Autolite and Motorcraft are more than related, they are the same thing. Roughly, Autolite is the 60s company name and Motorcraft is the 70s and later company name. For example, if you watch the auctions on eBay, you will see NOS BF32 spark plugs fairly often. If you look closely, they usually have a Motorcraft box, but the spark plugs themselves are labeled Autolite. From this I assume that they were boxed in the 70s, but Motorcraft had a lot of left over stock from the 60s that went into the boxes. At 08:46 PM 5/23/2022, Gary Wittman via groups.io wrote: That is some great information.
Chris, I knew that Autolite and Motorcraft were somewhat related, but I didn't know their part numbers were also related. I saw the part numbers were partially the same, and suspected they were basically the same distributor but did not know the break down into the meanings. Thanks for the verification and interpretation. I feel very confident that I can get the right vacuum advance unit now.
Lloyd, I knew the old style vacuum advance units that came apart were adjustable, but I thought the newer ones were not adjustable. The one I have is the newer style. That knowledge of adjust-ability is so valuable to me. Now ,I know I can set it to get the proper timing advance (I was shooting for 42 full advance). You were right on about the distributor shaft end play. I went out and measured it and got about 0.045" end play. That will be corrected.
With all this good information coming out of this conversation, my Cobra is going to be running so good I will never want to stop driving it. That is a good thing but with premium at well over $6.00 a gallon plus a little 110 race fuel, that could get expensive.
Thanks fr the help,
Gary in SoCal
On Monday, May 23, 2022, 05:19:05 PM PDT, LLLLllllloooyyydd via groups.io <heintz58@...> wrote:
Gary,
On the original vacuum advance units you adjust the amount of total vacuum advance the unit will provide by unscrewing the vacuum port (nipple) from the advance unit housing and changing the shim washers inside. There is also a spring and a spacer sleeve inside. If you go with the new style DD190 replacement that does not have the removeable vacuum port you adjust the total vacuum advance by inserting an allen/hex wrench inside the port and adjusting a stop screw inside the vacuum housing.
Our FE engines usually like between 40 and 44 degrees total advance which includes the 16 degrees initial you are running, the mechanical and full vacuum advance. It would be nice to have your original unit in the car to see what the total advance was set to, but the vacuum leak may skew the true number. The vacuum advance is more for drivability so adjust the replacement, be it by allen wrench or shims relative to the style of vacuum advance, until you are in that 40 to 44 degree total, all in, then listen for spark knock. If it pulls nice without knocking you are good. if you get some detonation, readjust the vacuum advance to reduce your total by a couple degrees at a time until the detonation is gone.
Regarding your previous post where you observed the timing retarding when you initially accelerated that usually indicates that the end play in the distributor shaft relative to the housing is a little loose. When you accelerate the pressure on the distributor gear wants to lift the distributor shaft which causes the timing to retard. You do need some end play. I suggest shooting for .010 to .015 inches of end play. To adjust that you to have to remove the roll pin through the drive gear of the distributor then pull the gear off the bottom of the shaft, install an appropriate shim the reinstall gear and roll pin. Be sure to mark the orientation of the gear to the shaft relative to one side of the pin in case the hole through the gear is not drilled dead center, otherwise the hole for the pin may not be properly aligned and give you a fight as you reinstall the pin.
Good luck!
LLLLLoooooydddd
-----Original Message-----
From: Gary Wittman via groups.io <gary.wittman@...>
To: [email protected] <[email protected]>
Sent: Mon, May 23, 2022 4:08 pm
Subject: Re: [fairlaneregistry] 428 CJ 735 cfm carburetor
Dave, I would like to answer your questions about the tune on my Cobra, but I decided to work on the timing a little more. While doing that I discovered some things that did not seem right. I decided to take the distributor apart to make sure everything is working correctly. The mechanical advance mechanism looked good and I lubed it lightly to make sure it moves freely. Upon reassembly, I checked the vacuum advance and it would move, but has a small leak. It needs to be replaced.
My distributor is an Autolite C8OF-12127-J which appears to be equivalent to a Motorcraft C8OF-J. The C8OF-J is listed as the stock distributor for my Cobra. The Motorcraft distributor takes a C5AZ-12370-A (DD-190) vacuum advance. Photos show it looks the same as mine. Do you or anyone know if this vacuum advance will work on my Autolite distributor or where I can get one for mine?
