I have two minor nags that I could use some advice on.

My 312 has idled flawlessly for about the last 500 miles. Now (at idle) it has a slight miss about every 5-8 seconds. Just a little "bump" that you can sense only for a slit second.

The second nag is at a steady cruise speed (+-60mph) the car surges a little. It stops pulling for just a second, then starts pulling again. If I hit the gas, it pulls as it should. The car has a new gas tank, fuel lines, mechanical pump, fuel filter, carburator, distributor, plugs and plug wires. None of these items has more than 1,000 miles since new.

Would any of you have some ideas as to what might be causing these two glitches?

Thanks, in advance, gentlemen.

Look here and this may help http://www.y-blocksforever.com/forums/Topic51072-3-1.aspx?Highlight=600+holley

Dissy doesn't sound right either, Go with whats been suggested, knock the idle back to closer to what it should be, A little high is ok with the Holley.  Your intial timing is best around 10 - 16 degrees but you will have to see what your total mechanical advance is. Plenty on this if you search..

Also I found that marking the crank pulley in stages to be just as good as using a dial back light.

You said there is awhite paint mark at what you assume is TDC.  Better verify that, someone may have put the dot at 42  degrees and used it to check total advance.  If it's at about 40 and you add 10 to that for the initial setting, you'll have 50 degrees at idle.  Way too much.

Can we start over please. Tell us what car, what transmission, what year? The car ran well for 500 miles with only a couple of minor items and the it suddenly did not run well ? Is this correct?

And now you are convinced that the problem is the timing, right? May I suggest that you first find the Ford factory mark on your pulley and that you put a paint mark on this so you can see it.

Try to determine if your Pertronix is Ignitor or Ignitor II (they are different) Ignitor will use a ballast and runs on reduced voltage not full 12 volts.

Try to keep an open mind about the cause of your problem it might be a lot of different things so do one thing at a time. Start with the engine timing and when that is set then find out what else is going on with your car. Pete

To help with diagonisis, get vacuum reading at idle and that may give ballpark indication of part of problem.

Take AussieBill`s advice and hook a vacuum gage to your intake manifold and post the reading you get at idle.

It seems impossible that your car had 55 degrees of initial advance and still started ( my experience is that it won`t turn over with that much advance)

Your timing lite might be giving you wrong info, make another mark about 1 inch from your white paint mark on the pulley  AGAINST the direction of rotation of the pulley and check with the strobe lite and your number one sparkplug wire as the engine is revved up and see if the timing is advancing as speed increases. Then set the timing with the strobe lite and WHITE paint mark not the dial-back feature of your timing lite.

Another possibility is your coil is failing but only consider that AFTER these simple easy things are done. Pete

Somewhat confused by WHERE you are getting the degree of advance numbers from

16.3 and 44.4. Are these from the timing light display?

Where is the engine timing tag pointer  points at white mark on pulley when the number one cylinder fires, engine at 550 RPM? This should be where the 8 to 10 degrees initial advance is set.

Vaccum reading will only be of value if it is engine MANIFOLD vacuum NOT CARB PORTED VACUUM.

At idle your distributor mechanical advance is close to ZERO  so set your timing light display to what advance you set at the pulley timing mark ( by turning the distributor)  Pete

Also - the Pertronix "Ignitor" model uno will work OK without the ballast resistor - and not hurt the gounding transistor - if the coil primary is over 1.5 OHMs. Are you running the original style of 12v coil?

Of course, when you got that reading of 55 degrees advance, I would imagine that chasing the ignition would be the first thing on your mind.

All of your troubles happen under load right, never under "park" or "neutral" trans conditions? That's why I would be thinking carb issue first.

Hope it works out for you...keep us updated with those great pics!

First do check the distributor internal grounding strap Mark talked about.

Do not try a new Pertronix and/or coil until the engine timing is set right. At this point I think that you should consider "STATIC TIMING" your engine. IE, with the engine not running. Do a Google search to find out how.

