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FINALLY, IM BACK ON THE FORUM (FIREWALL PROBS). WOW, THE FORUM HAS CHANGED...ANYHOW, HERES A
PROB I WANTED TO SHARE FOR ABOUT 2 WEEKS NOW, AND THE CAUSE I FOUND. SOME FACTS YOU NEED TO
1. 1500 MILES ON REBUILD, NO PROBS
2. STOCK EVERYTHING EXCEPT CAM (270 COMP)
3. .030 OVER, STILL 10:2.5 TO 1 COMPRESSION
RAN GREAT FOR FIRST 1500 MILES. THEN I STARTED TO GET A SLIGHT TICKING FROM THE VALVE TRAIN,
BUT ONLY ON ACCEL AT LOAD, NOT AT IDLE. HERE YOU GO....
In case you read the original post. I started getting a ticking noise in the valve train on by 68/427,
with about 1500 miles on the rebuild.
Well, I inspected all the lifters (Hyd) and pushrods, nothing unusual there. I then took the heads
off, and took them to the local head shop for an inspection. I got a call about 3 hrs later, asking
me to come back to the shop. The valves were coated with a dark brown, baked on goop, that
was wrinkled in appearence. I mean, this stuff was about an 1/8 inch thick. He said he had never
seen anything like that before. He said he had seen heads with sugar dumped in the fuel that
looked somewhat like this, but valves usually lock in thier guides when that occurs, and the valves
slid right out of thier guides when dissasembled.
With that info, I went home, and looked at the top of the pistons. Upon a close look, I could see
the top of all the pistons were coated with the same thing. I mean, I scraped a good helping off
the top of each piston. I mean this stuff was gooped in the valve relief portion of the pistons so
bad, they were hard to tell where they were. So I beleive the ticking was actually knocking,
caused by excessive deposits on the pistons and heads. So the next step was to drain all the
gas, and check it out.
Now, when this first happened, I gassed up full on the way to work with 93 octane as usual. I use
no fuel additives. It sat all day at work, and when I got off, I drove to my dads house, 3hrs away.
About 2 hrs into the trip, I got this ticking noise when the engine was under load. Not at idle or
acel, but only when under accel under engine load. I checked valve adjustment, readjusted from
scratch, no better, no worse. When I got to half a tank, I gassed up again, came home, with about
1/4 tank left in the tank.
So when I drained the tank after I saw the heads, I couldnt believe it. The gas looked the same
color and opaqueness as Mountian dew (green). When I placed some on my finger, it didnt even
smell strong, like gas will. It had a very weak gas smell. So of course, I drained the gas, and
when I put the engine back together, I turned the engine over so all the fuel lines/pump could
purge before hooking the lines back to the carbs. I took the carbs (tri power) apart, cleaned all
parts with carb cleaner, and cleaned the intake manifold with barsol.
This weekend, I put the heads, intake, etc back on, and fired it up. It was raining, so I didnt take
her out for a shake down. I will today after work.
So whats the deal? Bad gas at the fuel up? Someone dump something in the gas? If someone
did, It would have to been at work that day after I gassed up in the morning as it sat all day. If that
was the case, I didnt notice the fuel was green until I ran the tank half empty, the ticking started,
then filled up again, got back down to a 1/4 tank, and then drained it. Someone would have had
to pour a whole bunch of stuff in the tank while it was parked at work for me to see it was like
mountain dew, especially after I had filled up again before I noticed and diluted it, which makes
me think the tank of gas I got that fri morning was bad. It didnt happen at home, as its parked in
the garage. Whats so bad about this, is that I was planning to drive up to Carlise this weekend,
and just got confident the break in was complete, and shakedown gremlins were gone, now this
happens. The saving grace is that I do all the work myself, so at least labor price wise, I didnt
have to pay, but what a lot of work.
1. Was the gunk build up causing the ticking (actually, it was knocking) 2. What in the world was
in my tank?
I welcome any input
Most importantly, who sells locking gas caps for 68-69 gas tanks. Couldnt find any in Ecklers,
ZIP, MAD, or Cor Central?
Yer probly never gonna know what the cause was. Maybe yer neighbor got back at you for yer dogs eatin' his chickens? If it was the gas, maybe someone else in your area will be having the same problem... ask around. If it was at work, the locking gas cap is the only cure. That would be a bummer.... your fellow workers dumping crud in your Vette. Time to get out the Spy kit. In any event.... if the stuff is heavier than gas, it will settle down below the gas level in the tank and unless you totally dried out the tank when you emptied it, there may be some of that gunk still in the tank. This happens with water... it sits way down in the bottom just out of reach of the pickup tube.... until the car tilts... and then it gets sucked up into the engine. Ask me how I know.
RE: Carlisle... as I expected... I cannot go this year. But you should still go- especially with that deal on accommodations you came up with. Although I've never driven my Vette there (always brought the family) it is simply breath-taking to see all the Vettes in one place at one time. Ya just gotta go!
Do you think it could have been Anti-Freeze? It's green and oily, I don't know if it will dissolve in gas or not but it might. I know that the glycol is a long chain hydrocarbon that has some of the properties of sugar, and I know that it will seriously gum up a motor if it gets into your oil.
I wonder if someone didn't dump a gallon of Prestone in your gas tank. The same feeble minded idiots that key cars, and ram them with shopping carts can do some distructive stuff.
Vadalism to a 'vette ought to be a hanging offense!! :smash: