I posted this on the 80-86 forum but am reposting it here cuz there are good engine people here. ;-) It's kinda long, it's basically the story of a fuel pump leaking gasoline into the crankcase. Been warned about hydrolock & bending connecting rods, also about damaging bearings. I kinda doubt I've bent any conencting rods because I suspect the gasoline had a place to exit (at the fuel pump junction and maybe through an oil pan gasket) and it was never put under any real load. Somebody else told me how this is very similar to an old trick of washing out the insides of an engine using diesel fuel or kerosene. In the end, I hope I haven't damaged the thing badly and that it'll last at least until Springtime.

-ct

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1981 F350, 400cid. I've had this thing for almost 3 years, I use it primarily for hauling firewood. The engine was supposedly rebuilt by a reputable machine shop but it's unknown as to when that was or what, exactly, was done. If I believe the odometer it had 94,000 miles on it when I bought it but nobody knows if there's an invisible "1" or "2" in front of those numbers.

It's my first truck but I've been working on cars - mostly Fords - since 1978 or 79. My first car was a 1970 Mustang. In all that time, I've never experienced anything like this; but this was another one of those times where I told myself, "Ah, sh%t, I think it's time to sell this thing to the junkyard."

When I got it, one of the first things I had to do was replace the mechanical fuel pump & rubber fuel lines, I guess that was around 2.5 years ago.

Fast forward to about six weks ago, that was the last time I had started or used that truck. I changed the oil and then put about 100 miles on it hauling firewood. When I finished, I backed it into the driveway and there it sat since then. My driveway is slightly angled, so the front of the truck has been somewhat lower than the rear.

Over the following weeks, I noticed a fairly significant oil spot on the driveway was accumulating underneath the engine. It was impossible to tell from where, exactly, it was leaking, but I had just changed the oil so I tightened the drain plug a bit and hoped that was the cause. But I didn't put any clean cardboard or anything on top of the exisitng accumulation so I had no way to tell + it's been too cold out to worry about.

As it turns out, that wasn't the cause.

Around two weeks ago, as happens here in Colorado winters sometimes, it got pretty darn cold out and I awoke to about 8" of snow on the ground. "Maybe I'll take the truck to work today," I thought.

Well, it wouldn't turn over. All the electrical accessories & buzzers indicated seemingly adequate electrical power was available but the starter couldn't turn over the engine. I tried to jump it with my daily driver but that wouldn't work, either. I figured the battery must've been discharged by sitting for four weeks in the sometimes subzero temperatures.

A few days later, when it had warmed up somewhat, I attached the battery charger on a slow charge for several hours. But I never tried to start it afterwards, I thought to myself that surely that should have taken care of that problem.

That was last week.

Yesterday, Saturday, it was sunny and 50*F and I wanted to take the truck to run an errand. But, again, the starter motor couldn't turn over the engine! And all sorts of possible reasons raced through my mind... Could an electrical short circuit someplace be slowly discharging the battery? Was the starter motor seized? Was the engine itself seized? "My upcoming four-barrel carb installation project that has expanded to include a head job might have to further expand to again rebuilding the bottom end," I thought to myself.

I have one of those high-powered battery chargers with which you can jump-start a vehicle, so I hauled it out and hooked it up. And, still, the engine wouldn't crank! The dash lights & buzzers were as bright & buzzing as they could be and it was sunny and warm out, there was no reason for this!

So, I left the battery charger connected and powered on at the boost (highest) charge rate, left it there for about 10 minutes and tried again.

...rrrrump... ....rrrrump... ...rrrRRRump... rrRRRRRump... ...rrrrrRRRRRRRRRrrrrrRRRRRRRUUUUUMMMPPPPP it started! It was running like crap and wouldn't idle without my foot on the gas but that was no real surprise, that existing carb has issues + it'd been six weeks since it last ran.

As I normally do, I watched the oil pressure gauge (both my parents have trained me well; as a kid, my mom's car was a 1970 Torino with a 4bbl 351C and a Hurst 4-speed shifter on the floor, dad had a Boss 302 Mustang and two Corvettes). The gauge went up to about halfway but then went down, down, DOWN to below the N in NORMAL!

So, I shut it off and crawled underneath to take a gander. There was a huge waterfall-type dripping of some kind of fluid emanating off the entire front of the engine and frame cross member. Raising one eyebrow in a Spock-like fashion I thought to myself: "That's odd. Sh%t. It looks like this thing has expired."

Tried to start it again to verify, was hoping it'd stay running so I could look at in operation.

But it wouldn't start again! It'd turned over and acted like it tried to catch once or twice but that was it. And the starter was having a hard time so I hooked it up to the charger again while I procedded.

