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08-19-2017, 11:31 PM | #1 |
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Pitting in block/combustion chamber
Pulled the head on my old 235 today due to a blown head gasket between #4 and #5. Was cleaning things up and noticed this pitting only on #5. What caused it and is it a issue?
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08-20-2017, 06:35 AM | #2 |
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Re: Pitting in block/combustion chamber
Cuased by a blown head gasket beeing run for a long time its time for the block to be re decked or replaced if the pits are too deep a new head gasket will never seal properly with the pitting tbere
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08-20-2017, 08:45 AM | #3 |
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Re: Pitting in block/combustion chamber
it's been a long time but if i remember correctly the head gasket does not follow the cylinder - as in it's not a round opening. lay the gasket on the block and if it fits around that area you are good to go.
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08-20-2017, 09:16 AM | #4 | |
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Re: Pitting in block/combustion chamber
Quote:
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08-20-2017, 09:43 AM | #5 |
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Re: Pitting in block/combustion chamber
Head gasket does not cover that area.....deck and align bore the block to see where you are...good luck.
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08-20-2017, 10:04 AM | #6 |
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Re: Pitting in block/combustion chamber
you can see the same pattern on adjacent cylinders but I'd deck it for good measure but it may be ok as is....here's 235 head gasket..
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08-20-2017, 10:32 AM | #7 |
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Re: Pitting in block/combustion chamber
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08-20-2017, 10:37 AM | #8 |
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Re: Pitting in block/combustion chamber
Thanks for the input guys! The pitting is directly below where to combustion chamber in the head is, not on any head gasket sealing area.
Think im going to slap a new head gasket on it and see what it does. If it blows out the gasket again im only out a little labor and $25 in a gasket. Id prefer not to pull the motor at the moment. If it blows again then ill pull it and do the whole shootin match. Its in a old 1949 2 ton that im only going to put a couple hundred miles on a year. Like to not put alot of money into it. Another factor is that I believe that this motor was rebuilt not long before I purchased it. It has strong compression (155lbs) and I can still see crosshatching on cylinders. Last edited by amadioranch; 08-20-2017 at 03:56 PM. |
08-20-2017, 01:12 PM | #9 |
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Re: Pitting in block/combustion chamber
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08-20-2017, 07:09 PM | #10 | |
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Re: Pitting in block/combustion chamber
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bty i think you said "Head gasket does not cover that area.....deck and align bore the block to see where you are...good luck." did i miss something? |
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08-20-2017, 09:10 PM | #11 |
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Re: Pitting in block/combustion chamber
Sorry was thinking about small block v8 if the gasket seals on a smooth part id let it ride
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David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube |
08-20-2017, 09:21 PM | #12 | |
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Re: Pitting in block/combustion chamber
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I dont miss anything...you can.... |
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08-21-2017, 07:59 AM | #13 | |
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Re: Pitting in block/combustion chamber
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08-21-2017, 05:22 PM | #14 |
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Re: Pitting in block/combustion chamber
LOL!!!! OK...maybe I get a call from several machinist thanking me for the work....LOL!!!!!
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08-21-2017, 07:39 PM | #15 |
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Re: Pitting in block/combustion chamber
Back on topic..... just saw 155 on the compression test. Is that in all cylinders? Might be worth throwing a head gasket at it. Then just keep an eye open for a cheap 235 to replace this one when/if the time comes and you can build it at your leisure.
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08-22-2017, 10:29 AM | #16 |
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Re: Pitting in block/combustion chamber
Yep. Obvious blown head gasket. That pitting is actually caused by 'cavitation' from compressed coolant I would say.
Not to scare you. Be sure to check radius of head combustion chamber for cracks too. Probably more than half the 235 heads I magnafluxed had one there. If not to water yet they can be in future.
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09-03-2017, 12:55 AM | #17 |
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Re: Pitting in block/combustion chamber
So would it be a good practice to have the head checked before replacing the head gasket ? most likely the answer would be YES.....
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