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Junior Member
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Discussion Starter #1
going to change camshafts in my 8pn c model when i inframe it.Is there a better spec. cam to use than is in the 7fb engines?
maybe one of the marine or gen set cams?
 

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Junior Member
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168 Posts
The 7FB 3012 cam depending on what one you have is better than the stock 8pn cam...the 3797 cam was used in most all other B and C models from late 7FB to the late 3zj's and is also a all around good working cam. Are you putting replacment 8Pn pistons and injector nozzles in it too?? Id definatly reccomend using an older, lower compression ratio/larger diameter bowl and nozzle combo if you want it to run better....the cam alone isnt gonna help it nearly as much as getting rid of the 16:1 pistons and nozzles will.
 

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Junior Member
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15 Posts
Discussion Starter #3
I already have a set of 14.6.pistons. I have a early 7fb that i am going to rob the pump off .
also have a set of 3421 nozzles from same engine.
if need be i will use the camshaft from that engine also.
but if one of the higher horsepower marine or genset cams will do better like it does in
the E & C models I will go one of them.Just trying to see if there is something better.
 

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Junior Member
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168 Posts
I already have a set of 14.6.pistons. I have a early 7fb that i am going to rob the pump off .
also have a set of 3421 nozzles from same engine.
if need be i will use the camshaft from that engine also.
but if one of the higher horsepower marine or genset cams will do better like it does in
the E & C models I will go one of them.Just trying to see if there is something better.
As far as im aware of they all use the 3797 cam. Their is a different one for lower horsepower. The 7FB cam could be the 3012, or 3797. i would use either befor i kept the 8pn cam.
 

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Junior Member
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Discussion Starter #5
If I remember correctly the 460 peec engine used a better cam.
but they now use the same #. I am in no rush as the engine runs
fine right now.I might just get a 800hp marine cam and get it checked
out on a cam doctor and see if it is the same as my 7fb cam.
 

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The other guy
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The 460 originally used a faster cam than anything but field replaces (NPR) to a 3797 in a B. no idea what the number was. it was strange and never reMan'd. There are several different ones for the C including four differnt versions of a 3014. A 3012 is a 400A DI cam and doesn't work beyond use with capsule nozzles. A 3013 is a 7FB above the 310 Economy thru 4MG03600 but field replaces (NPR) with a 3797. It is not, however, the same. either works with 14.5/ 14.6 but the correct match is a 3013. The 3797 was originally designed for the 15.2 4MG and also used in a few later non-economy 310 7FB's at 15.6/1. Look at the number in the front of the 7FB cam you have to verify what it is. And unless they are brand new, your 3421 nozzles are correct for the 10R 14.6/1 two piece, but only as cores. I'd replace them with a new motor. But with new, not reMan.
 

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Junior Member
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15 Posts
Discussion Starter #7
thanks for the replies all input is welcomed.Tony, should i use the 8 bolt timing advance unit with the 7FB pump
or should i go with the 4 bolt off of the 7FB. I rebuilt it just before windowing block.
I also just rebuilt the eight bolt on the 8pn engine.I will have to get the other engine(7FB) apart and see what
cam is in it and go from there.thanx again everybody!
 

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Senior Member
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2,824 Posts
If I remember correctly the 460 peec engine used a better cam.
but they now use the same #. I am in no rush as the engine runs
fine right now.I might just get a 800hp marine cam and get it checked
out on a cam doctor and see if it is the same as my 7fb cam.
There is no 800hp marine cam for a mechanical engine. The 580hp marine C models uses the 0r3787 and as well as the 587hp generator set engines that the 10r1439 cylinder pack comes from.

Have your C model pump built so you can use the actual matching 0r8789(65% more fuel then a 3421) nozzle that comes in those engines.

Use pump cam 4p-0990, this is a pump cam that works in your C housing with your barrels and plungers that will allow you to use your 7FB timing advance and also has timing specs like the 24* pump cam used in the 7FB.

When the cams were changed from the 0R3013 to the 0R3787 this is the information that came out along with it.

 

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Junior Member
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168 Posts
There is no 800hp marine cam for a mechanical engine. The 580hp marine C models uses the 0r3787 and as well as the 587hp generator set engines that the 10r1439 cylinder pack comes from.

Have your C model pump built so you can use the actual matching 0r8789(65% more fuel then a 3421) nozzle that comes in those engines.

Use pump cam 4p-0990, this is a pump cam that works in your C housing with your barrels and plungers that will allow you to use your 7FB timing advance and also has timing specs like the 24* pump cam used in the 7FB.

When the cams were changed from the 0R3013 to the 0R3787 this is the information that came out along with it.

