chrysler 440 chuffing noise from tailpipe

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Jon hamilton
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chrysler 440 chuffing noise from tailpipe

Post by Jon hamilton »

Hi there,
I am new to the forum and hoping someone can help with an issue I have with a chrysler 440 engine. I have just changed the chrysler cast iron inlet manifold and thermoquad carb on the 440 in my Jensen Interceptor for a 2191 edelbrock manifold and 1411 carb. The new valley pan is the blocked off crossover version. I now have a fairly loud chuffing noise from the offside tail pipe on idle (nearside is similar but not as bad) I think that I can rule out general engine issues (valve and timing problems etc.) and exhaust system issues as the engine ran fine before the swap. I have also changed the plugs/leads/coil and ECU but to no avail. The engine starts fine and runs/drives without any issues at all other than the noise just at the tail pipes. I have a video of the issue but the file is too large to attach here or to e mail. I should be able to whatsapp it to anyone who thinks they may be able to help with any suggestions. You could send me a whatsapp message my number is 07970 025705 or reply with a mobile number here if easier.

Many thanks,

Jon
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Steve
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Re: chrysler 440 chuffing noise from tailpipe

Post by Steve »

Hi Jon and welcome to the club.

Not sure if you can upload your video onto YouTube maybe? Then you could post a link on this post. Would be interesting to hear what's going on.

Lots of members here with a ton of experience and I'm sure they will be along soon to help.

Just out of interest, what numbers do you have for your timing (initial and total)? The only reason I ask is that my pal had a 440 that was making some strange noises at the tailpipes. He said he always just set the timing at 'what the book says'. Most of us now run quite a bit more initial than the book suggests (16 to 18 deg instead of 5) limited to around 36 deg total advance. I suggested he set his initial to 18, noises gone, ran like a dream. He fitted a limiter plate in the distributor (from FBO) and now runs the same numbers as my car (18/36). Worth a try maybe?

Cheers Steve :thumbright:
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Jon hamilton
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Re: chrysler 440 chuffing noise from tailpipe

Post by Jon hamilton »

Hi Steve,

Thank you, I’ll get some advice from the IT gurus at work tomorrow how to upload to YouTube. I take your point about timing. I don’t know what the timing numbers are as someone set it up for me last time. All I can say is that it is the same as it was with the old intake/thermoquad carb. Maybe different intake/carb set ups need different timing advance ?

Thanks again

Jon
Jon hamilton
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Re: chrysler 440 chuffing noise from tailpipe

Post by Jon hamilton »

Hi Steve,
Forgot to ask in my previous post, are you running a Chrysler 440.

Thank you,

Jon
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Steve
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Re: chrysler 440 chuffing noise from tailpipe

Post by Steve »

No probs Jon. I have a 383 HiPo in my Polara and a 1406 Edelbrock carb. Very similar to your 440, both big blocks just mine is smaller in displacement obviously (6.3 as opposed to 7.2). Same block and ancillaries etc.

Cheers Steve
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Dave999
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Re: chrysler 440 chuffing noise from tailpipe

Post by Dave999 »

well i guess the chuffing may be down to differing state of tune between carb/inlet combinations
distribution will be different at least

the right themoquad works quite well. the new edelbrock will be a universal performance carb so will need a bit of work to get it tuned right
and to be honest carb tuning and timeing go hand in hand
if it still has the advance curve it left the factory with, there is a good chance that it doesn't quite fit with todays fuel and your new performance carb and inlet.

you will probably need more initial timing to account for ethanol rich fuels that although have the same RON numbers as older fuels achive it in a different way and burn in a different way

if you just add in more inital timeing your total timeing can then start to exeed a sensible level at 3000 + rpm so a bit of ingenunity with the distributor is necessary to limit total timeing and allowing you then to run more initial timeing

i do not have a v8 so this is just an exmaple

my 6 cylinder as standard came with initial timeing of 5BTDC and total timeing of 34 BTDC
these days i run a distributor that has been altered so that i can run 14BTDC at idle and only 28 BTDC total at 3500

i have altred cam carbs valve size compression ratio and exhaust you would not need to be so extreme in your change

