

https://www.brattons.com/DISTRIBUTOR...uctinfo/17110/

Sent from my iPhone using Tapatalk

Patrick L. · 06-19-2022, 04:30 PM

Spray the intake runner for a vacuum leak.

old31 · 06-20-2022, 08:39 AM

I just checked the intake with Propane and then WD-40 and it did not make any difference

. I also put in a new set of spark plugs and I’m still having the same problem with cylinders one and two.

I am open to ideas.

WHN · 06-20-2022, 09:16 AM

Quote:

Originally Posted by old31

I just checked the intake with Propane and then WD-40 and it did not make any difference

. I also put in a new set of spark plugs and I’m still having the same problem with cylinders one and two.

I am open to ideas.

I think you are missing the obvious problem here. You have two cylinders that basically have little compression. Your two rear cylinders are running the engine. Fronts might be firing but don’t have any real power. Hence, when you disconnect 3 and 4 the engine goes to hell. When you disconnect 1 and 2 there isn’t much change because they are really not helping.

This is my understanding based on how I read your texts.

Good luck.

nkaminar · 06-20-2022, 09:43 AM

The lower compression on 1 and 2 are going to be most noticeable at idle and would explain your spark plug test results. They are high enough that you can run the car for a while but save up for some engine work. It may be that you will only need rings and a valve job which most people can do themselves.

Are you getting any funny noises out of the engine or is it low on power? What prompted you do the spark plug test in the first place?

ETAModel · 06-20-2022, 04:58 PM

I'm far from an expert but I agree with nkaminar. Sounds like a ring job is in order. This will give you an opportunity to look the bottom end as well.

Chuck Sea/Tac · 06-20-2022, 05:24 PM

I would do a leak down test. It could be a gasket leak between 1&2.

old31 · 06-20-2022, 06:07 PM

nk, no funny noises from the engine.

What prompted me to start looking is that the last 3 or 4 times I took the car out it ran fine at first but would start to break down terribly after 30 minutes or so, mostly between 40-50mph.

wwirz · 06-20-2022, 07:01 PM

Seems odd that this should occur now. Has the car been sitting for a while? If it were me, I would run it. It is possible that for whatever reason the rings may need to re-seat to the cylinder bore. Don't run it hard. 40 - 50 may be a little much. Nothing over 40 for a while. Also keep in mind that if the engine gets hot, it may cause a problem with the condenser if it is of the original design and location on the distributor. Have fun for a while and it may get better.

Rob Doe · 06-20-2022, 09:54 PM

Did you have the throttle wide open when you tested your compression? If not block it wide open and retest, engine warm.

nkaminar · 06-21-2022, 06:04 AM

Chuck has a good point. It could be a gasket leak between 1 and 2. This is common as there is very little meat there and the copper or steel gaskets can wear a groove.

CT Jack · 06-21-2022, 08:05 AM

Hey guys he is telling us he has an electrical problem with plugs 1 & 2. They are not firing.
Ernie Vitucci and shew01 have good suggestions that I would follow through with.

06-18-2022, 08:17 PM	#5
noboD Senior Member Join Date: May 2010 Posts: 319	Re: What would cause this spark issue at the plugs? Also check continuity with an ohm meter to make sure the plug is grounded. If threads are dirty or rusty the plug MAY not be grounded.

06-19-2022, 11:17 AM	#6
old31 Senior Member Join Date: Jan 2016 Posts: 2,097	Re: What would cause this spark issue at the plugs? Sponsored Links (Register now to hide all advertisements) Follow up: Plugs to ground, OK Rotor to dist body .030. With electronic ignition that should be ok, but changed to .025 Compression with 4.2 head WET 1 49 49 2 39 50 3 59 59 4 58 60

06-19-2022, 11:42 AM	#7
WHN Senior Member Join Date: Mar 2017 Location: Connecticut Shoreline Posts: 1,823	Re: What would cause this spark issue at the plugs? How many miles on your engine? I would be worried about your compression, especially on your #1 and #2 cylinders. If you testing is correct? Two of your cylinders, #3 and #4 are doing most of the work. I would have liked to have seen your compression in the mid 60’s. Good luck.

06-19-2022, 12:07 PM	#8
old31 Senior Member Join Date: Jan 2016 Posts: 2,097	Re: What would cause this spark issue at the plugs? No clue on the mileage. I redid the test with another distributor body and I got the same result. although I am getting spark to all 4 plugs the car only runs on 3 and 4. When I take off the plug wires on 1 and 2 it makes no difference. i have also mixed up the plugs so what was in 1 is in 4 now. I don't get it, what would cause this?

06-19-2022, 01:06 PM	#9
shew01 Senior Member Join Date: Sep 2016 Location: Roanoke, VA USA Posts: 1,908	What would cause this spark issue at the plugs? Do you or a friend have a spare distributor body to swap out for testing? https://www.brattons.com/DISTRIBUTOR...uctinfo/17110/ Sent from my iPhone using Tapatalk

06-18-2022, 06:08 PM	#1
old31 Senior Member Join Date: Jan 2016 Posts: 2,097	What would cause this spark issue at the plugs? What would cause this? With the car running i pulled the spark plug lead from the top of each spark plug about 1-2 inches and got a good spark at each plug. But, when I totally removed the wire from plugs 1 and 2 the car made no change in running or sound or rpms. 3 and 4 when the plug wire was removed the car immediately dropped rpms and sounded different. The dist body, rotor and cap are new within 100 miles. The plugs are new within 300 miles.

