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By Gene Purser - 6 Years Ago
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I've said before, I'm relatively new to the details of overhead valve engines and the y block so be tolerant with me please. I have this 272, supposedly rebuilt, that is using a quart of oil every few hundred miles. The left side tail pipe is burning clean, the right side is oily. I pulled the plugs and #1 is the only one not clean. Recently I headed the car down a steep embankment to turn around and a puff of blue smoke blew past me from the right side exhaust. I pulled the valve covers and ran the engine to check for anything unusual. At idle, the right side rocker assembly is putting a lot of oil onto the head in the center and filling up the valley at the bottom of the head before it can drain out. The drain at the end of the rocker shaft is clear and draining oil. I just pulled the right side rocker assembly to check for wear in the shaft or rockers that would let too much oil out before it makes it to the end drain. Obviously they weren't replaced at overhaul. I found wear, but not as much as I expected to find. Using my Harbor Freight digital calipers, there seems to be about .003-.004 wear at the rocker locations compared to the other unused portion. I can just catch it with my finger nail. I haven't pulled the assembly apart to check for rocker wear, but I can't wiggle them on the good part of the shaft, maybe because of the spring pressure.
I know it is good that the rockers are oiling that well, but excess needs to go the the end drain. My question is: Does this amount of wear sound like enough to overwhelm the head drains and allow the oil to flood the valve stems? The engine internals appears clean as a you would expect from a rebuilt engine, absolutely no sludge. I see the shafts are available and not that expensive and would change them in a heartbeat if it would minimize oil escape. I would appreciate you sharing your valuable knowledge and experience.
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By 55 GLASS TOP - 6 Years Ago
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Just a few things I wonder about how many miles on the newly rebuild engine could be your high oil consumption could be because nothing has really seated. Also the down hill puff of smoke is usually a sign of bad valve seals they could be dry or installed improperly slight puddle in of the oil should be ok but I guess if there is to much oil it could overwhelm the seals. I am no expert but it's quite possible your engine was rebuilt but the heads were not and you may have excessive wear on the valve stems and no material what condition of the seal you are going to suck oil down in the intake stroke . I do not think rocker shafts are the issue . Just some thoughts
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By Gene Purser - 6 Years Ago
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You could very well be correct about the heads. This car showed 82,000  miles on the odometer at the time it was rebuilt from a very weathered Arizona car. I just pulled the left side rocker assy and it is hardly worn under the rockers. Upon looking closely at the oiling holes in the shafts and arms, I see several that are packed with hard crud. They were still oiling some because I see oil accumulated on the valve retainers. I think they just got washed in a parts washer and reinstalled, and maybe the heads, too. The stem seals are there and look good from what I can see through the springs.
Anyway, I've decided to replace the shaft on the right side and clean up the rest of the parts and the complete left side assembly. That needs doing anyway. I'll run the car for a while and monitor it. Maybe will wind up pulling the heads to be rebuilt
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By 55 GLASS TOP - 6 Years Ago
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Looks like you did a nice job on the car , I think after what you have said the valve stems are worn
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By Gene Purser - 6 Years Ago
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I didn't build the car. I had sold a '40 coupe that I did build as a street rod and drove all over the southeast for 20 years. The builder of the '55 did a good job cosmetically, but sorted or adjusted nothing. I knew some of it before I bought the car, but found a lot more afterward.
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By Hoosier Hurricane - 6 Years Ago
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You may not have noticed, but did the arched metal tube on the end of the rocker assembly dump into the pushrod hole at the end of the head? That tube ensures that the rocker shaft stays full and the excess comes out of the tube. If the tube dumps onto the head surface, the drain holes may be overwhelmed and oil rises in the valve cover area and floods the guides. Also be sure the small drain holes at the front and rear of the head are clear.
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By Gene Purser - 6 Years Ago
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The tubes are pointing into the push rod hole. This engine has the little catch pans under the rocker stands. It is evident that most of the oil is draining into the center two pans and onto the heads. From the condition of the heads and rockers, I believe a half-a$$ed rebuild was done on the engine. It might not have even been bored, just bearings and rings installed. In the end, I'll probably have to go through it again. It does have good oil pressure though.
