The newly rebuilt 225 in my 78 half ton has a pinging problem. Running a 3 spd std w 3:55 gears. I've searched the threads here, and am looking for suggestions. Checked for vacuum leaks around manifold and carburator-no leaks w propane torch. Running about 10 degree base timing, EGR blocked off at manifold. I just rebuilt and installed a BBD from a 318 (throttle plates are w/o holes), throttle shaft is tight) to replace the /6 BBD that was suggested by a tuning tech. I still get a slight pinging when accellerating at highway speeds/under a load, and I get a slight surging at times at highway speeds. Vacuum advance is working, but I'm not 100% clear on what the adjustment should be. Engine was completely through less than 1000 miles ago (.030 over, head trued .020, 3 angle valve job, new timing set, dist gear, etc). I'm suspecting today's lousy fuels may be part of the problem. Would changing the PCV valve to one w a smaller orifice be a possible solution to reduce the amount of air that she's getting, or do I look elsewhere? Looking for ideas, solution. Mike

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Good gun control is hitting your target repeatedly

retard timing a bit more.....i usallly find a hill and back it off till it just stops pinging


keep on roddin'

Trying higher octane gas before making adjustments; I just did that two days ago & my 65 Dart 225 (with 10 degrees base timing) ping disappeared. My ping had occurred at manifold pressures below 10 in hg. which took a fairly steep hill or hard acceleration to achieve.

I also added a fuel line water seperator since local fuels are not good.....my 30's vehicles have water showing in the glass fuel bowl frequently.

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1965 Dart 110k, 225, Carter BBD Super Six, 2 1/4 single exh., sbp manual scarebird front disc, 7 1/4 rear 2.94 sure grip, 14 x 4.5 OEM wheels, 833 OD with hyd. throwout bearing, HEI, electric fan, ram air/heated air, Accusump. http://plymouthcarclub.com/

Disabling the EGR and skimming the head means you will likely need less spark advance to avoid pinging, but first try a colder spark plug. Today's fuels are not really "lousy"; I'd like it if they didn't contain alcohol, but with or without alcohol they burn cleaner than anything we've had before and the octane levels are not lacking. Their cleaner burn means you can drop down to a colder-running spark plug and still not have it foul. Try a set of NGK UR6 plugs (or UR6IX if you want the really fancy ones you won't have to replace for years).

Messing with the PCV valve will only make problems; it will not cure your ping. Use only the correct valve. Surge at steady throttle on the highway suggests you are running lean; the carburetor may not yet be quite correct.

If the ping persists even after these measures are taken, then it's time to ask hard questions about how well the block was cleaned out during the rebuild.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Thank you Dan. I know for a fact that the block was extremely well cleaned during the overhaul-it was hot tanked before and after the machine work, and it was clean to begin with. Other than the float level, and the metering rod adjustment what would cause a BBD to run lean? I have the same pinging issue whether I use the /6 BBD or the one for a 318. I'll try the colder plugs. I did go to a larger exhaust last year just before the rebuild-would that create a need for larger jetting in the carb?

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Good gun control is hitting your target repeatedly

At what rpm does it ping at?

What vacuum advance are you using? Look at the arm and see if says 6.5R, or 8.5R or 11R, etc.

With old soft springs in the distributor it may have too much mechanical advance and and vacuum advance combined. You may need new stiffer springs and or a different pod.

If your set at 10 degrees initial, how much mechanical do you have at 2000, 2500 and at 3000 rpm. Check with the advance unhooked and the carb line plugged.
Is it over 30 degrees? Record the advance again with the vacuum pod hooked back up and tell us what you have.

Between colder plugs and new distributor springs you should get under control. You can order new springs from bigslant6fan.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Switched to colder plugs-no change. Next process is to check and maybe replace the distributor springs to reduce the amount of mechanical advance. While I'm waiting for the springs, what is the proper method to adjust the vacuum pod and start dialing that in, or would I be better off just disconnecting the vac line and plugging it to see if the vac is the true culprit?

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Good gun control is hitting your target repeatedly

Mike,

The simplest thing to is to plug the line for now and take it out of the circuit.....then you can eliminate one variable. Look at the 4th .jpg on the distributor recurve instructions. It shows/explains how to set the pod for a baseline and then how to adjust it.......You need to look at the number stamped on the arm. That will give you the range of advance it will provide.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Before we go changing things, have you taken a drive with a tach and vacc. gauge installed?

what RPM and vacc. reading are you getting ping at?

If you plug your dial back timing light in and run the car up to that RPM and apply appropriate vacc. level to the advance on the distributor how much timing is showing?

With out any hard data we can keep telling you to retard things and richen the carb, and use colder plugs but not really see what's going
on in there, for all we know the dizzy is set at 20 degrees initial and
has a 15L governor with mopar perf springs and an 11x vacc pod
and at highway cruise you're hauling down 71 degrees of advance...

