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Discussion Starter #1
Im gonna put this post out again to see what I get from you all...
I bought the car on ebay last summer.. The previous owner had the Motor completly gone thru, and i mean completly by a reputable builder... I spoke to him and have receipts showing what he did. Again a complete rebuild, the blocked was decked as well.. Performer Intake and an Edelbrock 600 4 barrel mated up to a fmx auto. tranny finish it up... The previous owner had only put a few hunderd miles on the car ((and this is true and documented)) after the rebuild before he sold it to me and was unaware of any oil problems.. ((so he says)) He sold the car to buy a big block 69... When I got the car, I did some work on it for the first 2 months and didnt drive it much.. When I started to last fall, i noticed that about every 300 miles or so I had to add about 1/4 quart of oil (10w40). This motor only has about 1700 miles on it now since the rebuild.. Ive checked the PCV system, the valve covers are baffled, the plugs look pretty good however a few are what appears to be carbon fooled and a little wet. (looks like gas), and i also ran a compression test and am getting between 170-179 lbs psi on all 8 cylinders. The car is in storage here in Michigan since november and i run it once every few weeks.. What I am noticing is that I am getting a lot of condensation out of the tailpipes as well as this watery/blackish discharge out of the tailpipes (not a lot though and more of it is out of the left tailpipe) and the inside of the tailpipes are kinda black sooty for a new flowmaster exhaust.. Also after about 8 minutes of running, every 20 seconds or so I get a puff or two of (white??) smoke out the both tailpipes.. NOT a lot of smoke but some.. Not sure if this is caused by the temperature though cause again its 25 degrees outside when i run the car...??..

I should say that prior to noticing the oil problem, while cruising last summer, the throttle return spring snapped. The car immediatly reved.. Instead of turning the motor off, stupid me put it in neutral and the motor reved, heck probably to at least 6K rpm's if not more. I then within SECONDS shut the motor. I fixed the spring the next day and everything seemed fine.. Now once again I didnt noticed this oil consumption problem until after this occured so am unsure if i caused this problem.. I doubt it however cause once again this whole thing happened in just a few seconds..

The distributor is a stock single point with a dual vacuum advance. Nothing special.. I am EXTREMELY FRUSTRATED with this problem and am considering a crate motor however id rather not spend 6k on it right now..

ANY AND ALL ADVICE IS GREATLY APPRECIATED..

Thanks for listening..

Mike...(69Mock1)
[email protected]
 

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Although a bit higher than I would expect, new engines typically consume oil for the first few thousand miles. Your piston rings are not fully broken in for at least 2 thousand miles... This is why I never switch to synthetic oil before 5000 miles. I would monitor the situation but not replace the motor just yet!

As far as water from the exhaust is concerned, this is a normal byproduct of combustion. Water will condense and pool after you shut down, so about 8 minutes after you start up you are probably seeing this evacuate your system.

Good luck,
Rory
 

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Have you tried calling the shop that built the motor? They'll know exactly what was done to it and may have some helpful hints. I'm wondering since you say it was decked that you may have some sort of mis match with the intake manifold & head not completely sealing and sucking some oil in.
 

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If I remember correctly, 1 quart of oil consumption for every 1000 miles is within reason for a 351w. As the oil burns off, it is replaced by condensation ( water) so it looks like your oil never goes down, it just gets dirty. Rings do use oil, worn or new, so don't think that the motor uses no oil, thats what the oil is there for. Sounds like you have a good motor that maybe hasn't fully broken in yet. Compression rating sound damn good. Should be 150 at each cylinder, at least, if I remember right, and they should all be within 5 to 10% of each other. I would get rid of the points, and change to a full electronic distributor, like a mallory unilite, for instance. You'd get better gas mileage, smoother starting, and the motor would just run better. The gas fouling may be due to weak spark, and incorrect plug gapping, 2 things to check for. A new coil wouldn't hurt either. Just my .02 cents.
 

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As the oil burns off, it is replaced by condensation ( water) so it looks like your oil never goes down, it just gets dirty.
Say what? That's nonsense. If oil is burned, it goes out the tailpipe and the oil level drops. How else do people know when to add a quart of oil?
 

