The Stovebolt Site Forums The Shop Area Engine Shop engine diagnosis

I had a gentleman approach me about fixing his '66 F*** p/u for him (ya, I know, I'll sanitize my tools and shop afterwards) anyways, we started it up and it has real loud valve train rattle and lots of smoke coming out from the oil filler on the rocker arm cover and some smoke out of the tail pipe. I drove it to my place (shop) 30 miles and you couldn't see behind me for miles. There is so much pressure in the crank case that it was spewing oil all over the engine out of the rocker cover. Prognosis? I think, from the looks of things that someone in the not to distant past has done some head work and a valve or something has gone through a piston, but there is no popping or back-firing. Have prepared him for the worst case scenario, getting a different engine, but hope it is only a hole in a piston. I haven't opened the engine up but will soon, anyone want to try to diagnosis this before I pull it apart just to see how close you are?

High pressure and blowing oil out the cap = plugged PCV valve - or the hose leading to it.

Try putting some Chevy Orange engine paint on it. That should make it run better...

My diagnosis would be that the rings are done for. This sounds like a ton of blow by past the rings which is pressurizing the bottom of the engine. This will make it smoke, blow oil all over the place, and be a real mess.

If you are lucky, its just the crankcase breather all stopped up with goo. I had an Ariel Square 4 and some bonehead screwed a bolt into the breather. This caused oil to be blown up past the rings and made it smoke like my 2 stroke race bike.

The easy solution? Just sell the guy a mosquito control officer's liscense.

Ok Bald Eagle, everything is at a halt. When going down the road the oil pressure was 45 lbs until I started running low on oil and it dropped to 20-25 lbs. The pressure I'm speaking of is forcing oil out the oil filler in the rocker cover. I checked and yes it has a PCV valve covered with oil. What you are saying is if I replace this "problem solved"? I will tell you that just at an idle there is a lot of smoke coming out of the filler int rocker cover. Boy if this fixes it I'm out the money for a rebuild but he wants a lot of work done on this truck.

Sounds like some serious mechanical problem. Bad PCV valve or no, there is way too much crankcase pressure here. I suspect excessive ring wear if there are no unusual noises from the engine. A broken ring or piston will make you ask: ''What's that noise?''

yep it's shot time for a 425 inch olds

Could be the drains are plugged in the head (with carbon and crud) that
allow the oil to drain back to the crankcase. Rocker cover(s) will fill quickly if so and the PCV valve will suck up that oil and dump it into the intake..............

Oil rings are broken or stuck in the groove of the piston. I had a 352 F**d that did the same thing. It would even blow the dipstick half way out of the tube. Tear it down, it needs help!!!

I'm not saying that the engine isn't worn out or even that the PCV valve is the only problem. What I AM saying is, that PCV valve is plugged up.

My ex-father-in-law loaned me his brand new 66 Impala convertible (cherry red w/ white interior) to make a trip, and during the trip the PCV valve plugged up. Blew oil all over the engine compartment, smoked like a son of a gun, rattled like crazy, lost four quarts of oil in no time. I barely got it to a shop, where they said the engine was gone - until a mechanic looked at it and diagnosed the problem.

You replace that PCV valve, and I'll bet you the oil loss goes away. Now, as to whether that's all that's wrong, it's hard to say. You didn't say anything about how long the truck has had the problem, how it ran before the problem started, whether or not it's always smoked, so it's not possible to say everything that might be wrong with it.

Heck, take the pcv valve out of your truck and stuff it in there and see if it works. Take you 5 minutes. If it doesn't, well, check compression and leak down, bet that tells you what you want to know. Another way is to hook up a vaccum gauge and look for a rythmic swing in needle, that would tell you one cylinder was not sucking it up right.

This is the reason I just love this board. It helps to keep me in check in more ways than just engines and Stovebolts. I spent the little time it takes and ran a compression test just to be certain of what may be up here. This is the results.-
#1-160 lbs
#2-120 lbs
#3-155 lbs
#4-60 lbs
#5-150lbs
#6-35 lbs

I didn't try a new PCV valve, I just pulled the motor. Will take the head off today and see what damage is done. I have already lined up another block in case this one is toast. I should talk him into a 425 Olds-LOL Will post an update of what I find under the head.

Sounds like cracked rings, piston slap & badly scored cylinders.

Time for a 455 wagon motor and a set of lakewood traction bars. Better replace the U-joints!

chip

Sounds like a broken piston or two.

bet my engine is the same. I have only looked at the plugs so far - but 4 was oily and 6 was corroded. I bought a big long cheapo screw driver so that I could stuff it down the distributor hole to preoil the motor and then compression check it, bet I get the same readings.

Oh well...neighbor has a big humping chrysler v8 sitting in his garage.... :p