67 Chrysler 440 issues

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[ARCHIVED THREAD] - 67 Chrysler 440 issues

Posted: 4/22/2017 12:44:38 PM EDT

Hi everyone,

Got a 440 that likes to back fire when giving it gas. It has a mild cam, edlebrock RPM intake and QF 750 CFM carb and MSD Ready2Race Distributor. It was running ok in Ohio and it would only have issues when really getting on it, but now that its here in SC its much worse and backfires even with a little bit of gas.

Should I be looking at timing? I haven't done it so I dont want to mess with it if thats not the case. Carb is fine. both bowls are right in the middle of the sight glass, idle is adjusted and it sits at 800 - 850 rpm. Any advice? or Anyone near me in SC that would help out for a case of beer :D

Thanks.

Posted: 4/22/2017 1:21:58 PM EDT

[#1]

I am guessing based on your description of what you checked it is a holley like 4160 or something.

Typically on those, if a pop is heard it is more likely the pump shot.

Holley makes a kit that has a bunch of different cams for the accelerator arm so you can make it bigger or leaner depending on what you need.

in my experience I just started with the biggest and see if it bogs when you hammer it first.
If not run with that. if it bogs, go down one till it doesn't.

https://www.summitracing.com/parts/aed-5560?seid=srese1&cm_mmc=pla-google-_-shopping-_-srese1-_-aed-performance&gclid=CjwKEAjw_uvHBRDUkumF0tLFp3cSJACAIHMYt9K0MTSgWuHp5CGDrYUNC98Rp12PYkwGgCgD3X6-zRoC3Zfw_wcB

I am guessing you changed altitude from higher to lower.

Posted: 4/22/2017 1:31:22 PM EDT

[#2]

From 788 Ft to 17 ft according to google.

Posted: 4/22/2017 2:21:13 PM EDT

[#3]

then yeah, I stand by my diagnosis.

you are now in a denser air environment and need more fuel to make up for it on the pump shot.

https://forums.holley.com/entry.php?428-How-To-Cure-Carburetor-Stumble

Posted: 4/22/2017 2:27:04 PM EDT

[#4]

So this has always been an issue but is getting worse with the move to (somewhat) lower elevation?

And the issue is, it runs fine until you really get on it and then it backfires or any time the vehicle is under load it backfires?

You need to at least check timing. Without doing so it's all just a guess.

Posted: 4/22/2017 3:16:08 PM EDT

[#5]

Quote History

Quoted:
So this has always been an issue but is getting worse with the move to (somewhat) lower elevation?

And the issue is, it runs fine until you really get on it and then it backfires or any time the vehicle is under load it backfires?

You need to at least check timing. Without doing so it's all just a guess.

View Quote

as long as it is only during throttle change and not while it is floored, I disagree.
timing doesn't change like that or cause that type of problem.
IF it was continuing OR during a transision where the throttle wasn't part of it, I might check, but if it was touchy before he made it worse by not adressing it due to the elevation change.

Also an elevation change would not make timing issues worse like that.

I mean sure go ahead and look, but I think the symptoms reflect what I said and what the link mentioned as well.

Posted: 4/22/2017 3:21:20 PM EDT

[#6]

Quote History

Quoted:

as long as it is only during throttle change and not while it is floored, I disagree.
timing doesn't change like that or cause that type of problem.
IF it was continuing OR during a transision where the throttle wasn't part of it, I might check, but if it was touchy before he made it worse by not adressing it due to the elevation change.

Also an elevation change would not make timing issues worse like that.

I mean sure go ahead and look, but I think the symptoms reflect what I said and what the link mentioned as well.

View Quote

I agree with you but his OP doesn't make this clear.

An if he has a vacuum advance on his dizzy, elevation or temperature change could explain that difference (vacuum leak). Or it could simply have gotten more of a vacuum leak over time.

Posted: 4/22/2017 4:45:48 PM EDT

[#7]

I may have jumped to conclusions.. I took her out and got her up to speed on the interstate and it seems have to cleared out whatever was causing the issue at lower rpm. Old gas maybe? She still has hesitation at higher RPM but no backfires when getting on it and judging by the smell she is running a bit rich.. I think its time to get a tune done.

