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valve covers blown off

18K views 32 replies 21 participants last post by  boater 
#1 ·
Do you guys remember the guy that said he had his valve cover blown off ? He did not lie, I have a 355 supercharged engine. Knowing that I had two fuel glass low in fule, I tried to start the engine, Big back fire. I blew off both valve covers, the dip stick, and the master cylinder clamp. I also have breathers on both sides of the valve covers, I must check the flote bowls.
 
#3 ·
I dont really understand how this would happen as the combustion events in the cylinder heads are seperated from what goes on under the valve covers by the valves. Unless you blew through valves I really cant see this happening.
 
#8 ·
I was checking for spark one time on a car that wouldn't start and had become flooded. I was checking for spark by holding the end of the spark plug wire by the oil filler hole, (the oil filler cap wasn't on,), The spark worked and it shot a flame about 3 feet out of the hole. Made a big POP too. (kinda sounds like that gas fumes theory might be right)

Singed the hair on my eyebrows.

DOH!

mikey
 
#13 ·
joseph brown said:
i never had much problem with valve covers on any of my cats... but i have 425cat here with a hole in the side big enough to stick your head in to see what went wrong ...i could laugh now but i cryed then
You should take a picture of that, I'd like to see it. Those are some pretty beefy parts to be chucking through the block. Did the driver mention how many rpm he was actually spinning the thing?
 
#14 ·
valve covers

i don't know how fast he spun it ..but he was smart enough to not come back for his last check ....i could tell you more damage stories about drivers.. funny but sad because it always comes out of my pocket i had a cummins 444 with a droped valve.. driver said it was my fault because it ran to fast...that one was half up the next hill...the driver said it made a loud noise .........one thing forsure he's not a liar...
 
#18 ·
Blown valve covers - ITS TRUE !!!

I have a 1982 boat with twin 350 chev motors with about 1000 hours on them- this week after having the local marine service center tune up both motors and running them for a couple of hours, we stopped and turned off the motors and let them sit for a while - When I turned the ingition switch to the port motor to start - INSTANT EXPLOSION - blowing both valves covers completly off the motor leaving the 4 bolts firmly in the motor and larger holes in the covers- after all the smoke cleared I replaced both covers the best I could on the lake and the motor restarted. DOES ANY KNOW WHAT COULD CAUSE THIS - and could there be other damage ??
 
#19 ·
Ok lets see, your first post and its on a thread thats over 4 yrs old.....you were on a lake and blew both valve covers off one of your engines leaving the bolts in the heads. Then you say you replaced the valve covers the best you could. Did you happen to have a spare set on the boat?....along with a spare set of VC gaskets? Or did you just repair The blown up parts??????
 
#22 ·
I know the original post is four years old, but this can happen as it did to me. I was working at a local Ford dealership when I was given a car that the owner had been working on and would not start. He had replaced the timing chain so the first thing I checked was the timing and it was way off. I set the distributor as close as I could and tried to start it. The plugs were obviously gas fouled as it cranked over for some time before it finally went boom. The valve covers were still attached but ballooned out as was the oil pan. The oil dipstick almost went into low earth orbit. The customer had been trying to get the car to run and had been pumping away on the carb and cranking. The extra gas had washed by the cylinders and diluted the oil with gas. It reached a point when I had set the timing close enough to fire that the combustion process went past the rings and ignited the mixture in the crankcase.

Vince
 
#23 ·
I have had a set of valve covers exploded in my face..car wouldn't start,, used about a half can of starting fluid,,(did not know there was hole in piston)tried to start ,, and BOOM... blew the crap out of motor...i was 17 years old then ..and now i'm a lot smarter...crap happens.. :thumbup:
 
#24 ·
We had a friend of ours show up with a 350 in his pickup that kept blowing off the valve covers, he showed us several sets. Upon stripping it down we found a hole in the number 7 piston so when the valve opened the fuel went right past the hole into the oil, he`d stomp it, a spark would occur and boom.
 
#25 ·
I have also heard of this happening on Marine Engines. I have been told if the gasket starts to leak on the Mechanical fuel pump it can dump fuel into the oil, and then this can happen.

Trust me, I sure check the Oil on my boat for gas smells before starting it. I sure do not want to be sitting on top of 30 gallons of gas and it go boom on me.

Bryan
 
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