Turned the key and BLAM!
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Fleet Mechanic
Joined: Aug 2014
Posts: 1,729
Likes: 50
From: Charleston, SC
Turned the key and BLAM!
Ran some errands in the truck, drove it for about 30 minutes then left it in the parking lot for about an hour and a half, maybe more. When it's been sitting that long I choke it and it stars right up without any pedal, so I did that. Cranked right up, as usual, but it backfired through the tail pipe as soon as I hit the key. Loud, sounded like a pistol shot.
Ran fine after that but I noticed as I drove back through my neighborhood a very short chirp coming from under the hood.
Sounds like it's definitely one cylinder making the noise and it only happens at cruising speed - light on the gas not too fast.
I checked the compression: 1)149, 2)132, 3)59, 4)132, 5)132, 6)130, 7) 130 8)35. Nothing new.
My next move is going to be removing the valve covers and looking for loose or bent push rods.
Any advice would be appreciated.
C
Ran fine after that but I noticed as I drove back through my neighborhood a very short chirp coming from under the hood.
Sounds like it's definitely one cylinder making the noise and it only happens at cruising speed - light on the gas not too fast.
I checked the compression: 1)149, 2)132, 3)59, 4)132, 5)132, 6)130, 7) 130 8)35. Nothing new.
My next move is going to be removing the valve covers and looking for loose or bent push rods.
Any advice would be appreciated.
C
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Fleet Mechanic
Joined: Aug 2014
Posts: 1,729
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From: Charleston, SC
No, it's not, but they are worse than I thought they were. I have been holding off on any major engine work until I can afford the time and money to put a crate 390 in it. I may go ahead and replace the heads, though.
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Fleet Mechanic
Joined: Aug 2014
Posts: 1,729
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From: Charleston, SC
I should clarify; this is a truck that sees between 50 and 100 miles of driving a week. With a new house and lots of work to catch up on, I'm having to put off all the things I would like to do to it probably until the Fall.
My main concern at this point is seeing to it that the engine doesn't self destruct before I can either rebuild it or replace it.
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Laughing Gas
Joined: Sep 2014
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From: Whittier
I would hook up an air line to those cylinders that are low and apply air pressure to see where the compression is leaking. If you hear air leaking into the carb, its the intake valve. If it is leaking into the exhaust, exhaust valve. If leaking into the oil pan, bad rings or broken piston.
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Fleet Mechanic
Joined: Aug 2014
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From: Charleston, SC
I took off the valve covers, spun the rods around. Everything looked fine. Ran the engine for a few minutes and watched them, revved it up a bit listening for any noises - nothing. I don't know what else to look for.
One thing, though; the thing floods when I shut it off and the engine is hot. Normally it just evaporates after 45 minutes or so but maybe some gas got dumped into the exhaust.
One thing, though; the thing floods when I shut it off and the engine is hot. Normally it just evaporates after 45 minutes or so but maybe some gas got dumped into the exhaust.
Hotshot
Joined: Mar 2013
Posts: 14,255
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From: Phoenix, Az.
I took off the valve covers, spun the rods around. Everything looked fine. Ran the engine for a few minutes and watched them, revved it up a bit listening for any noises - nothing. I don't know what else to look for.
One thing, though; the thing floods when I shut it off and the engine is hot. Normally it just evaporates after 45 minutes or so but maybe some gas got dumped into the exhaust.
One thing, though; the thing floods when I shut it off and the engine is hot. Normally it just evaporates after 45 minutes or so but maybe some gas got dumped into the exhaust.
That flooding problem has to be addressed soon. Flooding like that can cause carb/engine fires. Or gas in the oil. Too much gas in the oil will wipe bearings.
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Fleet Mechanic
Joined: Aug 2014
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From: Charleston, SC
Don't know. Would have to check again. Why?
Hotshot
Joined: Mar 2013
Posts: 14,255
Likes: 199
From: Phoenix, Az.
As an example lets say the intake valve rocker is moving but not as much. Less lift and/or lift time equals less the piston going down can suck air in that cylinder to create good compression test numbers.