12 Valve 2nd Gen Dodge Cummins 94-98 Discussion of 12 Valve 5.9 Liter Dodge Cummins Diesels with P7100 Injection Pumps

question about boost

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Old 03-03-2011, 10:54 PM
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back n the day (last summer ) i could plug my wastegate and it would build boost very quick if i got on it in like say 3rd gear.. id have to get out of the throttle so it wouldnt build too much boost. stock turbo btw (wh1c). well i took the head off and had it milled .10 then put a .20 headgasket on, put a 3 piece manifold on and headstuds. along with 22.5* timing, it was at 18* b4 pulling the head. anyway i got it back together and hooked the wastegate up like it should b. drove it for a while without much boost, i then plugged the wastegate and i couldnt build boost like i should with it plugged. i thought maybe the wastegate was not working.. so i took the wastegate off and just wired the arm on the turbo in the direction i got the most boost. it builds boost as if it had a wastegate hooked up (30-35psi depending on the gear and my foot) but if it was like it used to b itd b making 50 or 60 (not that i want it to). anyway im just trying to figure out wat happened to make it lose the boost. i have 1 tiny leak at the oring at the mouth of the turbo.. i mean tiny! have tested for leaks and theres no other leaks. maybe the turbos goin south? it sat for a few months on my garage floor while the head was off.
 
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Old 03-04-2011, 04:04 AM
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.020 head gasket why? shaving head does not change comp.
 
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Old 03-04-2011, 06:48 AM
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Originally Posted by pukie370
shaving head does not change comp.
How do you figure?
 
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Old 03-04-2011, 10:11 AM
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head was shaved to insure flatness and the .20 headgasket was more avaliable than the .10
 
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Old 03-04-2011, 11:16 AM
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what injector washers did you use?
 
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Old 03-06-2011, 05:14 PM
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Originally Posted by pukie370
.020 head gasket why? shaving head does not change comp.
... thats 100% not accurate advice
 
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Old 03-06-2011, 08:24 PM
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Originally Posted by pukie370
.020 head gasket why? shaving head does not change comp.
WHAT??? yes it does

anyways because the 20 over u may have lost some idk i lost 2psi with my 20 over and 10 off the head and lost another 3 when i went to fly cut pistons but dont forget i have 700cc of fuel so the impact might be more for u but i dont know much about this so thats just my 2 cents but u do loose compression when u go .010 over on a gasket from stock

---AutoMerged DoublePost---

Originally Posted by 94 12valve
what injector washers did you use?
yea thats a good point what one?
 

Last edited by justin c; 03-06-2011 at 08:24 PM. Reason: Automerged Doublepost
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Old 03-12-2011, 11:11 AM
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uh whatever chris at sdx gave me..
 
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Old 03-12-2011, 02:33 PM
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were they the same thickness as your old ones? if so you should swap to a thinner washer
 
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Old 03-13-2011, 01:31 PM
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think thatll make much difference? ill get some thin washers
 


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