The Stovebolt Site Forums The Shop Area Engine Shop Gas in the oil

Gentlemen, I need to pick your brains,

I got a 261, that was rebuild (the whole 9 yards) and driven about 500 mls without any problems, but than just sitting there for 10 years.
Now i fired her up again, and found a ton of gas in the oil.

Looks like I don't get fire on cylinder 2 and 3.
Of course I checked the low hanging fruits.
Distributor, wires, plugs - also tested with glas plug, I definitely get spark, just no fire in the hole - compression is fine (still have to do a leak down test though).
Vacuum gauge shows a vibrating needle just under the green zone, which is valve guides (as far as I know) but since they are pretty much new I doubt it.

Valve train looks working fine, at least while looking at it, while running her without a valve cover - no valves seem to be stuck.
Got an electric gas pump, so that rules out a leaky pump problem.

Got a dual exhaust - I observed gas droplets coming out of the tail pipe of the first bank.
So the only thing I can think of is damaged rings.

Is it possible that they got bad, just by sittig there for 10 years?

Any ideas?

Thanks, Frank

Carburetor issues.

John

So you are saying that you run an electric pump with no mechanical pump correct?

When you say compression is fine, what do you mean? Did you test it? How and what were the results? The reason I ask is that if the rings are bad, your compression is not going to be very good.

How long has it run since setting for ten years? Rings could be stuck letting compression past, that would explain the gas in the oil. If it has gas coming out the tail pipe, you have a major problem somewhere, my guess it's actually condensation that smalls like gas / exhuast. It may take it a while of running to loosen up, just a few minutes is not enough time. First step at this point is a valve guide test. You need to mechanically open each valve to be sure the guides are not sticking, this would be a really good time to adjust the valves. Second step is do a compression test, if you don't have a gauge, at a minimum, fill the cylinders with compressed air and to see if or where it's leaking out.
You could have bent a valve right off the bat and not know it. Guides stick, then free up, but when they are stuck, they can bend valves really quickly. It only takes two full crank revolutions to bend stuck parts!
Carburetors can go bad in a few months, I would never attempt to put fuel in one tens years old. Did you rebuild them?

First is to get that excess gas out of the crankcase. You might really have "fire in the hole" if you are not careful.
If the old fuel pump is still on the engine & the gas is running through it from the electric pump then the diaphragm is bad. Other wise the carb is flooding.
The miss on 2-3 could be from the wires crossed or carboned up plugs. Check 153624.

George

re carb issues:

I run a Fish carb, that worked fine before, and since all other cylinders are firing just fine, I don't think there is a problem.


re fuel pump:

no, the original pump is removed, and a plate on the hole.


@Joe: I was driving a few miles after I fired her up after all those years.
I noticed that she had way less umph (no wonder if 2 cylinders are not doing their job ).

Next step is pulling the head and make sure the valves are good, also pulling one of the pistons and have a good look at the rings.
I do an other compression test, and also a leak down test before.

What carburetor are you running?

A Fish carb - and yeah, it's rebuild and serviced.

Little update on this: I pulled the head, and everything looks good so far.
No bent pushrods, valve train is fine, valves and valve guides also.

Side question: I noticed that all the valve guide seals (kind of rubber coups - originally from a Ford I believe) are sitting pretty much high on the valve stem, caught in one of the two grooves.
I was under the Impression, that they should sit right on the guides. But they are kind a "riding" the Valve. Is that normal?

Before I pulled the head, I did an other compression test and got 155ish across the board.
Than I did leak down test, and it was enough to move the crank, but I also heard air coming down the crank case.

That leaves me to the rings (can't think of anything else).
Is it really possible that rings go bad, just by sitting 10 years?

I am not familar with this specific engine but seals riding up and down with the valves will act like little oil pumps pushing oil down the valve guides. I am sure that would impact oil consumption over time but probably not involved in your original gas in the oil problem.

The rubber seals on the valve stems act as little umbrellas to prevent excess oil from getting to the top of the guides. They were typically used on engines with oil fed thru hollow pushrods to the rockers. I've seen them on SBCs. Not sure if they'd be appropriate for an inline six, but they shouldn't hurt. I don't think they'd pump oil down the guides.

Those umbrella seals are supposed to ride up and down on with the valve stem. That is what they do on the lesser vehicle which they were designed for.

What is a Fish carburetor?

Otto,

Here is the information on the Fish carburetor.
Harold

http://www.rexresearch.com/fishcarb/fish.htm

Invented by Bob Fish in the 1930s, mine is from the 50s - actually a bit of race history.
It was run by Fireball Roberts in Daytona.

It seems pretty conventional. I doubt that anyone ever got 30-60 mpg in a conventional 3500+ lb vehicle with one of these installed. How does it perform on your truck?

Maybe the carburetor needle valve (fuel valve) is not sealing properly.
Did you drain the old gasoline before trying to run the engine?

Variable jets on a throttle shaft are IMHO far from "conventional", and no - nobody is getting 30-60 mpg out of a Fish carb (unless you run it in a VW Beatle maybe).

I'm getting 21 mpg at best (cruising at 50ish) on a good day.
Performance, umph and response is quite good over a stock setup, and even over the dual setup (Langdon) I had before, wich was always a bit - pun intended - fishy.
Love the simplicity and how easy it is to tune.