AMC Eagle

[MIPS]

At this point I have every vacuum line memorized. A bunch of my extra plumbing comes from several temperature controlled valves which modify the vacuum advance or enable and disable he EGR when it's cold. I actually added a new T-junction for the manifold vacuum when I ahd the intake off so now I have all the ports roughed in for the center console package. I just need to drill a hole to pass the wiring harness and bulkhead plug through and it's ready to go.

So today I finished off the upper control arm bushings and balljoint on the drivers side. This time I had the proper coil spring compression tool which sucks the spring up and into the pocket and it worked AMAZING. The parts were cleaned up and painted before being reinstalled. Ignoring the day I left the paint to dry it was a two hour job.




I also received my replacement harmonic balancer today. I found when inspecting the old one that the rubber had swollen and was starting to come out of the sleeve and was causing screeching and nasyness like that. Turns out when I compared to the replacement my timing mark had also shifted four degrees, explaining why the car was such a pain in the ass to tune.

[MadMan]

lol good thing you found that timing mark issue.

[beat_truck]

Originally Posted by ESigma25

I know, my first car was a 1987 "Chevy Nova" (a Corolla in disguise) with a single-cam carbureted 1.6 engine that was just a constant nightmare to start, especially if it was hot out. What a frustrating little car, when its transmission failed I was honestly kinda thankful.

We had an '84 Corolla and an '87(?) Chevy Nova. They were both total junk. Those had to be the worst cars Toyota ever made.

The Corolla ended up having a cracked engine block, and the Nova lost 4th gear in it's manual transmission for no apparent reason. We kept driving it without 4th gear, and before long, something in the valve train took a dump. They were both rust buckets, too.

And I can confirm that they had about 100 vacuum hoses.

[beat_truck]

Originally Posted by MadMan

Lean Burn. It was semi-computerized, that may be why.

Yes, it had the Lean Burn crap that controlled the ignition timing. It had a regular Holley 1945(?) 1bbl carb, though.

[mr_rye89]

Huh I hadn't heard of 80 series 3a/4a powered corollas having issues like that. The one my sister had had issues with the carb for sure, and a tie rod end broke lol. I had a '91 Geo Prizm GSi (redtop 4AGE engine)for a few years and that little turd was a blast to drive. It's 5 speed was making strange clunking noises when I sold it a few years back.

[beat_truck]

The Nova was definitely a turd, and it sure wasn't fun to drive.

Being an automatic, the Corolla was probably worse. I say probably because I bought it not running correctly. It supposedly had a bad head gasket or cracked head. I had a known good head overhauled by a machine shop and installed it myself. It ran ok for about 5 miles, and then it started pumping oil out of the breather tube and lost all power, just like it did for the previous owner when he put a head gasket in it with the old head.

I was pissed that I had wasted all that time and money on a POS, and beat the ever loving crap out of it and sent the remains to the scrap yard.

[MadMan]

Originally Posted by beat_truck

Yes, it had the Lean Burn crap that controlled the ignition timing. It had a regular Holley 1945(?) 1bbl carb, though.

LeanBurn was really cool in concept. It even worked, too. Unfortunately, it suffered from two things. One, being that computer-ish electronics were still somewhat in their infancy, and two, they put a delicate piece of technology on top of a hot vibrating engine. Not Chrysler's finest moment...

[beat_truck]

Originally Posted by MadMan

LeanBurn was really cool in concept. It even worked, too. Unfortunately, it suffered from two things. One, being that computer-ish electronics were still somewhat in their infancy, and two, they put a delicate piece of technology on top of a hot vibrating engine. Not Chrysler's finest moment...

Mine still worked, surprisingly for being ~35 years old when I had the truck.

What was the actual benefit of it supposed to be, though? It basically read the ported engine vacuum and advanced the timing? Didn't a regular vacuum advance distributor do the same exact thing, and according to many people, do a better job of it too?

[old_tv_nut]

Originally Posted by beat_truck

Didn't a regular vacuum advance distributor do the same exact thing, and according to many people, do a better job of it too?

The regular vacuum advance was not precise enough to produce the right setting under all conditions. Plus, spark was deliberately retarded from optimum performance on the early pollution-conscious cars. And with no feedback, the result would deteriorate between tune-ups.

My dad was a Ford mechanic and later service manager. Back before mandatory smog regulations, my dad's car was ready for a tuneup, so he did it and said let's have some fun; and on a fine Saturday we took it to the Lung Association free smog check. The guy running the test did it twice because he thought his instruments had failed. My dad told me that of course, it wouldn't stay that good and would also vary greatly with weather conditions (mainly temperature?).

