Thread: Newbie with a question

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I have a sbc 355 that has had some issues lately, While I have sorted most of them out, something strange has happened recently and I was wondering if anyone could help me out.

My engine has chrome valve covers with breather valves in each. In the last month, the right side breather cap has been blown off the engine with enough force to tear the rubber grommet.

I canot afford tokeep replacing chromed breather valves s can anyone explain to me why this is occuring?

Any help would be appreciated.

Assuming that one of the breathers operates through a PCV valve and is plumbed to the intake manifold and the other breather is open to atmosphere, I'd say you're developing so much crankcase pressure due to blowby past the rings that it's time to consider a rebuild.

The breather valves (caps) fit into fittings in the valve covers and are not attached to the manifold, and the engine was freshly rebuilt less than 10,000 miles ago, is there any other explanation?

I will say that I recently had work done on my engine and the shop did not reattach my electric water pump power supply correctly causing the engine to overheat, but I shut the engine down before it got too hot, I think.

This problem occurred before the mysterious disappearing breather valves occurred.

First off, why would you be running an electric water pump on the street? There's no way it will move enough coolant to cool the motor compared to an engine-driven water pump. If you think you are going to pick up some horsepower by not running a mechanical pump, you're mistaken, especially if you did by accident find an electric pump that would move enough coolant. It takes the same amount of power to move the coolant, whether it's mechanical power from the crankshaft or electrical power from the battery. Since the battery is recharged by the alternator and the alternator is driven off the crank, you're still using mechanical power to drive the water pump. The main difference is that you've invested way too much money in an electric pump, money that could have been used to actually improve the efficiency of the motor.

Secondly, you have the motor all plugged up. The crankcase has to breathe in one manner or another, whether you use one or two breathers open to atmosphere or one breather open to atmosphere and the other plumbed to the intake manifold through a PCV valve.

I'm surprised that you haven't complained about the oil dipstick being blown out of the tube and I'd also be a little surprised if you didn't hurt the rings when you overheated the motor.

Yep, I think your electric water pump cooked your rings a bit, and the poor crankcase ventilation can't handle the extra blowby. Get rid of the pump, and hook up a PCV valve to the intake. Hopefully, there's a lot of miles left in the engine before it'll need rings again.

Thank you both for your response.

the reason I am running an electric pump is space. My v-8 is in a fiero and the set up I have would place the water pump in the pssenger rear wheel well. The water pump I am running is a Meizere and I have never had a problem with overheating, even in 100 degree weather in traffic, except when the shop did not properly reconnect the power to the pump earlier this year. I will run out today and get a PCV valve and plumb it to the carb.

As for the rings, I may be pulling the engine this winter to replace the heads with a better flowing set (currently has heads from a mid-eighties monte carlo). I may also be adding a more radical cam because the one that was put in this summer is too mild for me. This time I will do the work myself with some help from friends to make sure it is done right.

The cooked rings could could also explain the little bit of oil I am getting in the exhaust at start up

Thanks again for your responses as they were helpful.

Kelin