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I've had an intermittent starting problem for a couple of months. You'd turn the key and it behaved like a flat battery. It only happened every 2-3 weeks and had me flummoxed. Later on it starts just fine.

I began data logging every time I drove until I finally caught it happening. The battery voltage had dropped to 8 volts while cranking despite being well over 12 before I hit the starter. I truly doubted that it was the battery and knew the alternator was charging.

I checked the tightness of all the connections and bought a spare starter switch to carry. It happened again on Friday after a 20 mile drive and I had a brainstorm. The previous failure had happened after a 45 minute drive.

It might be a failing connection that heated up while driving. The only other thing I had inline with the battery was a cutoff switch. Before we headed out yesterday for a staycation on the other side of the island, I bypassed the switch. No problems so far. I might have found the culprit!

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Probably not related, but this sticks in my head.

Many, many years ago, vacationing on your island, we had to call the rental car company the second morning there to come start our almost new Nissan Sentra.

They knew what it was as soon as we called and said it happens there 'all the time'.

Turned out to be condensation inside the distributor cap (I told you it was many, many years ago).

I'd grown up in east coast winters and in humid summers, but something about the combination of climate factors there seems to somehow make condensation in auto electrics more an issue than in most places.

I just chalked it up to part of the daily hell of living on Maui.

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...We've got 3 huge green sea turtles working the reef in front of the condo...

Dammit, Michael, now that's what I'm talkin' about.

Who cares if the car breaks down someplace, anyway?

Wherever it happens - at the hardware store, laundromat, or gas station - just leave it for a few hours, put on some flip-flops (okay, okay - slippers, then) and it's 50 yards to the nearest beach.

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Solution found on the starting problem. I've got a 90 amp alternator because of the external oil cooler fan and the fans on the air conditioning condenser and evaporator. I logged voltages on my trips around the island and found that when the engine was hot and I had the AC on, the battery voltage dropped well under 12 volts at 2200 RPM. So, long trips and the car wouldn't start the next time. 

I measured the DC amps on the alternator at full draw and it only hit 52 amps output. Checking the output for alternating current showed over 8 VAC. My thoughts were that a diode or two had failed.

I ordered a 90 amp Compufire alternator as a replacement. It was heavier and had extra vent fans compared to the EMPI one I bought a couple of years ago. They claim to use USA parts for the Compufires. Stuck it in and instantly charged over 13V at idle.

I'll take apart the EMPI and rebuild the diode pack and call it a spare. It was clearly 2nd class quality.

So, I'll reconnect the battery cutoff switch and see if it introduces any problems, but otherwise, I think the partial failure of the alternator was the culprit.

@Michael Pickett

I had an auto electric shop bench test my alternator. It seems the 55 amp Bosch will do that for a few minutes, but 30-35 amps constant load is all it can handle. I'm guessing the 90 amp can probably handle 50-60 amps continuously. Just something for people to keep in the back of their minds that output is rated at peak.

Great catch on the bad diodes! Good on you!

Last edited by DannyP
@barncobob posted:

EMPI( every manufactured part inferior)

No, no, no. EMPI: Every Mistake Passes Inspection

... but seriously, it's nearly impossible to build a car without EMPI parts, and a lot of them are really pretty good. A lot of them are really pretty bad as well. The difficulty is in knowing which is which.

FWIW, the same can be said of some of CB's catalog, as well as AA Performance.

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A few weeks ago, I learned the working lifespan of an EMPI interior door handle.

It turns out to be eight years.

Shorter than I would have hoped, but longer than I should have expected.

In 56 years of driving, this was the first door handle ever to break in two in my hand. And I’ve used quite a few door handles in that time - sometimes in haste, sometimes in exasperation, and occasionally in anger. Before this, though, every other door handle has been up to the task every single time.

But not the EMPI.

DoorHandle

It’s not like I wasn’t cutting the EMPI door handle some slack. I knew it was a cheap copy of a handle that had been designed by an engineer to withstand certain expected stresses. The EMPI was designed just to look like the original and manufactured at the lowest possible cost.

So, knowing that, I haven’t been using it like a real door handle. I’ve made allowances. I work it gently. Never in anger. I make sure I never use it to pull the door shut. I’ve treated it like a museum piece that should be preserved for future generations.

It still broke.

So, I manned up. I did what I should have done eight years ago. I went to the Stoddard catalog and laid out 70 bucks for a pair of handles that look almost exactly like the EMPI handles, but that cost three times as much.

Why didn’t I do that eight years ago?

Well, this probably won’t make any sense to you, but I was thinking short term. Why waste 75 bucks when I can get almost the same thing for 25? How much difference could there be? Now understand this is just me. I’m pretty sure most of EMPI’s customers would gladly pay three times as much for a properly engineered handle if EMPI stocked their warehouse with them, right?

It must be the nutball, cheapo fringe types like me that EMPI caters to.

There are only a few of us out here, so I don’t understand how EMPI makes any money at all serving this market.

And I’m sorry if I’ve ruined it for the rest of you and you can’t find a decently made door handle at EMPI any more.

It’s mainly my fault.

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Last edited by Sacto Mitch

You could always try JB-Welding the thing with some sort of support behind it

but your story reminds me of having a 1983 GTI living where GM has a cold weather testing center and coming out in the AM, at minus 42 and I try to turn the crank handle on the window.  The handle button peels off as if I am peeling an orange around the metal shaft.  Could not believe it neither did the dealer.



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  • mceclip0

This sort of thing didn't originate with EMPI.  Both my brother and I had Ford Pintos for a while in college and the cheap pot metal window winders, door handles, and sun visor brackets in both of them broke regularly.  I think we replaced all of them in both cars at least once.  I sold mine after 18 months while he held onto his for years.  I think all of those parts were broken in his when he sold it.  The amount of cost cutting Ford did with those cars was criminal.

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Is it possible they made only about 200 Pintos, but they all got passed around a lot?

Maybe you guys all had the same Pinto, just at different times.

If you think about it, you see absolutely everything at Cars and Coffee - Ford Falcons, AMC Gremlins, even Yugos. Some guys have no shame.

But never a Pinto.

Some cars didn't survive because they were good demolition derby cars.

But that can't be said of the Pinto.

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"The shop Foreman screamed"   I had a Vega GT w/a 4 speed , if I down shifted ata a higher rpm it would back fire, took it back the the Dealer 3 times to get the muffler replaced because it would blow open at the seam. ( think turning off the key and back on again)

On the 4th new muffler visit the shop foreman goes for a ride with me in the passenger seat . He runs the car to about 60 and then drops a gear ( I cover my ears ) that's when the muffler and tailpipe exhaust system retorts parting company with the rest of the car . "Post scream" ...the fix was my local Chevron station guy replaced the $60 EGR exhaust diverter valve.

Sorry about bringing that painful memory back, Alan. I actually liked my Vega GT when it wasn't coughing up oil, putting a rod through the block or stranding my Mom and little sister on the railroad crossing with a train coming.

I was actually a little bit cross with my Mom for getting a big guy to help her push it out of the path of the train. It could have saved me a lot of future time pulling the engine, again and again. The flaw was a smog control device built with a short wiring harness. The engine rocking broke a wire that grounded out the engine spark. I mention the details to add weight to my assertion that the Vega was a Pinto with a bowtie.

Ah, memories of youth. When life was easy.

We had a Pinto wagon with the 2.3 engine.  It was a good engine, except for really sucky valve stem seals made of soft ceramic or something (maybe compressed pound cake?  I dunno).  They would only last about 75K miles.

I found out a little late, that the cause of the huge cloud of blue smoke around us every time we stopped at a light was those bad seals, but that was after I replaced the first engine over a weekend (I was commuting to a company place in southern NH back then and really needed the car).  

I bought a rear window with the defroster wires in it from the dealer (the car didn't come with that) and installed that myself with the greased cord trick, but then I needed a dash switch to turn it on so asked around at work to see what might pop up.  We were working for a defense electronics company back then and one of the engineers gave me a push on/push off switch for an F-15 that simply stated:  

Speed
Brake
Deploy

I often wondered what the second owner thought that was for.....  And how long it took for them to try it.  

