71 LA 340 timings moved!! how?? looking for help

[nm9stheham]

Awesome.. .that looks good. Again, just checking. And OK on the fuel; some areas over here get 'winter formulations' on the gas.

I hope T56 nailed the problem for you!

 

[Shane pearce]

The backfire occurred after the coil change and ignition timing adjustment. I’d put the old coil back on. But then you say you have a 4 point ballast. Any msd coil is designed to be wired to 12 volts, not a current limiter like a ballast. The ballast was originally designed for an older style coil that had a different amount of turns. You backfired because you don’t have enough spark energy (due to the ballast) at higher rpm to light the mixture and a full mixture dumped into the headers instead. Spark energy is weaker at higher rpm, greater number of cylinders/plugs, dwell setting, temperature, coil turns, primary voltage, etc. in this case, your coils primary voltage is probably around 6 (if I can remember back that far) when it needs to be 12. Which in reality it’s operating at 14 when the generator is helping charge the battery.

You need to bypass the ballast for the coil so it is fed 12v w/ ignition is hot. There is a lot of mopar ignition ballast resistor removal threads on the internet if you need a walkthru. You can also simply use alligator clips and jump the resistor at the terminal lugs but a full ignition system rewire is what I’d do. Recheck ignition timing after any adjustment and try again. I hope this is your issue

Thanks very much for that sir... you saying that has reminded me seeing something about a MSD ballast... I will switch back to my Blaster 2 in due course until I get a GM HEI.... Like an idiot I thought the only difference was the longer lead connection :-(

Not happy as car is outside and we have terrible weather so have had to cover it as I leak into footwells and its not the wiper shafts? guessing windscreen, anyhow I now have micro blisters on roof.. so more money!!! at least I can now get it up to a indoor garage 7 mile away once I sort this.. but pouring with rain and strong winds of upto 80-90mph so stuck indoors again..

Gutted as she is pretty clean as came from Orlando a year ago

 

[T56MaxTorq]

You don’t want any type of ballast with any msd coil unless specified by msd. You may have just gotten lucky with the blaster 2 coil. I looked on msd site, the blaster 2 and 3 have the same number of coil turns. Maybe the 2 is an older model and truely has a different number of turns, maybe not. Either way, shitcan or bypass the ballast for testing and set total timing to 33-35 and let us know

 

[Marcohotrod]

have you used the top dead center tool yet? because that looks like a homemade timing tab bolted to a 1969 and earlier timing cover-I would not trust it. the chrysler 4 pin ignition box wants around a 1 ohm resistor, no matter what coil. an msd box does not use a resistor. and stop calling the vibration damper a pulley

 

[Shane pearce]

You don’t want any type of ballast with any msd coil unless specified by msd. You may have just gotten lucky with the blaster 2 coil. I looked on msd site, the blaster 2 and 3 have the same number of coil turns. Maybe the 2 is an older model and truely has a different number of turns, maybe not. Either way, shitcan or bypass the ballast for testing and set total timing to 33-35 and let us know

Yeah its been fine with the MSD Blaster 2.. is there a correct way of by passing it? or can I just jumper wire from right to left??

On a side note whats up with the stern telling off's about using certain words?? driven American cars all my life and used forums for this time too, never been corrected ever but on this group I've been "Told off" twice now in as many weeks lol!! is it a Mopar thing?? I'm from England UK and as we know there is many a word with different meanings between us, I try to get it right but not going to google check every word lol!! I mean a hood is something on a jacket? its what we call a Bonnet, A trunk is something a elephant has, its what we call a boot...

 

[Marcohotrod]

have you checked tdc with the tool yet, to check that fabricated timing tab? with a chrysler ignition box and no ballast resistor any coil will overheat and die, try it and get back to us

 

[nm9stheham]

On a side note whats up with the stern telling off's about using certain words?? driven American cars all my life and used forums for this time too, never been corrected ever but on this group I've been "Told off" twice now in as many weeks lol!! is it a Mopar thing?? I'm from England UK and as we know there is many a word with different meanings between us, I try to get it right but not going to google check every word lol!! I mean a hood is something on a jacket? its what we call a Bonnet, A trunk is something a elephant has, its what we call a boot...

