progress update: 9mm head, 500K+ miles... no cracks?!
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Joined: Mar 2008
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From: Orange County, California
well i'm back from a weekend of camping. didn't drive my truck since i didn't think it was road-trip worthy just yet. i checked my vacuum and ordered a thermocouple before i left on friday. the thermocouple should be here by tomorrow or tuesday. then i'll be able to see what kinda temps i'm running with these 4x.014's so that i can determine if they're within the normal range or if a 60mm upgrade is needed to push a bit more air. it should be a noticeable difference increasing 10mm from 50mm to 60mm.
i hooked up my vacuum gauge at the "T" fitting. which, because i'm only running one diaphragm, is now between the booster and the one diaphragm. it's pulling 20" of Hg (mercury) at an idle. my brakes and a/c / heater controls work just fine. the brake pedal feels a little more firm, but the good kind of firm. how can i isolate the booster from the pump to check it? what numbers should i be seeing to tell if it is good or bad? also, i rewired my tach (due to stiff and exposed wiring). it should still be calibrated from the last time. when i started it this afternoon, after sitting since thursday, the tach read about 600-650rpm's but after driving and letting it warm up, it read around 750rpm which is normal. i may try to bump it up to 800rpm and see how it feels. i wanna give a big "THANK YOU" to everyone who responded to this thread with the information you gave. i owe you all a lot, but all i can return to you is my knowledge and ideas (creative or not
).
i hooked up my vacuum gauge at the "T" fitting. which, because i'm only running one diaphragm, is now between the booster and the one diaphragm. it's pulling 20" of Hg (mercury) at an idle. my brakes and a/c / heater controls work just fine. the brake pedal feels a little more firm, but the good kind of firm. how can i isolate the booster from the pump to check it? what numbers should i be seeing to tell if it is good or bad? also, i rewired my tach (due to stiff and exposed wiring). it should still be calibrated from the last time. when i started it this afternoon, after sitting since thursday, the tach read about 600-650rpm's but after driving and letting it warm up, it read around 750rpm which is normal. i may try to bump it up to 800rpm and see how it feels. i wanna give a big "THANK YOU" to everyone who responded to this thread with the information you gave. i owe you all a lot, but all i can return to you is my knowledge and ideas (creative or not
).
Thread Starter
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Joined: Mar 2008
Posts: 4,389
Likes: 114
From: Orange County, California
good observation!! yes i am. my inners are new since they were once mounted on the fronts and were removed soon after due to feathering. my grandpa told me they didn't wear well up front. he gave them to me earlier this year and i mounted them to the original stock steel wheels he still had. i had the tires mounted to the steels when i got them and put them on the truck back in june/july. still have the other inners in my backyard. my grandpa ran them at 80psi all the time, so the centers got worn really fast. then i got my hands on the truck and i only run 40psi in them when i'm empty as there's not much weight to be supported.
DTanklage over on cumminsforum had his valve covers polished
not cheap from what he tells me, but they're nice looking!!
DTanklage over on cumminsforum had his valve covers polished
not cheap from what he tells me, but they're nice looking!!
i hooked up my vacuum gauge at the "T" fitting. which, because i'm only running one diaphragm, is now between the booster and the one diaphragm. it's pulling 20" of Hg (mercury) at an idle. my brakes and a/c / heater controls work just fine. the brake pedal feels a little more firm, but the good kind of firm. how can i isolate the booster from the pump to check it? what numbers should i be seeing to tell if it is good or bad?
Put the vacuum gauge somewhere you can see it and push the brake pedal with the engine running. The vacuum will drop momentarily but should pick back up if you hold the pedal down.
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Joined: Mar 2008
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From: Orange County, California
i received some info from justin (93flatbed) regarding the upper engine gasket kit and the mushroom style valve seals not fitting on his motor either. since the machine shop i used for head work had the seals needed, i had no reason to ask cummins for the correct replacements. justin paid a visit to his local cummins and they were able to order some of the older/correct style valve seals needed. the seal P/N: 3921640. of course you would have to get a set of 12. thanks for bringing that to my attention and making me (and others) aware of the availability of the old style seals, justin!!
Thread Starter
Registered User
Joined: Mar 2008
Posts: 4,389
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From: Orange County, California
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