Help, Oil blowing out of breather

A

Anonymous

Guest
Hello!

I'm new here and am hoping someone might be able to help me. I've got a 65 Mustang with a 200 I-6. The engine is not original and I'm afraid I don't know an exact build date for it.

The problem I'm having is when the engine is operated at higher RMP's (interstate driving, ect) I am loosing oil out of the breather. The car runs like a top, doesn't smoke, ect but at interstate speeds I loose almost a quart of oil per hour. What would be a probable cause for this?

Thanks! :D
 
wow i havent herd that one before. i would check timing, what type of oil you putting in? how much? how many miles on it? auto or stick? its kind of odd to here of a story that sounds like too much oil presser?? has it done this sence you got the car or did it just start up? do you know if it has been rebuilt? and sence you said it was a "different engine" do you know for sure its a 200?? make sure the breather can "breath" you know make sure that its just not a plug. check those things then get back to me. and i hope someone else has herd or had this problem because im just thinking off commin sence on this one. have fun and for now i recamend staying off the highways :LOL:

ponyrider66
 
The engine is definately a 200, manual transmission. Oil type doesn't seem to be a factor, it's blown a bit of everything out.

I've had the car for 11 years, and rebuilt the engine about 8 years ago. The car has been in storage at my parents house for the last 6 years. The blow by problem was present BEFORE the rebuild, that's one of the reason I tore it down. In the process of the rebuild I discovered the head was cracked and replaced it with another from a salvage yard. The new head was magnafluxed and no cracks were found. The head was milled .060. I've got a Clifford camshaft, 6-1 headers and a three autolite carbs. I have more specific data about the engine/cam ect but right now that info is in storage along with car at my parents house.

I've rebuilt several engines for both cars and aircraft (I'm an aircraft mechanic by trade) and I've never seen this. As I said before, the problem existed BEFORE the rebuild and that was with a different head.

You might be wondering why I'm asking this now, since I've had the problem for so long. I'm preparing to take the car out of storage and make it roadworthy again. I'd really like to find the cause and correct this problem this time around. :D
 
Wingspan,

Did you use the same rocker arm assembly between both heads? Is the assembly the adjustable type? I thought maybe if it was the adjustable type, the front bleeder pedestal has a cap on top that might be cracked/leaking/squirting only at high pressure shooting the oil over the baffle in the top of the cover. Or maybe the cap is missing?

Just a thought

Cheers Mike
 
Oil blowing back thru the breather is usually a symptom of excessive crankcase pressure caused by inadequate venting or excessive blowby.

You say that the engine runs well and doesn't smoke, so let's assume blowby is at normal levels.

Is the engine equipped with a PCV valve? The PCV sucks fumes out of the crankcase and burns them. I evacuates the crankcase and will even maintain some negative pressure. Properly operating, you will not see fumes or oil from the breather.

If not, does it have a road draft tube on the left front of the engine? The road draft tube is just a pipe connected to the block that opens to the atmosphere. Between it and the breather, excess pressure is vented directly to the atmosphere. When it's properly working you should see wisps of vapor coming from the tube or breather.

Many times, though, valve covers have been mixed and swapped. A valve cover with no PCV on an engine with no road draft tube really has no place for crank pressure to go, except as blowby thru the breather.
 
Many times, though, valve covers have been mixed and swapped. A valve cover with no PCV on an engine with no road draft tube really has no place for crank pressure to go, except as blowby thru the breather.
Click to expand...

Ah, I think we're getting somewhere. I've got an Edelbrock cast aluminum valve cover, no PCV. I don't recall any draft tube either. I'll check for sure when I see the car next. This sounds like a very likely suspect. Thanks! :D
 
Regarding the Road Draft Tube that Jack mentions. Is that the hole on the front of the block on the '63 170 CI that I have that has a hose connected to it that runs up to the air filter assembly?
 
Geez Wingspan,
If you ever figure this one out let me know :( I've had the same problem for years now. Cant figure it out :unsure: The only oil being lost is what comes out the dipstick and breather. I can see oil vapors when the engine is hot. The car does not smoke at all though. I was thinking wore out head but time has run out and it's gonna have to wait awhile. If you figure it out let me know. Thanks!

Ron

Mine is a 68 so it has a different PCV set up.
 
The earliest engines had a tube that fit that hole and just hung down to the bottom of the pan. Later engines may have had a hose or tube to the air cleaner, but I'm not sure. The Falcon guys may be able to elaborate.

PCV valves started showing up in 1965, I think, and the road draft tube was eliminated. They put a plug in the hole. Later blocks were revised to eliminate the hole altogether.

Ron, do you have a PCV? It normally draws enough vacuum that you can't see any vapors at idle. You may have a plugged fitting on your carb base.
 
I checked my car yesterday, and as I remembered there is no draft tube. I've got a later model engine and there isn't a place for one. No draft tube, no PCV, just the breather. I'd like to hope that this is the problem and I just need to come up with a PCV. :D
 
If your valve cover is like this one:

showpic.asp
Click to expand...

Yes sir, that's exactly what it looks like. I really like that valve cover and don't want to take it off (permanantly) . Maybe I'll mill a spot in the fins for the PCV... :p
 
is it just me or does it look like there is a pcv valve in the far back of that one...other wise he would have the same problem you are having. cause he doesnt have the other hole on the side of the block hooked up for pcv...just somthing i noticed. :LOL:

ponyrider66
 
is it just me or does it look like there is a pcv valve in the far back of that one...other wise he would have the same problem you are having. cause he doesnt have the other hole on the side of the block hooked up for pcv...just somthing i noticed.
Click to expand...

No there isn't a pcv in the pic. The chrome thing your seeing at the rear of the valve cover is one of the cover bolts. That's probably an early engine that has the road draft tube MustangSix mentioned in his post and it wouldn't need a PCV. :)
 
Wingspan":15bhz5f2 said:
That's probably an early engine that has the road draft tube MustangSix mentioned in his post and it wouldn't need a PCV. :)
Click to expand...

Those valve covers were made in the early 60s(Dennis and Dave put a 1960 ad in their handbook), so like Jack said, they're made for the blocks with the draft tube. I wonder when production ended, and if some came with a PCV grommet :unsure:: .

Personally I would just sell it on Ebay and make a good amount of $$$ before I attempted to mill it. Then just a get finned cover from Mike when he gets them(I assume his will have the 2nd grommet :unsure:: ), and pocket the rest of the money(or throw it at the car :eek: )
 
Personally I would just sell it on Ebay and make a good amount of $$$ before I attempted to mill it. Then just a get finned cover from Mike when he gets them(I assume his will have the 2nd grommet ), and pocket the rest of the money(or throw it at the car )
Click to expand...

Just out of curiostiy, what do those covers go for now? I picked mine up at the swap meet in the Mustang 30th anniversary show back in April '94. I think I paid $75 for it and a 170 head that I sold later for $40. :D
 
Go find another. You'll be surprised how dear they are. That was a GOOD SCORE. We have repro "Falcon" script ones available here, but not as nicely made (poor gasket retaining); they aren't cheap. $400 AUD, IIRC.
 
I'll buy it. Just say the word. I've been looking for almost a year for one of those aluminum covers
 
Back to the topic - what is the cause of excessive blow-by?

My car, at low RPM's, has blow-by coming out of the cap. It appears that the PCV at low vaccum can't get rid of the pressure fast enough.

I've also noticed that at high-rpm there will occasionally be oil splatter on the valve cover.

What could be causing this?
 
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