Ditching LeanBurn on a 1987 Fifth Avenue

"Steve Reinis" wrote in news: snipped-for-privacy@corp.supernews.com:

Why would you want to go to point instead of the much better and fairly rock solid electronic ignition?

If it was me... I would stick with the electronic ignition (single pickup), but switch to the Carter AFB or equivalent.

Mopar basically makes/made 4 distributors: Single point, dual point, single pickup electronic, dual pickup electronic.. all others are a variation of these four. All with pretty much interchange with the other. 318/360 are interchangable. Find a 1972 or earlier 318/360 and lookup the part tag to find the advance curve.

Why? The Chrysler electronic ignition is fairly bulletproof. The only issue that you're going to have is likely the ballast resistor, and you still have that with the points style ignition.

That said, if you are looking for ultimate reliability and side of the road repairability, how about a points style distributor and a CD box, then you can unhook the CD box if it craps out on the road but you have a much hotter spark. I don't like just points because they need to be maintained, if you run a CD it greatly slows point wear.

nate

I had thought of going that route, but wasn't really sure about it. In the past I had a 1968 Scout 800 with a 392ci V8 and it had been converted to some unknown brand CDI box and it ran fine the entire time I owned (and abused) it, but I didn't see the reason to have an extra piece of electronics under the hood.

I've got my dwell meter and I don't mind adjusting points from time to time. I guess that's one reason I like older cars, so I can always be fiddling with something. And yeah, I am looking for reliability, but the ease of (cheap) service is the big thing. I like to get under the hood and replace or maintain items myself and know what does what and HOW it does what it does.

Like I said, I'm peculiar! But I'll look into the CDI again and see where I end up. The ignition doesn't worry me as much as the feedback carburetor does!

Thanks,

-Steve

aftermarket

Well, I'm just odd is all! lol I'm all for technology and improvments, but I just kinda prefer something that is simple as can be over an electronic box to take all of the fun out of things. I really don't mind adjusting points - It gives me reason to use my vintage Sears Dwell Meter! ;-)

Nate Nagel suggested a CDI setup and I will look into that. I know they are pretty darn reliable and easy to install as well, so we will see.

Thanks for the tips on Mopar dizzys.

-Steve

OK, but then before you go making major changes, you need to do some homework so you don't throw the baby out with the bathwater.

It *can* be, but it isn't necessarily. When everything is working correctly, the cars run fine. That's not to say you can't make them run better, you can.

You're probably referring to the steady-throttle surge between about 30 and about 55 mph. It is caused by the EGR system introducing too much exhaust gas into the intake tract, and it affects all '85-'89 non-cop M-body cars (this includes yours) with the Holley 2bbl. It *can* be fixed!

And this is just exactly what you'd want to do, *IF* you don't have to pass emission tests. If you do, you will almost certainly fail if feedback mixture control is not present, because it is what allows the catalytic converter to do its job.

If you don't have to pass emissions tests, go for this. The CHrysler electronic ignition system was the first on the market in '71 and has proven to be *extremely* reliable and durable. And the Carter BBD carburetor is the one to pick.

Why? I mean, they work, but the Chrysler electronic system works better and extends the interval between underhood service needs.

Any '62-'72 318.

Why are you making all these changes? There's nothing wrong with the external resistor or stock coil.

DS

You will want to get the camshaft from that old pre-1973 engine as well. Lean burn modified ignition, fueling, AND cam timing, and replacing any 2 of the 3 will NOT work properly.

Just make sure you have the procedure for switching from CD to Kettering ignition down pat - because you WILL need to do it.

How sure about that are you? There is an M-Body forum with lots of folks who tossed LeanBurn without having to swap the cam.

Quote from an M-Body forum:

I already purchased the new carburetor needed to convert, but I'veyet to start to prcoess. Kinda waiting until summertime.

You are dead on about a throttle surge taking place. I hate it. The engine has super compression, uses no oil, leaks no oil, sounds smooh as can be, so I've come to the conclusion it was LeanBurn choking it. One moment it feels GREAT with smooth acceleration and crusing power, then it kinda shudders and stumbles, then it feels great.... Get the idea?

I'll pull apart the EGR system and clean it out and see what I can do. Thanks for that tip. If the car performs better, I'll keep LeanBurn for now. If that sucker leaves me stranded just once, LeanBurn is going out the window immediately! I use my vehicles for long interstate trips and expect them to perform. I take care of them, too, and realize parts do fail, but I won't have something *flakey* under the hood.

