Hello Windsor,
I had a push rod fail last year. I know what you mean. It sounds
terrible. I
swore I sucked a valve. The reason it failed was that I was tardy in
checking my
valves and the lash had increased. (They're solids) The increased
pounding due
to the large lash broke a push rod. I had to remove the intake manifold
to
retrieve the broken push rod and lifter to make sure that the lifters
and cam
were OK, they were. I then performed a leak down test of the cylinder
and found
it to be 90% low, leaking out the exhaust. That is, with 80 psi applied,
the
tester was reading 5 psi. For good measure I then tested the remaining
holes and
found another bad one on the opposite bank with a similar reading. I was
baffled. I pulled off the heads and found two exhaust valve seats had
sunken
into the head, and were cocked. The weekend before, the engine had
enough power
to repeatedly hit 130 mph on the straights. The valves weren't burnt yet
but it
wouldn't have been long. I bought new aluminum heads and gained 30 hp.
The rod bent for a reason. If you can't find the reason, fixing it
becomes a
matter of luck. I suggest that you disassemble enough to verify the
reason. Then
you will know how to eliminate the root cause.
Good Luck,
Craig Wright
Windsor Owens wrote:
> Hello all,
> I've been absent from the list for several months due to a job
change.
> Over that time, I managed to go on one of my annual pilgrimages, The
> California Melee. 500+ mile rally over some of Northern California's
best
> backroads. It was a great time. My 67 Mk 1A ran great, except my
battery
> crapped out in Stewarts point. Fortunately, they had one their all
chartged
> up and ready to go. I even had a bit of fun with a couple of Porsche
911's
> on Bolinas-Fairfax road. It is a very tight, narrow, bumpy road- it
was a
> blast. I manged to hold off the Porsches, but just barely. I'm
going to
> need posi before I try that one again!
> More recently, I went to my first STOA meeting up in Santa Rosa.
It was
> a great meeting, lotsa nice folks, and some very generous hosts. I
managed
> to get my car TAC'd as well. Unfortuantely, on the way home, my
recent
> troubles began. Over the previous few weeks, (since the rally), on
trailing
> throttle my car had been making what sounded like valvetrain noise,
> basically a subdued valve tapping. I spoke to Dino Fry who buiolt the
motor
> 20+ years ago, and he said it is probably an exhaust manifold gasket.
Sure
> enough, the exhaust manifold was a bit loose, so I snugged it up
before the
> trip to Santa Rosa. It didn't really fix the problem, but I really
wanted
> to go to the meeting. It wasn't to loud, and I thought the car could
go
> another 100 miles before further investigation. I WAS WRONG!!
> So, I've just left this great club meeting, and I'm about 5 miles
south
> of Santa Rosa, heading back to SF, when all of a sudden the valve
train
> noise gets really loud! OH SH**! I limp back over the bridge, and
get the
> car towed back from the Golden gate bridge across town to my garage.
(That
> part of the trip took 4+ hours, but that is another story...). Upon
> examination, I found I had two bent push rods. So, two questions
remain:
>
> 1. Do I get a new set of Ford Motorsport pushrods or a set of the
Crane
> push rods? Is there a third choice that is better that I am not aware
of?
> 2. Do I pull off the heads and see what horros lurk beneath (I know,
OF
> COURSE I should do that) or just put new push rods in and see how it
runs?
> When I last shut it off, temp, oil pressure and idle were fine, it was
just
> the loud bangs due to the pressure wave exiting the intake valve
because the
> exhaust was no longer opening. I know, I should do a thorough
inspection,
> that is the right thing to do. But is there any slight reason why I
should
> think that it was just failed push rods, and that I can escape without
> pulling the heads? CAn I pull tghe heads with the motor in the car,
or do I
> have to drop the motor/Trans out the bottom to get the heads to clear
teh
> firewall?
>
> thanks,
>
> Windsor
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