With the engine off and number 1 cylinder at TDC and the timing mark on the pulley lined up at the white paint mark ( whether it is TDC or 8BTDC or 12BTDC or whatever ) this value should show in your timing lite display AT IDLE and WITH THE VACUUM ADVANCE DIS-CONNECTED.

So if the pulley and pointer are at ZERO or TDC then you should see ZERO on the dial of the timing lite. Or 8 or 12 or whatever.

After you get this straightened out then back to the problem.

My experience is electrical faults are ON/OFF, runs or will not run and this leaves the carb to be sorted out. Pete

You wrote

" Did read up on static timing. Am I only trying to confirm the mark on the pulley is TDC with this procedure? "

ER, no. You are setting the inital timing. Ford put marks on the pulley so you will know when the number one cylinder is at TDC and after 360 of crankshaft rotation at the top of its stroke but this is not TDC because the valves are not closed. After another 360 degrees of crankshaft rotation number one cylinder is again at TDC and the distributor should be turned so that the spark fires now and goes to the number one spark plug. The other marks on the pulley are to allow you to adjust the initial timing. That is why static timing works. Nothing is moving except the distributor to cause it to fire at whatever point you have the pulley mark and the timing pointer at.

If you set it to fire at exactly TDC you have set ZEO advance and your initial engine  timing is 0 ( zero). If you set your initial timing at 8-10 degrees BTDC (before TDC) your initial timing is set to 8-10 BTDC
 

Pete

The only probem I can see with changing the ignition is you are introducing a new variable. If you do so I would run the car before and after installation with NO OTHER chages made so as not to confuse matters.

Mike

We are hoping that the maximum advance (initial and centrifugal summed) adds up to something in the neighborhood of 36°-38° - with no vacuum applied. If it would all be in by say 2700-2800 rpm, you would enjoy some increased low end torque and avoid (most) problems with bad gas causing a knock on acceleration (with low/no vacuum advance).

The Pertronix "Ignitors" that are mounted on a swivel plate (to provide vacuum advance) must ground through the plate (hence the concern about retaining the old braided strap used with points) and then through the distributor body back to the block. Installing a "ground extension" that goes from the distributor "point plate" clear to the block is a good idea because every OHM that uses up voltage on the way to the block -eats coil power. 

Because this problem occurred over time - and the engine was still firing - I doubt if it shifted time. It is more likely a carb problem. What concerns me is that it looks like your builder utilized one of the new style Holley "non-adjustable float" versions of the 600 cfm carb. Like maybe P/N 0-80457S or something like that? Most of us are familiar with the Holley external adjustable float bowls - and know what to do with them but I don't have any idea what the design scheme of the the new carb is. Older versions of this arrangement had to be set with a guage - after you disassembled the carb - a horrible set-up - but cheap. The presence of alcohol in the "new" gas may be working on the needle material - Viton - and making the setting unstable. 

The ground braid is intact inside the distributor. I could add a ground wire fron the distributor to the block to assure a good ground.

When I get home this weekend, I can try the centrifugal only advance and see where it tops out at.

I note that the carburatort will have to come apart to check the floats. And, if I take it off the car to do so, I may just replace it with something more current. I have a question in at the Holley technical department to see if there is a direct or near direct replacement. The list a 570 CFM version with externally adjustable floats, but it is dual feed so I would have to re-do my fuel feed line. that would not be the end of the world.

This begs another uneducated question: Just how reliable or otherwise are the stock Ford mechanical fuel pumps?  Do many of you either supliment the mechanical with an electric or would using only an electric be a popular option?

During last nights practice run, smashing the pedal at ~50mph the car just lost all power. I let my foot off the gas and pulled off the expressway only to have it pick power back up like nothing had happened. It only did this once, but here again, the trust factor is compromised.