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By oldcarmark - 6 Years Ago
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When I rebuilt my 292 I had the new Camshaft oil Groove machined to I think .019 which is the recommended Groove Depth. As a result I got good oil Flow to the Heads. Too much actually. I had to tap the oil Feed Hole in the Rocker Stand and install a restricter to cut down the flow to the Shafts. If You are getting too much oil to the One side you could do the same. A small Pipe plug with a hole drilled will cut down the Flow. The Rocker Shaft Stand is easy to Tap. Soft Metal. Have You done a Compression Test to get an Idea of what kind of Shape the Engine is internally? If You have even One low Cylinder that could be where the Oil is being burned.
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By Gene Purser - 6 Years Ago
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No, I haven't done a compression check. I know I should have already but I don't relish it with the plugs so hard to reach. I'll do it while I'm dealing with the rocker shafts.
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By oldcarmark - 6 Years Ago
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I just re-read your original Post. If You have One only oiled Plug as You indicated that would be the Cylinder to check Compression on. If You have the type of Compression Gauge that screws into the Plug Hole testing is not that difficult. If only One Plug is oiled possibly there is a broken Oil Ring or One not properly installed with the Expander not keeping tension on the Rings. Or it might just be the Valve stem Seals not installed properly or split if they were not replaced. If you only getting Oil Smoke from One side that at least gives You an Indication of which side the problem is on.
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By 55 GLASS TOP - 6 Years Ago
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I may be wrong but you could still have decent compression in a cylinder and still have a wet plug if the compression rings are good and the oil control ring is cracked or broken also if oils is dripping down the valve guides your compression will be fine. I think your engine was rebuilt, the heads were removed and washed down in the parts washer the crud that builds up around the valve stems was washed away the heads were reassembled with new seals and no machine work was done . I think if you remove the keeper and the valve spring on the cylinder you have the fouling on you will find excessive play in between the head and the valve stem. The fact that you have the heavy smoke condition and the high oil consumption makes me think your issue is valves not rings. But I am just a 70 year old guy so do not quote me .
1955 Ford Crown Victoria Glass Top
1956 Ford Club Sedan Daily Driver
1971 Volvo 1800 I have owned this car 40 years
1966 BMW 2000cs under restoration I cant afford a new car
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By Gene Purser - 6 Years Ago
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I think you are right. Because of the condition of the rocker shaft on the right side I think the engine was not oiling correctly on that side, leading to excessive wear on the rockers and valve guides. That being said, the only time I've seen smoke is when I put the front of the car in a steep downhill drive to turn around and the wind blew a puff by me. It doesn't smoke otherwise.
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By KULTULZ - 6 Years Ago
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"...the only time I've seen smoke is when I put the front of the car in a steep downhill drive to turn around and the wind blew a puff by me. It doesn't smoke otherwise."
I think what you will find is that the oil supply is overpowering the cylinder head forward drain and is pooling on a downward slope so as to flood the #1 cylinder valve seal(s). As the vehicle levels out, the smoking subsides.
The valve guide(s) and or seal(s) may or may not be bad.
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By Hoosier Hurricane - 6 Years Ago
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I remember seeing a service bulletin from Ford about unequal oiling from side to side. As I remember, a certain combination of camshaft and cam bearing caused one side to over oil and the other to under oil. Their fix was to put a restrictor in the oil passage in the rocker stand of the over oil side to try to equalize the flow side to side.
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By 55 GLASS TOP - 6 Years Ago
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I think after you get it all back together you should put a vacuum gauge on the engine it will tell you tons more than a compression gauge will. The readings are true indications of what is wrong .
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By PF Arcand - 6 Years Ago
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You would appear to need to concentrate on the suspect cylinder 1st. Then from your posting, the fact that you can tilt the rockers side to side is not good. At the least the shaft needs replacement, and probably some or all that sides Rockers. As noted, due to poor previous oiling possibly, you may have badly worn valve guides or a bad valve seal.. Valve guide replacements are available, but require machining to install. There are guide liners available, which might work, but our moderator Ted, recommends one type over the other, & I don't have that info at hand at the moment..Good luck.
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