Scott Flatt
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• Phoenix, AZ, USA |
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• Registered on 1/31/2004 |
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• 8 posts |
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 Posted:1/31/2004 14:15 |
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My 68 302 stinks, makes your eyes water and shows a light smoke from each cylinder bank at idle. My plugs look dark (rich) and I can't seem to get it to change. I have an Edelbrock 1405 with a performer rpm air gap intake. I am running a Competition cams 280H stick which has a rough idle to it. I have tried the whole idle mixture screw thing, I have adjusted idle mixture by vacuum and I have advanced initial timing in an effort to stop it.
Do I have an intake leak? Could it possibly be my miniscule PCV valve (it seems ok). I already did the propane torch trick of shooting propane around the manifold and in the crankcase to see if I could determine any shifts in idle to no avail.
I'm at my wits end this smelly wretch and tired of my clothes stinking every time I'm around this car. Any suggestions? |
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D.B. Roberts
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• Renton, WA, USA |
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• Registered on 11/15/2003 |
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• 56 posts |
• 2 Vehicles
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 Posted:1/31/2004 16:08 |
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A few more details might help to point you in the right direction...
Are you running a mechanical or electric fuel pump?
Are you using a fuel pressure regulator?
Have any changes been made to the jets/metering rod setup?
It sounds like you're getting way too much fuel (dark or black plugs)
Go to the Edlebrock site http://www.edelbrock.com/automotive/eps_intro.html
and read all the info about tuning the carb... It takes more than just adjusting the air/fuel mixture screws if the jet and rod combination is wrong.
'67 Ranchero 500 - 351C-4V/AOD - Daily Driver 
'69 Titan Mk.5 Formula Ford |
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Scott Flatt
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• Phoenix, AZ, USA |
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• Registered on 1/31/2004 |
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• 8 posts |
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Posted:1/31/2004 16:44 |
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Thank you for the response. I have turned that Edlebrock site inside out and read my carb manual from cover to cover. The only changes to the carb I have made from stock is to go from a .100 main jet to a .95. That was a recommendation from a local speed shop who claimed that the 1405 was plenty of carb for my application. The thing I keep coming back to is that it really should not be a main jet or metering rod issue since I am only trying to eliminate problems with the idle circuit.
Additional details, I am not currently running a fuel pressure regulator as the Edelbrock manual claims the carb prefers 5.5 lbs of pressure but can handle up to 6 lbs. The red electric Holley pump I have cranks out about 7 lbs so perhaps that could be a problem. Do you think 1.5 lbs would make that much difference? Probably a stupid question, as I'm sure anything out of spec has the potential to cause a problem. |
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D.B. Roberts
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• Renton, WA, USA |
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• Registered on 11/15/2003 |
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• 56 posts |
• 2 Vehicles
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 Posted:1/31/2004 22:27 |
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Ok Scott, as I said more information makes for better answers...
If the problem only occurs at idle, it is very possible that the fuel pump is overpressuring the floats in the carb. Too much fuel, super rich mixture, possible fouled plugs, all the other associated symptoms.
5 to 5.5 PSI is plenty of fuel pressure unless you plan on running a full race setup.
I'd say, spend the money for a quality fuel pressure regulator, set it using an accurate gauge, and I'd set it to 5PSI even... That's what I run to the 1405 I have feeding the 351C 4v in my Ranchero.
It is plenty of carb... It just has to be fed right!
'67 Ranchero 500 - 351C-4V/AOD - Daily Driver
'69 Titan Mk.5 Formula Ford |
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Scott Flatt
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• Phoenix, AZ, USA |
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• Registered on 1/31/2004 |
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• 8 posts |
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Posted:2/1/2004 00:39 |
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D.B., once again thanks for the response. You're helping me to maintain my sanity! What type of fuel pump do you use that would require a fuel pressure regulator in your Ranchero? Also, are you running the Edelbrock factory set metering rods, jets and step-up springs in your 1405?
Tonight I stuck a fuel pressure gauge on the fuel line and was only getting 5 psi at the carb :-( How I did it was I hooked the fuel pressure gauge directly to the line coming from the tank near the base of the mustang's fenderwell. In other words, I did not hook it inline with the carb which meant I could not start the car. Now the electric pump certainly spins faster when the car is running because of the increased voltage (amperage) from the charging circuit so I am wondering if I would get a higher psi reading with the car running. Is the best way to check this scenario by measuring fuel pressure inline while the car is running or the way I did it? If I do check it inline, won't the carb bleed off some of the pressure when the engine is running?
If it's not fuel pressure, where would you go from there?
Even though I run two fuel filters, I wonder if I should just by a rebuild kit and go through the thing to be sure it's clean. I have the original tank in the stang, but don't usually see too much debris in the filters. But you and I both know that it doesn't take much to clog a minute orfice somewhere in the carb. |
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D.B. Roberts
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• Renton, WA, USA |
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• Registered on 11/15/2003 |
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• 56 posts |
• 2 Vehicles
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Posted:2/2/2004 02:25 |
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| Quote: | | But you and I both know that it doesn't take much to clog a minute orfice somewhere in the carb. |
You may have just answered your own question...
Most fuel pumps will not allow pressure to bleed back through the pump. So, if you connect a pressure gauge to the line using a "T" light off the pump until it hits max pressure then shut off the pump it should not lose pressure quickly. If it does it's an indication that the needle valve on the carb is leaking. Overflow will go straight into the venturi. It wouldn't be a problem at anything above idle. Otherwise, I'd say a carb rebuild might be in order...
'67 Ranchero 500 - 351C-4V/AOD - Daily Driver
'69 Titan Mk.5 Formula Ford |
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Scott Flatt
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• Phoenix, AZ, USA |
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• Registered on 1/31/2004 |
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• 8 posts |
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 Posted:2/3/2004 07:15 |
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Thanks D.B., I'll do a rebuild this weekend as the carb is over two years old and just sits most of the time. A carb kit is certainly cheaper than some of the alternatives I'm looking at. I'll let you know how it goes.
Also, saw your post about the granada brake swap. My 65 stang has the disks on all corners along with the lincoln 9" rear. I love the set up except I still can't find a rear sway bar for that combo.
Good luck with your swap, you won't be disappointed! |
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D.B. Roberts
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• Renton, WA, USA |
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• Registered on 11/15/2003 |
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• 56 posts |
• 2 Vehicles
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Posted:2/16/2004 14:10 |
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Hey Scott,
Did the rebuild fix it??? 
'67 Ranchero 500 - 351C-4V/AOD - Daily Driver
'69 Titan Mk.5 Formula Ford |
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Scott Flatt
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• Phoenix, AZ, USA |
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• Registered on 1/31/2004 |
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• 8 posts |
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 Posted:3/22/2004 21:53 |
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No DB, it got real ugly. To make a long and expensive story short, I ended up buying a set of Edelbrock Performer RPM heads for it. I found that my existing heads had been worked so many times since 1965 that the alignment was off due to repeated milling and that the miling had removed a significant amount of sealing surface from the bottoms of the intake ports. Someone who had the car since 65 did the old school trick installing large Chevy valves in the heads which resulted in intakes being 1.94 and the exhaust being 1.50 which isn't bad had the intake not been leaking.
After much agonizing research comparing competing brands, I bought the 2.02 intake, 1.60 60cc Edelbrock RPM heads and proceded to worry if the larger valves would contact the tops of my pistons. I did the whole clay on the piston thing and came up with a measurement that I thought would work. But somehow using clay to check tolerances that if wrong, could cost me thousands of dollars, left me awake and literally staring at the ceiling at night. I finally broke down and bought a cam degreeing kit containing test springs and a dial indicator. Ironically, the measurements I had taken with clay and a caliper were within .001 of what I found with the dial gauge. But now I knew I could turn the ignition key with confidence.
Fast forward, the heads are installed and this thing absolutely screams! Not a hint of smoke, in fact the exhaust pipes finally have that grayish color to them. The motor jumps to six grand and pulls like never before.
It is. without a doubt, the best $1,200 I have ever spent on the car. While my wife might not share that opinion I did see a bit of a smile on her face after I took her for a ride in it.
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D.B. Roberts
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• Renton, WA, USA |
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• Registered on 11/15/2003 |
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• 56 posts |
• 2 Vehicles
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 Posted:3/23/2004 00:32 |
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Sorry to hear that it was such an intense fix!
But, it sounds like the end result was worth all the pains. 
I recently spent some time working on a 75 Merc Monarch with 53K original miles that was given to my sister.
It had been part of an estate, and had sit for over four years. Put a new battery into it, primed the carb, and it started right up. After it had run for about ten minutes it started doing exactly what you described your 68 as doing. The floats were sticking and flooding it at idle. Fortunately all it took to fix it was a rebuild kit for the carb and a new set of plugs. I also flushed the old gas and changed fuel filters. Now it runs so smooth I have to keep checking to see that it's still running... (Way too quiet for my tastes... LOL) 
'67 Ranchero 500 - 351C-4V/AOD - Daily Driver
'69 Titan Mk.5 Formula Ford |
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