Not a Mopar thing..... just some individuals It seems like Americans are more likely to express themselves on trivial matters like that than the more polite individuals from the British Empire. And it always worse on the Internet, where body language and tone of voice don't come through to help the communications. Try not to let it concern you; I bet if you met the same individuals in person, you would be soon laughing over a beer together and trading Mopar info.....

On the topic of languages: I've sold product for German and Italian companies for over 20 years and I try to use English sentences that are easy to understand when communicating with them. Colloquial expressions will always cause confusion because my correspondents in Europe can only interpret the literal meaning of the words. I feel I owe it to them to change how I communicate as they understand English and I don't speak German or Italian; in that way, they are better than me.

 

[67Dart273]

I'm leaning towards incorrect cam timing.............not that it has "slipped," but rather was never correct. If you look up the cam specs, or estimate them if you don't know them, you can judge cam cam timing by putting an indicator on the no1 valves or even just watch them and obtain opening / closing events. Mark the balancer if needed.

Did this engine EVER run right?

What ARE the cam specs do you imagine?

What are you using for a timing light? Is it just a "straight" timing light, or is this a fancy "dial back" setup? These have screwed up sometimes

Just some rough general guidelines:

A dead stock low performance 273/318/360 should idle "ok" at anywhere from TDC to 15 BTC or maybe approaching 20 BTC. I AM NOT SAYING "run" it there, I am saying a healthy engine should idle OK

A hotter cam, equivalent to the factory 340 cams, should idle maybe anywhere from 8BTC to 20BTC or more

If you have a "real thumper" of a cam, then you would not want to try and idle it less than say, 15BTC, but it might run at 20.

In other words, "let's say" I have an unknown "startup" situation, an engine I have never encountered, and want to "fire it up". Maybe I have to install a distributor, because there isn't one, or because it's a greasy POS. I should be able to drop one in with the above "general ranges" and at least get the thing to run on it's own.

If it won't do that, I'd look elsewhere, cam timing, stuck valves, other engine interal problems, carb problems, vacuum leaks, etc, in no particular order

 

[Shane pearce]

have you checked tdc with the tool yet, to check that fabricated timing tab? with a chrysler ignition box and no ballast resistor any coil will overheat and die, try it and get back to us

Yes checked TDC with tool and its correct, I think I'll go back to either a stock coil or add the GM HEI module to save the headache.

I'm leaning towards incorrect cam timing.............not that it has "slipped," but rather was never correct. If you look up the cam specs, or estimate them if you don't know them, you can judge cam cam timing by putting an indicator on the no1 valves or even just watch them and obtain opening / closing events. Mark the balancer if needed.

Did this engine EVER run right?

What ARE the cam specs do you imagine?

What are you using for a timing light? Is it just a "straight" timing light, or is this a fancy "dial back" setup? These have screwed up sometimes

Just some rough general guidelines:

A dead stock low performance 273/318/360 should idle "ok" at anywhere from TDC to 15 BTC or maybe approaching 20 BTC. I AM NOT SAYING "run" it there, I am saying a healthy engine should idle OK

A hotter cam, equivalent to the factory 340 cams, should idle maybe anywhere from 8BTC to 20BTC or more

If you have a "real thumper" of a cam, then you would not want to try and idle it less than say, 15BTC, but it might run at 20.

In other words, "let's say" I have an unknown "startup" situation, an engine I have never encountered, and want to "fire it up". Maybe I have to install a distributor, because there isn't one, or because it's a greasy POS. I should be able to drop one in with the above "general ranges" and at least get the thing to run on it's own.