The Pinto and the Fairlane both were dangerous ! They both used the top of the gas tank as the rear trunk floor to save weight and a piece of sheet metal. This was the primary problem in a rear end collision. The tank would get sheared open by the surrounding trunk floor and spill gas all over inside and out. The Fairlane was rarely ever mentioned but it had the same problem. One good thing that came out of the Pinto was their two liter, 4 cyl. engine.  It came with a 5 main bearing crank and a cross-flow cylinder head.   (the intake manifold was on one side of the head and the exhaust manifold on the other side). A super strong, high-rev, super good breathing engine.   I would love to have a 300 CID, Ford 6 cyl engine with a cross-flow head. I would use it in a Hybrid Lotus 7............Fun stuff !..................Bruce

I'm afraid I have to correct you, Bruce. The early Mustangs had the trunk floor/gas tank combo, but our Pintos didn't.  The safety issue with them was that the filler neck would pull out of the tank an a rear-end collision, spraying everything down with the tank contents - with the inevitable result.  Another cost-cutting measure on what could have been a decent little car.  They actually drove pretty well (for the time) when nothing was breaking or being run into.

I stand corrected. Thanks Lane for catching that. It was the Mustang and the mid size Fairlane.  We were involved in  testing the Fairlane for potential use as a Patrol car for La County Sheriff Dept. We heard about the Pinto "Let um Burn" letter and did more research on the data collected and provided by NHTS  and found that they discovered an issue with the tanks shearing open. Regardless, we disqualified the Fairlane because of this. Our issues were the unsafe rear end collision potential and that we kept the Officers shotgun mounted in the trunk at that time and had one incident where the Officer somehow discharged one through the floor of the car.  That year (1966) we purchased full sized Chevy's with 396 V-8's. No A/C and no power brakes ! I thought they were dangerous !................Bruce

@aircooled posted:

The Pinto and the Fairlane both were dangerous ! They both used the top of the gas tank as the rear trunk floor to save weight and a piece of sheet metal. This was the primary problem in a rear end collision. The tank would get sheared open by the surrounding trunk floor and spill gas all over inside and out. The Fairlane was rarely ever mentioned but it had the same problem. One good thing that came out of the Pinto was their two liter, 4 cyl. engine.  It came with a 5 main bearing crank and a cross-flow cylinder head.   (the intake manifold was on one side of the head and the exhaust manifold on the other side). A super strong, high-rev, super good breathing engine.   I would love to have a 300 CID, Ford 6 cyl engine with a cross-flow head. I would use it in a Hybrid Lotus 7............Fun stuff !..................Bruce

I clearly remember the Pinto debacle as Ford not wanting to put in a simple metal shield behind the differential, which would pierce the tank in a rear-end collision. I think the shield would have cost only a few dollars back then.

Mike, I had a 74 Vega GT. Wasn't a bad car overall, except for the crappy GM aluminum cylinder plating process. Didn't last more than 75k without needing a hone, new rings, and/or steel sleeves. Maybe they lengthened the wire by 1974? I had none of your issues or Alan's exploding muffler.

FWIW, the Pinto engine (the 2300) was worlds better than GMs dime-store Nicasil attempt. Best-man Steve was going to put some euro go-fast stuff on it before discovering that Hooker made an engine swap header for a Windsor, and the rest was history.

Fun fact: Ford used a single progressive Weber carb as well as that crossflow head on the Pinto. My '73 Opel Manta (purchased for $50) used the same carb. My senior engines project was to get the Opel running in top kit. Day 2 of class, I unbolted the carb from best-man Steve's 2300 (up in the pallet racking by then) on the Opel, plugging every vacuum line except the distributor advance. I spent the rest of the semester sitting on the hood of that car eating an entire bag of Dolly Madison powdered sugar donettes (washed down with coffee from the percolator I brought in) every day.

I got an "A".

I wasn't allowed to take auto shop. Lord knows I wanted to.

