Turn up an older Cummins? [Archive] - TheDieselGarage.com

: Turn up an older Cummins?


ash_flat_diesel
03-25-2007, 01:19 AM
I think its a 400 Cummins but not sure exactly. Its in a Tri Axle International Dump truck about mid 80's. What can be done to it to help with power? It makes hardly any smoke at all now. Thanks!

John_G
03-25-2007, 01:26 AM
More power is rather simple on those older engines.

If you want smoke, that's something else entirely.

Lack of smoke does NOT mean lack of power, in fact, it means you are getting power from ALL the fuel you are using, instead of blowing 1/2 of the fuel out the stack as soot

bmoeller
03-25-2007, 01:28 AM
Don't exactly recommend doing this,but, if it has a PT pump, just put a pair of vice grips on the fuel return line. Just don't pinch it off completely. It raises the fuel pressure, and gives more power.

JohnG is right, though.

curtmu
03-25-2007, 03:30 AM
What is your gov setting. Sometimes lack of power is just the engine not winding high enough.

ash_flat_diesel
03-28-2007, 12:37 AM
Thanks guys. I will check a few things & get back to ya.

chris142
03-28-2007, 01:38 AM
There are "Buttons" in the pump you can change to get more fuel to it. I heard that setting the injectors loose will give it a little more fuel too.

Edit: Finding buttons can be a little hard. Probly due to emission reasons.

curtmu
03-29-2007, 12:07 AM
The pump uses a spring and washers to change the governor setting. There is a screw in the middle of the governor spring that I think raises the pump pressure. The more washers the faster the governor setting, there are also different springs rates to course adjust the setting.

chris142
03-29-2007, 12:28 AM
There is a screw in the middle of the governor spring that I think raises the pump pressure.


The screw in the govenor plunger adjusts the idle speed only.

kevin
03-29-2007, 12:33 AM
put a different button in your fuel pump,then your truck will haul ***** :smoke

chris142
03-29-2007, 12:37 AM
put a different button in your fuel pump,then your truck will haul ***** :smoke

Ya dats what I said:Thumbup: But you can't just buy a button anymore. At least not here in SoCal, Better off finding a pump to steal the button out of.

curtmu
03-30-2007, 04:45 PM
where are these buttons located?

bmoeller
03-30-2007, 06:16 PM
Inside of the PT/PT-G pump. There are also orfices on the fuel inlet on the injectors, that can be swapped out for more power.

Evildiesels
03-31-2007, 07:55 AM
The correct way to increase your fuel is to remove the anti tamper ball that is fitted in the throttle shaft (the actual throttle shaft not the lever), it will either be a piece of lead or a ball bearing, if a ball bearing it's a bit more difficult to remove but it is made of mild steel unless some sick ***** fitted a proper ball bearing then your screwed, the overhaul kits for the PT pump come with the anti tamper ball now and can be drilled no problem. Once you get the lead or ball out there is a screw inside the throttle shaft, turn it anti clockwise and you will get what you are after as long as the pump is in good condition, this is the correct way to increse the pump fueling I worked for 4 years in the fuel room at Cummins Engine Co in Auckland New Zealand

Good luck

imported_ESJDIESEL
03-31-2007, 12:34 PM
:Thumbup: :Thumbup:

diesel dan
03-31-2007, 01:05 PM
The correct way to increase your fuel is to remove the anti tamper ball that is fitted in the throttle shaft (the actual throttle shaft not the lever), it will either be a piece of lead or a ball bearing, if a ball bearing it's a bit more difficult to remove but it is made of mild steel unless some sick ***** fitted a proper ball bearing then your screwed, the overhaul kits for the PT pump come with the anti tamper ball now and can be drilled no problem. Once you get the lead or ball out there is a screw inside the throttle shaft, turn it anti clockwise and you will get what you are after as long as the pump is in good condition, this is the correct way to increse the pump fueling I worked for 4 years in the fuel room at Cummins Engine Co in Auckland New Zealand

Good luck
:whs I did this to a friends truck and it made a pretty good amount of power. Of coarse if you want a lot of power and smoke, get you a #8 button for your pump ( IIRC, I think the lower the # the more power)...:Thumbup:

chris142
03-31-2007, 02:13 PM
:whs I did this to a friends truck and it made a pretty good amount of power. Of coarse if you want a lot of power and smoke, get you a #8 button for your pump ( IIRC, I think the lower the # the more power)...:Thumbup: I wonder whats been done to my 280.
It has a #57 button


http://usera.imagecave.com/chris142/smokey3-copy.jpg

1040 WreckerMan
04-03-2007, 04:11 AM
If you want different buttons for your pump and can't find them locally call and have them shipped. H&H diesel is Fife Washington has been building high HP Cummins for years. Duncan Diesel also can get buttons for you, they are also in Washington. Oregon Fuel Injection also used to sell pump parts. #8's are a good size.

Chris142, doesn't look like you've got a load on that are you just rolling into the throttle? If so it just looks like you have a non-AFC PT pump which will smoke more than a AFC pump - doesn't necessarily mean it's been turned up.

Dualie
04-03-2007, 05:58 AM
Hey 1040Wreckerman NICE to see you made it!

