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By HazardTBird - 3 Years Ago
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I just got my 1955 272 back from the machine shop. The machine shop re-assembled the block, heads, valve train and front timing cover. There have been a few surprises:
1) The machinist did not re-install the small timing chain oiling ramp near the crank (the part was in a small box of returned parts). I think I have read that these ramps are often omitted in early Y rebuilds and that these were not included in Y's after 1955; is this correct?
2) The shop did not install the front oil seal slinger that I provided. It is my understanding that these were not used in 1955 but I would have liked to have it if it will fit. Since they were not used in 1955 is this a big deal?
3) By far the biggest surprise is the force required to rotate the assembly (although I try to limit this rotation). It takes 45-50 lb-ft with the plugs and pushrods removed to rotate the assembly; should I be worried?
I appreciate any help or thoughts.
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By Joe-JDC - 3 Years Ago
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What ring pack was used? Older stock style rings, or newer metric rings? Crankshaft turned undersize? What bearings used? did they give you the specifications? How much torque needed to keep the assembly rotating? Break-away torque will be higher than continuous torque required. Bore to piston clearances? Too little piston to bore clearance will add friction. What type piston material, forged or cast? Lots of questions to determine if it is too much. Joe-JDC
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By Ted - 3 Years Ago
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All Y-Blocks excluding some of the marine applications had the oil slinger that slides on in front of the lower timing gear. Have not found a stock 1954 or newer Y engine that did not have those front oil slingers. Some of the early Ford parts ‘blow apart’ drawings did not show that piece but those drawings were done before actual production started. I pull down a number of core engines that are missing the front oil slingers but that’s a piece that’s easily forgotten during a rebuild. By the time the timing cover is installed and then realized that the oil slinger is not on, some mechanics are not going to go to the trouble of removing the cover which is also going to require another timing cover gasket to put that slinger back on.
The timing chain oil trough was discontinued during the late ’56 model year but can be found on all 1954-1955 engines. If the shop left yours off, you can try to put it back on but those troughs typically installed before installing the timing chain set.
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By HazardTBird - 3 Years Ago
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Thank Joe & Ted!
I was hands off during the rebuild so I will have to ask most of those questions but will. Pistons are cast alum., cam was reused as it was reported to be in excellent condition and (I assume) the lifters were reused. I will ask all other questions and report back. Sounds like step one is to pull the timing chain cover & install the slinger. Maybe having the cover off will reveal more.
After I get the slinger installed should I feel as hesitant to rotate the assembly by hand as I have been? Is there any treatment I could use in the cylinders to limit any damage done by dry hand rotation? Any benefit (or harm) to go ahead and get the oil up into the engine while it is on the stand?
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By Ted - 3 Years Ago
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I don’t see a problem in hand rotating the engine as long as the camshaft lobes are lubed and there’s some oil on the cylinder walls. I would be concerned about piston skirt scuffing in the event the cylinder walls are dry. I am not a fan of the 0.0015” minimum wall clearance recommended by some of the piston manufacturers for cast pistons. It does make the pistons susceptible to early piston damage if the engine runs hot.
Adding oil and prelubing the engine while it’s on an engine stand is always a good idea.
Just my two cents worth so other comments always welcome.
I had a 460 engine in 1987 that took an extreme amount of effort to turn over after installing new rings and bearings. I was worried if the starter would turn it over but the engine fired right up. Engine ran on the hot side first 100 miles but then the rings seated in and all was good. Ended up being a very good engine as it was in my truck used for pulling a race car. As Joe brings up, you likely have an engine that’s built on the ‘tight’ side just making it harder to turn over. Ask your machine shop those questions anyhow just to keep them honest.
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By KULTULZ - 3 Years Ago
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... cam was reused as it was reported to be in excellent condition and (I assume) the lifters were reused .
Now that is a little scary ...
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By HazardTBird - 3 Years Ago
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Thank you Ted, that makes me feel better about things! I had the same concerns about the starter being able to turn the engine over. I will ask those questions. Although the Shop that machined /rebuilt the 272 is about 60 miles away I believe I can get a road trip out of them.
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By 2721955meteor - 3 Years Ago
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IT IS unfortion that you did not ask this group some questions before enter into your rebuild.
so many opertunitys to getting a excellent results hear blocks forever
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By HazardTBird - 3 Years Ago
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Yes 2721955, wish I had!
I got the timing chain cover, sprockets and chain off. Cam turns freely, smoothly and quietly. Crankshaft still takes 40-45 lb-ft to get it started, a little less to keep it going, does not do it quietly and makes a "scruffing" sound which sounds to me like piston noise. I don't have the oil pan off but will do that next to make sure the walls are oiled. I will add the oiling of cylinder walls to the questions of the rebuilder.
Since I have things apart installing the timing chain oil trough would be 2 minute job. Should this be put back on or is it best to omit it?
I also have the rocker shaft assemblies off on both sides. When I feed air down the oil supply hole in the head (still on the block) on the drivers side (LH) I hear air, although it's muted, in the bottom end. When I try to feed air down the passenger side head there is no flow and no sound in the bottom end. Is it likely I have an issue with an oil passage or the dreaded 3 hole lineup? Should I be hearing this air at all in the bottom end or should I be hearing this air flow on both sides?
Thanks to everyone for their replies!
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By darrell - 3 Years Ago
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turn your cam a little at a time and try the air again in case you have a cross drilled cam.
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By Ted - 3 Years Ago
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The ’55 272 engines did have cross-drilled center camshaft journals and by design, the oil to each bank alternates depending upon the position of the camshaft in relation to the bearings. With the cross-drilled camshafts, only one side of the engine oils at a time. As Darrel mentions, just rotate the camshaft and see if that gets you some air going thru the oil passageway.
Install the timing chain oil trough before reinstalling the timing gear set. That was eliminated as a cost cutting measure and definitely helps with timing chain wear assuming the passenger side rocker arm oil tube has not been blocked off.
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By HazardTBird - 3 Years Ago
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Thanks Darrell & Ted:
I'm 90% sure that getting air in the bottom end from the LH side and no air from the RH side is independent of cam rotation but I will confirm tonight.
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By HazardTBird - 3 Years Ago
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As happens a lot I was wrong. The LH (driver side) blows into the lower end continuously but for each full rotation of the cam it also blows thru the oil filter hole (just about full bore) 4 discreet times. The points where it blows out the filter seem to be equally spaced and seem to cover just a few degrees of rotation. Nothing muted about it when it blows out the oil filter hole.
The RH side doesn't do anything (even to the bottom end) and cam position makes no difference. Tried a half dozen or more full and slow rotations and got nothing.
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By Ted - 3 Years Ago
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Based on your description, it does sound like the center cam bearing is not clocked correctly and only two of the three holes are aligned with the corresponding holes in the block. There’s also the possibility that the wrong cam bearing set was used as the cross-drilled camshafts require a different cam bearing set than does the center grooved camshafts.
Two potential fixes but both requires some engine disassembly. One is with the heads off and the camshaft removed to simply take a long drill bit and punch a hole into the cam bearing starting the drill bit from the deck. I'm not a fan of this one but have seen it done. The other fix is to remove the cam bearing and re-clock it but that almost requires the rotating assembly to be removed from the block so that the holes can be properly aligned. The fix I do not want to mention is putting an overhead oiler on the right bank which I have seen done on several rebuilds where the center cam bearing was put into the block incorrectly. Regardless, this needs to go back to the original engine assembler to be correctly fixed.
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By HazardTBird - 3 Years Ago
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Thank you Ted and everyone else who responded; back to the shop it goes!
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