If it won't do that, I'd look elsewhere, cam timing, stuck valves, other engine interal problems, carb problems, vacuum leaks, etc, in no particular order

Hey Dart.. Yes it run perfect for almost 1000 miles since complete rebuild, I say perfect but it was a bugger to start but that was a choke issue and choke now totally removed.

The cam is a Comp cam XE274H which is 242 duration @.50 .492 lift.

For timing light its a cheap basic light with a trigger, + and - lead and No 1 cyl lead.

its pretty modified and 500bhp ball park, stroker 418, balanced, 10.75:1 compression ratio, etc.. as we know it was idling at 32!!! only found this when it suddenly started popping if more than 1/4 throttle was applied, right or wrongly I assumed it had shifted as it seemed just way to high. Oh and vac timing is not connected and is plugged.

Anyway I knocked it back to 17 but also fitted the MSD Blaster 3 to add confusion, but since then weather turned, so will be putting the Blaster 2 back in and trying again.

You guys don't know how lucky you are with no doubt a list of local garages that could solve this in an hour lol!! or of course have the knowledge yourself, sadly we all start somewhere... I'm new to the older stuff, but give me a LB7 or 7.3 Powerstroke and I know my way around them, had to do the injectors on the Duramax, what a job!! even rebuilt and uprated the Allison 1000 trans as was pushing 450bhp and hauling a 34' Newmar 5th wheel...

 

[T56MaxTorq]

You’re right, we all have to start somewhere and we all knew nothing before we knew anything.

I’ve been a fan of gm HEI for a while. They’re simple and create a nice spark. They just get hot and need to have a heatsink screwed on or bolted to something cold. I originally thought your problem was the mopar ecu. Whatever you do, scrap the ballast in the circuit to the coil. It’ll help with spark energy.

 

[Shane pearce]

You’re right, we all have to start somewhere and we all knew nothing before we knew anything.

I’ve been a fan of gm HEI for a while. They’re simple and create a nice spark. They just get hot and need to have a heatsink screwed on or bolted to something cold. I originally thought your problem was the mopar ecu. Whatever you do, scrap the ballast in the circuit to the coil. It’ll help with spark energy.

Cheers, yes I see they mount to an alloy plate and use PC paste.. fixed many an Xbox, so used to that stuff...

I am learning slowly, but the learning curve is steep.... I mistook a full rebuild as trouble free driving lol!! only Mopars owned previously was my 06 Charger police cruiser from Dickson City PA. and 94 Viper so very different from a 73 Duster.. both never gave any grief, well other than the Viper's power steering pulley bracket snapping while out having a meal lol!!..
I did indeed replace the ECU just in case, good to have spares, got a spare ballast, voltage reg, light switch, belt and filters.... need to replace door rubbers but so flipping expensive for what they are!!

 

[Marcohotrod]

if we run a chrysler electronic ignition box with any coil without a ballast resistor it will overheat and quit

 

[67Dart273]

"The backfire"

Have you done something that might have affected rotor phasing? Any way that the pickup coil wires to the distributor became reversed? Google "rotor phasing"

 

[T56MaxTorq]

if we run a chrysler electronic ignition box with any coil without a ballast resistor it will overheat and quit

Not quite...I have ran without a resistor for many thousands of miles without harm. Tho, I have had a coil leak on me and caused it to overheat. Will a stock setup last longer? Probably. But this isn’t a stock engine, either. It needs a hotter spark. The coil is also mounted on top of the intake and soaks a lot of heat, it’s best bolted to the fender away from the engine and allow some airflow around it. IMO, running a basic electronic ignition to include MSD and mechanical advance is so old fashioned that it may as well be breaker points. For the price of a new distributor and an msd box and coil, you could run a stand-alone ignition system with compete control over ignition timing events and never rely on mechanical or vacuum advance, probably for a cheaper price.

