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Chevy 350 Problems

Colbykz's Avatar
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Join Date: May 2011
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May 30th, 2011, 9:27 PM   #1  
Chevy 350 Problems

A few months ago I purchased a 1984 Chevy Camaro Z28 5 speed, the previous owner put a 4 bolt main 350 in it from a 1983 Chevy Suburban. Immediately after purchasing the car I replaced the Mallory Distributor Cap and Rotor With an MSD one as well as Replacing the coil, plugs and wires, they were all burnt up and needed replacing. I gave It an oil change 10w30 and a new filter. I also replaced the Carburettor with a Holly, I believe 600 CFM but I could be wrong. The car had and oil leak, took about a quart a week, I figured it was a mixture between the intake manifold gasket/valve cover gaskets/oil pan(just about all the seals I figured would need replacing) Up until a few evenings ago the car ran great, had all sorts of power but had a problem with overheating which I can't seem to figure out.

A few evenings ago I brought it to a fairly deserted highway and ran it through the gears up to about 5000 rpm except for fifth up till i was going 120, then i decelerated, the car was running just before the red warning lines on the temp gauge. I decided to pull into a parking lot and let the car cool down. I noticed a ticking noise in the parking lot, I killed the car and checked the oil level and was at the add label, after letting the car set a little the ticking seemed to die down some. I drove to a local gas station and filled the car with a quart of oil, this brought my oil level up to the full line. I figured the sound i was hearing was valve ticking, so i removed the valve covers went through each cylinder found tdc(plugged the plug hole w/my finger till air was blown out) I then adjusted the valves by taking a .015 feeler gauge tightened the rocker arms down out it removed the feeler gauge and then tightened it 3/4 of a turn. The ticking went away. I filled all the fluids and drove about 20 miles, car was running excellent. I then took a trip to the local auto-zone to pick up a new taillight bulb and when i left i ran it through the first three gears, at the top of third their was a loud pop/hiss noise as if i lost pressure, the noise was similar to the sound you hear using my method to finding TDC(my oil pressure gauge does not work). There was then a sudden decrease in power across the RPM range, but particularly noticeable at low RPM where the car jerks, and at about 2500 rpm the car feels like the engine is not balanced. The car wants to stall after any heavy acceleration. The car does however in neutral blow out some white smoke. Haven't checked the coolant for oil or vice versa.

What could cause this? My thoughts are...

Bad valve seals
Blown head gasket
Blown Piston ring(s)
Bad plug(they are all new, but possibly one isn't firing?) I did check to make sure all of my plug boots were connected to their terminals
Bad cam

any thoughts? Thank you.

I haven't done a leak down or compression test yet, the plugs are a pain to get at but i checked all of the wires and i plan on getting my oil gauge working buying a new pressure sending unit asap.

baycitygreasemonkey's Avatar
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Join Date: Apr 2011
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June 11th, 2011, 10:52 AM   #2  
I never run an engine without knowing my temp & oil pressure.
You need to get that o/p issue taken care of.
If you have white smoke you have coolant in the exhaust.
I would put the front end on jack stands.Let the care sit for a bit & then crack the drain plug.
Oil sits on water so if there is coolant in the crankcase it will be at the bottom of the pan.Crack the drain plug & see if you get any coolant out.
Also see if your coolant is low.
The pop sounds like you may have jumped time,bent a pushrod or something.
Good luck.

Last edited by baycitygreasemonkey; June 11th, 2011 at 10:54 AM.
wolfy692005's Avatar
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Join Date: Jun 2011
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June 13th, 2011, 8:33 PM   #3  
had a similar issue some time ago.. i had pulled the head rocker arm stud up out of the head( they are pressed in).. it also did it on decel jusat like yours.. if you did this and you have a valve not opening this could be your issue.. worse is it may have bent the pushrod.. i dought that though as you would likely have known when you adjusted them.. did any seem really loose?

wyotechisajoke2012's Avatar
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Join Date: Feb 2012
Posts: 2

February 5th, 2012, 10:46 PM   #4  
chevy 350 coolant leak

so i got stuck in about 4 feet of snow out in the middle of wyoming friday night and had to spend the night, i tried to keep it running as much as possible but i didnt have enough fuel. when i finally got it pulled out the next day it was running fine till i started to get on it. i had a leak out of my lower radiator hose. my thermostat had gone out. i replaced the thermostat, the coolant, and the hose and it ran just fine heat worked thermostat opened and everything without problems i drove it again tonight and it ran well untill i steped on it and when i looked behind me there was a large cloud of smoke, i pulled over and it was steaming (not overheated) and it was gushing my brand new coolant onto the ground. upon further inspection i noticed it was coming out from the block underneath the exhaust manifold and behind the engine mount. what could it be? freeze plug? i didnt hear a bang so i dont think im missing part of my block or anything but im completely stumped. i removed the tire and fenderwell and im in the process of taking the exhaust manifold off tomorow and trying to figure out why this is being such a pain.

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