Help Sick 401!

[HotJimmy]

:(: My 401 recently started smoking and blowing some oil from the front breather. My PCV is fine. Started very slowly (some noticable smoke and oil when the hood is up), but yesterday it was smoking so bad it was leaving a trail of smoke behind me and the bottom of my air gap had a pond of oil (probably half a pint). I am 100% positive the oil is being pushed out from the breather. I have very minimal to no power change since this occured and no other problems. I'm thinking head gasket, but would love to find out it is something else! 8) ANY OTHER IDEAS? before i tear it appart?

[jeepsr4ever]

Yes before you do take and run a tube from the pcv and one from the front side and run them both into a canisters. My guess is that you are sucking up oil. Check the can to see if its still bleeding and which one is filling

[JeepsAndGuns]

I know before I rebuilt my 401 that when it was running if you took the breather off, the oil fill tube would blow little puffs of white smoke out. My engine looked like a choo-choo train. I did a compression check and all were good except for one, it had like 30-40 psi. I tore the engine down and looked at the piston and the ring lands were broken off about half way around the piston, and one of the rings were broken too, but luckyly it didnt score the cylender wall. I am currently about 90% done with a complete rebuild.

[HotJimmy]

Thanks for the info, i'll work on it this weekend and let you know what i find.

[youdidwhat]

I would have to say I agree.

you are getting back pressure in the lower half of that block. most likley from a cracked/broken ring. less likley would be the head gasket. Check your fluids for signs of contamination. that would be a sign of head gasket faliure. and a pressure test would indacate from which one.

Thats just my $.02

[Goose]

I would definately recheck the pcv system also.. If it isnt working right you will build pressure in the crankcase and push that oil right out..

[HotJimmy]

Compression tested all cyllinders- all 140psi except #7. It was 30 psi. Pulled it out, secondary ring broke up as well as the piston between the rings.
Good news is that the cylinder has no wear. :lo1l: I'm lucky

Today I ordered some .40 over 9.8:1 speed pro forged pistons to replace my stock dish pistons, but my machine shop questioned if i was going to be able to swap them in so easily. My block is a fresh rebuild and great condition, but they had some clearance issues.

My question-- can't I easily swap these pistons? Both pistons are made for my bore. Whats the issue?? are they just looking for more money?

[JeepsAndGuns]

Yea, if your old pistons are stock, and your new ones are .40 over, they will not fit without the block being bored out.

[HotJimmy]

No my old pistons are .40 over 'stock dish'

[JeepsAndGuns]

Oh. Well I dont see any reason they shouldnt work, but I am far from being a expert on engine building. :-|

[jeepsr4ever]

You will have to bring them in to a engine builder...they will need to be heated and pressed to remove the pins and re-heated to install new ones

[HotJimmy]

Thanks guys, the shop is going to press them on next week. Ill let you know how it all works out. good times! At what point do I have to worry about pump gas? 11:1?