For example, I run megasquirt. Which was designed for fuel injection but also controls spark. They sell kits that can run spark only. You can set any level of spark advance, rev limit, cold eng advance, dwell, hot eng timing retard, knock sensors, nitrous/boost timing retard, spark cut if you overspeed the eng - lots of options. I use a Bosch bip373 chip w/ a ford style E coil and that’s what controls every spark event on a 12x12 spark table that I can adjust on-the-fly with a laptop. The distributor is simply mechanically locked out and the megasquirt does the rest.

 

[Shane pearce]

"The backfire"

Have you done something that might have affected rotor phasing? Any way that the pickup coil wires to the distributor became reversed? Google "rotor phasing"

This end was not touched so don't think so, besides we think the backfire is caused by the MSD Blaster 3 not getting enough voltage at higher revs.. will find out today as just got up and the sun is actually out!!! so about to swap over back to the Blaster 2 thats been on for 1000 miles and fix the minor fuel leak at Holley blue pump, only leaks very slight when idling, guess someone tried servicing it without replacing the gasket.. so hopefully by end of day I'll know if the backfire is gone and if it runs good at timing at 17 (from the previous 32 peak 50!!!) also need to check under valve cover driver side as there is a creaky noise when cold??? (everything up top is 1000 mile new)

On the other subject of running with no ballast and causing issue?? I've read in countless places Inc MSD forum that its fine although it can shorten coil life.. but at $60 its replaceable if indeed the case? eve nthe MSD instructions said fit a ballast only if running points? which I'm not.. I'm just wondering what others think? not saying the poster is wrong, but I don't know the guy and have read on hotrod sites and MSD forums and enclosed instructions... but to confirm at present running the 4 connection ballast, stock ECU.

 

[Shane pearce]

Not quite...I have ran without a resistor for many thousands of miles without harm. Tho, I have had a coil leak on me and caused it to overheat. Will a stock setup last longer? Probably. But this isn’t a stock engine, either. It needs a hotter spark. The coil is also mounted on top of the intake and soaks a lot of heat, it’s best bolted to the fender away from the engine and allow some airflow around it. IMO, running a basic electronic ignition to include MSD and mechanical advance is so old fashioned that it may as well be breaker points. For the price of a new distributor and an msd box and coil, you could run a stand-alone ignition system with compete control over ignition timing events and never rely on mechanical or vacuum advance, probably for a cheaper price.

For example, I run megasquirt. Which was designed for fuel injection but also controls spark. They sell kits that can run spark only. You can set any level of spark advance, rev limit, cold eng advance, dwell, hot eng timing retard, knock sensors, nitrous/boost timing retard, spark cut if you overspeed the eng - lots of options. I use a Bosch bip373 chip w/ a ford style E coil and that’s what controls every spark event on a 12x12 spark table that I can adjust on-the-fly with a laptop. The distributor is simply mechanically locked out and the megasquirt does the rest.

Have actually relocated the coil now, the Blaster 3 is on fire wall nr where the heater hoses used to connect (replacing with the Blaster 2 today due to backfire) I'm reading to jump the ballast with the blaster 3, but to be honest don't understand how to correctly do that... so just going to put the 2 back on as I know it was fine before.

At present I've been cleaning up various little issues from previous owner, so funds are a little tight to be throwing in MSD ignitions, I did look but at $500+ for the unit alone, the cars been a bit of a dick while in my ownership, I actually owned a 348 Ferrari which was less temperamental years ago, well until it blew!! So I'm in two minds on carrying on or going back to modern with my tail between my legs lol!! was looking at 2008+ Challengers and Camaro V8's but here in the UK we seem to have all your crashed then exported and repaired motors lol!! with no real way of know what there damage was... most state hail damage but I call bullshit on that and I used to work in the bodyshops so know unless repaired correctly (costly) they can be death traps on the next impact

 

[Shane pearce]

See car is being a ***** again.. went out to swap the coil back, to find the neg brass terminal threaded shaft has broke!!