-D.Idiot

DI,

Your right on....
I already suggested to Mike in a PM that he needs to create a map of the timing at various rpm points like wjajr did for his engine.
See Recurve Threads under the Engine FAQ sticky for wjajr's experience.
I am sure Mike will get started on documenting what is taking place with the advance and when soon........

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

itlldo1,

If you don’t have a dial-back timing light, one can make 4 little nicks on the edge of the timing pulley at 10 degree intervals, and fill them with white-out, or white paint. By doing this you can SWAG* any reading over 10 degrees up to 50 + degrees with your calibrated eyeball.

Ted knows what he is doing, and making a base line spread sheet of rpm, vacuum, timing mechanical only (vacuum line disconnected & caped off at carb., and mechanical + vacuum advance up through the rpm range to 3000 rpm is key to correcting any problems with a minimum of farting around.

I just screwed the idle speed adjusting screw down incrementally to get a nice steady rpm to collect my readings for each data point. I used 500 rpm steps starting with curb idle in gear, than idle in park and on to 1000, etc., but as you run up engine speed you will observe that different vacuum events may take place within those 500 rpm steps. This is where that idle screw is your friend, enabling one to nail the exact rpm that the advance takes place which is an important point to document as well.

Once you have reached 3000 rpm, or where no more advance occurs, back off from there in 500 rpm steps and see if the timing retards at the same speeds it advanced all the way to curb idle in gear.

Now the fun begins, tuning!

I’ll step back and let Ted have at it…

Bill

*SWAG = Scientific Wild Ass Guess

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

If you want a Excel spreadsheet for both centrifugal & vacuum already made up which includes superimposed comparision plots of stock, Doc's suggested, & one to enter your data....send me your email address in a PM & I'll forward the file.

The visual graphs help to compare the initial slope, starting values, & final slope as well as superimpose centrifugal & initial timing.

I used a vacuum pump with built in gauge from a Tune Up & Brake Bleeding Kit to get the vacuum advance curve. Disconnect the vacuum line at the carb (& plug carb fitting) & hook it to the vacuum pump. Pump to different vacuum pressures & check out the timing change.

Adjust the vacuum diaphram based on what vacuum initiated the first signs of timing increase.

I built up two distributors with different centrifugal curves to swap back & forth for comparisions on pep & ping over a range of driving conditions for the particuliar engine compression, HEI longer duration spark & intensity, & extended plug among other influences.

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1965 Dart 110k, 225, Carter BBD Super Six, 2 1/4 single exh., sbp manual scarebird front disc, 7 1/4 rear 2.94 sure grip, 14 x 4.5 OEM wheels, 833 OD with hyd. throwout bearing, HEI, electric fan, ram air/heated air, Accusump. http://plymouthcarclub.com/

DonPal,

Can you send it to Ceej so he can post it under the Recurve sticky? That way all the folks can use it......

I know when you order MOPAR springs from bigslant6fan he sends a photocopy of how the spring combinations perform which would be another good sticky item to post.

Thanks!

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Distributor Recurve Comparison Spreadsheet has been added to Engine Sticky Frequently Asked Question "Timing Curve/Recurve information" by Ceej and should open for Microsoft Word Excel version 97 or 2007.

The user enters their own data for their particuliar recurved distributor in the green areas and the spreadsheet produces a comparision between Doc's suggestion, stock 65 configuration, and the recurved distributor.

The user can also go further and modify the stock configuration to match their own particuliar year.

If enhancements or modifications are needed let me know.

This allows a comparision over the normal operating range which should be an improvement over simply adding the initial, centrifugal, & vacuum timing together for a total possible advance.

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1965 Dart 110k, 225, Carter BBD Super Six, 2 1/4 single exh., sbp manual scarebird front disc, 7 1/4 rear 2.94 sure grip, 14 x 4.5 OEM wheels, 833 OD with hyd. throwout bearing, HEI, electric fan, ram air/heated air, Accusump. http://plymouthcarclub.com/

Thanks Donpal!

Great idea! This feature will make entering this sort of information into a discussion, and graphing the data points quite easy, both for the reader, and the data gathering person looking for advice.

One little request from some of us not so spread sheet savvy; could you add a primmer illustrating just where & how one would enter his data. My wife, also my Micro Soft Office mentor, would love you for it, getting me off her back with such trivial and frivols requests.

The poor dear can’t see why one should spend so much time on cars & their inner workings, she considers a car no more or less of an appliance than a refrigerator. After 33 years of married bliss, I have worn her down to the point she will now ride in my old junk for short trips, but still rolls her eyes & gears up with hat, sunglasses, coat, lip balm & hearing protection when we take that “yellow thingâ€￾ for a ride… Oh well.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC