timing? points? vacuum issue? valves?
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Senior User
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From: Appleton, Wisconsin
dirty plugs
My plugs only have a few hundred miles on my v8 flattie, but the white porcelain keeps getting blackned up on the outside. Carbon? ANy thoughts on whats causing it?
It wipes off off
Just Curious
Todd
It wipes off off
Just Curious
Todd
Last edited by snipa; Aug 26, 2005 at 07:42 AM.
Fleet Owner
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From: NM
You could need to re-jet, but if you are using the Holley 94 (stock type) carb, it's common to have the power valve gasket leak, or a bad power valve itself. This is a pretty involved topic but the bottom line is, the power valves that came with these carbs had a square shoulder near the threads, and all modern replacements have a radiused shoulder, and it is difficult to get a good seal with the modern style gasket. The best bet is a 1/2"-ID copper crush washer, AN-900-8, used on AN fuel line fittings. Many hydraulic parts stores carry them.
94's also tend to plug up on the tiny holes in the emulsion tubes, check a parts diagram and you'll see what I mean. They have very small holes drilled in them and it doesn't take much crud to plug them.
What jets are you running (and what altitude are you at)? Usually somewhere around 50 - 52 is right.
94's also tend to plug up on the tiny holes in the emulsion tubes, check a parts diagram and you'll see what I mean. They have very small holes drilled in them and it doesn't take much crud to plug them.
What jets are you running (and what altitude are you at)? Usually somewhere around 50 - 52 is right.
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From: Appleton, Wisconsin
It is a stock Holley. I just had it rebuilt last fall so all the seals are new with standard carb repair kit from the Ford Barn here in Appleton.
The seal leak in the new gaskets could explain what your talking about.
I'm around 700 feet altitude
I'll have to check the other info you mentioned
I've also smelled a faint gas oder in the cab recently. Maybe from this gasket leak?
Thanks!
The seal leak in the new gaskets could explain what your talking about.
I'm around 700 feet altitude
I'll have to check the other info you mentioned
I've also smelled a faint gas oder in the cab recently. Maybe from this gasket leak?
Thanks!
Last edited by snipa; Aug 26, 2005 at 09:46 AM.
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From: Appleton, Wisconsin
Follow up to this topic
When I idle the engine and look under the hood, there is a grinding/ rattle sort of noise coming from the distibutor. I shut off the engine and checked the points (1000 miles on the replaced points)
they are almost gone already
Is the dirty plug problem, quickly worn points related?
Could the rattle noise be a worn out ditributer cap?
When I idle the engine and look under the hood, there is a grinding/ rattle sort of noise coming from the distibutor. I shut off the engine and checked the points (1000 miles on the replaced points)
they are almost gone already
Is the dirty plug problem, quickly worn points related?
Could the rattle noise be a worn out ditributer cap?
Fleet Owner
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From: NM
Yes, a rotor that isn't on all the way, or a shaft that's bent, or a cap on crooked, could be causing spark plug problems.
There are all kinds of things that could make a noise; try putting a screwdriver on the base of the dissy and the handle against your ear, while it's running, see if the noise is coming from it. There is an oiler cup on the dissy so make sure it's getting lube. Did you install the poiints? What kind of cam lube did you use?
With an engine this old, it's possible someone switched dissy's and put in the wrong kind. Some had an extension past the gear at the bottom that fit into a bore in the housing, some didn't. I don't know what the effect of switching would be, but seems like it could cause problems. Have you had the truck long enough that you know this is a new problem, or could it be an inherited problem?
There are all kinds of things that could make a noise; try putting a screwdriver on the base of the dissy and the handle against your ear, while it's running, see if the noise is coming from it. There is an oiler cup on the dissy so make sure it's getting lube. Did you install the poiints? What kind of cam lube did you use?
With an engine this old, it's possible someone switched dissy's and put in the wrong kind. Some had an extension past the gear at the bottom that fit into a bore in the housing, some didn't. I don't know what the effect of switching would be, but seems like it could cause problems. Have you had the truck long enough that you know this is a new problem, or could it be an inherited problem?
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From: Appleton, Wisconsin
Albuq F-1
I updated my gallery with pics of the issues I have with the plugs and distributer
I set the points myself with a kit last fall. first time The points/ plugs were replaced in the 12 years I had the truck.
I dont need to pull choke to start now-Always had to before
my mileage seems poor-I tried yesterday to back off the idle mixture screw a turn counter clock wise
I'llput in some new plugs today and maybe gap a little over?
Is jh10 what you use on your flattie?
I know I have a lot of questions on this post-thanks much for your time and help
Todd
I updated my gallery with pics of the issues I have with the plugs and distributer
I set the points myself with a kit last fall. first time The points/ plugs were replaced in the 12 years I had the truck.
I dont need to pull choke to start now-Always had to before
my mileage seems poor-I tried yesterday to back off the idle mixture screw a turn counter clock wise
I'llput in some new plugs today and maybe gap a little over?
Is jh10 what you use on your flattie?
I know I have a lot of questions on this post-thanks much for your time and help
Todd
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Fleet Owner
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From: NM
Backing out the mixture screw lets more mix in and richens it. Wrong way! Best to set timing first (assuming points are properly gapped), using the vacuum method. Set timing to get peak manifold vacuum (not spark vacuum) and then adjust so that vacuum drops 1" from highest value. Then set idle speed, then adjust mixture by screwing in the mixture screws (one at a time) until idle RPM starts to noticeably drop, then go out about a 1/4 turn. Re-adjust idle speed if needed.