I am concerned that it may fit but will not be tuned for my engine.
Gary in SoCal
On Sunday, May 22, 2022, 01:22:11 PM PDT, D. Hadley via groups.io <dhadley390@...> wrote:
Gary,
To try and rule out detonationas a possible heasitation cause, you could either dump a bottle of Octaine Boost in OR Add in some of that 110 Octaine Race gas IF you have it on hand and see what happens/IF any change or imovement.
What is full timing advance at and at what RPM does that happen?
With the car in park do you get any of that hesitation with similar gas petal movement on the low end?
Did you have this same hesitation issue before the timing and carb adjustments?
You may need to revisit carb adjustment where the throttle plates are at in relation to the idle circuit outlet and when it transitions to the next circuit.
As for your cam, from the looks of it, it looks quite a bit hotter than stock. From what I understand the 428 CJ/SCJ used the same cam as the S Code 390 GT. The cam I put in my 68 S code 390 GT is at least a level hotter than stock (Comp Xtreme Energy XE262H) and your cam is about a couple levels or so hotter than that.
David from Western NY
On Wednesday, May 18, 2022, 01:39:13 PM EDT, Gary Wittman via groups.io <gary.wittman=<mailto:[email protected]>[email protected]> wrote:
Wow, this groups.io email system gets very confusing as it gets longer. It is hard to find the latest messages. At least it is on my computer.
Dave, this in in reply to your message. I have the timing set at 16 BTDC at 750 rpm with the vacuum disconnected. That is advanced 10 degrees more than factory spec. Both vacuum and mechanical advance seem to`?? be working well. I don't have the vacuum retard, only advance. One thing I notice though is the timing drops a little when stepping on the accelerator pedal from idle with the vacuum hooked up.
My gas is fresh 91 octane with about 10% of 110 octane race fuel (with lead). It is stock compression ratio and I think it is spec'd at 10.6:1. I don't hear any detonation but the exhaust is pretty noisy so it could be hidden.
My cam is a Crower 280HDP. I understand it just a little better performing than the stock CJ cam. The transmission is a stock C6 automatic with the R code servo. I am pretty sure the torque converter is stock. I know it is pretty tight because it pulls the rpm down a lot with a jump when I put it in gear.
Pete, I went through all that when I rebuilt the carb in 2006. I have those nice blue gasket and a set of vacuum secondary springs as well as a few sizes of primary jets. I don't have the book but I communicated with a guy in San Diego that was a Holley guru. I can't find him any more though. I think he retired. One thing I never did get into was the different options for the accelerator pump. The carb worked well without changing anything there, so I just left the accelerator pump as it was. I may take a look at that now.
Gary in SoCal
On Tuesday, May 17, 2022, 09:21:33 PM PDT, D. Hadley via groups.io <dhadley390=<mailto:[email protected]>[email protected]> wrote:
Good to hear it is running better.
What is the timing set to right now? (FEs like their timing)
Is the vacuum advance working correctly and is the distributer advance plate and weight`?? s working smoothly and without sticking or binding?
How fresh is the gas in the tank and how much is left over from last season/year?
What Octane gas are you running and what is the current compression ratio?
Are you getting any detonation?
What cam are you running?
Is this an auto or manual trans car?
David from WNY
On Tuesday, May 17, 2022, 07:36:32 PM EDT, Gary Wittman via groups.io <gary.wittman=<mailto:[email protected]>[email protected]> wrote:
Well my drive went great. It is idling better than it ever has since I bought it in 2005. It is pulling strong too. I may have advanced the timing a little too much. When I take off easy from a stop. it moves but feels like it hesitates a little before accelerating. I will play with the timing a little to see if I can fixe that.
The engine did like the extra timing on WOT. The rear tires were trying to break loose all the way through first gear, and that was after I got up to about 20 mph before flooring it.
Gary in SoCal
On Monday, May 16, 2022, 09:18:54 AM PDT, Gary Wittman <<mailto:gary.wittman@...>gary.wittman@...> wrote:
I took the carb off and disassemble the front bowl and metering block. `?? I found the baffle for the vent was not installed properly. Then I checked out the primary transition slot and found it was not set right. I set the exposed portion of the slot with the butterflies in idle position to what is called square (height = width). I then blew out all the passages with carb cleaner and air. Then reassemble everything making sure the vent baffle was correct. I had to adjust the idle position of the secondary carb to compensate for closing down the primary to get the transition slot adjusted.