06-18-2022, 07:02 PM	#2
Ruth Senior Member Join Date: May 2016 Location: Glide, Oregon Posts: 1,339	Re: What would cause this spark issue at the plugs? Sounds like #1 & 2 are weak. What is your compression? __________________ Ruth "Sometimes you really DO need to read the whole thread"

06-18-2022, 07:41 PM	#3
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,426	Re: What would cause this spark issue at the plugs? The high tension will jump a pretty fair gap when everything is working as it should. If it's only running on two cylinders then it needs to have a compression test. Plugs could be fouled but a good inspection of them is in order anyway.

06-18-2022, 07:52 PM	#4
Ernie Vitucci Senior Member Join Date: May 2016 Location: Scottsdale, Arizona Posts: 612	Re: What would cause this spark issue at the plugs? Good evening...you might consider checking your distributor body and rotor. There should be 25 thousands between the tip of the rotor and the four studs in the body. Occasionally a body becomes bent out of shape or it cracks and the spark excapes through the crack and does not get entirely to the plugs...just a thought...I found this out by experiencing it in the garage at night...or I would not have seen the spark jump out of the crack...made me say bad words...Ernie in Arizona

06-19-2022, 04:30 PM	#10
Patrick L. Senior Member Join Date: May 2010 Location: Largo Florida Posts: 7,225	Re: What would cause this spark issue at the plugs? Spray the intake runner for a vacuum leak.

06-20-2022, 08:39 AM	#11
old31 Senior Member Join Date: Jan 2016 Posts: 2,097	Re: What would cause this spark issue at the plugs? I just checked the intake with Propane and then WD-40 and it did not make any difference . I also put in a new set of spark plugs and I’m still having the same problem with cylinders one and two. I am open to ideas.

06-20-2022, 09:43 AM	#13
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 3,897	Re: What would cause this spark issue at the plugs? The lower compression on 1 and 2 are going to be most noticeable at idle and would explain your spark plug test results. They are high enough that you can run the car for a while but save up for some engine work. It may be that you will only need rings and a valve job which most people can do themselves. Are you getting any funny noises out of the engine or is it low on power? What prompted you do the spark plug test in the first place? __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

06-20-2022, 04:58 PM	#14
ETAModel Senior Member Join Date: May 2013 Location: Along the Red River, Texas Posts: 360	Re: What would cause this spark issue at the plugs? I'm far from an expert but I agree with nkaminar. Sounds like a ring job is in order. This will give you an opportunity to look the bottom end as well.

06-20-2022, 05:24 PM	#15
Chuck Sea/Tac Senior Member Join Date: May 2010 Location: Between Seattle & Tacoma Posts: 2,354	Re: What would cause this spark issue at the plugs? I would do a leak down test. It could be a gasket leak between 1&2.

06-20-2022, 06:07 PM	#16
old31 Senior Member Join Date: Jan 2016 Posts: 2,097	Re: What would cause this spark issue at the plugs? nk, no funny noises from the engine. What prompted me to start looking is that the last 3 or 4 times I took the car out it ran fine at first but would start to break down terribly after 30 minutes or so, mostly between 40-50mph.

06-20-2022, 07:01 PM	#17
wwirz Senior Member Join Date: May 2020 Location: Corning NY Posts: 244	Re: What would cause this spark issue at the plugs? Seems odd that this should occur now. Has the car been sitting for a while? If it were me, I would run it. It is possible that for whatever reason the rings may need to re-seat to the cylinder bore. Don't run it hard. 40 - 50 may be a little much. Nothing over 40 for a while. Also keep in mind that if the engine gets hot, it may cause a problem with the condenser if it is of the original design and location on the distributor. Have fun for a while and it may get better.

06-20-2022, 09:54 PM	#18
Rob Doe Senior Member Join Date: Apr 2021 Location: Central Illinois Posts: 490	Re: What would cause this spark issue at the plugs? Did you have the throttle wide open when you tested your compression? If not block it wide open and retest, engine warm. __________________ "It ain't what you know for certain that gets ya in trouble. It's what ya know for certain that just ain't so!"

06-21-2022, 06:04 AM	#19
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 3,897	Re: What would cause this spark issue at the plugs? Chuck has a good point. It could be a gasket leak between 1 and 2. This is common as there is very little meat there and the copper or steel gaskets can wear a groove. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

06-21-2022, 08:05 AM	#20
CT Jack Senior Member Join Date: May 2010 Location: Hebron, CT Posts: 432	Re: What would cause this spark issue at the plugs? Hey guys he is telling us he has an electrical problem with plugs 1 & 2. They are not firing. Ernie Vitucci and shew01 have good suggestions that I would follow through with.