The next step was to check the oil level. Pulled the dipstick and it showed nothing. Well, kind of, but it was hard to discern anything reliably. It appeared that one side of the dipstick was wet with something but the other side didn't indicate the same. "How bizarre," I thought. So, I added two quarts of oil and checked again but still, it was hard to determine anything. Clearly the dipstick was wet with something but it was wet for several inches up the length of it, and it didn't really look or feel like oil. My inital thoughts were of anti-freeze but that should be green and have a telling odor.

By this time, all sorts of newly-conceived horrible situations were going through my head. Did all the oil leak out of it while I hauled several thousand pounds of dead trees to my house? Yes, it's been leaking onto the driveway over the course of the 6 weeks but it hasn't leaked THAT much, certainly not 5 quarts of oil!

I figured something must be wrong and the dipstick was lying to me; late last year I replaced the dipstick tube while replacing the clutch & installing headers and I thought I must've done something wrong though I couldn't for the life of me imagine what.

And my mind went back to the no-start problem. It tried to start but it wouldn't. Spark, gas, compression. I knew the front gas tank from which it was presently pulling gas was almost empty, so I flipped the switch to the full rear tank and got it to start again! But it was sputtering really badly and wouldn't idle so I couldn't go observe the motor while it was running.

Called my father, had him come over and take a look. Started it up and he discovered gasoline spraying out of the joint between the fuel pump & engine block, the crank damper was spreading it all over the front of the engine compartment. I verified this as he started it up and I observed the situation.

You'd think I would have smelled gasoline during all of this, but I guess I've been desensitized to it because of all the chain saws I have and use in my garage + it was somewhat breezy outside where this was taking place.

So, I pulled the fuel pump, thinking I'd take it to NAPA and get another one. This present one had also come from there and it was only around 2 years old, it really shouldn't have failed in such a manner so soon but sh%t happens sometimes.

With the fuel pump off, it was real easy to take off the oil filter. As you may have anticipated by now, it was half full of gasoline.

Drained the crankcase, this required some time. Because I drained close to three gallons of gasoline & oil from it! The starter motor couldn't turn it over because it couldn't force the pistons to compress the fluid in there.

Went and got a new fuel pump and a bunch of oil & filters. Installed new filter, replenished the oil in the crankcase, and vrrooommm it started right up, the starter motor turned it over like it was powered by its own nuclear generator!

Let it idle for about 8 or 9 minutes to warm up, then turned the truck around so all the oil (and leftover gasoline) will end up in the rear sump on the angled driveway. Removed the oil fill cap and let it sit overnight, my thoughts are the warmed-up engine will encourage the gasoline to vaporize. It's cold & snowing out today but is supposed to be near 60*F by Tuesday, I plan to repeat that warm-it-and-open-it-up process at least two more times before I drain & replace this oil.

Gasoline doesn't make for a real good engine lubricant, about all I can do is hope that I didn't fatally damage the engine by running it like I did. It was for a short amount of time at low RPMs but still.

I still have the old fuel pump, I wonder if I can disassemble it and do some sort of post-mortem on it. I'm hypothesizing that the diaphragm in the pump failed, and because the nose of the truck was angled down, gasoline siphoned from the side tank into the engine over the course of 6 weeks. I really have no idea when the failure occurred, it's entirely possible it failed while pulling a trailer filled with dead trees but I guess it's just as possible it failed after. There was no indication of a problem when I changed the oil 6 weeks ago, and I don't recall any oil pressure problems while hauling.

Before I replaced the pump, I stuck my finger in that hole in the side of the engine and found that I need a timing chain badly. So, the 4V carb project for the coming Spring has morphed into... into... I don't know what. I hang out on the 335-series engine forum, too, and I suspect I'll be talking to Tim Meyer in the next few months....

-chris
colorado, USA

 

Had that happen 15 years ago on my 71 GT 351C. The car had sat for 11 years until I got it. I found this out when I went to check the oil one day and found there was MORE than what I put in, then smelled it: Bingo. Smelled like raw gas. The pump had ruptured internally and was leaking gas into the engine. After a new pump, it ran fine.

My dad had an old Charger that would be very hard to start and found it was burning the gas vapour from the crankcase from underneath the pistons, and blowing the oil pan gasket out at the same time. Not sure exactly how it was igniting, unless some blowby combustion went past the rings??? Anyway, wasn't my story! lol

 

had this happen to me on a 46 chevy truck i had with a inline 6.. best internal engine cleaning u can get.. ran like a top after that! just let the pan plug out and air dry a day before you put the new oil in..

