please help with excessive oil blowing out of motor.

grantur01

Founding Member
Nov 7, 2001
226
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16
Dayton, OH
Well we have been fighting with oil getting blown out of the breather cap for some time. We have tried 4 different types of caps but nothing really helps. It just a PITA when I pull up at a car show and have to wait till no one is around and wipe oil off the valve covers etc...

My took took the valve covers off and ran a coat hanger down the return tubes and found some gunk in them. Changed the oil and same thing. Where is the excessive oil pressure coming from? Is it normal? Where unsure of where to look now. He plugged up the cap with a sock and now it seems like the oil wants to seep out of the left valve cover/gasket. I will say that the oil pressure guage is always almost touching the line @ Hi.

Any help would be appreciated.
 
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Wow that sucks. How many miles are on your motor?

I had excessive oil pressure on my stang back when my third engine was going down. I had managed to crack a couple rings and they'd cut pretty large gruves into three cylinder walls so gasses were making it past the rings into the crankcase and over pressurizing the block. Blowing oil out everywhere including the dipstick.
 
there is about 12k since the rebuild... We did not have the car before the rebuild though. I believe my father said that the oil had blown out of the dipstick also. Did you car run ok with the cracked rings? man you got me scared now, lol
 
I put a little over 50 thousand miles on that engine before I had to remove it. I think probably the last 10 were with the cracked rings.

I know exactly when I did it and how. I paid bigtime for that cheap, 82 cents, low octane gas in San Antonio. My car ran like crap on that tank and I think it's what did my rings in.

Anyway, once the oil started coming out the dipstick I only had probably 6 thousand miles left before the engine fell flat as far as power went, and I was only getting 11 miles to the gallon highway, down from the 20 I had been getting.
 
Max Power said:
Lotta blowby there. It can't be good. Is your PCV system hooked up correctly?

We have wondered if the lines were plugged in any way but it does not seem so. Do you know where I can find a diagram of what the blowby setup is actually supposed to be so I can compare what we actually have? That would be great...yeeeaaaa.. :D
 
I had this same problem on a good running 302 I dropped in my '66. I went thru everthing until I got the proper PCV installed. I was not getting enough suction thru the engine for the factory designed system to function. I had oil from the breather and the dipstick, especially at higher rpms. Took me three different pcvalves to get the corrrect one. Ended up using the stock setup from the '85 Lincoln Town Car that the engine came from. I even tried running the breather on the drivers side into the air cleaner with the little filter. Now, I have proper flow from the drivers side with an air flow into the valve cover thru the small filter in the air cleaner and then thru the engine internals and out thru the pcv into the base plate of the carb. You could use the open filter type breather cap also. One reason I went with the more closed system was for cooler air. My entire engine now recieves cold air only because of this setup plus the scoop sealed to the air cleaner setup I built.
 
thanks for the help guys. I really appreciate it. You all are top notch at helping people out with there problems. I wish I knew more so I could help people out.

Since they are cheap I think we will buy a PCV for a lincoln town car like was mentioned. I'm not sure at what benefit one PCV has from another. Its just a very basic design. but its worth a shot?

AZ Pete- the 302 is from the lincoln town car? Is the blowby setup different from that of a 289 other than a different PCV valve? Can it be adapted to the 289??

I'm really starting to wander about the cracked rings or possibly a valve not seating.

So let me get this right- if I do a leakdown... if I take the oil cap off and hear air then it would be a cracked ring? If I hear air coming from the exhaust pipes then it is an exhaust valve not seating/or bent? And if I hear air coming from the carb/intake then it is an intake valve bent? Is that correct? I've never worked internally on a motor before but I am mechanically inclined enough to do bolt-ons and I've done a few superchargers on modulars.
 
If you buy a device to check compression at the auto parts store it should have instructions. Depending on what the readings do, you can determine whether you have worn rings, valves and seats, or a bad head gasket. All info is from the readings on the gauge, not listening for sounds. If you buy a gauge and need help, just post here but it's really a pretty simple process and will either ease your mind or let you know what you are in for.
 
There is no difference in the "system" other than having the PCV for the specific engine. I found out that each PCV unit has a different spring ratio inside. If you have more than one valve around, turn it upside down and you can feel a slight difference in the spring when pressing on each one. I guess there is a different spring ratio needed for the different vacuum amounts from each engine. I know when I got the correct one for the engine, I had no more oil problems.

It will not stop blowby if the engine is worn out.
 
thanks again for the help! I have one more stupid question for you motor guys. Since I haven't done a leakdown before, how do I know that particular cylinder is at TDC? Is it just positioning of the crank? The haynes manual is at my fathers house, but I'm sure it is in there.

we are going to
1) buy a town car PCV
2) put my open filter breather from my 01 gt on his valve covers
3) do a leakdown

Maybe I'm just used to my Procharged gt but I think the fastback doesn't feel as fast as it once did. It has me wondering about the rings or valves. :notnice:
 
It's the #1 cylinder that needs to be at the top on the compression stroke for the engine to be at TDC. I think you can tell that by the positon of the rotor in the distribitor. When it's pointing at #1 then the engine should be at or close to TDC.

This one guy said you could take out the #1 sparkplug and stick your finger in there to feel or see the piston at the top. I never tried that though.

Hope it's just the PCV valve.
 
well i have to bring this thread back from the dead unfortunately.

My father has the fastback put away for the winter so we have not done a leakdown.

He did try the 302 pcv valve and we thought it fixed it initially. Now we are back to the same so its leakdown time! He wants to put a 302 in it but I think we should just build the 289!

What are some builds/setups you guys have done with your 289's?
 
The only real difference between a 289 and a 302 is the crank. the 302 pistons go farther down because of the crank allowing it to pull in more fuel and air. The 302 has more low end torque while the 289 has more top end. But anyways onto building the engine. One thing i would recomend it 2 piece gapless rings. These allow the absolute minimum blowby and claim up to 15 HP increase (realistically i think i got 3-5, but every bit adds up)
 
Is there a metal plate covering the holes on the inside of your valve covers? This plate helps to block oil mist coming out of your valve covers. Also if they are too close to the bottom of the PCV valve they can actually cut down in its flow. They do need to be there but sometimes they are left off of aftermarket valve covers or the bottom of the PCV valve is too close to the top of the plate (oil baffle). Good Luck
 
Is there a metal plate covering the holes on the inside of your valve covers? This plate helps to block oil mist coming out of your valve covers. Also if they are too close to the bottom of the PCV valve they can actually cut down in its flow. They do need to be there but sometimes they are left off of aftermarket valve covers or the bottom of the PCV valve is too close to the top of the plate (oil baffle). Good Luck


Thank-you!

I was reading this whole thread thinking "Why hasn't someone mentioned the valve cover baffle?" I must have seen 50 other threads hear at stangnet about this topic over the years and over 50% of the time it's the lack of a baffle that is causing problems.

Also.. leakdown test is overkill. Start with compression test 1st.

And.. a simple test to check for blowby is to start the engine and put your hand over the the valve cover breather hole. If you can feal "puffs" of air comming out then it's a good indicator of excessive blowby.
 
I agree with thehueypilot and bottlefed70, if it was a cracked ring or anyother type of mechanical problem that car would be smoking like a crop duster out the exhaust.
Vavle cover baffles and the pcv setup and you should be set.
 
I don't know if this is much help but I had the same problem with a 66 about 10 years ago. I had bad blow by and then rebuilt the engine. Even after the rebuilt the engine it still happened. I finally (fixed) the problem by adding breather cap extenders on both sides. Never happened again. I hope this helps.