I'm stumped...maybe two problems going on

I've never ran an Edelbrock carb, but my buddy Lary has on on his Maverick and it has always kicked @$$. Holleys have their own set of quirks. Welcome to the world of the automotive performance hobby...

 

the vacuum leak in the lifter valley is BS

 

Also keep in mind that ford had at least two different mounting points for the timing tab indicator. 10 o'clock and 11 o'clock I'm not sure what years or apps. Anybody else have any more info on this to add to my less than informative information.

 

Have you read your plugs??? Do they all look fairly close in color. If not it could indicate an intake gasket vacuum leak. I would also make sure the carb is tight to the intake. They do back off sometimes.

 

one more worm for the can...has your outer ring slipped on the inner part of your ..balancer? bring #1 piston to TDC and look at the marks...make sure it is on the comp. stroke...frank...

 

Lance suggests something that crossed my mind. Vacuum leak? They have plagued me with problems like this in the past,, bad problems that gave me fits.
Dan

 

think he said he checked for vac leaks and the plugs all looked about right in another post ...i think you need to work on one thing at a time the carb seems to be one of them if the top of the secondary is not opening ....it will have the problems running when you open it up ..... the rear secondary work off demand of the engine the top has to open before gas will (will say) be sucked from the bowl for the rear secondarys as air goes in it passes the metering circuit it pulls the gas into the incoming air your prob is in the secondary circuit,,make sure the chock is opening all the way

 

some great advice up there. id do it in this order from what all have said

1. check all the plugs for leak indication.
2. make sure the vac advance is on the correct port and adjust it to only allow max of 38 degrees adv. check the rest of the movement in there as well as being smooth.
3. run it out and check plugs again.
4 if it shows mixture off then worry about carb, if it is running the same goto 5.
5. pull passenger valve cover and #1 plug and crank it to TDC. from ther you can check the timing mark on the balancer and on the block both at once.also at that point youd be able to see if your dizzy is pointing about where it should and if the valves are lined up about right.

im suspecting you shouldn not have to get to 5 though. Good Luck.

 

my I think you have done a great job diagnosing the problem.
Your problem is in the secondaries.
Skipped timing chain is posible but unlikely
Quit messing with the timing, it ran great before, highly unlikely it just moved all by itself
The guys make some good points as to why your readings are off but over advanced engine will run hot, spark knock, and probably woulda blown up after a short time of playing
Go with what your right foot is telling you.
Its been awhile since i messed with them but make sure the secondaries open freely and pull the top off and check for dirt inside the bowl areas.
As for edelbrock carbs ; a years ago i replaced a few holleys with edelbrocks for guys and recently ive pulled edelbrocks and installed bolted on holleys or barry grants.

 

Verify TDC by piston stop method. If timing is going as high as 50 - 60 degrees, You will have rotor phase problems, Especially if you have small cap dist. (A MSD with a large cap would have problems with that much advance) Unplug the vaccum at dist. throttle up engine till total mechanical advance has maxed out, then rotate dist. till you get no more than 34 degrees total timing.( you MUST verify TDC with piston stop method first) Lock everthing down and drive, If problem is still there carb is at fault. I have tuned and worked on several Edelbrock carbs, My opnion of these carbs is not good. Holleys and Barry Grant are much easier tuned. Like i say you MUST verify that you are actully seeing TDC on the balancer by piston stop method

 

Lots of good suggestions, it will take me a week, at least, to check all this out (along with installing a new shower in the house, which is of course, top priority!). I doubt it is the problem, but I will check the TDC and dampner.

Just to verify, I am, and have been running the vacuum advance on the low side, which is passenger side on the Edelbrock. It has 0 vacuum at idle, then goes up to 6 or 8 with throttle. The high side starts around 12 then drops to 10 or 12 (flutters depending on rpms).

I will go ahead and take the manifold off, install with new gaskets, and skip the cork front and back. Again, just to double check and it is a cheap and easy fix. Then take apart the carb and verify no gunk. Then I will mess with the recurve of the dizzy, as much as I can with the stock parts.

Like Bluegrass said, it is taking time, and i have a long list of vacuum readings, and performance changes after adjustments on a legal pad in the garage.

THis is just one of those problems where I think there are two or three things going on all interacting, and I keep getting frustrated when I fix one, and the entire system fails to respond as I expect it to. I will get it, eventually, but I keep having to come back to you guys for further suggestions and a chance to cool down and get my head back on straight before I start working on the next area.

Thanks for all the suggestions. I have a much better starting base to work from now.

 

From the symtoms you describe, it seems you have narrowed it down to the carb secondaries. If it was a timing problem, you would have bad running after a certain rpm(over advancing) regardless if you had the secondaries open or not. I do not believe you have a vacuum leak as when you covered the front barrels it tried to die. Also you would have erratic idling, oil fouled plugs from sucking oil from the lifter valley. You might be able to block open the secondary air valve(top) and with the engine idling manually open the secondary throttle valves gradually and see if it will still run. You might have to remove the link from the primary to the secondary to get the secondaries to open independent of the primaries. From what you describe you are not getting much or any fuel through the secondaries, just air.

 

I went ahead and took off the intake manifold yesterday morning, cleaned everything up, and this morning, my 24 curing time for the RTF silicone has been met, so it should be safe to run after breakfast. I have blocked off all the vacuum ports, even though I don't believe that to be my problem. I will run the timing at 38 degrees at 3000 rpms, and lock it down, since the centrifugal/mechanical advance is good for about 30 degrees without vacuum, and the vacuum seems to want to push it too far, into the 50s (yes, even the low side vacuum, which is what i have been using).

The local OReilly has the rebuild kit in stock, so if it continues to be a problem, I will take the carb apart and just clean it and install the new jets and gaskets from the kit. Shouldn't hurt to throw $40 at the carb after almost 4 years. I have done nothign else to it except feed it gas and run it hard (and complain lately).

I will let you all know what I find.

 

for 180 more you could get 555-15821 http://www.jegs.com/webapp/wcs/stores/servlet/CategoryDisplay?catalogId=10002&storeId=10001&categoryId=22549&parentCategoryId=10271&langId=-1

 

and then spend another 100 buying the vacuum secondary spring kit, accelerator pump kit, power valve repair kit so it still works the first time it backfires while your adjusting it. if hes going to go away from the edlebrock hed be better off to save his money and buy a barry grant, but any carb is going to need some tuning.