The 600 cfm carbs will behave just about exactly as you described out of the box - the auto trans fails to downshift and the carb opens the front holes to atmosphere - at zero vacuum - and she just flat quits. Using the Holley "black" spring in the vacuum secondary housing is a good step toward getting things under control. A 600 cfm carb is just about too much for a daily driver and the stiff black spring will tend to make the carb act more like a big two barrel.

Are you utilizing the vacuum pump style of fuel pump - with the two vacuum ports on the top - to operate the wipers? If not, the FE (352/390/428) engine fuel pumps fit right on the Y block and are much cheaper to come by. Mine has the pump from a 428 Police engine with minor plumbing changes - it will feed 300+ HP without too much difficulty.

Before you get too deep into replacing the carb do some trouble-shooting and find out what is wrong. If it is the secondaries opening at 50 as you step on the gas ( I doubt this is it) you can check by disconnecting the linkage from the secondary vacuum diaphram to the carb and drive a what is now a straight 2BBL and see what that does at 50.

One of the things that happens when you floor the car at 50 is the fast loss of vacuum advance and the plate inside the distributor snaps back. Recheck that ground strap.

"Just an update for anyone wth the Holley 600 situation... I am running 64 main jets and have gone up to a 35 squirter and am using the heavy "blue" cam for the pump [aftermarket one]which I  can only get on no. 2 possition. This is working well and I dont need to much throttle to get her going, I have the brown spring from memory for secondaires [other than the very light springs all should be ok as the secondaries would hardly open anyway] . I do have a PCV setup. This is on a B manifold "

bare in mind I am in Australia I dont know how much better our fuel is?

Have you adjusted your float levels yet?!

Inspite of myself, I think you are going to get me on the right path sooner than later. Your collective sage advice is registering albeit sometimes it takes a complimentery hammer blow to go with it.

If I made a shopping list for the existing 600 cfm carburetor, would it include more than adjustable float bowls and larger secondary jets, and a rebiuld kit?

Steve,

The fuel pump is the type with two vacuum lines on it. One is plugged since I have electric wipers. The other appears to go to the back of the manifold for manifold vacuum. What is the rationale for plumbing the vacuum wipers via the fuel pump and not direct from the manifold?

Seeing as how you’ve converted to electric wipers, then simply run a piece of vacuum hose in a ‘U’ connecting both ports on the vacuum booster.  This will keep the dirt out of the booster diaphram while also insuring that the booster pump internals are not being stressed by having the inlet/outlet ports individually plugged.  Be sure to plug the intake manifold connection that originally went to the vacuum booster pump as that’s a potential miss or hesitation if it leaks vacuum within the pump.

Clay  - Take a good look at the Holley web site and see if there are specific intructions for your carb - the "list number" should be on the front of the choke horn - driver side. Its always a good idea to have some replacement gaskets in hand - even if the carb is supposed to have come with the "no-stick" / re-useable type. If you remove one of the lower front bowl screws and use a little catch basin / cup, the primary bowl fuel will drain into it without soaking the engine. A look-see / cleanup / reassembly will be reasonably quick - and as Pete says, won't cost a new carb.     

It's located back by the vacuum secondary pot's attachment to the secondary throttle shaft - passenger side of the carb.

The idle speed being up makes me suspect a vacuum leak as well. You might try using a plumbers propane torch (off) to introduce  some fuel around the manifold seal - just to see if the speed jumps up somewhere.

Richard

Richard

The '56s have the exhaust coming out the corners of the rear bumper and the "Continental Kit" exterior tire carrier as the standard arrangement. The tin internal part the tail pipe exits into - and the bumper itself - suffered from the caustic effects of the exhaust and water vapor over the years. The previous owner of my car had the turndowns added as a "self preservation" move I'm sure.

Glad you got your "nags" worked out and I have to agree with the others, That is a great color combo and I really like it sans the kit.  Today they'd say "That is one sweet T Bird".  But back in my day we'd have said, "That T Bird is tuff!"