Also, I wanted to replace the coil because the current one looks to be original and at 16 years old, it looks like it's actually swelled and leaking some oil (?) used for coolant or insulation. Either way, it's old and I want to get a new one under the hood pronto just for good measure.

Thanks,

-Steve

aftermarket

That's wrong. Replacing ELB with a conventional carburetor and ignition system works great, a cam swap is not necessary.

DS

It's not a question of it needing cleaning. It's poorly calibrated. The real fix is to open up the EGR vacuum amplifier and replace its mainspring with a stiffer one (the spring from the lockup control body in an A998 or A999 auto trans works well) but you can also recalibrate the system by buying a new aftermarket EGR valve (my preference is for a Standard-brand unit). The new valve will come with several orifice plates. The idea is to use an orifice plate that has a smaller calibration hole than your original valve. There's a bit of guesswork involved here, since the orifice in your original valve is built into the valve body, rather than a separate plate. However, the new valve will come with a chart that tells which plate to use according to the original equipment valve part number. So you can start from there and select a plate with a smaller hole. Alternatively, you can easily make your own orifice plate by drilling a hole in the center of a correctly-sized round metal disk. This is all fairly obvious once you buy the new valve.

Coils don't deteriorate from age alone. But if yours has swelled and is leaking oil, then yes, replace it. However, don't mess with a coil that has an internal resistor. Get the correct replacement coil; it's the same for lean burn and non-lean-burn.

DS

Thanks for clearing up the EGR valve bit for me. I made the assumption the valve was just carboned up or worn out. I'll swing by a few parts stores and see what I can find regarding a new EGR valve.

One good reason to listen to DS' advice is that an internal coil resistor will make your car harder to start in cold weather. The stock ignition circuit has a bypass circuit built into it that puts full voltage to the coil when the starter is running (bypassing the ballast resistor) putting the resistor in the coil eliminates the possibility of doing that.

nate

I've been a Mopar guy for 25+ years, and you do NOT want to do this. Trust me. The Mopar electronic ignition system that has been recommended to you is one of the most reliable ignition systems ever put on a spark-ignition engine of any type. Points don't even come close to the reliabilty you'll get with the electronic setup.

Uh... no.

The 2-bbl 318 cam grind didn't change more than a gnats eyelash from the late 60s until the roller cam replaced it in the mid/late 80s, and even the roller cam has virtually the same profile. Lean Burn modified SPARK timing by having the computer replace the mechanical weights and springs in the distributor, but worked with the same valve (cam) timing as the

Okay, I'll take the advice of everyone and stick with the electronic ignition when I do remove the LeanBurn setup and go with a conventional carburetor and distributor. Don't crucify me for saying this, but I really didn't have much faith in late 70's through the late 80's Chrysler products and so I wasn't about to stick Chrysler branded electronics back under the hood! But I'll give it a shot and maybe I'll eventually become a die-hard Mopar fan myself! lol

Thanks,

-Steve

I had a 1977 Dodge Aspen with the slant 6. That car never stranded me, the body rotted off it instead. Finally got rid of it in the early 90's.

If you search around and really want to 'splice' something in, you can use the Mopar EI distributor and use a GM HEI module instead of the mopar black box...some guy over at

-rob

Mopars from 75-85 have a deservedly bad rap, to be sure. But here's my take on it- the actual engineering DESIGN of those cars was just as good as Chrysler was always known for but assembly quality control was a nightmare. But its 2004 now. Time has performed quality control on the surviving ones- the ones that are still running are the ones that were put together WELL. And they're better designed than a Ford or GM from that era, even if the Ford and GM was a safer buy when new because of the Chrysler QC/QA problems.

I'll never forget an '83 Gran Fury that my father had years ago. It was an ex highway-patrol unmarked car. No pursuit package, just a 318-2bbl administrative/undercover sedan that had 90,000 miles on it when he bought it at auction. Butt ugly too- obviously had been stationed in far west Texas and was sandblasted nearly down to primer. Even the windshield was hazed with sand pits. But the darn thing consistently got over 20 mpg and logged another virtually trouble-free 130k miles on top of the 90k before he traded it for a 92 Dakota. I don't think he ever added a pint of transmission fluid or had the A/C charged! On the few occasions I drove the thing (not many) I was always amazed at how quiet, smooth, and tight it was in spite of its reputation and the life it had led.