I have a serious case of blowby. Im not sure what causing it since my engine only has 20K miles on it. Can a clogged exhaust cause to much pressure to build up in the crankcase. I ask because a few monthes back I had a convertor break apart. I dropped the exhaust to gut the 2 cats and one was already gutted. I bought them new so I know what they looked like. I take it all the stuff is somewhere in my pipe or muffler and not helping matters at all. I havent dropped the exhaust yet to find out but Id figure Id get some info here first.

 

Well the clogged exhaust would build pressure up through the exhaust system and into the heads... The extra backpressure would probably cause the exhaust gases to vacate slower..which will lower your engine's efficiency... It MIGHT cut back on the amount of intake charge than the cylinders can take in, but I'm not sure. But I don't see how this could affect the pressure in the crankcase at all. If you have excessive crankcase pressure, first of all, check to make sure your entire PCV system is in place and operating correctly. You might have a clogged screen.

Do you run a PCV system or just 2 breathers? If breathers, consider returning to a PCV setup...it might relieve extra pressure since it's forcing air in and out of the crankcase.

 

Worn rings ca cause massive crankcase presure. Have you ran a leak down or compression test lately?

 

I am runing the stock PCV system. I replaced all the hoses and got a new PCV valve and it didnt help at all. I cant do a leakdown test now since I took the intake off to prepare the engine to come out. The engine has to come out anyway since I have to replace the oil pan gasket.