Posted: 4/22/2017 5:02:01 PM EDT

[#8]

that car was built to run on leaded hi test....... not this no lead ethanol crap ..

find some race fuel 105

Posted: 4/22/2017 5:03:18 PM EDT

[#9]

Sounds fuel related especially if it is "burn your eyes" rich. Lean it out a bit and see? I haven't fucked with a Holley in years but primaries and secondaries are adjustable through replacement parts. A/F screws are isolated to the idle circuit correct?

But my first thought was maybe a wonky vacuum advance. Do you know how much total is dialed in? Vacuum advance does not operate at wot only at cruising and off on throttle. Could be putting too much timing it causing the backfire. Unhook it and plug the vacuum line and drive it around, then you are limited to mechanical. How long ago was the cam put in? Degreed? You can check stretch by watching the rotor while turning the crank forward and then back.

You never said....does it backfire through the exhaust or through the carb? For it to backfire at all there has to be a disruption in timing or pre ignition while the valves are still open...

Posted: 4/22/2017 5:24:27 PM EDT

[#10]

pics of the car or none of this happened.

Posted: 4/22/2017 9:03:00 PM EDT

[#11]

Quote History

Quoted:
Sounds fuel related especially if it is "burn your eyes" rich. Lean it out a bit and see? I haven't fucked with a Holley in years but primaries and secondaries are adjustable through replacement parts. A/F screws are isolated to the idle circuit correct?

But my first thought was maybe a wonky vacuum advance. Do you know how much total is dialed in? Vacuum advance does not operate at wot only at cruising and off on throttle. Could be putting too much timing it causing the backfire. Unhook it and plug the vacuum line and drive it around, then you are limited to mechanical. How long ago was the cam put in? Degreed? You can check stretch by watching the rotor while turning the crank forward and then back.

You never said....does it backfire through the exhaust or through the carb? For it to backfire at all there has to be a disruption in timing or pre ignition while the valves are still open...

View Quote

It was the exhaust. Cam was done years ago. Not sure now.. as the backfiring went away, but hesitation is still there. And yes burn your eyes rich.. acrid smelling too haha.

Posted: 4/22/2017 9:25:17 PM EDT

[#12]

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Quoted:
pics of the car or none of this happened.

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Absolutely!

Posted: 4/22/2017 10:44:48 PM EDT

[#13]

Hearing stories like this sure makes me happy to have my computer controlled EFI on my 440.

I would weld up the vacuum advance slot so it was limited to 10deg total. Set total timing to 35deg all in by 2800 RPM. Idle timing for your combo should be around 15-18 initial.

Take off the carb, and put it in the trashcan with your AK's.

Purchase an FItech conversion for $900

Enjoy car!

Posted: 4/23/2017 4:56:15 AM EDT

[#14]

Quote History

Quoted:

It was the exhaust. Cam was done years ago. Not sure now.. as the backfiring went away, but hesitation is still there. And yes burn your eyes rich.. acrid smelling too haha.

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The only time I have had that happen was when the float got stuck open and it dumped the fuel in. I replaced the float seat valve and fixed the problem. If you continue to run pig rich you will wash down the cylinder walls and cause problems.

Posted: 4/23/2017 5:19:03 PM EDT

[#15]

Timing and accelerator pump . Make sure timing is advancing properly and is set at proper base timing . The accelerator pump on a Holley can be adjusted with both nozzles and pump cams . There is a lot of options

Posted: 4/23/2017 7:27:35 PM EDT

[#16]

Here's the answer to your problems OP.

Attached File

Posted: 4/23/2017 10:17:55 PM EDT

[#17]

Been thinking about an EFI kit :D

Posted: 4/24/2017 7:56:45 AM EDT

[#18]

Quote History

Quoted:
Been thinking about an EFI kit :D

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The various kits on the market right now are without question the best they have ever been, and most of them would serve basic engine management needs very well. Picking one out is mostly a question of options and preferences.

Posted: 4/24/2017 9:53:11 PM EDT

[#19]

FItech seems to be a good one.. both for features and price wise.

Posted: 4/25/2017 7:31:31 PM EDT

[#20]

Quote History

Quoted:
FItech seems to be a good one.. both for features and price wise.

View Quote

My issue with that system (and also the similar Holley Sniper) is I absolutely do not want the ECM mouted on the throttle body. If that is not an issue for you then yes, they are incredible for the price.

Posted: 4/30/2017 9:28:31 PM EDT

[#21]

Ok for those of you that requested.

Attached File

Going to talk to the place that is doing a resto on my 70 RR tomorrow about if they can fit Purple Car in this week for that tune and a paint touch up.

ETA: The title of the thread is about the 440 in this one hahah. Which came from a 67 New Yorker. I thought being more specific would net me more info.

Posted: 4/30/2017 11:03:03 PM EDT

[#22]

If you were closer id help.

You need to do some reading. Id check timing, check the distributor advance vac and centrifugal. If you dont know what that is, buy an msd billet distributor.

Id guess ignition. Possibly carb related but less likely.

Either way through, great car!

Posted: 5/5/2017 6:38:14 PM EDT

[#23]

More than likely its a timing or carb tuning issue as mentioned.
I'd check the timing chain also as mentioned above.
Have you checked for vacuum leaks?
I had the intake on my Power Wagon leaking before and it would pop when i gave it gas. New valley pan and it was fine.

How much does the car sit? Doesnt take long for this gas to start fucking things up.

Carbs work perfectly fine when set up right and it aint hard to do. I run a tunnel rammed 440 in my daily driver and have zero problems. No chokes and it fires on the coldest days.

Attached File

Posted: 5/6/2017 9:40:00 AM EDT

[#24]

Backfiring through the exhaust is usually a sign of ignition system cutting out. Gas builds up in exhaust from cylinder not firing. When it does, backfire. Check ignition system throughly.

Posted: 5/6/2017 12:09:21 PM EDT

[#25]

Quote History

Quoted:
More than likely its a timing or carb tuning issue as mentioned.
I'd check the timing chain also as mentioned above.
Have you checked for vacuum leaks?
I had the intake on my Power Wagon leaking before and it would pop when i gave it gas. New valley pan and it was fine.

How much does the car sit? Doesnt take long for this gas to start fucking things up.

Carbs work perfectly fine when set up right and it aint hard to do. I run a tunnel rammed 440 in my daily driver and have zero problems. No chokes and it fires on the coldest days.

https://www.AR15.Com/media/mediaFiles/301946/IMG-20161213-142629-202266.JPG

View Quote

Thanks for the ideas and tips.

The backfiring has gone away with driving and giving it some gas here and there. I think it was due to when it was picked up and started it was running rough and they found that the 5 plug wire had come off so i think it needed time to get that excess gas out of it. Now its just hesitation/cutting out when going strong on the pedal from low speed. Which I think is timing related. So its going to a hot rod shop here in Charleston for them to look at it and correct a paint issue it has.

Posted: 5/6/2017 3:00:37 PM EDT

[#26]

Take it here if you really love your car.

Posted: 5/6/2017 11:14:39 PM EDT

[#27]

Quote History

Quoted:
Take it here if you really love your car.

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Been here a year. I am on all the MOPAR sites and have never heard of this place.. its not far from my place either. thanks.

Posted: 5/7/2017 9:18:44 AM EDT

[#28]

Not a problem! Randy was the go to Mopar guy when I was running the streets of North Charleston back in the early '80's. Ahhh.....The glory days of cruisin'. No ricers, all American V8 muscle and hanging out at McDonalds parking lot looking for a race and pissing off the cops!
K9 cop showed up one night to intimidate us with his GSD. Friend of mine walked up to the dog, gave him a French fry and started loving all over him. Cop was like WTF?! We all died laughing. Guy was about 6'6" with huge head full of wild hair and full beard. His name was Animal for a reason.

Posted: 5/12/2017 9:13:49 PM EDT

[#29]

Ok gents and ladies if you are reading this. So I bought me a vacuum gauge and tuned the idle richness circuits tonight. Very much improved. I had some backfires at first but it cleared up and I only had that odd hesitation/surging at speeds over 60 mph again which I think is a timing issue.

I do however think that my throttle linkage/kickdown are binding somewhere as when I was adjusting the idle it seemed to be hesitant to change the throttle position until i reved it a few times.. I think a set of Lokar throttle/kickdown linkage are in my future. Otherwise tomorrow is the day I and another guy who has done timing before will take a stab at it on the car and we will see what we can do.