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Discussion Starter #6
ya the reading on the dipstick shows about 1/4 low right before i refill it...

I guess ill give it another 2000 miles or so and then see what happens...

thanks..
 

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Not to be an alarmest but it could be the valve guides. Are the heads new or reconditioned? You can easily go through a quart of oil in no time with bad guides. This is sometimes overlooked on a cheap rebuild...Not sure it's your situation but you never know.. Good luck.
 

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I have a '69 351W that I rebuilt 3 years ago and it still uses a little oil. I installed Edelbrock heads and intake, Holley 600 and MSD ready to run distributor and MSD Blaster coil. This engine runs very well with the upgrades, I baby the car but on a trip or doing alot of driving it uses some oil. I too live in Michigan and start it regularly and I also get the wet, black soot out of the tail pipes for the first few minutes it is running. I considerd this normal as the car sits alot.
 

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The moister out the tailpipe is normal. Burning 1 qt every 1000 is more then it should, but is prob. within or close to within being considered normal. With such good compression readings, and no other issues, drive it and keep an eye out. Although "breakin period" is not completed, technically, I doubt at this point it will change much. If you had to try something for piece of mind, I would agree to try valve guides first.

How else do people know when to add a quart of oil?
Thats easy....when they see too much water on the dipstick.
:rofl:
 

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I think you're okay. Could it be that you have low retention rings? Sometimes they are used so the engine will rev faster. That could let more oil past. The other thing is what kind of valve guides and seals you might have. If you have non-bronze guides and those crappy umbrella seals you're loosing oil in my experience. Again, 1,000 miles per quart is not bad though it might be frustrating. As was said, let it break in more. Like a couple thousand more miles and then re-eveluate. Stay away from synthetic until the engine is fully broken in because it is just too slippery and will prevent the scuffing necessary for the rings to seat.
 

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As the oil burns off, it is replaced by condensation ( water) so it looks like your oil never goes down, it just gets dirty.
Say what? That's nonsense. If oil is burned, it goes out the tailpipe and the oil level drops. How else do people know when to add a quart of oil?
This is what I was always told. I was raised around a lot of old shadetree mechanics. It always made sense to me, since it looks like oil waters down as the miles add up. I was told that you get some condesation in the oil pan, as not all of the moisture escapes out the tail pipe. There's a lot more people here that know a hell of a lot more than I do. I don't know why I bother posting.
 

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Call me crazy but neither my 302 or rebuilt 351w in my 70 cars burn more than a quart of oil in 4-5000 miles. I've never had to add oil between oil changes. Maybe i'm lucky? Not sure.....


Sometimes it can be obvious things that are overlooked. Does the car leak oil when parked or when running? You may not notice until you crawl under the car and peek around.
 

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If the oil pressure is ok, just give it some seriuos boot. If there is something wrong, it won't harm it anymore. But if it just been *****-footed, the rings may not have set-in yet. Old recommendations about how to drive the first 500miles were invented when oils inferior. The new race engines are driven-in at dyno for a couple of minutes and then they are dynoed at WOT. And if it doesn't change anything, so what. If your car consume a quart of oil per week and that's you only problem, so what, oil is cheap. Wait until you discover the rot and bent transmission tunnels and such.

I guess you just have new owner of some hp -scare. I was one once, too. These cars are truly Mustangs, they need to be tamed. The more I have trashed my car, better it has become.

BTW, why do you run it in for a few minutes weekly?
 

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Discussion Starter #15
wow, you guys are great.. thanks for all the tips... so again, i guess ill just put another few thousand miles on it and re-evaluate the situation. According to what im hearing, this is probably normal for this motor.. I guess im just not use to a "new motor" burning oil. I may just live with it or maybe get the 392 crate motor in the distant future..... ha ha...

by the way, it has new bronze valve guides.. i still might perform a leak down test however with good compression #'s, youd think that this would be a waste of time..

thanks again to all who responded..

mike
 
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