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bobistheoilguy

so wild guess, broken rocker arm?

bobistheoilguy

is interesting to say the least.. but given the information at hand, either the pvc got clogged creating excessive pressure in the crank, or maybe a leak had occurred thus losing the oil. leak could have been anywhere from the sending unit, leaking oil filter, head leaking into the radiator, or maybe oil passing by the rings.

7937

This could happen on any engine. Is that your final answer?

Actually you're right. Even the German Chevs of that era, (1980's, don't know what they use now) used pressed steel rocker arms that use a ball nut as a fulcrum. The exhaust rocker on #3 cylinder had broken. Removing the nut and replacing the rocker is a simple job. The #3 cylinder was firing but on the exhaust stroke the valve did not open so the gas was forced past the piston and into the crankcase creating interesting effects and noises. There seemed to be no lasting effects though after repairs were done.

shipo

Back in the late 1970s, I started working in a shop that was a NAPA storefront and a repair shop in back. One of my co-workers who was a very accomplished wrench was having a very unusual problem with his fathers' car. While I cannot take credit for the proper diagnoses (he had a working theory about the cause when I came on board), I did help him explore other possibilities, however, in the end, we kept coming back to his theory as the only possible explanation, which, in the end, turned out to be correct. Without further ado, here is how the problem was explained to me when I first met this individual:

My friends’ father bought a new full size Chrysler in 1973 (I think it was a New Yorker) with a 440-4 BBL engine, complete with a full add-on trailer towing package and “Desert Cooler” radiator. Every summer, “Dad” would go on vacation with his wife and any family/friends that wanted to come along. Said vacation consisted of towing his “Airstream” trailer up to the northeast portion of California along the Nevada state line, and then lots of beer and fishing. The drive from San Diego, CA to Buntingville, CA includes climbing Sherwin Summit (US-395, just north of Bishop, CA), which if I remember correctly climbs from Bishop, CA ~4,000’ above sea-level to the top of the summit (Tom’s Place) which is just over 7,000 feet.

The first year Dad drove the trailer up there, while climbing Sherwin Summit; he heard a loud bang and felt a momentary shudder come from the engine. When he got to the top, he pulled off the road to see if he could discover any damage. He immediately noticed that the car was running rough, but otherwise, no problem. Dad was not much of a mechanic, so, he simply continued on his way. When he got back to San Diego, he took the car in to his dealership to have the roughness fixed. What they discovered was that the valves had been blown up into the head on the number 8 cylinder, damaging the head and destroying the pushrod/rocker assembly in the process. It was suspected that coolant had made its way into the combustion chamber from a possible cracked head (the head was damaged enough that they could not determine if there had been a pre-existing fault or not). The dealership promptly replaced the cam, head and two lifter/pushrod/rocker arm assemblies under warranty (the car had only about 4,000 miles on it at the time).

A year later, after operating perfectly for the intervening 12 months, Dad embarked upon his annual journey again. Just as with the year before, halfway up Sherwin Summit, he heard the Bang and felt the shudder, this time, he did not even bother stopping at Tom’s Place. And again, Chrysler replaced the head, cam and the lifter assemblies, this time with 18,000 on the car (and out of warranty), given that this was deemed a “Pre-existing Condition”. My friend asked them to check the block for a crack, which they did, results were negative.

For the next several years, the story repeated itself. One year the dealership even tore down the block and had it “Magna-fluxed”, checking for the possibility of a microscopic crack that they could not find via their other methods. Once again, the results were negative.

What was wrong with this engine?

Best Regards,
Shipo

bobistheoilguy

looking at this problem shipo,

there is some common denominators, only while pulling up the summit, thus, heat is playing a role since there is very little air flow across the engine while pulling would mean engine is hotter. #8 cly is next to the a/c compartment against the firewall suffering even less air.

maybe preignition from the excessive heat while the valves are in the closed position and the cam is trying to open them would be the only way to cause damage. now this is assuming the timing was correct since it was running fine prior. of course if timing was the problem the first time would have showed that so given that, that's out of the question.

the thing that puzzles me is, why a cam shaft? if the cyl damage messed up the push rods would bend in most cases and may at best collapse the lifters but to cause damage to the camshaft is puzzling.

well, thats' my story and i'm sticking to it!

lets see how far off i am.

shipo

... and one that we did not think of.

If I remember correctly, Chrysler replaced the cam as a “Just in case”, due to the severity of the damage to the lifters, push rods, and rocker assembly. We were always of the opinion that the cam was unnecessary, however, it was their nickel.

As for the actual problem, the fact that the #8 cylinder exists in close proximity to the A/C box, and suffering less airflow *MAY* have caused a few extra degrees in the cylinder, but, given water cooled nature of this engine (and the fact that the car was equipped with a massive 4-Row "Desert Cooler" radiator), the most that could be expected would be a degree or two. With the benefit of hindsight, I can tell you that detonation was not the problem.

FWIW, for those who have never climbed Sherwin Summit in the summer, it is HOT (over 90 on most days, with some rising to well over 100) most of the time and the bulk of the 3000' plus elevation change occurs within a 10 mile stretch. Needless to say, what with the A/C running full bore and the load of the large car and trailer, we are talking about a seriously heat soaked engine.

Best Regards,
Shipo

bobistheoilguy

first, climbing that summit (which i have been on) is extemely slow with a load thus the air flow even across a 4core would tax the temp on that engine.

now lets look at this another way, with it being a 440 with 4 barrel intake, older car, no mass sensor, the barametric pressure would change on the climb up the hill, thinning out the air as you climb the air mixture would tend to go out of adjustment the higher up you get, and if too much fuel would "load up" in that cyl during the climb since there was more fuel than air getting in thus cause a higher combustion explosion.

like i said.. a stretch.

7937

A real nasty one - a 1984 Toyota Corolla. On a good day the starter starts the car easily. On other random days the starter is sluggish. The interesting part is that when the starter is sluggish even though the ignition is switched off and the key removed, the starter continues to crank the engine until the wretched thing runs the battery down. You have to scramble to disconnect the battery cable to stop the action. Put the cable back and things are restored to normal and the car starts easily - assuming you've disconnected the battery cable before the battery is flat.

Close inspection of the starter on removal reveals no problem. Brushes are OK. The solenoid works fine. Connect the starter to the battery while out of the car and the starter has speed and torque. Yet, quite by accident one day I spotted the fault inside the starter. The fault was fixed within minutes. What was the problem?

bobistheoilguy

my guess would be, ....

to have a starter hang on you and have to disconnect from battery means you have a completed connection on the selenoid. so, to make a connection from the battery to the starter its self, your selenoid has to be engaged where the contacts were connected to the starter plate inside. so if not a selenoid, then the starter had a mechanical hang up keeping the bendex out thus pushing the selenoid plunger back keeping the contact across the plate.
now, either you had a burr on the shaft or gears(not likly) or the bearing on the end of the starter was worn thus putting a bind on the gears so not to release.

now all this is assuming the selenoid is in fact not bad. of course another thing to look at if electrical would be to see if the key circuit was getting energized by shorting against 12v somewhere.

bob in jville.

7937

I forgot to mention that other circuits and relays for the solenoid were all checked and found OK - nothing was hanging up. This was not a mechanical fault either. It was electrical.

Mr_Shiftright

CHRYSLER----this description doesn't make sense actually (to me). The valve can't be pushed up into the head and break the rockers, this is physically impossible.

The valve could drop into the combustion chamber and get scrunched up in there, OR

The rocker shaft studs could pull, jamming the pushrod or valve and causing the valve to drop.

So what I mean is that the "event" had to occur initially in the rocker arm area. Then, if the valve is dropped, it can damage the engine internally.

OVERFULL DIPSTICK--what happened is that as the cold weather hit, the enrichment valve jammed open and filled the crankcase with fuel. This was misread as "too much oil", when in fact the oil was heavily diluted with gasoline, too much to "burn off". This diluted oil could not properly lubricate the engine under load.

Why the lube shop did not smell all this fuel in the oil when they dropped two quarts is a mystery. Also, it seems to me that the oil would have been very dirty.

The valve can't be "pushed" unless it is dropped first.

tboner1965

could break keeping the valve always shut.

TB

shipo

When I looked at the head, from the bottom, the two valves were physically pushed into the head past the seat, and the valves looked sort of like an umbrella that had blown inside out (although not that severe). The other damage included the rocker arms which had both ends bent up slightly up (and slightly bowed out in the middle), the pushrods were bowed (I did not see these, they were apparently found laying in the lifter valley) and the internal valve mechanisms of the lifters were suspect (I never saw these either), as was the cam itself. The rocker shaft did not seem to suffer any damage, however, these were replaced along with the head each time. Fortunately, given that the valves never dropped (ala 351 Windsor valves) there was never any apparent damage to the lower half of the motor.

Best Regards,
Shipo

shipo

Maybe I never studied hard enough, however, I always thought that while a carburetor of that era may have run a little rich at 7,000’, I was/am under the impression that the mixtures did not get really out of hand until 9,000’ or 10,000’. Either way, it was ultimately shown that coolant was the “non-compressible” that was causing the problem, the question is, how did it get there?

Best Regards,
Shipo

Mr_Shiftright

How very strange. I supposed hydraulic locking could do this, as otherwise the piston could not reach a valve that hadn't dropped, at least not on an old underhead cam American V8 (uhc?).

If a rocker breaks and the valve stays shut, then it's just sitting there, out of harm's way. There would be no combustion in that cylinder.

One other possibility that comes to mind would be some very nasty form of detonation. I suppose if detonation can punch a hole right through a piston it could drive the valves into the head. This would require some radical change in engine timing or a huge glowing carbon pile in the combustion chamber.

shipo

Ultimately, it was proven that Coolant had made its way into the combustion chamber at a very inopportune moment, and, as coolant is not compressible, something had to give.

What surprises me is that the valves gave way before the piston deck or the connecting rods. Back in 1996, when I was working for MBUSA, the CEO drove his S600 through a “puddle” (one would think that he should have known better), and the engine quit. When the car was towed into the shop, the first thing that the technicians did was take a dump of the OBC. It showed that the last several moments of the engines’ life had been spent motivating the car at a steady speed of about 40mph at 80% throttle! The air intake horns on that car were about 2’ above the road surface, and he must have caused a “Bow Wake” high enough to allow the engine to gulp water through the intake system. The end result was that the connecting rods were bent sort of like a three dimensional “S”, with both left/right distortion as well as fore/aft distortion. In this case, the piston decks survived as well (I cannot say as much about the piston skirts), as did the valve train. Maybe the fact that the old 440 had a push rod/rocker assembly (which I suspect is easier to distort than a connecting rod) is what saved the lower end of that motor.

Best Regards,
Shipo

Mr_Shiftright

Hmmm.....very interesting, thanks. I've never seen a hydraulic lock distort the valves either but like I said it is a plausible thing, and, obviously, you actually saw proof of it or heard proof of it.

Hydraulic lock was not uncommon on Mercedes of the late 60s, early 70s era, as the air horn for the injection was down pretty low and very close to the grille opening. 280SLs were particularly vulnerable, but really, this could happen to just about any car if the water were deep enough.

Another way for hydraulic lock to occur is a seeping head gasket, where you turn the car off and it's fine and then next morning you go to start it and get just one "clunk", as you had one or more cylinders full of water.

shipo

Hydraulic lock was/is very common with radial aircraft engines. Left long enough on the ramp, oil will seep into the lower cylinders in quantities equal to or greater than the combustion chamber space. A common misconception among many aviation types is that if you “Pull the prop through”, you will clear any potential hydraulic lock conditions. In reality, if there is enough oil in a cylinder to cause hydraulic lock, a propeller has enough “Arm” to actually bend connecting rods when turned by a single person.

I never considered hydraulic lock occurring from water/coolant seepage into a car engine. Given that coolant is just as compressible as oil (as in not compressible at all), clearly, just as much damage can occur from water as well.

Best Regards,
Shipo

shipo

The final solution to this problem turned out to be when we finally convinced Chrysler to disassemble the block and stick it in a Kiln. At something ridiculous like 500 degrees, a fairly large crack opened up in the #8 cylinder wall, proving what my friend had been telling them all along (since the second event that is). The regional tech from Chrysler said that they had never seen a crack that was not diagnosed by a magnaflux test; as a result, the entire engine was shipped back to Detroit, to Chyslers’ metallurgy lab. In exchange, Chrysler put a brand new 440 in Dads’ New Yorker, even though there were something like 88,000 miles on the clock at the time. Dad then drove the car another 120,000+ miles, including a trip over Sherwin every summer. Needless to say, he never had another problem with the engine.

Best Regards,
Shipo

sddlw

This forum moves along a bit quick for me. I was away from my computer for the weekend.

The problem ended up as a bad "convenience control switch" which alows the windows and sun roof to be closed by holding the key in the lock position for several seconds, about the only place the sun roof and window circuts came together.

catam

I have an 86 Camry that did essentially the same thing. The only difference was that my starter only "locked up" on cold mornings. During the summer it never gave me any trouble. Just like clockwork the first cold morning in late fall it would start sicking again, I could turn off the key and the engine would still crank, but it my case it only lasted for a few seconds. I lived with the problem while I lived in Houston, because there weren't that many cold mornings. When I moved to Salt Lake I ended up replacing the starter/solenoid assembly.
I assumed the problem was the solenoid possibly arcing and sticking in place. I am interrested to know waht you discovered the problem to be.

catam

I had an 81 Malibu with 3.8L V-6 and auto tranny. The engine burned some oil and leaked some oil, as well as leaking a fair amount of tranny fluid. Here's the problem, after topping off the levels the engine would blow copious amounts of smoke thru the tailpipe, and the engine would run "Weak", poor acceleration, slow up hills etc. The engine would continue blowing smoke for a couple of days, then it would quit, and run normally. I had to top off the levels about every 2 weeks in both the engine and tranny. Engine ususally took about 1/2 to 1 quart, the tranny took up to 2 quarts. What was the problem?

catam

Here's a hint the final fix ended up being a $15 part and 30 minutes labor.

tboner1965

Engine or Transmission mount broken. Your readings were wrong because driveline not aligned properly.

How'd I do?

TB
Computer Tech 8^)

bobistheoilguy

the trannie has a modulator valve on the side which had a vacum line hooked to the intake of the engine. the smoke would come from the oil being sucked through the leaking modulator valve.

Mr_Shiftright

But why does the engine lose oil then?

7937

As I said, I found the fault in the starter. The field coils are wound with flat copper wire and are connected in series. The connection from one field coil to the other was intermittently touching the starter housing where the insulation had worn through. A new bit of insulation around the conductor fixed that.

Now here is where things get murky. Why was it locking up the solenoid when half of the field was shorted to ground? It would explain the sluggish action of the starter but how could it effect the solenoid?

A typical solenoid has 2 windings connected in parrallel. When the key is turned on and power applied to the solenoid, both windings are energized. This ensures that there is enough magnetic force to bring the solenoid in. However, in order not to overload the ignition key circuit, one coil is then cut off by the action of the solenoid contacts leaving only one coil to hold the solenoid in.

Somehow, when the field had shorted to ground, one coil remained energized even when the ignition key had been turned off. If you look at the circuit of a solenoid and starter they look deceptively simple. However, there is more to the circuit than meets the eye. I still haven't been able to completely figure it out yet. Be that as it may, I had no further problems after I fixed the short.

catam

You nailed it on the head. WTG. It is actually the kickdown vacuum sensor that downshifts the tranny when you step on the gas. This had developed a leak, and when the tranny was full, the engine vacuum would suck tranny fluid into the intake manifold. I think the problem progressively worsened, I figured it out after I had added only tranny fluid one day, and the car immediately began smoking.
As for the oil loss, I think the oil control rings were not up to the task after the repetitive flood of tranny fluid, The engine burned a lot of oil after I fixed this problem. Needless to say I didn't keep the car long after this.
7937 thanks for the info on the starter, now if I had only read this last September before I replaced that starter... Oh well.
Lets all keep this discussion going it is good, oily, fun.

doitmyself

When I start the engine on my '93 Dodge pickup on cold mornings and move the shifter to reverse, the engine starts to run very rough, black smoke, etc.. This doesn't happen in warm weather, or even after the truck is warmed up in winter. If I put it directly in forward drive, it takes right off. I spent $800 on it already and no one can fix it. Any ideas?

bobistheoilguy

first, is it an automatic or standard we are talking about?

lets say automatic for this problem... black smoke indicates that you are getting too much fuel in the cyls and that when you put it in reverse, you are lowering the idle on your engine and the air mixture ratio is being loaded up with too much fuel and not enough air. , this would be due to a stuck choke if you have a carb. this problem would not exist when warmed up since the choke would normally be open by this time.

as for dropping it into drive and it working, maybe you have gotten to the point that your not idling like you do in reverse so when going forward your already pushing the pedal allowing more air to fuel flow thus not staggering like it would in idle.

now this is just going on what you have. if you would, it would help to know the engine type model, transmission standard/auto, milage on car, and any other thing you can supply us with.

bob

tboner1965

So you didn't really fix the oil burning problem with 1/2 hour labor and a $15 part. You listed several problems, but only fixed one of them.

Foul!!!

8^)

TB

Mr_Shiftright

Yeah, I thought it was a technical foul as well. Nothing wrong with throwing some curve balls but we were led to think that the engine oil and trans oil consumption were connected. If he had not mentioned engine oil, the diagnosis would have been much easier. Here I was wracking my brain to think if this car shared engine/trans oil.

bobistheoilguy

figured since he mentioned leaks and such that had to be seperate and the only connection with trannie fluid and engine would be only through the modulator, had to be it. see, simple minds for simple problems.. guess that's why i'm so good at that huh..LOL.

bobistheoilguy

when i ran a mechanic on wheels business in texas, i had a guy call me. his car was running bad pulling up the hill, bucking, had to put his foot in to the gas, and not running good at all while in gear. gas mileage went to heck as well. he had the fuel filter replaced with a new one and he thought he had it fixed, but it started to do the same exact thing again in less than 75 miles. so, since he just replaced filter, i suspected maybe tune up problem. that wasn't the problem.

what next?

stever

Wild stab by someone who can't turn a wrench:

Oxygen sensor?

Steve
Host
SUVs, Vans and Aftermarket & Accessories Message Boards

tboner1965

I was thinking since the driveline was out of line, the leaks were from seals that we behaving similar to when you overfill your oil. Ditto for both oil and tranny fluid consumption. If you overfill your tranny, you will have a big cloud of smoke following you for a while. (Don't ask me how I know.)

FWIW,

TB

bobistheoilguy

i should have mentioned, 85 model, 350 chev engine. no oxygen sensors on this older model.
if there was, it wasn't the problem

Mr_Shiftright

Well, it's interesting that the problem was fixed temporarily, from your/his description.

Is that true? (I don't want to be mislead if I'm reading something into the puzzle that's not realy there).

Did the new fuel filter temporarily alleviate the problem?

dpwestlake

Heres one:

1975 GMC 3/4 ton pickup with a 350CID V8 2BBL carb. owned by a trucking company I worked for.

One of the mechanics went to start it. The engine would not turn. Without checking it was assumed the engine was siezed. The engine was replaced with a target master complete engine. A week later the same thing happened. This time when the dip stick was pulled it was full of gasoline. The crankcase was drained, the plugs were pulled and the engine turned by hand to get the fuel out of the cylinders. The engine was filled with oil and was fine. another week later the same thing happened again. Crankcase full of gas, hydraulic lock, etc.

What was the problem? BTW, it was summer and the truck was parked over a week end in the shop.

alcan

Any chance the truck was parked near something that was creating a vacuum at the tailpipe? If an intake and exhaust valve are both open in overlap (end of exhaust stroke, beginning of intake) the vacuum might be enough to draw raw fuel through the carb and hydrolock a cylinder.

7937

It's summer so the fuel vapors are building up pressure in the fuel tank. The float in the carb is either set too high (allowing the level in the float bowl to be too high) or, the valve is leaking. The pressure in the tank forces fuel into the float bowl which then overflows and runs into the intake manifold.

jlflemmons

From problem number one: I would have also checked for a blocked radiator. At highway speeds, the return from the waterpump will exceed the flow rate of the radiator. If the blockage is below the cap, the excess will overflow the overflow tank and loose coolant. At speeds below 35mph, it will keep up.

Jim

7937

OK, this is a funny one and it really happend. It will test your knowledge of 2 stroke engines. I put it here as a matter of interest only as it won't pertain to any modern car.

The car is a German DKW 2 cylinder 2 stroke of around 1937 vintage. It belonged to a friend of mine. On occasion after starting the engine, the gears are reversed - ie, reverse gear becomes a forward gear and all forward gears become reverse gears.

What was happening and what is the fix?

tboner1965

I think two strokes can run either way, so this one somehow got running the wrong way.

Dunno the fix.

TB

shipo

The engine started running backwards, fairly easy to do for a 2 stroke motor.

Best Regards,
Shipo

0patience

Fuel pump.

catam

I apologize for providing info that misled you about the problem/ solution. At any rate, bob saved anyone from stressing for too long.
As for Bob's problem: I was thinking fuel pump until I reread the post and you stated gas mileage went to hell. You said it wasn't tune up so I assume timing is correct, and no fouled plugs. If both of these are true, I am going to guess a cylinder is down, worn cam profile perhaps.

Mr_Shiftright

300 Diesel Mercedes. Owner can no longer shut the car off when they turn the key to "off". They are forced to push a sock into the air cleaner to get the engine to stop. The fuel pump is NOT electric on this car. Problem? (even if you don't work on diesels you should be able to figure this out more or less).

7937

Yes, the engine was running backwards. But how? Firstly, the starter/generator was integral to the flywheel - shades of things to come. So there was no starter pinion to prevent the flywheel going backwards. Also, any side-port 2 stroke engine (which this was) can run backwards.

The cause of the engine reversing was that the ignition timing was too far advanced. As the piston approached top dead center, the spark plug fired and the piston was forced down before going over top dead center. In the opposite direction the timing is now (relative to the piston) retarded. The engine is now much happier with the state of affairs and keeps on running.

The fix of course is to retard the timing.

bobistheoilguy

shiftright...Did the new fuel filter temporarily alleviate the problem?...

it appeared to have, but started to do the same thing with a new filter in less than 80 miles.

catam.. would seem reasonable but in this case, not it.