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Discussion Starter #1
351W with Holley 670 Avenger carb. PCV off of passenger side Cobra - Powered by Ford valve cover to base of carb. Breather cap on driver side valve cover. Valve covers have "baffle" plate under hole in cover.

Was adding 1 qt. of oil every 250 miles. I know this from the 1100 mile trip I took driving the car home from Chicago. Driving since has been around town and so the oil consumption is less noticeable.

Had a leaky remote oil filter engine mount. Entire remote oil filter relocation system is now Canton with SS braided lines. No leaks. Good pressure.

Fresh engine rebuild. Less than 2000 miles by professional shop. Leak down was excellent. Plugs all look good. Sidepipes are dark and velvety but not oily. Bottom of engine is, for the most part, dry. A little wet around oil pan seal. Nothing excessive. Slight oil drip around one oil pan plug.

Drove the car over the weekend for a four hour round trip of about 250 miles. Some oil consumption but not as bad as when I drove the car home. Maybe 1/2 quart. This still seems like a lot for the miles.

My thought is that I had a combination of a leak and, from all of the threads that I have read, possibly a PCV that is sucking oil. Thoughts/comments requested. If it is PCV, how do I keep so much oil from being sucked through? The PCV hose definitely has oil in it. I don't know how to determine how oily is too oily.

Sorry for the long message. Thanks for any help.

Joe.

[ November 07, 2004, 08:11 PM: Message edited by: FFR4187 ]
 

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Discussion Starter #2
ttt
 

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THRAMP-master
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THRAMP drinks alot of oil, too. I suspected the PCV too, but everything is plumbed correctly so it seems unlikely. A few months ago, my Dodge Durango (5.9L) developed quite an appetite for oil. Turns out there's a TSB on the problem: the intake manifold on those engines is "open", with a steel pan, about 6x12, covering it. The gasket goes, and it starts inhaling oil from the lifter valley. Although the SBF manifolds don't have the open bottom, I wonder if it might have a vacuum leak on the underside, allowing oil in. The procedure Dodge recommended to check it is:
- Warm the engine up
- Disconnect and plug the PCV hose and port
- Disconnect and plug the vent hose port
- Connect a vacuum gauge to the vent hose and start the engine. If you see a vacuum, there's a leak.

Drive on!
 

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Discussion Starter #4
ttt

Read some other posts about oil consumption and some say a quart every 500 or 1000 miles isn't so bad. Any other comments?
 

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We had high oil consumption on a rebuilt engine and it turned out to be an oil ring not broken in yet. Once the van got good and warm, it went right back down to almost nothing. (like it should)

Your's sounds high... A new production engine wouldn't use that much oil, even at the beginning so you wouldn't expect your's would either.

Just some thoughts..

R
 

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Discussion Starter #7
Wouldn't oil consumption due to valve seals show signs on the plugs? The only oil on the plugs is a very little bit around the threads.
 

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Can valve seals be changed out without removing heads? Should the guides be replaced as well for good measure?
 

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Does the car smoke at all? Either on acceleration or deceleration?
 

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Discussion Starter #10
Smoke has never been seen either while I have been driving the car or when someone has been following behind me. At cold start, exhaust is noticeable. It is not white smoke. I believe it is effect of choke since after the car is warm and the choke turns off, the exhaust is gone.

In the words of someone I talked to about the problem after using 4 quarts in 1100 miles, "...with that much oil consumption there should be a mosquito screen behind the car".

I think I am going to try running the car with the PCV hose disconnected from the carb (placing in in some sort of container) to see if oil is getting pulled through at a constant rate. Any reason not to do this?
 

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Here are some instructions that come with a compression gauge that might be helpful.

1. On a normal cylinder, compression should increase quickly and uniformly during each compression stroke of the engine until a top (or peak) reading is reached.

2. If compression is low on the first stroke, builds up on following strokes, but does not reach normal value, the piston rings may be worn or leaking.

3. If compression is low on the first stroke and does not increase on following strokes, leaking valves may be at fault.

4. If the compression value is higher than the manufacturer's specifications, carbon build-up ay be present in the cylinder or on the piston.

5. If compression readings on two adjacent cylinders are 20 pounds (or more) lower than the other cylinders, the cylinder head gasket may be defective.

6. Recheck cylinders with low compression readings by injecting approximately one tablespoon of mediumgrade oil into each cylinder (through the spark plug hole) and retesting. If compression readings increase, worn, broken, or poorly seated piston rings are indicated. If compression readings remain the same, leaking or damaged valves may be at fault.

7. Before re-installation of spark plugs, clean and re-gap all plugs. Reinstall spark plugs. Reconnect plug wires, paying close attention to the cylinders from which they were removed. Crossing spark plug wires will result in rough running, misfiring, poor gas mileage, and may cause damage to the catalytic converter or the engine.

8. Be sure to return the throttle plate to it's original position, and reconnect the coil wire or reconnect the ignition system primary connection.
NOTE: Periodically examine the valve core at the
14MM/18MM hose end for tightness using a standard
valve core tightening tool.
 

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i had a similar problem. i envisioned all sorts of dire consequences. but when i changed the oil, 9+ quarts came out. my dipstick was hard to read and i overfilled it. hope your problem is as simple.

james
 

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I'd agree with the idea that burning that much oil would have oil all over the side of the car behind the pipes. You would definitely see smoke.

It must be going someplace though, right? I'll look forward to hearing of the easy resolution to this one!

R
 

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I would say my fresh build (same setup) is burning at a similar rate. After break in I had dropped the oil and replaced with fresh 20 50. Since then I put about 300 miles on it. I checked the oil the other day and it was down to the fill line. I suspect the PCV and will likely get rid of it.
 

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Discussion Starter #16
On my 1100 mile trek where I used 4 quarts, the passenger side of the fuel tank shield was covered in oil. I believe this was the result of a known oil leak at the remote oil filter port that attaches to the motor. Hoses were leaking and my theory is at 80mph, the oil that was leaking out of the hose was getting sucked under the car and onto the tank shield. I thought this had to be the source of my problem. Since then, the remote filter parts have all been replaced with Canton and SS lines. No leaks there any more and no wet tank shield.

I think I am going to replace the PCV (bought a new one today for $4), drain the oil, put heavier weight oil in and start a new baseline to determine my oil consumption. The engine builder used straight 30 weight oil to start. Since I have replaced so much, there probably isn't that much of it left but I have been using 10W-30. I live in S.C. so 10W-40 or 15W-50 should be fine.

I'll call you tonight on my way home from work, Todd, to discuss.
 

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I had the same problem-I was getting about 150 miles to a quart. I switched to a smaller volume PCV valve & put 1- O ring on the valve where it seats on the vale cover to stand it off the baffel a little more and that fixed mine.
John.
 

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Discussion Starter #18
WOW, John Miller. Smaller volume PCV? How do you determine the volume of the PCV? Smaller size? Amount of pressure required to open the valve? I noticed on the valve that I bought today that the bottom of the valve had a "40" stamped on it. I don't know what my current one has stamped on it, if anything. I'll check when I get home. My dad seemed to think there were different valves that had different pressure ratings.
 

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good question. how do you determine PCV valve size?
 

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I had a small block use 2 quarts per tank of gas. After replacing valve seals, it didn't use any oil. Pull the valve cover and poke the seal with a small screwdriver. If its hard as a rock, replace them, it's easy and cheap.

r
 
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