Holley 600 4160 "popping" loudly. Sad Mustang.

[foothilltom 33]

Hey guys,

 

I think I'm close to the end of my skills here and would appreciate any pointers/advice. Long story, short:

 

351W slept for 20 years. Carefully coaxed it to life. Ran GREAT from external fuel tank until I put in my "sealed" tank. Motor pinged something fierce on its maiden driving voyage (maybe 5 mile drive total). Got it home, reset the point gap to .017", and it ran even worse. Noticed the red gas finally.

 

Blew out fuel lines, running from remote tank again, changed points, and made an attempt at setting the timing. That failed because I couldn't get her to run long enough to sprint between front seat and engine compartment. I've turned it to and fro with no real good outcome -- POPPING is horrendous.

 

Undertook a carb rebuild. Bought the NAPA kit for 4160, cleaned out the bowls, replaced the needles, power valve (it's a single pumper), pump, and all gaskets. I couldn't bring myself to unscrew that big screw down the throat of the primary that has the 2 tiny tubes coming out of it (what the hell is that called?) for fear of never being able to get them back in.

 

In short, I guess it was a 50% rebuild, but it's all I felt comfy doing in one day. Replaced it, snugged everything, re-connected all vacuum lines, and tried to fire her up...

 

...she ran "better" but is now POPPING rhythmically: like one loud POP every cycle of the engine. Doesn't get better at any RPM. I was able to keep her running (despite the awful noise and the fear of blowing my new power valve) and mess with the timing. I didn't have a light hooked up, but I was just moving it slowly to see if I could get that popping to go away.

 

Needless to say it did not. I'm pretty much out of ideas. Since she ran so good before the fuel disaster, I'm not really sure where to go from here. I forgot to buy the SeaFoam at the store today when I bought the points. Me dumb. I'm wondering if that is my next step.

 

I've scanned the hell out of the Holley site and it doesn't include a FAQ for the "dumb-ass that runs pink gas", and all I can see is "lean this", fuel filter that. I've tried all the obvious stuff -- or so I think.

 

I'd really appreciate any similar experiences and suggestions. At this point, I'm considering calling in paid help -- what a failure that would be.

 

Tom

[Pakrat 1,043]

As I mentioned before your popping is likely coming from the point gap not the timing. Try closing it up a bit and see if goes away, if not try opening it up more instead. I know your .017 is by the book but just try it. Once you fix that throw all those useless new points away and get pertronix for pete's sake Tom, step into the 80's!:tongue_smilie:

 

BTW, when you replaced the points did you replace the condensor too? They should always be treated as a unit and done together. Also, if you have a vacumm advance dizzy and you didn't plug the vacumm before trying to change the timing then you really weren't doing anything by moving it.

[foothilltom 33]

More lessons learned. In my penny-wise, pound-foolish approach, I bought just the points. I actually had the guy look up the Electronic Ignition kit at the parts store and was put off by the $100 price tag. I wound up paying $20 for points and continuing my dinosaur ways. But like you say, if it's the point gap, then my original points were probably fine anyway...I just replaced them mostly because I knew how.

 

I'll try messing with the gap. The backfiring definitely started in during that part of my "shotgun" approach and I perhaps I haven't tried closing them enough. I think opening them started me down this backfire-path.

 

And I didn't know you had to plug the vacuum on the distributor (dizzy, eh?) when messing with the timing. I'll make sure to do that next time.

 

I'll post an update later. My "job" has a way of taking me out of the garage and I hate it for that :)

 

Tom

[Pakrat 1,043]

See that's the biggest problem with parts stores these days, most not all anyway, have no old school people, just folks that look up items on a computer so it ends up being up to you to know what you need for antiquated parts. No parts guy worth his salt should ever sell you a new set of points and not sell yo a new condensor also, especially since it's like $5.

 

As far as the Pertronix is concerned a good Mustang site should only charge like $75 and if you buy it from say someone like CJ Pony on a Wednesday than shipping would be free. That's the price of 3 sets of points and condensors but it's pretty much a lifetime part barring any freaky circumstances and well worth it in the long run becasue you never ever have to mess with it during it's lifespan. Points just tend to burn and fuse together and always need to be checked, filed, cleaned, regapped etc. that's why tuneups used to be so much more popular and frequent back in the day. Plus a Pertronix isn't as finicky, it works the same with a mild variance in gap so you don't have to be spot on as points as you are finding out with your popping.