Posted: 5/13/2017 5:39:05 AM EDT

[#30]

Quote History

Quoted:
Ok gents and ladies if you are reading this. So I bought me a vacuum gauge and tuned the idle richness circuits tonight. Very much improved. I had some backfires at first but it cleared up and I only had that odd hesitation/surging at speeds over 60 mph again which I think is a timing issue.

I do however think that my throttle linkage/kickdown are binding somewhere as when I was adjusting the idle it seemed to be hesitant to change the throttle position until i reved it a few times.. I think a set of Lokar throttle/kickdown linkage are in my future. Otherwise tomorrow is the day I and another guy who has done timing before will take a stab at it on the car and we will see what we can do.

View Quote

Best way to set idle is with the throttle and kick down removed. That way there is no interference. I have had a throttle cable that was a touch short give me heartburn while dealing with surging and stalling. The motor would tug at the cable and add in rpms lol.

Posted: 5/13/2017 3:18:06 PM EDT

[#31]

Ok.. So discovered that the motor was @ 20 degrees advanced at idle so no wonder it was running like garbage and not burning gas properly.. so got it back down to 11 degree advanced at idle and with the idle richness circuit adjustment all the backfiring and what now was rough idling is gone.. Motor ran cooler and the car just behaved much nicer on the road instead of seeming like it was super angry at the world. Biggest lesson learned is that I want to do an aftermarket harmonic balance with the timing range already on it.. Would have saved a bunch of time.

I am thinking I will fiddle a bit in the 12 - 13 degree range and see how that plays out. But overall I am super excited. She is much happier now. And i can do burnouts... or I mean.. I've heard you can do burn outs when a 440 is operating correctly via carb/timing adjustments

Posted: 5/13/2017 7:26:59 PM EDT

[#32]

Quote History

Quoted:
Ok.. So discovered that the motor was @ 20 degrees advanced at idle so no wonder it was running like garbage and not burning gas properly.. so got it back down to 11 degree advanced at idle and with the idle richness circuit adjustment all the backfiring and what now was rough idling is gone.. Motor ran cooler and the car just behaved much nicer on the road instead of seeming like it was super angry at the world. Biggest lesson learned is that I want to do an aftermarket harmonic balance with the timing range already on it.. Would have saved a bunch of time.

I am thinking I will fiddle a bit in the 12 - 13 degree range and see how that plays out. But overall I am super excited. She is much happier now. And i can do burnouts... or I mean.. I've heard you can do burn outs when a 440 is operating correctly via carb/timing adjustments

View Quote

Glad you got it figured out!!

Be warned, aftermarket balancer with timing marks may not be correct. You will still need to find TDC on #1 compression stroke and mark your tab. I just went through this and mine was off 4 degrees.

Now, with your initial timing set, do you know what your total timing is? i.e. initial + mechanical = total. If you dig into your distributor, the advance plate is marked with numbers(ex. 12)...take those numbers and x2 + initial and you have your total. So if your plate is marked 12....times 2 = 24 + 11 initial = 35 degrees total. What this means is the more initial you go , the less mechanical you need. Too much total, say above 36-38 the motor will start pinging due to detonation.

Also, if you want better response to advance, take the factory heavy distributor spring out and add in a light spring. It is good to have the advance all in at a lower rpm, say 2400 to 3000 rpms depending on the engine.

I could go on for days, but there is a lot of tuning involved to find that optimal setting

Posted: 5/14/2017 12:44:35 AM EDT

[#33]

Your cam isn't big enough, my car idles at 25deg advance.

Nice work OP glad it's runnin' good now!

Posted: 5/15/2017 1:33:24 AM EDT

[#34]

Quote History

Quoted:
Here's the answer to your problems OP.

https://www.AR15.Com/media/mediaFiles/61196/391D0101-BDC9-46BA-B137-91C437338FE9-zpsrbhm5pbg-193854.JPG

View Quote

This

Posted: 5/16/2017 12:03:55 AM EDT

[#35]

I got back in there today and set the timing to 14 degrees. It seems to have smoothed out the idle and the car is much more responsive when you touch the pedal than it was so I think i am gonna leave it there for now.. see how it starts up tomorrow if its cranky or not.

[ARCHIVED THREAD] - 67 Chrysler 440 issues

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