If you are still running 6V, I'd be suspicious that the condenser is no good. This is a real common problem. A 12V condenser won't cut it, and the 6V repro parts are 3 out of 4 worthless. A real good argument for 12v electronic ignition!
If you are still running 6V, I'd be suspicious that the condenser is no good. This is a real common problem. A 12V condenser won't cut it, and the 6V repro parts are 3 out of 4 worthless. A real good argument for 12v electronic ignition!
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Fleet Owner
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From: NM
PS if you get pinging with timing set at the above method, back off the timing advance slowly til it goes away. That method provides the optimum for power, but depending on the condition of your engine, it may not be acceptable for pre-ignition.
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From: Appleton, Wisconsin
thanks or the helpful info Ross
its 12volt system, I just picked up a vacuum testor
never used one, but i'll read up on what and how to test
what idle speed (rpm) should be standard?
PS my dwell is reading 25 degrees at 625 rpm
I think this means the point gap is ok, but since the points are not new now I know I cannot accurately use a gap gauge now
I read 58 to 63 percent dwell means the gap is good, but my tach/dwel meter doesnt show percent --just degrees
its 12volt system, I just picked up a vacuum testor
never used one, but i'll read up on what and how to test
what idle speed (rpm) should be standard?
PS my dwell is reading 25 degrees at 625 rpm
I think this means the point gap is ok, but since the points are not new now I know I cannot accurately use a gap gauge now
I read 58 to 63 percent dwell means the gap is good, but my tach/dwel meter doesnt show percent --just degrees
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From: Appleton, Wisconsin
follow up
at 700 rpm with vacuum advance plugged with golf tee, the timing light showed right on the mark
next i tried the vacuum gauge in the line right off of the carb
no reading at idle until I opened the choke like the instruction said
17-21 reading at sea level was normal-i'm 800 feet above
my reading was 10, and when i reved the engine the needle only moved a cuple pounds up and down
any thoughts?
also my tach/dwell meter has a points switch
I turn to this and the needle goes off the charts
I'll post this in another forum also besides plugs, just because this may no be plug related
todd
at 700 rpm with vacuum advance plugged with golf tee, the timing light showed right on the mark
next i tried the vacuum gauge in the line right off of the carb
no reading at idle until I opened the choke like the instruction said
17-21 reading at sea level was normal-i'm 800 feet above
my reading was 10, and when i reved the engine the needle only moved a cuple pounds up and down
any thoughts?
also my tach/dwell meter has a points switch
I turn to this and the needle goes off the charts
I'll post this in another forum also besides plugs, just because this may no be plug related
todd
Thread Starter
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Senior User
Joined: Sep 2004
Posts: 279
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From: Appleton, Wisconsin
timing? points? vacuum issue? valves?
at 700 rpm with vacuum advance plugged with golf tee, the timing light showed right on the mark
next i tried the vacuum gauge device in the line right off of the carb
no reading at idle until I opened the choke like the instruction said
17-21 reading at sea level was normal-i'm 800 feet above
my reading was 10, and when i reved the engine the needle only moved a cuple pounds up and down
any thoughts?
also my tach/dwell meter has a points switch
I turn to this and the needle goes off the charts
I'll post this in another forum also besides plugs, just because this may no be plug related
todd
next i tried the vacuum gauge device in the line right off of the carb
no reading at idle until I opened the choke like the instruction said
17-21 reading at sea level was normal-i'm 800 feet above
my reading was 10, and when i reved the engine the needle only moved a cuple pounds up and down
any thoughts?
also my tach/dwell meter has a points switch
I turn to this and the needle goes off the charts
I'll post this in another forum also besides plugs, just because this may no be plug related
todd
Last edited by Earl; Sep 4, 2005 at 05:48 PM.
Fleet Owner
Joined: Jul 2004
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From: NM
It sounds like you're connected to the vacuum line that goes to the distributor? You need to be connected to the one that goes to your vacuum wipers (under the carb). If you have electric wipers, the hole may be plugged.
Flatties typically idle very slowly, as little as 450 RPM as I recall (can't lay my hands on the spec at the moment). They have huge flywheels. If you are seeing 10" vacuum on the line to the distributor, that confirms it's too high an idle, there should be close to zero.
I think the "points" position is either to measure points resistance, or to allow you to see when the points open when setting timing initially (i.e., continuity tester mode).
Flatties typically idle very slowly, as little as 450 RPM as I recall (can't lay my hands on the spec at the moment). They have huge flywheels. If you are seeing 10" vacuum on the line to the distributor, that confirms it's too high an idle, there should be close to zero.
I think the "points" position is either to measure points resistance, or to allow you to see when the points open when setting timing initially (i.e., continuity tester mode).
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From: Appleton, Wisconsin
thanks very much for your info!
i have electric wipers, and there is a plugged port at the back of the carb facing the driver positon
that must be the port you are talking about that i need to connect the vacuum testor to
at 400 rpm i dont think my engine would run smooth at all
625 has been my slowest i can get it too idle
i did connect the testor to the distributer line, at idle there was no vacuum at all
when i pulled the choke out completely, the vacuum went to 10
then moved a few pounds up and down when i reved it
i have electric wipers, and there is a plugged port at the back of the carb facing the driver positon
that must be the port you are talking about that i need to connect the vacuum testor to
at 400 rpm i dont think my engine would run smooth at all
625 has been my slowest i can get it too idle
i did connect the testor to the distributer line, at idle there was no vacuum at all
when i pulled the choke out completely, the vacuum went to 10
then moved a few pounds up and down when i reved it