[beat_truck]

Originally Posted by old_tv_nut

The regular vacuum advance was not precise enough to produce the right setting under all conditions. Plus, spark was deliberately retarded from optimum performance on the early pollution-conscious cars. And with no feedback, the result would deteriorate between tune-ups.

How was that primitive Lean Burn setup any more precise? It didn't monitor any other engine parameters like temperature, exhaust gasses, air flow, or anything else. I'm pretty sure it literally just monitored the vacuum from the same carb port that would have went to the distributor, and nothing else. The Lean Burn "computer" even had a diaphragm that looked very similar to what is mounted on a regular vacuum advance distributor. At least that's how my '83 was.

On paper it might have looked better, but nearly all people that replace it with late '70s electronic (no points) vacuum advance distributors report better performance and usually economy too.

[old_tv_nut]

Originally Posted by beat_truck

How was that primitive Lean Burn setup any more precise? It didn't monitor any other engine parameters like temperature, exhaust gasses, air flow, or anything else. I'm pretty sure it literally just monitored the vacuum from the same carb port that would have went to the distributor, and nothing else. The Lean Burn "computer" even had a diaphragm that looked very similar to what is mounted on a regular vacuum advance distributor. At least that's how my '83 was.

On paper it might have looked better, but nearly all people that replace it with late '70s electronic (no points) vacuum advance distributors report better performance and usually economy too.

I didn't mean to imply anything about the primitive Lean Burn System, which I know nothing about, just pointing out what it was supposed to improve.
All the early smog fixes made performance worse, as far as I know, and I can easily believe that this one made no reliable improvement in smog either.

[MadMan]

Originally Posted by beat_truck

What was the actual benefit of it supposed to be, though? It basically read the ported engine vacuum and advanced the timing? Didn't a regular vacuum advance distributor do the same exact thing, and according to many people, do a better job of it too?

https://www.allpar.com/mopar/lean-burn.html

The short version is that the guys at Chrysler discovered that if they had super precise control over the ignition timing, they could run the carb super lean and still achieve the same performance as a richer mixture with a regular old fashioned vacuum advance distributor. Yes, it was motivated by meeting emissions standards, but in theory that sounds plenty better than the 'old way' and it should improve fuel economy and keep the same performance.

It was a simple system, but not as simple as you might think.

The system measured:
1. Engine speed (r.p.m.).
2. Engine load. [likely the MAP vacuum]
3. Throttle position.
4. Speed of throttle movement.
5. Air temperature entering the engine.
6. Engine coolant temperature.
7. Carburetor throttle open or closed.
8. Engine starting.

As for the old fashioned carburetor and ignition system being 'better' - that sounds entirely typical of all the grumbly old farts in the repair industry. It's not that anything is 'better' it's that they are used to something being a particular way. They all said the same things about fuel injection, front wheel drive, unibody, disc brakes, MacPherson struts, I could go on and on. I'm sure that 'many people' also thought that hand cranking your engine was 'better' than having a starter, and that acetylene lamps were better than those new-fangled electric lights. lol You could probably go even further back and some guy would've said that steam was better than internal combustion.

[Eric H]

Computerized fuel control using Carburetors was never going to work well. too slow, too imprecise. Things only got better when Fuel Injection became the norm.

[ESigma25]

Originally Posted by Eric H

Computerized fuel control using Carburetors was never going to work well. too slow, too imprecise. Things only got better when Fuel Injection became the norm.

GM dragging their feet on fuel injection compared to Ford and Chrysler really was pathetic.

[MIPS]

This weekend was just more odds and ends work, mainly tightening hoses and oh, fitting the instrument package.

When I was working on the car I added a T-point on the port for the oil pressure switch to add an electronic pressure sender and on the intake manifold replaced the single vacuum port with a dual and plugged it off temporarily. Today I pulled out a box of parts I salvaged from a donor car which had the full package. The pressure sender, the wire and hose harness and bulkhead plug and the console package itself. The idea is you knock out one of the ports int he firewall, route the harness through, everything just plugs into awaiting connectors and the package fits around the automatic shifter.






Initially it did all work great, then after a few hours the oil pressure reading dropped off and I was able to determine that internally a seal had failed and it flooded with oil, so a new sender will have to be purchased. Again, they seem to be really simple devices used by a number of manufacturers so another one will be readily available.




My new hurdle however is this interferes with the mounting bracket I fabricated for the car phone and the satellite radio controller, so I will need to fabricate something new to fit in its place.