Take computers(yawn) and Spanish(yawn again) they said. Programming a TRS-80(Radio Shack) PC clone in basic, and saving programs on friggin' audio cassette tapes! What a crock. My Speeduino ECU has way more power than that rudimentary PC on DOS.

The Pinto engine is still not a bad engine, especially once they fixed the valve seals. We don't even have them on aircooled stuff.

The one engine I hated was the GM Iron Puke 151 cu.in. boat anchor. What a POS. Another crapbox? The Citation. Anybody who bought one should get a citation for being stupid!

Last edited by DannyP

When I was in school shop class was for the guys who weren't going to college.  Lord knows that wasn't me!

In retrospect that was pretty stupid.  Learning meaningful skills doesn't only happen in a lecture hall or lab.

I took every shop class offered by Tremont High School from 1977 until I graduated, and every English class as well (that you Mrs. Evans). I was the editor of the school newspaper in Senior Journalism, which meant I could write an editorial criticising some aspect of school administrative policy every other week. Principle Butts was not amused, but it was as close to a "get out of jail free" card as I was going to get in 1980/81.

No electronics courses were offered, and programming was some black art for college kids. Only girls took keyboarding (which was called "typing" back then) or accounting classes.

I tried one day of community college 2 years after graduation. I got through the first third of a Humanities lecture, and walked over to the admissions office to get my money back. By the time I was really ready to be a student, I was married and had 2 kids with one on the way. I compensated by reading voraciously - everything from Plato to Kierkegaard. I got a "great books" list and just started plowing through books that I thought a well read person ought to read. Nobody actually reads most of them unless they've been assigned, but I was the weird kid who did. I read that list for three years, until the pace of life just overtook my desire.

Everything worked out in the end. I found a trade that pushed buttons inside me that I didn't know I had, and I've had a much happier life fixing refrigerated supermarket cases than I ever would have teaching Western History.

@edsnova posted:

Why'd you hate the Pontiac 4, Danny? Simple, durable, easy to work on and, by bore and stroke, the Iron Duke was basically half a Z-28 engine and probably could've been built to perform on that par.

Here's Hemmings on the real story (I also thought the 4-cylinder option in my '67 Chev was an "Iron Duke"). Nope.

Because it's a really heavy, industrial lump that makes no power? Because if I want pushrods it should be aircooled, flat, and 4 cylinders.

I'm not a big fan of most things GM. Look at the Fiero: Chevette front suspension and Citation front clip moved to rear mid-engine. That's a real parts bin special there. The only somewhat smart thing they did was put the fuel tank down the center tunnel, good for handling and impact protection. But they powered it with an Iron Puke. What a dog.

@DannyP posted:

if I want pushrods it should be aircooled, flat, and 4 cylinders.

I'll respectfully disagree.

There is no engine producing more power for less money than the GM LS/LTs, Ford V8s, and Dodge Hemis. Pushrod engines all, making more usable power, more reliably and for a lot less money than any Asian or European OHC engine.

The LS/LT in particular is a miracle of engineering and manufacturing, and may well be the high-water mark for industrial production (and perhaps of civilization).

OHC engines are unduly complex, and do not make enough additional power to offset the complexity. They're cool, no doubt - but during the recent Porsche 547 love-in, all I could think was how much more desirable a nice, big T4 is by any objective metric. I feel the same way about almost all European V8s - they're crazy complex, crazy expensive, and not much more powerful than their 'murican pushrod counterparts.

The supercharged, dry-sumped LT5 crate engine made 755 hp at 6500 RPM, and cost about $19K dressed and ready to install. a Hellephant Mopar 426 supercharged crate engine makes 1000 hp and sells for $30k, out the door.

Pushrod V8s are where it's at.

Hating the Iron Duke seems to me just the same as hating the Malaise Years in general. GM screwed the pooch by making an aluminum L4 and putting an iron head on it. I mean, yeah, there were many other sins invested in the Vega program but that one epitomizes the project. The Vega's entire engineering ethic was akin to the scene in "Dumb and Dumber" wherein, somewhere in Kansas, the fuzzy van gets traded straight across for a moped.

The Duke was the next logical step. But instead of utter failure on all fronts, what was produced was...

A generally reliable lump which (like everything else of that era) made disappointing power at a low redline.

In the context of the Carter years, that was progress.

Now as to the Fiero? The story is well-trod, and we all know it by now. The car was a hodgepodge of compromises hemmed by budget considerations. And damned if it didn't almost work. By the time it was canceled almost every stupid mistake had been remedied. Alas, that is the story of GM during the time of Rivethead.

@barncobob posted:

nothing sweeter sounding than a Porsche boxer six winding up

I wondered when we'd get to that.

I've made my thoughts on "the sound" as a metric of anything tangible known before. The automotive press (or what passes for it these days) all wax glassy eyed about "the sound" a car makes, as if there's no greater virtue for an engine to possess.

There is. Power. Power and reliability. The Porsche flat 6 is not especially powerful and pretty horribile from a reliability standpoint. And cost. Any engine Porsche builds or has built is horribly expensive for the power and reliability obtained from it.

What they do build are very, very special cars - a nearly ideal combination of beautiful shape, careful and thoughtful assembly, and otherworldly ride and handling. They ooze "quality". They're worth what the sell for, but the engines themselves haven't been a strong suit since... well ever (3.2L Carrera engine excepted). The early 6s had problems with the engine cases, the cam chains were always klugy (until they figured it out with the 3.2), the 964 and 993 were a mess of complexity. And the 996? The 996 and 986 were time-bombs, waiting to eat themselves. The ship was righted with the 997.1 and 987.1, but the damage to the legacy of the Sainted German Engineer (IMHO) has been done. They've made as many mistakes as the powertrain engineers at GM, and maybe more.

Scratch that, definitely more.

From my practical vantagepoint, Danny's exactly right - if the engine in any Boxster, Cayman, or water-cooled 911 blows, there's one logical choice for replacement: an LS/LT Chevrolet. That makes me a mullet-wearing, mouth-breathing, NASCAR watching, blue-collar fanboy, and it's sacrilege to the keepers of the flame - which is why it's so very, very appealing to me.

I'd love to roll into a PCA meeting, with my gen-you-wine Porsche VIN, and have a modified LS engine sitting behind the seats to cause the faithful to soil their bermuda shorts. I'd make sure it was displayed so everybody could see it, and then I'd use it to blow the doors off of every single vehicle there.

Such a device would be rendered essentially worthless as a museum piece, which is another reason to love it.

Back to the sound - any engine in a good state of tune, from a 125 hp 2-stroke single coming on the pipe to a 1000 hp supercharged pushrod V8 sounds fantastic. I've come to LOVE the "angry bumblebee" sound of a 2L pushrod air-cooled flat 4 in the heart of the powerband. I'll agree that an air-cooled Porsche 6 spinning up to 6500 RPM sounds like angels singing, but it also sounds a lot like something really, really expensive might happen soon (at least to me, anyhow).

A cammed V8 with all the appropriate go-fast stuff spinning that same 6500 RPM sounds pretty special as well.

Last edited by Stan Galat
@Stan Galat posted:


…an air-cooled Porsche 6 spinning up to 6500 RPM… sounds a lot like something really, really expensive might happen soon…



That’s how I’ve always felt about my engine over 5000, so that’s where I stop. The builder claims it’s safe to 6200, so am I being a wuss?

At those revs, I don’t hear angels singing. They sound more like the loan officer at my credit union.

I will note that I’ve logged about 33,000 miles on this engine, and so far, no blue smoke.

It's interesting to be talking about sounds in these days of new cars having fake engine sounds being piped into passenger compartments.

Then, there is the question about what electric cars should sound like.

I took a little device (thanks, cheap Chinese stuff on fleabay!) and put a recording of the Jetsons car sound on it.

Placed in the front end of our LEAF it made an appropriately amusing sound that kept parking lot pedestrians from wandering into our path.

It died after a few weeks (EMPI?) and went the way of many of my harebrained schemes.

@Stan Galat posted:

A forged crank with forged pistons and H-rods and heads with dual valve-springs will hold together kissing 7000 RPM from time to time. I try not to spin past 6000.

Sometimes I fail.

I have used a 6500 hard limit for almost 45k. I rebuilt the top end of my 2165, but the case and bottom end are as-delivered from Jake, with the exception of the pressure plate.

My oil pressure is perfect, endplay was still 0.004".

Last edited by DannyP

When I was in school shop class was for the guys who weren't going to college.  Lord knows that wasn't me!

In retrospect that was pretty stupid.  Learning meaningful skills doesn't only happen in a lecture hall or lab.

Yup Lane. When I was in high school the kids who were going to college like me didn’t take shop or typing. In retrospect they would have been the most useful classes I could have taken. And it’s obvious to me that some of the most brilliant folks on this site took these classes and didn’t go to college. Framed pieces of paper on the wall in no way equates to intelligence or success.

We had shop class through junior high and then the curriculum changed depending on major (college course, business or trades).   My school was no where near big enough then to offer automotive shop or electronics technician or healthcare courses (all we had was metal shop or wood shop), but it did offer typing which everyone, college, business or trades, had to take.  We all hated it, but it probably saved our cookies later in life.   BTW, my class had only 108 people in it.  I know some of you came from schools with a whole lot more (and Stan came from that one-room schoolhouse in Morton with 12 students)    

Sometime in the 1980’s a regional vocational school was started locally for all those trade courses and a whole lot more and they have done a terrific job of preparing young people for the local job markets.  My old company, and several others locally, invested heavily in that school to insure a steady stream of hardware and software technicians for us and it paid off big time.  It soon became a badge of honor for kids to say that they were going to “Blackstone Valley Vocational”.   Before the pandemic, we used to go there once a month or so for lunch at their student-run restaurant and it was always excellent.

And like a lot of companies, mine would pay for follow-on courses once you had a year or two working for us, so some of those techs went on to later get their college degrees without being crushed by student loan debt.

Last edited by Gordon Nichols

We had auto shop in high school. Everyone that owned a car took it. I didn't own one, but being somewhat mechanical, I took it anyway. Our shop teacher would let you do work on your car and he'd grade you.

One time my buddy with an Alpha Romeo Sprint wanted to replace his brake pads. He only had time to do two wheels during class. Later on that night, him and I were cruising down some street and he was so happy that he had brakes, he slammed on  the brakes to show me. We immediately did a 180 and slid sideways between two parked cars and hit the curb. We got lucky we didn't hit anything but the curb. Apparently he did two wheels on one side of the car. He wasn't the brightest, but he was lucky. I remember more of what happened in this class than any other class. Art was second.

Those were the days.

Last edited by Carlos G

@Stan Galat - My Grandfather had a big ol' farm house that had a "Summer Kitchen" - That was a big addition off the side of the house, all by itself, with big windows on two sides to let the breezes through and cool the kitchen from the wood-burning kitchen stove.  Under that kitchen we could store the 12 cords of wood needed to heat the house in the winter (I'm not making this up) and off to the side down there was the outhouse.  It was a 3-holer.   I never quite figured that out, the three holer part, but it came in handy when the power went out during storms and the water pump didn't work and the toilet wouldn't flush.  

Shot myself in the foot, again. In the first post in this thread I talked about being suspicious that the battery cutoff switch was the cause of the starting problem. It turned out to be a few bad diodes in the EMPI alternator, but I removed the cutoff switch prior to finding that out.

Recently, I totally rewired the ECU and engine compartment. In the process of doing electrical work, I added a battery switch back in. In an abundance of caution, I used an 80 amp circuit breaker instead of the old switch.

Since that rewire, I've had the breaker pop on at least 3 occasions. I finally figured out that it only did it when the engine was totally warmed up and I was restarting the car. Aha, 80 amps was borderline when the oil cooler fan was on and I was starting the car.

I got a killer deal on 3 - 100 amp breakers and replaced the undersized one. So far so good. My foot is feeling better until the next unplanned event.

If someone needs a 100 amp breaker and wants it for the cost of postage let me know. I'll keep one as a spare.

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'Battery cutoff switch' and 'blown alternator diodes' in the same sentence rang a bell in the increasingly fuzzy recesses of my head. So, I've done some googling and found this on a British car forum (where else?).

Basically, using a cutoff switch to stop a running engine is nonsense up with which alternator diodes will not put.

Of course, you knew that and would never do that, but, you know, sometimes we get forgetful in our dotage.

If it matters, or is at all relevant, I've never managed to blow out diodes on an alternator. Too sheltered a life, probably.



"The regulator's job is to maintain about 13.5V at your battery +. If your alternator is turning disconnected from the battery, the regulator "sees" nothing, which is equivalent for him to Ov. So it gives more field to the rotor, to increase the output voltage which goes to the rectifier diodes. Voltage can go up to 80ish V, enough to "burn" the diodes. If you use a master switch without a resistor (or uncorrectly wired resistor), that's what happens if you cut your engine with the switch, especially at high revs (emergency, ...) On well built switches, the resistor is between the output and the earth. Low resistance -> high current -> low voltage -> safe diodes. Jeff LHD 1990 BDR"

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@Sacto Mitch posted:

.Basically, using a cutoff switch to stop a running engine is nonsense up with which alternator diodes will not put.

Of course, you knew that and would never do that, but, you know, sometimes we get forgetful in our dotage.

"The regulator's job is to maintain about 13.5V at your battery +. If your alternator is turning disconnected from the battery, the regulator "sees" nothing, which is equivalent for him to Ov. So it gives more field to the rotor, to increase the output voltage which goes to the rectifier diodes. Voltage can go up to 80ish V, enough to "burn" the diodes. If you use a master switch without a resistor (or uncorrectly wired resistor), that's what happens if you cut your engine with the switch, especially at high revs (emergency, ...) On well built switches, the resistor is between the output and the earth. Low resistance -> high current -> low voltage -> safe diodes. Jeff LHD 1990 BDR"

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Great point, Mitch. I haven't tried that trick (removing the battery from the circuit) since the days of mechanical regulators. It worked fine then, but I can see that some cars might go unregulated if the battery is disconnected.

Remember, I haven't done that, and don't plan to. However, would it really work that way for a type 1? Say the engine is running and the alternator is charging the battery at 13.5V. If you disconnect a battery terminal, the charging light, regulator and alternator are still in place in the circuit, there's just a little less load on the alternator (and the regulator will keep the voltage at 13.5V to reflect the lower load).

It seems to me that to make the regulator runaway, you'd have to remove the feedback from the alternator output to the regulator. At least on my car, that's no where near the battery terminals.

Thoughts? @DannyP?

It is certainly possible that a hinky/defective switch could cause a voltage spike that would turn an alternator's diodes to burnt toast in a millisecond.

I recommend keeping the battery in the circuit at all times. LOL!

I don't use one of those battery disconnect switches. I do have a thumbwheel battery cable though, so I can disconnect quickly when working on the electrics. It is secured with a ty-rap, I drilled a few holes in the wheel so I can secure it wherever it's tight.

Circa February 1992 I drove from Hartford Connecticut to Concord New Hampshire in my 1980 Honda Accord in order to cover the Presidential Primary the right way, in person, with an experienced photographer. On Day 2 of this field trip Theresa, our comely intern joined us in her jalopy, and we all had an enjoyable several days galavanting around the Granite State through the slush with the likes of Pat Buchanan, Bill Clinton, Paul Tsongas and . . . Tom Laughlan, erstwhile star of the "Billy Jack" movies.

On the way home Theresa's car would not start after a gas stop. Chivalrously, and with my car running, I carefully removed my battery and placed it in her car's battery box, replacing hers with mine and mine with hers. We all drove home without incident.

Just putting that out there.

Last edited by edsnova

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@edsnova posted:
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...Chivalrously, and with my car running, I carefully removed my battery and placed it in her car's battery box, replacing hers with mine and mine with hers...



If Ed were to try that today, he'd probably fry half the computer chips in a modern car.

I wonder how much an overabundance of technology has led to the death of chivalry in this century.

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Last edited by Sacto Mitch

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