Hope you find it to your likeing! We try to keep the IDE's out as best as we can here.

dhooks
04-04-2007, 01:02 AM
Change your fuel button out to something close to a 15, drill the little ball out he talked about above to give it some more fuel, turn the little allen head scew on the side of your pump ( it has a lock nut on it ) an set your shims so you can turn around 2500 rpms an you'll be good to go. Dont expect a ton of extra HP but its not bad for a cpl hours work. Get yourself a good pyro as well.

dhooks
04-04-2007, 01:03 AM
where are these buttons located?

On the back of the pump inside the little square housing.

chris142
04-04-2007, 01:35 AM
Chris142, doesn't look like you've got a load on that are you just rolling into the throttle? If so it just looks like you have a non-AFC PT pump which will smoke more than a AFC pump - doesn't necessarily mean it's been turned up. My pump is from a NTC 335 so what kind of pump is that?

Lowboy
04-04-2007, 03:49 AM
My pump is from a NTC 335 so what kind of pump is that?

The 335 never had an aneroid valve on it so itís just ole straight mech pump. The later 350ís had the smog valve..

1040 WreckerMan
04-04-2007, 04:31 AM
I've got a NTCC 335 with a AFC pump. You maybe correct that the NTC 335 never had a AFC. If Chris142's pump doesn't have an AFC pump then it's probably not turned up at all, it's just smoking from overfuel on accel. Put a new button in it and crank the fuel screw a bit.

Daulie, yep I made it. I thought I'd see what was going on over here, so far I like it - some people here who actually know something and actually drive and work on the stuff, not just read it out of the magazine :)

SmokinCAT
04-05-2007, 02:50 AM
The lowest button i have heard of is a 5, can be used on the street but you have to watch your gauges. If you have a pump with the aneroid and want to show off just find the line that comes down from the intake and unhook it, it is on there so that the pump dosent deliver fuel until a certain amount of manifold pressue is reached.

Evildiesels
04-06-2007, 10:17 AM
The lowest button i have heard of is a 5, can be used on the street but you have to watch your gauges. If you have a pump with the aneroid and want to show off just find the line that comes down from the intake and unhook it, it is on there so that the pump dosent deliver fuel until a certain amount of manifold pressue is reached.

Not too sure what ya mean there dude "Show off" he will efectively turn his truck into a gutless piece of **** by removing the pipe to the AFC, the pipe supplys boost presure to the AFC, boost pressure = more fuel, there is a plunger controled by a spring and rubber diaphram in the AFC housing, as the boost pressure increases, the pressure acts on the diaphram and against spring pressure forcing the plunger to open the fuel flow port further. Removing the pipe will not allow the diaphram/plunger assy to be moved against the spring and result in no excess fuel being delivered, and an upset driver, just like when the diaphram ruptures in normal day to day use. From memory when running an AFC pump on the stand without air pressure being applied to the AFC and then with air pressure applied (to simulate boost) the difference in fuel delivery was night and day
cheers

SmokinCAT
04-07-2007, 02:03 AM
On my 400 when I unhooked that line, my truck it smoked like a chimney, just the effects i noticed by doing it. If all he wants is smoke that it an easy way to do it IMO.

Lowboy
04-07-2007, 02:40 AM
Not too sure what ya mean there dude "Show off" he will efectively turn his truck into a gutless piece of **** by removing the pipe to the AFC, the pipe supplys boost presure to the AFC, boost pressure = more fuel, there is a plunger controled by a spring and rubber diaphram in the AFC housing, as the boost pressure increases, the pressure acts on the diaphram and against spring pressure forcing the plunger to open the fuel flow port further. Removing the pipe will not allow the diaphram/plunger assy to be moved against the spring and result in no excess fuel being delivered, and an upset driver, just like when the diaphram ruptures in normal day to day use. From memory when running an AFC pump on the stand without air pressure being applied to the AFC and then with air pressure applied (to simulate boost) the difference in fuel delivery was night and day
cheers

Good accurate description of the AFC. :Thumbup: Speaking of simulating boost to get the fuel rate up. I had a buddy that disconnected the AFC line on the manifold and plugged it into an adjustable air regulator in the cab. He would just give it 10 lbs or so and fool the pump into thinking it had boost..LOL

Hotrodx199
01-11-2010, 12:49 AM
Taking the aneroid out of the trottle shaft is quite the improvement. Dad did it to an 81 peterbilt and he can actually take off loaded without needing manifold pressure.

bmoeller
01-11-2010, 11:14 PM
Man, this thread is an oldie! LOL

fest777
01-12-2010, 04:04 AM
335's had aneroid valves they were mounted in between the fuel line from the pump too the head inlet, afc was built into the pump, evildiesel seems to know what he is talking about, backoff the forward stop lever behind the throttle cover plate, the shaft stop lever inside the afc type pump,so in aint a dog, need to take it to a pump shop and have it calibrated , nowadays thats risky business jacking up a pump, there is someone that will do some where

LOG HAULER
01-13-2010, 02:35 AM
I think its a 400 Cummins but not sure exactly. Its in a Tri Axle International Dump truck about mid 80's. What can be done to it to help with power? It makes hardly any smoke at all now. Thanks!
The first thing to do is get a dual fuel line installed in the head will add about 25hp then change the #10 fuel line to #12 add larger fuel filter...........then gen get a button.maybe a size 7 or 10......this is the most inexpensive way if you need more info .let me know....what cpl is it?

ynot
01-14-2010, 03:14 AM
The first thing to do is get a dual fuel line installed in the head will add about 25hp then change the #10 fuel line to #12 add larger fuel filter...........then gen get a button.maybe a size 7 or 10......this is the most inexpensive way if you need more info .let me know....what cpl is it?

Don't forget the throttle shaft screw with the button :o

LOG HAULER
01-14-2010, 03:19 AM
Don't forget the throttle shaft screw with the button :o

Help me out.......what exactly does it do...what is the max gain of it.....

ynot
01-14-2010, 03:32 AM
Help me out.......what exactly does it do...what is the max gain of it.....

The fuel goes thru the throttle shaft. Screw is in the middle of the outside of shaft covered with soft metal ball. Pop out the ball, give it anywhere from 1 to 6 or more turns to let the extra rail pressure thru :tada

LOG HAULER
01-20-2010, 03:04 AM
The fuel goes thru the throttle shaft. Screw is in the middle of the outside of shaft covered with soft metal ball. Pop out the ball, give it anywhere from 1 to 6 or more turns to let the extra rail pressure thru :tada
Thanks captain!!!

Lmackattack
01-20-2010, 03:22 AM
regarding the android valve, us mack guys mess with what we call the "puff limiter:" the way we mess with it is to tee into the line that runs from the puff limiter on the intake manafold to the android valve on the fuel pump. you mount a dash air switch that has its air supply from somewhere behind the dash. you simply send or cut off the air press going into the line that you Tee'ed into. with the switch in the off position the puff works normaly off of turbo boost presser. with the dash switch in the on position it feeds the line presser and opens the aindriod valve fooling the pump into thinking it has boost all the time. When the pump/android valve sees more than about 10psi of air press it will allow full fuel flow regardless of what the turbo is currently putting out. smoke show and throttle responce is what you gain. no real HP increase besides maybee down in low RPMS?

niceguypmp3
01-20-2010, 05:08 PM
Lmackattack, not meaning to hijack this thread, but i have a question regarding your post about the puff limiter. I have an early 80s mack with the 235 and what i did on the puff limiter is unhooked the line coming from the dealy bob on the intake and just blocked it on the intake. Now it has more power and will actually smoke, but it's still gutless. It is a truck that weighs 33k empty and only has like 235 horsepower with a top speed of 53 mph, so maybe thats it. From what I understood on the bigmacktrucks forum, that's how to bypass that puff limiter. Does that sound right to you too? Thanks! This gave me a great reason to register on the forum.

Lmackattack
01-20-2010, 07:29 PM
From what I know on all the R models I have wrenched on the puff limiter needs to see boost presser before it lets the pump send off full fuel.to test the puff limiter to see if it works as intended (on a stock truck with no mods) set the parking brakes, mash on the throttle and see if it throws black out the stack (it should). Now release the parking brakes and mash the throttle again(its should not smoke at all or nearly as much) The puff limiter has a air line that comes off of the yellow? parking knob. when you release the parking brakes it cuts the air supplyto the puff. So now with the parking brakes released the puff needs to see boost press before it will allow the pump to give full fuel. I dont know why they hooked the puff to the parking knob. I never did ask or figure a reason for that.

If the air line from the parking valve or the air line to the pump is just removed from the puff limiter and pluged I would think it will not send air press through the signal line to the pump. If air cant get to the pump,the pump thinks there is no boost and it holds the fuel back. this was all for emissions and to save a little fuel in Low RPM low boost driving. I do know there were a few versions of puff limiters so you may have a set up that works in reverse?

FJH or other mack guys might be able to add to this.

379Longhood
01-20-2010, 08:55 PM
The puff limiter doesn't do any thing when it is unhooked the plunger stays in the cylinder
but if the pump came with one it will work better with a well tuned puff limiter
If the engine is not inter/after cooled you can only fuel it to temp limit
The puff limiter has an inversion valve It takes "maxi" air and uses boost to regulate the limit cylinder.
some pumps work ok with out the limiter unless youmash the pedal others are more sensitive and you get surge and black smoke
you can remove the limit cylinder to make sure it is fully retracted and you can test the inversion valve with shop air and a regulator
I could always get better performance out of the E-6 with a properly set puff limiter

if the system passes the shop air test
Put maxi air to the supply port or shop air at about 90 psi
connect a low pressure regulated line to the sensor port
remove limit cylinder from pump and connect its line back up
slowly increase regulator pressure to see when the limit cylinder fully retracts
it shouldn't need more than 15 psi or so usually not that much
check to make sure the boost line from the intake manifold is not plugged

if it all checks out reassemble and road test truck. We used to have a mirror on suckion cups so you could see the stack when driving. I usually shimmed the limit cylinder out from the pump until mashing the pedal gave medium grey smoke out the stack this was usually the best performance i