Exactly what i was thinking Cody...why would a guy of his knowledge go and reccomend a 3421 that in any other post of his would say it doesnt match the bowl?? And yes their was good reason why they stopped offering the 3012-13 cam in them and it wasnt cause it made too much power. You can only mix and match so many things without bad stuff happening and when they offer parts that match the 1439's (OR8789) and (3787)with big horsepower why not just go with them and not have too worry!? I havent built 15million motors or whatever he has but common sense will take a guy a long wayz in the right direction right?? Just sayin...hope i dont strike a nerve! haha:nerd::eek:wned
 

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Junior Member
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292 Posts
O???? Is that why he put 0R-4943 excivater packs in mine with the 8789s ? Advanced the timing so much it was over spraying the bowls... Not to mention not changing the junk main bearings cause thier fine, plus the billet high volume oil pump from cat, sure looks cast to me 0r 9449 and a Huge 3408 oil cooler that's a factory replacement 0r 5511, 164,000 miles and had to tear it down to the short block...
 

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Junior Member
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168 Posts
O???? Is that why he put 0R-4943 excivater packs in mine with the 8789s ? Advanced the timing so much it was over spraying the bowls... Not to mention not changing the junk main bearings cause thier fine, plus the billet high volume oil pump from cat, sure looks cast to me 0r 9449 and a Huge 3408 oil cooler that's a factory replacement 0r 5511, 164,000 miles and had to tear it down to the short block...
Wow! Ive always said his timing specs were wacked like bad! after a point you can feel it hold back and when you loose a bunch of boost from just changing timing specs you know its way too advanced! sorry to hear about this man....thats bull**** when somebody basicallly uses you and your money, motor, and truck to be the test dummy for their careless attempt at re inventing the wheel with a bunch of drempt up theories! :serious:
 

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Junior Member
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168 Posts
O???? Is that why he put 0R-4943 excivater packs in mine with the 8789s ? Advanced the timing so much it was over spraying the bowls... Not to mention not changing the junk main bearings cause thier fine, plus the billet high volume oil pump from cat, sure looks cast to me 0r 9449 and a Huge 3408 oil cooler that's a factory replacement 0r 5511, 164,000 miles and had to tear it down to the short block...
And seriously, A billet oil pump huh?? I wouldnt even dare guess how much extra that descriptipn cost??!! Man idk how people that do that kinda **** can sleep at night?? I mean ripping somone off is bull**** but not having any pride and putting your name on the line like that would eat me up alive! Jeez theirs times when i will tell people that dont want me to completly clean, paint, and straiten all the hoses and wiring out that ill just include it in the price of the inframe or whatever im doing just because i take pride in what i do that much and to me a motor job isnt complete unless it looks professional.
 

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Junior Member
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Discussion Starter #14 (Edited)
as always thanks for the info.besides the cam # given what barrels & plungers go with it ?
or will the ones in the pump now do the job?I will have to pull the 7FB down in the next few weeks and check the cam out. If it is junk i will get the 3787 coming for it.I am trying to get all the parts rounded up before i start on the 8PN so i only have it down for a couple weeks.
 

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292 Posts
Thank god they are steal pistons, 14.6, spitting oil out the blow by at hard mountain pulls, so rings , liners , rod bearings and mains, plus a lifter trying to spin tore the cam up, not blaming anyone on that - lifters and cam, a lot of work
 

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Senior Member
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2,824 Posts
as always thanks for the info.besides the cam # given what barrels & plungers go with it ?
or will the ones in the pump now do the job?I will have to pull the 7FB down in the next few weeks and check the cam out. If it is junk i will get the 3787 coming for it.I am trying to get all the parts rounded up before i start on the 8PN so i only have it down for a couple weeks.
You would use the barrels and plungers that are in the 8pn pump, keeping the dual scroll barrels will be key in running the 8789s.
 
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Junior Member
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I have 2 questions from this thread and i hope I'm not stepping on the op's toes, just glad to see the the good ol boys online here again!
The OR8789 being mentioned compared to OR8785s.... bit more fuel or less? I inframed with PAI kit, head was good even the block deck was beautiful and HASNT had counter bore done. Spacer plate had the yellow plastic washers(?) In the rubber coolant passage gaskets(?). Sorry got carried away, ive noticed you guys like info 😆
Can i throw 8789s in place of 8785? I'm looking to do a turbo and possibly a cam upgrade also (front cover gasket leaking) and im always looking for more giddy up go.

Second question,
Do i need to swap pump cams to time that hot to match the above components? I have another 3zj available to me i was thinking about building over time into a big dog and swapping whenever this one gets tired.

TYIA
 

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Senior Member
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Well that pump cam may not be so easy to get after checking availability with cat.

Before changing engine cam it is best to figure out what you are running.

As for nozzles that's another one, depending on piston you are running on if the upgraded would be feasible, I would not try running 8789 nozzles on aluminum pistons. They are around 30% more flow then a 8785. I can tell you there are a handful of generator set engines that make 603hp at the crank with 8785s on factory pump settings and 1800rpm limit.
 
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