Ray

 

Wow, it's so cool to find that this has happened to other people!!! ;-)

OK, here's another question - six weeks ago I changed the oil and I replaced it with Mobil 1 20W50 synthetic because I've been led to believe it's allegedly helpful in the gas mileage arena with old engines such as this. This was the first time I've ever used synthetic oil in my life. Could this have somehow neutralized the smell of the gasoline? You see, neither me nor my father detected any gasoline smell until I pulled the hoses from the fuel pump, at which time gas from the tanks started leaking onto the ground and the odor was then plentiful. But, gasoline that had been in the engine with that synthetic oil appears to become odor-free. How odd.

I've got a gallon of some sort of concrete clearner & degreaser that I've been using to clean the stain off the driveway (I've used this in the past with regular oil stains) the stuff turns purple with this synthetic oil. Hmmm. Well, so long as it cleans the driveway and keeps the HOA off my back, I'm happy.

It's about 40*F outside and I started it up for its second time, it runs OK and the oil pressure is back to normal with 10W30 in it, I kinda suspect it'll recover from this OK.

The 4V carb project has grown to include a head job because the thing started burning a slight bit of oil on startup around a year ago, and I'm hoping that's caused by the valve guides. Removing the heads once you've got the manifold off isn't too much additional work, and it'll let me measure & inspect some things to get a better idea of what I've got.

I replaced the clutch and installed headers & new dual exhaust late last year and found that the rear main seal seems to be leaking a bit. But it's a 4WD and dropping the oil pan from an installed engine just looked like more work than I was willing to get myself into at the time.

But I now find that I need a timing chain, which means removing the entire front of the engine. So, now I've got the top and the front off. But removing the oil pan to measure & plastigauge the crank is still gonna suck no matter what, maybe it's easiest to just remove the entire engine and disassemble it all over the garage floor (in reality, I'd prolly borrow my brother's engine stand). Already have the Performer 400 EGR & Holley Truck Avenger and a few other miscellaneous parts (oddly enough, I want to re-enable the EGR valve (it's been disconnected and the hole under the carb sealed with a gasket) because I have yearly emissions tests to pass + I'm sick of creating intentional vacuum leaks and fiddling with the carb before the e-test and then adjusting it to run good after). I see in these forums that you're supposed to mess with the timing if you're gonna disable the EGR; ya know, I have no idea what the PO did, and I have yet to put a timing light or vacuum gauge on that thing.

Or, maybe I should just buy a builder and build it, there'd be no rush for time that way.

All for what started as a 4V carb project.

I use this thing for hauling dead trees, sometimes from over 9,500 ft. in the Colorado Rocky Mountains down to Denver (5300 ft), other times no mountain altitudes involved, all my activity is down in the flatlands. No need for a hi-RPM racing engine but low-end torque is most important.

-chris
colorado, usa

 

The oil burning on startup might just be valve stem seals. Pull the valve covers, get your spring compressor out, your air compressor with air fitting for spark plug hole, and have at her!
I don't much care for synthetic in older engines, unless they don't leak at all. It seems like if you have a small leak, the synthetic leaks even more than dino oil.

 

I remember my father doing this to his Boss 302, I wonder if he still has his valve spring compressor (a home-made dealie). In his cse, new seals didn't 100% fix his problem, he still had bad guides on one or two cylinders.

When I installed the headers late last year I found one cylinder in particular (I guess #4 - pass side rear) that had LOTS more black gunk accumulated in the exhaust port than the others. Didn't pull the valve covers to investigate, it was late in the year and I wanted the vehicle for hauling wood during the heating season (although I *did* get new valve cover gaskets).

But here's something else that concerns me... I know the clickity-clackety sound of many rocker arms. But I'm detecting a sound that sounds like it could be just one that's misbehaving, the time interval between clicks/taps/knocks is more consistent with one device rather than many. But I haven't yet investigated, I guess it could be anything.

March is approaching, traditionally our snowiest month, and I may need to get one more load of firewood to last me through this season. During this time I need to replace my compression tester gauge, get a vacuum gauge, see if I can find my timing light. And I want to get the Tom Monroe book; my father has been doing this stuff for 40 years but I have very limited knowledge & experience in much of the engine internals (rotating assembly portion).

And I have no idea what quench chambers are but I read about 'em here quite a bit.

-ct

 

Might be a collapsed lifter, or a broken pushrod. I would investigate if the sound is worse than a noisy lifter.
I bought a spring compressor that has a crank **** on the top instead of the fulcrum type. I found it works good with most motors, including some OHC 4 cylinders. I try to buy multipurpose tools when I can! It wasn't that much money, either...