Mopar Muscle Association UK

Had a lovely drive to Brighton and back on Sunday, Plymouth ran fine despite the heat. But while dropping dropping Rob & co off back in Hemel the engine cut out.
Strange we thought, it doesn't usually do that. Even though the fuel gauge said very low there should have been plenty in there.
Tried to restart and it ran for a second or 2. Subsequent attempts didn't even get a cough, despite putting a couple more gallons in just in case it was the obvious.
So while waiting for a recovery we took the hose off the carb dual feed, and nothing was coming out while cranking.
With the car back home via Classicline Insurance's recovery (4am after getting to Rob's at 5.15pm), yesterday I removed the pump (Holley mech 12-440-11) and rigged it up with the inlet hose in a fuel can, operated the lever with a 19mm spanner (for mech advantage), and it shot a fair amount of fuel with just one pump. So i figure the pump is ok.
Pushrod end felt fine when in situ but thought it best to measure seeing as the pump's out. It measures 3.204" long. There's a small witness at the lever end on the centre but the cam end looks fine. Doesn't feel at all concave.
Q : I've seen different lengths quotes on 'net as to what the rod should measure. Some 'experts' on Moparts etc say 3.250" but the Hughes engines #HUG 10010 states 3.200 nominal. So can i rule out the pushrod as well?
I wouldn't have thought 50 thou wear would result in NO fuel being pumped?

Note, engines done probably 2-3000 miles, all new parts, new tank, lines, sender, filter etc.

If this is unlikely to be the problem the next step is to blow the lines through, so i'm trying to get the hoses off the sender unit, which have been crimped on just to make things difficult.
Q : Will the sender come out of the tank without dropping the tank? It's got hard lines up to the tank so I'm resigned to disconnecting the rubber hose ends at least.

We did also take out the float level sight plug, and there didn't appear to be anything in the primary bowl, or the feed hose.

Of course it all might have been caused by the hot weather and vapour lock or whatever, but it's got a return line to the tank, and was running fine until it cut out.

any advice gratefully received.
Stu

blocked breather or blocked hole in filler cap or wrong filler cap i.e cap for car with tank breather on a no breather tank.... causing vacuum that overcomes the SUCK the pump creates

was there a big suck of air when you added a few more gallons?

mechanical fuel pump has two valves that open and close alternately between 2 chambers if one sticks or is blocked open by bits then i guess you might get a similar problem. you seem to have flushed it through now though. one continuously open valve compromises sucking and pumping action

did the push-rod jam at the the pump end (i have no idea how a big block pump works) i've only had that on a VW flat 4 and a sharp rap with a mallet or a new pump mounting boss (phenolic plastic in this case) usually fixed it

sock on tank pick up gunged up?

all new though isn't it?

tres odd

Dave

Before pulling too much apart, pour some fuel down the carb and run it. This might drag the fuel up if it was vapour lock. If that doesn’t work, attach a length of hose to the pump and into a fuel container and see if it will run off that before disturbing the sender end of things.

Regarding the pushrod, the machined area at each end starts off the same length and usually only wears one end away so visually you can normally see straight away if it’s ok or not.

problem with fuel pumps at the front is the drag of the fuel from the tank will lower the pressure slightly in the pipe and lower the fuel boiling point. Some additives in modern fuel boils at 30 degrees C. Modern cars run very high pressure systems with the pump in the tank to avoid this.

It may just be a heat thing and be fine again when the weather cools down.

appened to me a few weeks ago rod was worn have new spare one will measure it tomorrow and tell u length also check hoses between tank and pump in case split as might be sucking air as it wont show a leak if ful tank is low

Blue wrote: ↑Tue Jul 20, 21 5:11 pm Before pulling too much apart, pour some fuel down the carb and run it. This might drag the fuel up if it was vapour lock. If that doesn’t work, attach a length of hose to the pump and into a fuel container and see if it will run off that before disturbing the sender end of things.

oops.
Carried on stripping out, got the sender out and looks pretty ok to me.
see pics below.
Sock filter looks clear, I've blown some air through it, and the return pipe. Blows through ok with not obvious blockages.
Strange black rubber sleeving seems to be deteriorating from fuel contamination. Is it just supposed to isolate the arm electrically from the inside of the tank?
Also stuck the air line up the fuel feed hard line and put the pump feed end into a bottle. It blew some fuel through maybe 50-100ml.
Return line was clear with no fuel in it.
Poor pic of inside of tank shows maybe a couple of bits of debris which may be flakes of paint from where the tank was painted before installation. I noticed that the paint was melted on the mounting face under the rubber gasket. That area should have been masked off.

So I'm inclined to think maybe it was some kind of vapour issue due to heat. But not really encountered it before so unsure how to prevent it? The tank is vented with what looks like the original 2 pipes (not blown them through though). Gas cap doesn't have a vent hole as far as I can see. (pic below)
It was quite difficult to remove when adding the extra gallon so maybe was being sucked closed. But it can be hard to remove sometimes if over tightened. Didn't noticed any 'pffft' when opened though Dave.

I'll re-assemble tomorrow.

Thanks Mr M, would be good to know the length of a new pushrod. And what make it is.
I measured the 2 (non) machined ends, they are within 0.025" of each other. Pump end is the slightly shorter end, but I can't see that it has reduced in length as the only wear mark is a small circle in the middle?

heres pic of new one and length with pt no

my old rod was worn by 7mm when it stopped working but spose it depends on pump also
my new pump from rock auto

Thank you sir,
So that's 0.020" (0.5mm in new money) longer than mine.
Hopefully I'll be ok. Pushrod, pump, filter and sender all back in now. I put some break in lube on the ends of the pushrod & lever.
Just the alternator to go & it's fingers crossed time.
Might leave the gas cap off while I crank it to help draw fuel through. And chuck some fuel down the carb - is the vent tube the best place to pour it?

Noticed while under the rear that the fuel lines run right above the over axle exhaust pipe. Not ideal so may consider something around the pipe or a shield for the lines. Though I was thinking a shield would just trap hot air above it and up under the boot floor. So some sort of lagging is probably best though i've avoided that in the past as it can cause corrosion.

BTW Mr M, absolutely loved your '66 at Brighton, shame Rob & I didn't get to catch up. Next time eh.
Is it a 383 Satellite? quite rare I would have thought?

Stu Twin wrote: ↑Wed Jul 21, 21 4:16 pm ..... And chuck some fuel down the carb - is the vent tube the best place to pour it?

Just take the Air Filter off, pour an egg cup's worth down the venturi directly, put the Air Filter back on, and give it 30 seconds. Then crank it....

Maybe the rod is ok but have you checked that it moves in & out as you crank it - as the cam drive could be damaged ??
Especially as when you operate the pump manually it seems to be working!

On a Big Block the actuator eccentric is part of the camshaft.

wrapped my fuel pipe over exhaust with heat sleeve, which silver asbestos type cloth

mr m wrote: ↑Wed Jul 21, 21 9:28 pm wrapped my fuel pipe over exhaust with heat sleeve, which silver asbestos type cloth

good idea, that might be the easiest way.

Good news is that with the help of an assistant chucking fuel down the carb and lots of cranking, we got the car started and let it run for a few mins, idled fine.
So at least I know the parts are in good order, but still a little worried going forward about the mythical 'vapour lock' issue.
How's best to avoid it in the future? would a strategically placed hole in the gas cap help?

Good job I've got this week booked off work. Not got much done round the house, mind.
Got 2 cars to clean up ready for the Nats so I predict a few more days spent over the next week in the garage.