I CAN NOT promise this will fix your chuffing

But i can say that FBO do a kit for a mopar distributor that is easy to fit that allows you to alter the advance curve of you distributor and limit total timeing to facilitate the kind of initial timing you want for modern fuels

id set it at the most extreme limiting
set inital at 15* BTDC
check i can start the car
and work from there

you want inital timing for peppy perfromance and no smell of fuel when idleing and total that gives smooth quiet operation at speed with no detonation when you lug it up a hill in the wrong gear

once you ge the limits right you can mess about with springs to fine tune

obviosuly i have assumed you are running the orgonal distributor and it is still configured how it left the factory
if not then there may still be some merit in working on timeing and advance curve

and obvioulsy tuning the carb again once done. Altering timing and advance will mean you burn more or less mixture, so carb tweaks come second

basiclaly if you improved carb and inlet, you will have improved the efficiency of the engine
the more efficent the engine is the less total timing it needs
and modern fuels dictate that you also need a bit more initial timing which conflicts with reducing total timing....
hence the need to limit how much timing the distruibutor adds as the rpm increases

Dave
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Jon hamilton
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Re: chrysler 440 chuffing noise from tailpipe

Post by Jon hamilton »

https://we.tl/t-h3i3R8cWhb

Hi there,

Thanks for the posts so far. I have now attached a wetransfer link to the video of the tailpipe noise. I think that my mechanic has already tried advancing the timing and richening up the idle mixtures to no avail but it seems that it may be a bit more involved than that.
Thanks for your posts so far and any observations on the video would be appreciated.

Jon
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Steve
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Re: chrysler 440 chuffing noise from tailpipe

Post by Steve »

That is a strange noise. I know it's a daft question but are you sure the exhaust isn't restricted or blocked in any way? I had an old car in my youth that I accidentally grounded on a kerb. It squashed a section of the exhaust. It didn't fully block the exhaust but it sounded just like that. Just a thought, worth a quick glance

Cheers Steve :thumbright:
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Jon hamilton
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Re: chrysler 440 chuffing noise from tailpipe

Post by Jon hamilton »

Hi Steve,
I’ll get that checked out but I don’t think so as the noise is there from the n/s bank also (but not as bad) and with the crossover blanked off now the two sides should be completely separate. Thanks for the suggestion anyway.

Cheers,

Jon
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Steve
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Re: chrysler 440 chuffing noise from tailpipe

Post by Steve »

Ah, yes, sorry Jon,you did say it was coming from both sides....apologies :banghead:
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MattH
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Re: chrysler 440 chuffing noise from tailpipe

Post by MattH »

I think this may just be the different carb and manifold set up that sounds different to before. If the manifold is in two halves that don't overlap then you have two separate sides to tune, and each may sound different unless they are tuned identically.
The noise doesn't sound that odd to me, it may just be that the carb set up is making it run differently. If it still drives the same or as well then I would just put it down to the changes and not a fault.
Its a similar idea to changing from SU's to webers on a Mini or Triumph, totally different sound at both ends.
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Dave999
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Re: chrysler 440 chuffing noise from tailpipe

Post by Dave999 »

with a dual plane inlet you have 4 cylinderse idleing on the left mixture screw and 4 ilding on the right with a mixed up runner length and a deeper plenum for one lot than the other. each of the cylinders will come on song at a slightly different rpm giving a nice wide torque curve


looking here https://www.gooze.com/2173/2191-Edelbro ... e4QAvD_BwE

it looks like each side of carb supplies both banks of cylinders, 2 per side of engine . obviously some cylinders on a short runner and some on a long one , and 1 set of 4 cylinders running off a plenum that is twice as deep as the other.
i.e mixture settings at ilde at least will need to differ a little bit between the 2 sides of the carb, you can't just go 1.5 turns out on both.

basically it turns your 4 barrel carb into 2, 2 barrel carbs fed from the same fuel bowl, each running 4 cylinders, hence potential for differing chuff noise left tail pipe to right tail pipe.

if the left hand side is tuned perfect for the 2 closest cylinders but not quite there for the 2 on the right
but the right hand side of carb is tuned to a better compromise that keeps all 4 of its left and right cylinders happy ,one side of the motor will idle better than the other and with a split exhaust system, 1 tailpipe will sound different

Dave
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