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Some 6.9 questions/discussion

Fellro

Moderator
Staff member
I'm going to post up some pm's a had with a user a while back. I'll work it a bit so that they can continue t remain anonymous if they choose. Bear with me on this, as i will be the only poster showing, so as to not use their name without their permission. The point of this is to put the info out here for others to access.

Question asked:
I have a 1986 Ford f350 6.9 liter dually that i brought for 500$ dollars. the guy who i brought it from sprayed ether in the motor one mornin when it was cold, so now i thank it has a bent rod or cracked piston but it's not spittin oil out the exhaust
 
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Fellro

Moderator
Staff member
What makes you think you have damage? Ether can be used, just not ridiculous amounts, and if used, the glow plugs need to be disabled. If they are non-operative, then it shouldn't be a big deal. Main concern is a couple of things, first being the glow plugs igniting the ether, the other the preignition taking out head gaskets or rings, but generally not bent rods. That takes hydraulic lock, which a head gasket can cause. My dad's 84 6.9 has been ether started many times, to the point that is the only way it will start, but then, the glow pugs are totally burned out as well, until I replace them and see if it will start without it then. Otherwise, it runs just fine, if you don't consider that the injectors are worn out...
 

Fellro

Moderator
Staff member
Response:
well there are a few glow plugs out on it and the injection pump is out also so thats probably the problem right? i brought the truck because the motor only has like 86K miles on it and 2,000$ worth of brand new wiring new clutch,break pads, aluminim wheels, and a sleeper on it and 500$ dollars hell i didn't thank that was a bad deal at all
 

Fellro

Moderator
Staff member
The truck alone is worth the price, I need a clutch, those darn things run $200 themselves, the starter under there is about $300, and you have more yet... The injection pumps are kind of a weak spot in a sense, there is a collar inside that is designed to break in the event the pump drags too much, rather than self destruct. Luckily, the pumps aren't too terribly expensive. Take an injection line loose, crank it over, and see if any fuel comes out, and that will tell you if there is any fuel being pumped. That isn't necessarily the end all though. If it has been sitting for a while, it is possible that the pump has simply lost prime and needs bled out.
 

Fellro

Moderator
Staff member
Response:
thanks ill try that on the injection pump, maybe it well work cause i sure dont want to buy a new one. do you know how much horse power those stans headers give your truck
 
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Fellro

Moderator
Staff member
I have heard they do pretty good, the trick to it is, still need to get air in. For the money on those headers, you can pick up a good used turbo and exhaust. What size pipes are you running? Other than the bit of restriction at the manifolds, with the duals you should see some decent flow. Those manifolds are still used by the turbo, so I don't think they are all that bad for flow. The next thing to check is the air cleaner. On my 86, the bottom hole of the air cleaner was about half the size of the intake. I cut that out, as do many others. The other possibility is what is called the "soup bowl", which is an extension of the air cleaner lid. If you have a flat lid, then you likely have the small hole on the bottom. If you have the big bowl attached to the lid, then cut it off to get a flat lid. After that, the plastic POS intake tube that goes past the power steering pump needs to go away, and run the hose to behind the grille. How I did this was to use a piece of 4" exhaust tube. I removed the driver side radiator mount plate and made a hole in it, flattened the exhaust pipe enough to fit, and stitched it to the radiator mount plate. Then you hook up the hose to that, and you have essentially a ram air type intake setup. I used a window screen from the door of an old microwave to keep bugs and debris from blowing in, I kept ist spaced a few inches away so I don't ever have to worry about it plugging up, and is well over twice the size of the hole. Any metal screen with small holes would do though. With that in there, it is hard to see that I even did that little mod...
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Fellro

Moderator
Staff member
response:
the truck has true duals and it had 4inch stacks but when the guy put the sleeper on the truck he had to take them off so now they are on the side like side pipes, so there is no muffler or nothin its straight all the way. i was thankin about gettin a cold air intake on it but if that intake you made works ill do that to save some money. i was also thankin bout gettin a torbo maybe the banks side winder turbo, and some marine injectors. i also have an 88 ford dually 5 speed single cab 7.3 liter that i got for 600$ and it runs great the motor in it is an ol power house it unbreakeable ha ha!!!
 

Fellro

Moderator
Staff member
Response:
do you know how to put the piano strings in your exhaust pipe to make it louder
 

Fellro

Moderator
Staff member
I haven't heard of that, but then, loud isn't a problem already, I made a custom high flow muffler, as well as a 4" outlet...
 

Fellro

Moderator
Staff member
response:
is that on your 6.9? yea i heard that if you put the small piano string in your exhaust pipe, you can drive by some ones car romp on it and it should shadder their glass cause its so high
 

Fellro

Moderator
Staff member
Yep, that's what I run for an exhaust, it isn't overly loud at idle, but stomp on it, the tone comes right up... I ran it through some tunnels out east, never realized how loud it was until I got in there with a trailer behind it...
 

Fellro

Moderator
Staff member
Response:
my 6.9 is very loud even at idle i haven't put a trailer behind it yet but i cant wait im gonna have to where some ear plugs ha ha. im still workin on it right now so i can get it out on the road.
 

Fellro

Moderator
Staff member
response:
on the 6.9 isn't there a screw you can turn up on the pump without advancing the timing, cause my dad wants to do it on my 88 ford 7.3 liter idi, he's drivin it right now and he said it just aint got enough get up and go. the guy who i got my 6.9 from already had the pump turned up all the way, i got my 6.9 runnin this weekend and there wasnt a knock or anything, it wasn't spittin oil out the exhaust so i asume its alright but it does need a new injection pump.
 

Fellro

Moderator
Staff member
On the left side, as you are looking down on the IP, there are two tiny little bolts on a triangle shaped metal plate. Behind that is where you will find the fuel adjustment screw. The motor needs to be at TDC to be able to get at it though. I cheat a little, I take the oil fill neck off so I can see the timing marks. Be careful adjusting though, as a little is a lot. When we talk about movement of this screw, we talk in flats, as in the flat side of the hex. 1/2 flat is quite a bit, so go easy, that is probably about as far as you want to go at first, and then keep tinkering with it. I doubt you will go much further, but that will be up to you. The main pita of this is that diesel will leak out each time you take off that cover. There is a little rubber gasket behind that plate, you will need to reuse it. I want to say the allen key is a 5/32, but not certain. I keep it in my ignition wrench set so I have it with the wrenches that fit. I think it was either a 1/4 or 9/32 wrench size.
 

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