I cranked the starter to fill up the bowls and checked the fuel level again. It was right were it should be. I then set the choke with a couple pumps of the accelerator pedal. It fired right up and I waited to see what happened as it warmed up..It did start to get rough as it warmed up, but I adjusted the idle needles and advanced the timing a little. It now idles at 800 rpm very well.
Unfortunately, 800 rpm idle is too slow because when I put it in gear the rpm drops too much. When I was doing some research on the Internet I discovered something about Holley carbs I never knew. It is advised to adjust the primary throttle stop screw to set the adjustment for the transition slot and not to use it for adjusting idle. The idle adjustment is done with the secondary. That is very difficult because that adjustment screw is only accessible with the carb off. The set screw on mine is also frozen so I had to bend the secondary stop lever to adjust the secondary idle position. That requires removing that lever then using a vice and wrench. It works but is a kind of hit and miss approach. I should get it right today and finally get it my Cobra out for a drive.
Wish me luck. I miss driving it.
Gary in SoCal
On Sunday, May 15, 2022, 06:57:`?? 11 PM PDT, William Sweitzer <<mailto:torinoman1@...>torinoman1@...> wrote:
Let us know if you find the problem
On May 14, 2022, at 10:48 PM, Gary Wittman via groups.io <gary.wittman=<mailto:[email protected]>[email protected]> wrote:
Thanks Linc and Steve for your suggestions. I already checked the fuel level in the bowl. Replacing the power valve was the first thing I did after checking the fuel level.
My problem is not excessive fuel, it is too lean at idle. I can get it to near idle if I hold the choke partially closed..
I think it has something to do with the idle circuit. Possibly, partially clogged, but I don't know how that would cause the fog coming out of the vent.
I think I will go ahead a take the carb off and try to figure out what would cause the fog in the vent. Then blow out all the passages. I will also make sure the idle slots are exposed properly.
Gary in SoCal
On Saturday, May 14, 2022, 06:50:00 PM PDT, Steve W <<mailto:fords65273@...>fords65273@...> wrote:
When I have signs of excessive fuel in a Holley carb, I always check two things. First is the floa`?? t level. If the needle and seat are stuck open, or the float is sunken, fuel will flow out the sight plug (with the engine running). The second thing I do is replace
the power valve.
Steve
From: <mailto:[email protected]>[email protected] <<mailto:[email protected]>[email protected]> on behalf of Gary Wittman via groups.io <gary.wittman=<mailto:[email protected]>[email protected]>
Sent: Saturday, May 14, 2022 4:39 PM
To: <mailto:[email protected]>[email protected] <<mailto:[email protected]>[email protected]>
Subject: [fairlaneregistry] 428 CJ 735 cfm carburetor
I am dealing with a Holley carburetor that won't idle after more than 15 years of working very well. When I start it cold, it fires up fine. When the choke starts to open up the engine begins to run poorly. It has an electric choke and I can turn off
power to it. This keeps the choke partially closed and the engine keeps running. This tells me it is running lean. I have checked for vacuum leaks and have found none`?? . I have some ideas of what it could be but before I take the carburetor off and take
it apart, I wanted to see if any of you have an idea of what it can be.
Once it is warned up, I can de-choke it and it will run well if I keep the rpm at 1300 or higher. It sounds healthy when I do that. If I try to lower the rpm, the rpm begins to drop and engine slowly dies. There are two vent tubes that stick straight up
on top of the carb. One is in front of the primary horn and other is behind the the secondary horn. They are both angled at the top. I don't know their function but the front one is doing something I have never seen before. There is kind of a fog/mist
coming out of it. I can even feel some small droplets coming out. I am pretty sure that has something to do with the problem, but I don't know what would cause it to do that.
I plan to take the carb apart and try to trace the galley to see if I can figure out what is casing the fog. I am hoping somebody already knows what it is.
Gary in SoCal ----------------------------------------------------------------------- Chris Scheers, Applied Synergy, Inc. Voice: 817-237-3360 Internet: chris@... Fax: 817-237-3074
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