Allan,
You mentioned "gallons" of gas would have been pumped into the engine.
You did not mention whether the car sat for hours, days or weeks before
the tanks were found dry, so let's look at the facts we have:
1. The fuel pump would have to be on and a float stuck open to allow a
steady stream of gas to flow. I have run the Edelbrock (Carter) carbs on
many engines, have never had a float issue unless the line pressure
exceeded 8 psi. The original SU fuel pump can flow about 35 gallons per
hour, but they only develop about 2-3 psi at the carb, so it would take
a sizeable leak to pump your tanks dry even if the ignition was on for
several days.
2. The carb would have overflowed and spilled gas through the exterior
vents onto the engine, and by your comments of gallons of gas, the
overflow would have certainly been noticed.
3. Edelbrocks use compound needle jets in the primary circuit, very hard
to flow much fuel through those into the carb, and while the secondary
jets are open and might leak, I've never seen or heard of it happening.
4. Even if all that gas somehow managed to flow through the circuits and
down into the manifold, the only way into the crankcase from there is
past the rings or past the valve guides. If gallons of gas were pumped
in there, certainly one of the cylinders would have been hydraulically
locked (filled with incompressible fluid, i.e. gas) and the intake
manifold would have filled up as well. The engine would have never
started and might have broken a rod trying.
5. The internal volume of a 260/289/302 is not that big, probably less
than three gallons total if you assume an oil pan already full of oil.
If you had more than that in the tanks, where did the rest go?? Even if
all the leaked gas got past the rings and into the crankcase the engine
would not turn over.
6. Per someone else's comments, a cam bearing is the last bearing I
would suspect to go if the oil had been diluted with gas. A big-end rod
bearing would be the primary suspect.
Now without more details it's hard to get an exact diagnosis, but there
would have to be a whole lot of wrongs lined up just right to create
this mishap. Yes it could be possible but the probability is very low. I
would be suspicious of the guy who told you this. I would also check
every bearing in that engine for damage.
Bugz
-----Original Message-----
From: tigers-bounces@autox.team.net
[mailto:tigers-bounces@autox.team.net] On Behalf Of Allan Ballard
Sent: Monday, April 18, 2011 6:15 PM
To: LIST TIGER
Subject: [Tigers] Fuel pump question
Under what circumstances would a stock fuel pump - pump gallons of gas
into the motor?
My new motor spun a cam bearing; the rebuilder said the fuel pump pumped
the gas tank dry, into the motor.
I will guess that the oil thinned accordingly, and that's why it was
idling at 230F, and that's why it spun a bearing - but how could that
happen...?
Would leaving the ignition switched on, or perhaps an electrical short,
do that?
I run a replacement pump from Sunbeam Classics, the version without
points, and an Edlebrock 500 cfm 4 bbl carb. Both have less than 4,000
miles.
Meanwhile the new engine comes back out to receive all new bearings,
possibly will need to replace the camshaft as well.
Allan Ballard
Mk1a Tiger
SIV Alpine
_______________________________________________
Tigers@autox.team.net
Donate: http://www.team.net/donate.html
Archive: http://www.team.net/archive
Forums: http://www.team.net/forums
Unsubscribe/Manage:
http://autox.team.net/mailman/options/tigers/mark.rense@ge.com
_______________________________________________
Tigers@autox.team.net
Donate: http://www.team.net/donate.html
Archive: http://www.team.net/archive
Forums: http://www.team.net/forums
|