Missouri Mike

Do you have a PCV system hooked up on the engine? Mine provided way too much air and drove the idle speed up - until I realized where the air was coming from and throttled it. I'm using the valve intended for the '64 292 truck and as far as I'm concerned - it's too much of a free opening. Mark used one from a newer smaller Ford and it seems to have done the trick. Anyway - you can quickly plug the PCV hose to the carb and check for this source of your extra idle air.

The 10°-12° advance initial idle position is OK - as long as you know she won't go over 36°-38° (vacuum advance disconnected) at full throttle.

You won't really be able to get the vacuum secondaries to show you much by blipping the throttle at a standstill. If - when driving - you floor it and there is a notable "kick" when it opens - its probably opening too early and will need a stiffer internal spring - another reason to visit Summit.....

This table helps sort them out as they come from the box.

Verifying vacuum secondary operation on the vehicle can be checked by placing a paper clip on the vertical vacuum secondary diaphragm rod against the housing and then looking to see if the paper clip has moved to a lower position after a test run.

The vacuum secondary operation also can be bench tested with the carb off of the vehicle.  This is performed by opening up the primary throttle to full open and placing a high speed air nozzle at the ~Five O’Clock position in the right front venturi at its top.  If all is good, you’ll see the secondaries open and close as the air is moved over the hole that’s located just below the venturi opening at that point.  Here's a picture that will help clarify what's taking place in the bench test.

Personally, I like the tops plain - no portholes, no ornaments - block sanded, "faired" and painted body color or 70's Corvette "Arctic White". What I would like to warn - is to be darned sure it is all secure - SpeedPro56 has had the back window pop out of his (at speed) - and I found a picture on the internet one night of a scarred lid lying on the freeway in Salt Lake City.....arrrrgh! Explain that one to the insurance company.

The secondary operation you describe actually might indicate too much spring? In which case you might experiment with the next size down the list - or skip two - whatever seems appropriate. You just don't want it to have the infamous pause .."ka.....wow" as it opens. The pause is actually a slow down of the vehicle as torque is lost - and the kick is when it picks back up. The most rapid smooth change is good. Holley sells a "quick change" lid for the secondary housing that sllows future changes without the teardowns of the vacuum pot. I ususally use the electric chokes - and so I trim off the plastic brackets for the manual to clean the new lid up a bit.

The "shooter" for accelerator pump has a part in this as well ... the "list" that comes with the carb may say which size came with it? 

I sold my sisters house in Atlantic Highlands this year. Took 2 years on the market and went for about $80,000 less than it should have. New Jersey counties just went through a reevaluation for taxes and changed a lot of appraisals. When all was said and done it was only about $10,000 under the NEW appraisal. I was sure glad when it was done. Had to deal with multiple offers, crooks and profiteers before we found the right buyer. Hope it all works out for you. Chuck

pops (7/16/2011)

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Next, I again took off the carb. Here is the slot on the primaries.



Here is the "no slot showing" on the secondaries.



This next photo has me saying 100 times:

Clay,

What is that jagged edge on your butterfly. It looks like you are going to loose half your butterfly.  

Very likely the reason for your rough running.

Cheers

Warren

That's better Odd what a camera can do at times.

Cheers

Warren

Do you have a vacuum gauge in your toolbox? I'm curious what the needle is doing when the engine is sitting at loaded (in gear) idle. 

When you check your plugs - set them up at standard gaps if they've been opened (as Pertronix recommends) - Ted has some dyno data that shows that the factory gaps give best power (on a Y-block). 

http://www.classictruckshop.com/clubs/earlyburbs/projects/vac/uum.htm

The tube you have disconnected from the fuel pump - direct from the back of the intake manifold - is as good a tap as you will find. Do you have a thermal break isolator under the carb? Drilling a passage - and adding a short piece of brake line tubing with JB weld or epoxy can add an additional manifold vacuum port. They work best when they sample both chambers of the split intake manifold.