Oil on plugs after rebuild.
11-10-2017, 10:30 PM
#241
There is always a certain amount of oil that gets past the seals because the valves HAVE to be lubricated. But the scant amount of oil is never enough to foul spark plugs. After doing some further thinking about this I have a hunch your engine "builder" bent the edges of the #1 and #4 oil rings because they weren't compressed enough to be slid into the cylinder. After an engine block has been bored the machinist will bevel the tops of the cylinders to remove the sharp edges on them so the piston/ring assemblies can be started into the cylinders easily. But I have seen many blocks that weren't beveled or were barely beveled; making it very difficult to get the piston/ring assemblies started. I have a feeling your engine builder just didn't have the rings compressed enough and hammered those two pistons in with enough force to bend their oil rings. When that happens the bent rings will leave a "shiny" area along the cylinder wall; not a scratch or gouge but a shiny area indicating excessive pressure against the cylinder wall.
And the 2nd compression ring is also a scraper ring so it has two functions. The early 71 Series V-12 Detroit Diesels I overhauled had four compression rings and two oil rings for each of their 12 cast iron pistons.
11-11-2017, 07:51 AM
#242
[QUOTE=NeverTooOld;1595945376]There is always a certain amount of oil that gets past the seals because the valves HAVE to be lubricated. But the scant amount of oil is never enough to foul spark plugs. After doing some further thinking about this I have a hunch your engine "builder" bent the edges of the #1 and #4 oil rings because they weren't compressed enough to be slid into the cylinder. After an engine block has been bored the machinist will bevel the tops of the cylinders to remove the sharp edges on them so the piston/ring assemblies can be started into the cylinders easily. But I have seen many blocks that weren't beveled or were barely beveled; making it very difficult to get the piston/ring assemblies started. I have a feeling your engine builder just didn't have the rings compressed enough and hammered those two pistons in with enough force to bend their oil rings. When that happens the bent rings will leave a "shiny" area along the cylinder wall; not a scratch or gouge but a shiny area indicating excessive pressure against the cylinder wall.
And the 2nd compression ring is also a scraper ring so it has two functions. The early 71 Series V-12 Detroit Diesels I overhauled had four compression rings and two oil rings for each of their 12 cast iron pistons.[/QUOTE
Lynn, hopefully you can sift through all this BS, some people have a hard time understanding although its really quite simple the hole that the valve goes through is not round and strait and does not have the proper finish and is TO BIG for the valve stem thus letting oil pass excessively between the valve guide and valve stem, in the mean while the valve is bouncing of each side of the seat not sealing any more fatiguing the head of the valve to the point it will eventually break the head of the valve off. Most shops are not capable of building a set of heads that will last the test of time, this would be my concern at this point.
And the 2nd compression ring is also a scraper ring so it has two functions. The early 71 Series V-12 Detroit Diesels I overhauled had four compression rings and two oil rings for each of their 12 cast iron pistons.[/QUOTE
Lynn, hopefully you can sift through all this BS, some people have a hard time understanding although its really quite simple the hole that the valve goes through is not round and strait and does not have the proper finish and is TO BIG for the valve stem thus letting oil pass excessively between the valve guide and valve stem, in the mean while the valve is bouncing of each side of the seat not sealing any more fatiguing the head of the valve to the point it will eventually break the head of the valve off. Most shops are not capable of building a set of heads that will last the test of time, this would be my concern at this point.
Last edited by Vortecpro; 11-11-2017 at 07:53 AM.
11-11-2017, 07:59 AM
#243
Burning Brakes
Thread Starter
[QUOTE=Vortecpro;1595946541]
Thanks. I going to the engine builders shop today to see if the heads are back. The builder is going to take the valve springs off to confirm that they were done correctly this time before putting them back on the car.
Geez I am really tied of this. If I had known that it would take this long I would have done it myself. At least I would have known what was done to it and any mistakes would have been mine.
There is always a certain amount of oil that gets past the seals because the valves HAVE to be lubricated. But the scant amount of oil is never enough to foul spark plugs. After doing some further thinking about this I have a hunch your engine "builder" bent the edges of the #1 and #4 oil rings because they weren't compressed enough to be slid into the cylinder. After an engine block has been bored the machinist will bevel the tops of the cylinders to remove the sharp edges on them so the piston/ring assemblies can be started into the cylinders easily. But I have seen many blocks that weren't beveled or were barely beveled; making it very difficult to get the piston/ring assemblies started. I have a feeling your engine builder just didn't have the rings compressed enough and hammered those two pistons in with enough force to bend their oil rings. When that happens the bent rings will leave a "shiny" area along the cylinder wall; not a scratch or gouge but a shiny area indicating excessive pressure against the cylinder wall.
And the 2nd compression ring is also a scraper ring so it has two functions. The early 71 Series V-12 Detroit Diesels I overhauled had four compression rings and two oil rings for each of their 12 cast iron pistons.[/QUOTE
Lynn, hopefully you can sift through all this BS, some people have a hard time understanding although its really quite simple the hole that the valve goes through is not round and strait and does not have the proper finish and is TO BIG for the valve stem thus letting oil pass excessively between the valve guide and valve stem, in the mean while the valve is bouncing of each side of the seat not sealing any more fatiguing the head of the valve to the point it will eventually break the head of the valve off. Most shops are not capable of building a set of heads that will last the test of time, this would be my concern at this point.
And the 2nd compression ring is also a scraper ring so it has two functions. The early 71 Series V-12 Detroit Diesels I overhauled had four compression rings and two oil rings for each of their 12 cast iron pistons.[/QUOTE
Lynn, hopefully you can sift through all this BS, some people have a hard time understanding although its really quite simple the hole that the valve goes through is not round and strait and does not have the proper finish and is TO BIG for the valve stem thus letting oil pass excessively between the valve guide and valve stem, in the mean while the valve is bouncing of each side of the seat not sealing any more fatiguing the head of the valve to the point it will eventually break the head of the valve off. Most shops are not capable of building a set of heads that will last the test of time, this would be my concern at this point.
Geez I am really tied of this. If I had known that it would take this long I would have done it myself. At least I would have known what was done to it and any mistakes would have been mine.
Last edited by LenWoodruff; 11-11-2017 at 07:59 AM.
11-11-2017, 08:03 AM
#244
Gasoline engines have been around for a little over 100 years but valve stem seals have only been used for the last 50 of them and often on the intake valves only. It's common practice to not use any valve stem seals in engines that run on "dry" fuels like propane or natural gas because the slight amount of oil that runs down the valve stem helps extend the valve face and seat life by providing a "cushion" to the closing valve. The point is bad valve stem seals will never cause spark plugs to oil foul as only damaged cylinder walls and piston rings cause that. If one of the bronze guides somehow got seized to the valve and the guide got demolished you'd know it because that cylinder would start missing from the sideways movement of the valve but that's highly unlikely because the guides are pressed in and then reamed for about 0015" clearance.
11-11-2017, 08:05 AM
#245
[QUOTE=LenWoodruff;1595946579]
Thanks. I going to the engine builders shop today to see if the heads are back. The builder is going to take the valve springs off to confirm that they were done correctly this time before putting them back on the car.
Geez I am really tied of this. If I had known that it would take this long I would have done it myself. At least I would have known what was done to it and any mistakes would have been mine.
Take very good pictures of the work.
Thanks. I going to the engine builders shop today to see if the heads are back. The builder is going to take the valve springs off to confirm that they were done correctly this time before putting them back on the car.
Geez I am really tied of this. If I had known that it would take this long I would have done it myself. At least I would have known what was done to it and any mistakes would have been mine.
11-11-2017, 08:09 AM
#246
Burning Brakes
Thread Starter
11-11-2017, 09:01 AM
#247
[QUOTE=LenWoodruff;1595946617]I have read alot of people accusing the builder of making mistakes, this tolerance is wrong, this was put together wrong, how many times have we ALL ordered something and it came in as the wrong part. It happens, although its the builders job to make sure everything is correct. Hopefully it gets resolved by finding out something came is as the wrong part, good luck len!!
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LenWoodruff (11-11-2017)
11-11-2017, 09:03 AM
#248
Bent Oil Rings?
Take a real good look at the bores of the #1 and #4 cylinders. If you see a shiny streak about an inch wide on the cylinder walls it would indicate the oil rings got bent on installation from not being compressed enough when the pistons were pushed in. I built a 454" about 7 years ago that didn't have adequate bevels on the tops of the cylinders and one of the pistons went in a lot harder than usual. I pulled it back out and found one of the oil rings had been bent a little bit because it had caught on the sharp edge of the cylinder. I used my Dremel to grind a slight bevel on the top of the cylinder, straightened the bent oil ring, then reinstalled it again and that time it slid in easily. To know for sure what is going on those two pistons must be pulled out and carefully examined and the cylinder walls must be carefully examined because any abnormality will cause excessive oil consumption in those cylinders. Pay close attention of the bore of #1 at the 2 o'clock position and the bore of #4 at the 4 o'clock position for signs of a pressure streak caused by a bent oil ring.
11-11-2017, 09:28 AM
#249
Take a real good look at the bores of the #1 and #4 cylinders. If you see a shiny streak about an inch wide on the cylinder walls it would indicate the oil rings got bent on installation from not being compressed enough when the pistons were pushed in. I built a 454" about 7 years ago that didn't have adequate bevels on the tops of the cylinders and one of the pistons went in a lot harder than usual. I pulled it back out and found one of the oil rings had been bent a little bit because it had caught on the sharp edge of the cylinder. I used my Dremel to grind a slight bevel on the top of the cylinder, straightened the bent oil ring, then reinstalled it again and that time it slid in easily. To know for sure what is going on those two pistons must be pulled out and carefully examined and the cylinder walls must be carefully examined because any abnormality will cause excessive oil consumption in those cylinders. Pay close attention of the bore of #1 at the 2 o'clock position and the bore of #4 at the 4 o'clock position for signs of a pressure streak caused by a bent oil ring.
11-11-2017, 09:33 AM
#250
[QUOTE=san;1595946858]
I have read alot of people accusing the builder of making mistakes, this tolerance is wrong, this was put together wrong, how many times have we ALL ordered something and it came in as the wrong part. It happens, although its the builders job to make sure everything is correct. Hopefully it gets resolved by finding out something came is as the wrong part, good luck len!!
Agreed, but before it gets to the builder its all about controlling the machine work, and that means using the very best your area has to offer, and 2000.00 doesn't get it done on a quality rebuild lets be realistic.
I have read alot of people accusing the builder of making mistakes, this tolerance is wrong, this was put together wrong, how many times have we ALL ordered something and it came in as the wrong part. It happens, although its the builders job to make sure everything is correct. Hopefully it gets resolved by finding out something came is as the wrong part, good luck len!!
11-11-2017, 09:52 AM
#251
Burning Brakes
Thread Starter
Could the soot on the top of the pistons come off (like #4) just by have some antifreeze getting the bore when the heads came off then rubbing a towel to clean it up?
11-11-2017, 09:58 AM
#252
Le Mans Master
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I really doubt it. I don't think of Glycol as a cleaner unless it was burned while engine was running. With water it becomes a cleanser. Interesting pattern on that piston though.
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LenWoodruff (11-11-2017)
11-11-2017, 10:01 AM
#253
NO, I wouldn't think so but you could try, but 624 casting heads are notorious for the ex seats cracking, but I would think if the seat was cracked you would have a combustion leak that WOULD cause the car to run hot and the temp would never recover. In my lifetime I can count on two hands the number of 624 heads that were not cracked, and two of them were on a 1980 L82 Vette.
Last edited by Vortecpro; 11-11-2017 at 10:05 AM.
11-11-2017, 10:08 AM
#254
If the mouths of the cylinders aren't properly beveled after being bored it's very easy to bend oil rings and that WILL cause spark plug fouling. I used a Lisle ridge reamer with it's 1 degree carbide cutter to bevel my cylinders so my pistons go in very easily.
11-11-2017, 10:11 AM
#255
Don't Lens cylinders look like they have a nice bevel to them? I thought they did.
11-11-2017, 10:15 AM
#256
Burning Brakes
Thread Starter
NO, I wouldn't think so but you could try, but 624 casting heads are notorious for the ex seats cracking, but I would think if the seat was cracked you would have a combustion leak that WOULD cause the car to run hot and the temp would never recover. In my lifetime I can count on two hands the number of 624 heads that were not cracked, and two of them were on a 1980 L82 Vette.
They were supposed to have added hardened seats for the exhaust valves.
These are the original heads that I took off and put new 624 on back in the mid 80's because some of the exhaust seats were cracked.
11-11-2017, 03:09 PM
#258
Burning Brakes
Thread Starter
11-27-2017, 03:06 PM
#259
11-28-2017, 07:48 AM
#260
Burning Brakes
Thread Starter
The heads are back at the engine builders with new guides and PTFE seals on the valves. These seals require the top of the guides to be cut down so they will stay in place.
I should have the car back in the next day or so.
