My roller moto 302 in my z28 did a freaky thing...

[Camaroresto]

If anyone has ever had this happen and knows why I would like to know. The car had been sitting. Dead battery. Charged battery. Pumped gas. Wouldn't fire. Let it sit. Turned it over it fired and the whole engine shuttered, carb fire and blew the timing cover seal, front oil pan seal and for some reason tried to push the mech. fuel pump off and cracked it. Crank case explosion? Motor has been fine running condition for over 10 years. I don't get it. Any thoughts?

[TDW]

Raw fuel in the crankcase. When you pumped it trying to start it, there was way too much fuel dumped down the intake. It has to go somewhere, and the only place is down into the oil pan.

[beater68427]

[ QUOTE ]
Raw fuel in the crankcase. When you pumped it trying to start it, there was way too much fuel dumped down the intake. It has to go somewhere, and the only place is down into the oil pan.

[/ QUOTE ]

Ditto!! Some reason you got alot of fuel in the crank case and well it flashed... I can not see you pumping it that much, but possible, I would also (when you get it fixed) check the carb needle and seat etc make sure it was not running fuel out. Also was the car running rich before you parked it, fuel will mix and stay with the oil for some time. A real bummer I feel for you a simple problem turned bad!! But on the better side of things the car didnt burn down...

[TDW]

Also you should check the floats and the float levels. If the floats have a pin hole in them, they will not shut the fuel flow off and it will seep. If the level is too high, it will flood it. Like said above, it could have been much worse!

[Kim_Howie]

Check your fuel pump. I wouldn't have thought that much fuel would go pass the rings.??

[Mr70]

It can if it's in liquid form and an abundance of it too.
I can relate and hope to never revisit that again..

[Big Block 69]

I have had fuel pumps fail & dump gas into crankcase.
Since yours is cracked, you need to change it anyway.

Rick

[Rixls6]

I had a similar thing happen to an engine with a 2-piece intake once.

One of the bolts inside the intake that hold it to the head came loose. When we fired the engine after sitting for a while, the bolt lodged in the intake valve and caused a similar explosion.

Both valve cover gaskets blew out, the oil pan mushroomed out and blew it's gaskets, and both mufflers blew out.

[Kim_Howie]

Rick, If that much fuel gets pass the rings I would say that motor has more problems than gaskets.JMO Most of the time the fuel stays on top of the piston and that is not a good thing on the rods when you try to start it.

[Salvatore]

The motor hydrauliced on gas!