 

I would seriously consider doing this upgrade still and don't think that the new points are a waste. I still keep a set of points and condensor in my road side kit in the trunk at all times. Because pertronix is electric it can be defective or suddenly fail as nothing is 100% and I would hate to get towed just beause of it. With my handy leatherman I could swap the points back in a second roadside, use a matchbook cover to gap it and get back home under my own steam.

 

It's too bad you already used the carb rebuild kit, I really don't think you needed it and the money would have better spent on this IMHO.

[foothilltom 33]

I hear you loud and clear. WRT the carb rebuild, that may have been money down the drain in terms of actual improvement (none), but I must say I learned a lot. There's value for me to not look at my carb like some kind of nuclear reactor like I did before. Hell, I now know what the parts are and where they go.

 

If I'm even remotely successful getting this biatch to run with my points, I will definitely get the electronic ignition kit from a good mail order place and swap them in eventually. I'll keep my old points/condenser as 'backup' only. If I can't get this thing to run, I'll probably postpone that purchase until I get things under control.

 

But I hear you about the parts folks. The Napa store in my neck o' the woods is staffed by kids for the most part. There's one old Ford guy, but he only works days and I tend to make my junkets after work. Maybe I need to change my schedule. :)

 

Wish me luck in getting this thing to stop exploding at me.

 

Tom

[69again 10]

In all the things that you tried, did you remove the wires from the cap and or plugs. You may want to ensure they are installed correctly. Also, you may want to pull the valve covers, remove the plugs and rotate the crank by hand to see if all the valves are moving up and down. Popping makes me thing spark plug wires on wrong/timing/valves. Just a thought. Dan

[foothilltom 33]

Hey Dan, I had not removed more than 1 spark plug wire at a time when I was cleaning, but there's always the possibility that I screwed up. I'll verify the firing order along the way.

 

I like the idea of hand-cranking the engine again (did that during the early coaxing into life days), but perhaps there is a stuck valve with all the bad fuel. I don't relish the idea of removing the radiator, fan, and whatnot, but that's life in the big city.

 

Thanks for the tip.

Tom

[69again 10]

Gets someone to help and have them rotate the crank from under neath the car with a socket while you look on from the top. You shouldn't have to remove any of that.

[69RestoRod 10]

Just loosen the belts and watch your hand near the fan and you can hand crank just the engine from the top. It's what I do when setting valves in their ballpark position. Just because you only took off one wire at a time doesn't mean the PO had them in the correct firing order.

 

Carbs are filed with tiny passages that clog easily. Everything needs to be flushed. Used to make easy money cleaning out carbs on small engines when owners would leave gas in them to long and plug up the pinhole passage ways. Carb cleaner and compressed air was the fix

 

You may also have a valve that's not sealing which is allowing it to pop back through the carb. Path of least resistance and all. There is a chuck that is designed to thread into the spark plug hole and it allows you to connect your air compressor hose. Put each cylinder at TDC and fill the chamber with air. If you get hissing back through your carb you've found a bad intake valve. There had to of been a reason the car was park so long ago and heads needing a rebuild could of been the reason.

 

Do a search for a remote start switch, they're rather easy to make in a pinch. Makes things much easier to trouble shoot solo. Leave the key in the on position and hook up the switch to you solenoid and crank the starter from under the hood. Pull the coil wire and in might be a faster way to check your valves.

Edited September 18, 2009 by 69RestoRod

[klevor 10]

A good strategy to use in these situations is to substitute a part that is known to be good for the suspect part or parts if you can starting with the fuel system components such as filter, carb, pump, points and condenser, Coil. I will also add ai dont know how many times I work on one problem and seems another comes up and confuses the crap out of me. Keep the faith foothill its probably something you will kick yourself for when you find it. And I am constantly cleaning off my shoes at times when it comes to stang troubleshooting some days. I know when I lived in cali I always had two carbs a holley and a ford motorcraft when smog testing came up. I would regress and rule out the carb first though then work my way out. Most holleys have a lot of small passages to clean out if the fuel got contaminated and sticky. And maybe someone around you will let you borrow their good carb and other parts to help you. Keep us posted . But when my stang was popping I changed the coil.

[foothilltom 33]

Thanks for all the good info, gents. I definitely have a list of things to tackle now. I like the idea of a "carb swap" to rule out some stuff quickly. I'll go hit up the only real Mustang friend I have (I live out in the country, not a lot of us).

 

For what it's worth, I verified firing order tonight when I had a few minutes. It was correct.

 

Unfortunately, I won't have any real updates for a few days. I am driving my little girl down to UC Santa Barbara to drop her off at college. Man, is that going to be sad. I really like her.

 

Down, but not out.

Tom

[Pakrat 1,043]

Well Tom I still am a believer that you should start with the simple stuff first and since none of this started prior to you messing with the points I still say the gap is your issue. You've got lots of good advice but before you start swaping carbs, pulling your valve covers and plugs and all that other stuff I would really start with the obvious 10 minute job, the choice of course is always yours though, good luck.

[LoneWolf2U 136]

From your discription it sound like a sticky intake valve from sitting so long.

If you can get it to idle, remove one plug wire at a time till you find the offending cyl.

 

Second possabilty is a spark jumping plug wire causing it to pop on an nearby cyl or bad dist cap allowing it to cross fire spark.

[Pakrat 1,043]

Any resolution here yet Tom?

[yamahasrx700 14]

Wrong firing order, flat cam, burned valve

[foothilltom 33]

Hey Pak and gents,

 

No, no resolution but only because I've had no time. I started out of the chute really fast on this project but the last 2 weeks -- nothing. Kid off to college, mild mid-life depressive tailspin ensued, work got busy, getting geared up for a Europe trip with the wife in 4 days, etc.

 

I need to get my sorry arse out to the garage and start from simple to complex. Gonna start with the points/spark and go from there. Firing order verified. Not ready to embrace the flat cam, but a sticky/burnt valve is definitely a possibility. Have a 600 cfm carb on my workbench from a friend in case I go that direction later.

 

Will definitely update y'all. Thanks for checking in.

Tom

[Print Dad 58]

Hello Tom.

I almost thought I saw a white flag. No quiting at least not yet.

 

I recently bought a vacuum guage for $20 and it is a great great tool.

It can tell you many things abut the condition of the motor.

A cheap investment but a good one I am now learning.

 

If it were me, I would try several simple things.

 

1. - Loosen all the spark plug wires at the cap. Not the center coil one however. You wan the boots to be in the cap but not pushed all the way down to a seated position. Start the car and try to let her warm up. The with insulated pliers, pull the wires from the cap one at a time. (There is voltage there so use rubber gloves or proper pliers.

When you pull a plug, notice the reaction of the motor. The motor should get rougher, Check one wire watch...then put it back in the cap and pull another.

Repeat this process for all the plugs. See if you locate a wire that has little or no difference to the motor. if you find one, then I would replace the plug. Perhaps a cracked plug. It could be a bad plug or wire.

 

2. - Open distributor and re-gap the points. I know you have done this.

While the cap is off, look at the underside. Do you see any cracks or odd markings?

 

3. - Next I would hook up a vacuum guage to a port on the intake. Check the needle action. This should tell us what is wrong.

 

I would seem rather odd, that a valve would hang up at the same time as the pink gas but you never know.

 

As far as timing, I would thow a timing light on it and see if it close to where she should be. A good starting point is 10BTC with the vacuum line disconnected an plugged. If the timming is close, I would leave it alone.

The less things you change the easier it should be to fix.

 

Sorry for asking Tom, but are you certain you are gapping the points correctly? Did you remember to re-hook the little copper pig tail wire?

 

I realize that this must be frustrating but don't give up the ship.

You have been doing amazing but you are at a little snag.

 

It could be a valve but I think it will turn out to be something simple like a bad plug or plug wire,

 

I had never used a vacuum test, but they can proove to be so helpful.

It can detect timmingf issues, valves etc. etc.

 

Hang in there and try just a b it more. Print Dad

[Pakrat 1,043]

Another handy little item to have in your aresenal is an inline spark tester, there are several different ones, I have the cheapo $3 one, I had actually gotten it free once with a $25 order from Whitney's but I have used it on several occasions. The light has a variety of pulses with a diagnostic chart on the backside to read the results an know what the issue is if any. It basically does what Printdad is describing and a little more.

 

http://www.amazon.com/gp/product/B0002STSC6