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6.7 Rail Cap?

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Is the 6.7 rail cap the same as the 5.9, anybody know? I know the rails are different, wasn't sure about the relief valves. I'm lookin at turning a few of these guys out for my vendors on here and i'm just checking things out.
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· Mr. Vehicle Destroyer
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Discussion Starter · #3 ·
Yeah, i'm actually looking to make the ones for the 5.9, but I was just wondering since I do so many parts for the 6.7 too, Thanks!
 

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for fear of cracking injectors I bet
 

· 700hp Club
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as long as you have a good rail pressure gauge and are not stacking pressure programs you will be fine. there are lots of guys here who have capped 5.9's who were having troubles with the prv letting go at 25k. Bosch injectors are tested to 30k without failure and my DDP tips are the same. i have never seen over 28k on my ISSPRO at WOT but recently i have noticed that the prv is letting go about 26k and the truck is bucking. I am installing a cap tonight and that should solve my issue, as i have no other leaks or troubles and fuel pressure is fine.:confused013:
 

· Smells like Bananas
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Is the 6.7 rail cap the same as the 5.9, anybody know? I know the rails are different, wasn't sure about the relief valves. I'm lookin at turning a few of these guys out for my vendors on here and i'm just checking things out.
Its different, You use one from a duramax, like a 05 would work. Thats what I have in mine, its from PPE. also 6.7 injectors, well it would be like putting 40hp sticks in a 5.9 if you want to compare. They are better sticks then in a 5.9 and can handle a bit more.

How many injectors have you heard about cracking on a 6.7?
 

· Mr. Vehicle Destroyer
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Discussion Starter · #11 ·
ok so conflicting reports here.... Anybody have a relief valve they've taken out they wouldnt mind parting with for a few days? or a bad one they have on the bench?
 

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Its different, You use one from a duramax, like a 05 would work. Thats what I have in mine, its from PPE. also 6.7 injectors, well it would be like putting 40hp sticks in a 5.9 if you want to compare. They are better sticks then in a 5.9 and can handle a bit more.

How many injectors have you heard about cracking on a 6.7?
Well I've had quite a few acctually. I've heard from the guys that work for cummins that do warrenty clams. They have seen rails crack and injectors too. I personally would not ever cap the rail unless it was to test for a bad valve.

I have had a 6.7 rail valve out and screwed in the 5.9 rail valve plug to see if it would work and it did. So I'm not sure mattpopp which plug you tried, but the one I got was from FTE diesel.
 

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as long as you have a good rail pressure gauge and are not stacking pressure programs you will be fine. there are lots of guys here who have capped 5.9's who were having troubles with the prv letting go at 25k. Bosch injectors are tested to 30k without failure and my DDP tips are the same. i have never seen over 28k on my ISSPRO at WOT but recently i have noticed that the prv is letting go about 26k and the truck is bucking. I am installing a cap tonight and that should solve my issue, as i have no other leaks or troubles and fuel pressure is fine.:confused013:
The Bosch injectors are not good to 30k psi. Most fail way before that. Speaking with Industrial injection they doesn't want anything over 26k on the Bosch injectors. Now the Piezo injector is rated to 30k, but can fail at anytime after that.
 

· 700hp Club
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well i've heard different specs on the 6.7 injectors from the cummins guys at home. my prv is sitting on the shelf now keeping the rest of the oem equipment company. i installed the rail cap last night and the truck runs great now, no more surging at WOT and rail pressure is steady at 26500psi with just the xrt, MP8 is off. all i can say is what i have done to my trucks and other guys i race with at the track. with the edge/MP8 i would see 29k WOT at the track and have been racing for 2 years without issues, i just put the DDP's on this spring and we had a good look at the stock tips, they were clean and crack free with about 35 runs down the track and 65000km on the truck. guys who stack pressure boxes or timing will have problems no doubt if they don't keep an eye on the rail pressure.
 

· Smells like Bananas
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Well I've had quite a few acctually. I've heard from the guys that work for cummins that do warrenty clams. They have seen rails crack and injectors too. I personally would not ever cap the rail unless it was to test for a bad valve.

I have had a 6.7 rail valve out and screwed in the 5.9 rail valve plug to see if it would work and it did. So I'm not sure mattpopp which plug you tried, but the one I got was from FTE diesel.
Well Eric and Richard Brown both told me the same. buy a Duramax Rail plug to cap your rail. So we got one from PPE.
 

· Smells like Bananas
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ok so conflicting reports here.... Anybody have a relief valve they've taken out they wouldnt mind parting with for a few days? or a bad one they have on the bench?
I have the PPE plug for a duramax in my Rail. I might be able to get my OEM valve sent to you. PM me your address and if Chris still has it I will ask him to send it to you. It is slightly damage. the sealing surface is raised a bit.
 

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ya iv got a dura vlave cap in my rail to, i was told the rail on are 6.7 is the same as the rail on an lly or lbz i dont remember. but the rail cap will work on both.
 

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ya iv got a dura vlave cap in my rail to, i was told the rail on are 6.7 is the same as the rail on an lly or lbz i dont remember. but the rail cap will work on both.
Well, the rails aren't the same, but the relief system in them is the same. All of our trucks have been capped and it is needed. The stock relief valve and shimmed valves are a bad design. Even the shimmed valves will get weak.

The new 6.7L injectors are all stainless now. The bodies handle the pressure much better than the older 5.9L injectors.
 

· Smells like Bananas
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Well, the rails aren't the same, but the relief system in them is the same. All of our trucks have been capped and it is needed. The stock relief valve and shimmed valves are a bad design. Even the shimmed valves will get weak.

The new 6.7L injectors are all stainless now. The bodies handle the pressure much better than the older 5.9L injectors.
I have been waiting for you to chime in
 
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