| 1953fords | -- 03-29-2019 @ 4:53 PM |
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Trying to get rebuilt flathead running but have one problem after another. Now the compression is low in all cylinders. Adjusted the number 1 cylinder intake and exhaust but only brought the compression up from 20 to 60. All the cylinders are reading low around 20-30 and only on had a reading of 56-58. What could be wrong after valves in number one is adjusted? Could the rings be next?
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| 40cpe | -- 03-29-2019 @ 5:01 PM |
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Are you sure the the crank/cam dots are aligned?
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| pauls39coupe | -- 03-29-2019 @ 6:15 PM |
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Who did the rebuild? Were the valves ground and lapped? Were the valves all good or were some bent or burned?Were the cylinders bored and if so were the correct oversize pistons installed? How much gap did the piston rings have? If you adjusted #1 valves and the compression came up I would suspect the other cylinders would do the same. Be sure the cam and crank gears are aligned properly and the the valve clearance is set correctly on both the intake and exhaust. Be sure the heads are torqued properly, and that the intake gasket is installed properly. Assuming the compression will come up if the valves are adjusted properly, the engine should start with 60 lbs of compression. Then it may need to be run to break in the rings, which will raise the compression more. Please give us some more information about how the engine was rebuilt,
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| mfirth | -- 03-30-2019 @ 4:39 AM |
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A year ago i got a new Mellings cam gear and the "dot" was in the wrong place ! Had to degree it in or timing would be off....just say'n. mike
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| 1953fords | -- 03-30-2019 @ 5:30 AM |
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This engine was partially rebuilt. I did the rebuild. Put new rings in and new seals. Engine looked like it was rebuilt before I got it. This was all done about 14 years ago. I just put the engine in the car in 2017. My son, a mechanic, did a victoria for me and that one ran good. I just got new seals and rings. I really don't remember what I did because it was too long ago. If I get all the valves adjusted and all come up to 60 or better you say it would run? I added oil to pistons and the 60 went to 90. This engine has sat on the stand for 14+ years and the rings and seals may be old now. I did turn it over every couple of months on the stand. I don't know what else to tell you and I hate to take the engine out again.
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| pauls39coupe | -- 03-30-2019 @ 8:47 AM |
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Did you hone the cylinders before installing the new rings? If not it may take a while for the rings to conform to the shape of the cylinders. I would adjust all the the valves to see if you can get the compression up around 60 or better, then fire it up. It should run, but don't expect the best performance unless you tear the engine down and do a complete rebuild. Oiling the cylinders indicates they are not sealing well. You should change the oil and filter after an hour or so run time to remove any loose metal shaving as the rings and cylinder walls wear together. Paul
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| 37RAGTOPMAN | -- 03-30-2019 @ 9:08 AM |
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hi 53 ford it seems odd to me that from sitting you would have lost compression, sticking valves open are what I would look for first, use a light and see if you can see them going up and down, I use my thumb in the spark plug hole to see if it has any compression,after adding oil to the cylinder, did you try a few different compression testers, just a thought, ? also open the throttle plate in the carb and remove the air cleaner,then take compression with all spark plugs removed, and make sure the exhaust system it not blocked up, like a mouse nest, if you have too remove a pipe to see there are nothing wrong with it, if it can nothing can go out nothing will come in, try oil in the cylinders , do a wet compression test, if the compression comes up, maybe the rings are stuck from sitting ? doing a leak down test is next, I would try get it running, this most likely what it needs, loosen everything up let hear how you made out, my 2 cents 37RAGTOPMAN
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| 1953fords | -- 03-31-2019 @ 11:32 AM |
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looks like the valves were set ok...removed heads and checked according to manual. Found out the bore is 3 3/16 which they told me is about an 80 ring size and I put in 10 rings. Didn't know that it was bored out when I took it apart and I am not a mechanic to know that I should have measured the bore. I guess that's why most of the compression test were around 20-28 and only one piston (8) had a 58. Sounds like I put in the wrong rings???????????????????????????????????????????????????????????????????????????????????????
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| pauls39coupe | -- 03-31-2019 @ 4:41 PM |
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I assume you are working on a 1953 8BA type flathead. The stock bore is 3 3/16 (3.1875). .010 rings would not fit unless it was really worn out. Time to get someone with an inside mic, to see what your bore actually is. This message was edited by pauls39coupe on 3-31-19 @ 4:42 PM
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| 1953fords | -- 04-01-2019 @ 4:22 AM |
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If the rings are to big wouldn't that be the problem that they are not gaped correctly which is giving the low compression readings?
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| supereal | -- 04-01-2019 @ 8:21 AM |
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Did you check the ring gaps by placing each ring into the cylinder to measure with a feeler gauge? Did you stagger the ring gaps on the piston before installation? A dry/wet compression check will tell you whether the problem is the rings. Be sure to have the throttle blocked open when you run a compression check.
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| 37RAGTOPMAN | -- 04-01-2019 @ 8:52 AM |
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53 FORD besure NOT TO USE CHROME RINGS, very hard to seat, use U.S.A. made ring set, my 2 cents 37 RAGTOPMAN
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| 37RAGTOPMAN | -- 04-01-2019 @ 10:08 AM |
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hi 53 FORD most pistons are marked on the top with the piston size, 010 020 030 040 060 080 0100 you should use the same size rings as the pistons, do the piston move when you wiggle them back and forth. ANY CLICKING ? if pistons are to small in the bore,you should see the piston move, should have some slop in the bore, if you pour oil on the pistons, if it goes past fairly quickly, you have a gap some were the oil is leaking past the rings, you can fit the rings by pushing them down in the cylinder walls and measure the end gap with a feeler gauge, years ago they filed or ground the butt gaps so they were the right gap for the pistons, even if the rings were over size set,, they were fitted to the bore of the engine, this is my 2 cents 37RAGTOPMAN a engine rebuilding book might help at this point, most parts resellers offer several , on FLATHEAD FORDS,
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| 1953fords | -- 04-01-2019 @ 1:27 PM |
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Well, today I got the bore measured and its 3.265 The piston has a 083 on them. What rings should be used?
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| 1953fords | -- 04-01-2019 @ 1:54 PM |
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if the pistons are 083 and the bore is 3.265 where do you get the rings?
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| pauls39coupe | -- 04-03-2019 @ 7:43 PM |
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You should measure your piston to wall clearance. I wonder what pistons you have. .083 replacement pistons were often oversize pistons for early V-8's with a 3 1/16 bore and steel sleeves. The sleeves were removed and the new pistons ran on the cast iron. Normally oversize pistons that I have seen are otherwise marked with even numbers .020, . 030, .080, etc. though the actual oversize should be determined by the machinist doing the work. If you have 3 1/16 (3.062) plus .083 pistons total 3.145 in a bore measuring 3.26 it would explain your low compression readings.
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