How can i detune a peugeot 1.7d xud??

[RedAdmiral]

Simplest way is to knock out one or two cylinders - feed fuel supply to selected injector(s) directly into fuel return at injector which retuns fuel to filter or into main fuel return to tank. It'll sound funny but will run probably for ever!!

 

[TQA]

"Simplest way is to knock out one or two cylinders - feed fuel supply to selected injector(s) directly into fuel return at injector which retuns fuel to filter or into main fuel return to tank. It'll sound funny but will run probably for ever!! "

Errr Not a good idea. Why The cylinders not in use will not generate heat leading to thermal stress and cracks in blocks and heads.

You can do this sort of thing electronically with solenoid injectors where different cylinders are cut out on rotating basis. This equalises the heat in the head and block.

 

[Bilgediver]

OOPS Bilgediver is correct in part. It would depend on the type of governor fitted. Max Min or constant speed. It is twenty years since I taught this. However I am pretty sure Max Min governors are rare nowadays. Restricting the throttle movement on a constant speed set up would not reduce the power the engine could produce at that restricted rpm.

The way to do that is to reduce the max fuel delivery.

Nop!!!!!


You are confusing the purpose of the two functions. Yes there is a maximum EXCESS fuel delivery setting however that is exactly what it is and it is to limit excess fuel amount for acceleration otherwise there would be clouds of black smoke everytime the governor gives a bit of welly the cold start on many volvos just allows even more excess for cold start and resets to normal excess once the governor has control.

Total control of a normally running diesel wether fixed speed or variable speed is by the governor speed control which we control with what folk here call the throttle.

We tell the governor we want 500rpm and come hell or high water within certain limits of accuracy that's what we get. If we suddenly raise the speed lever to 1000 RPM then this is where the rack limiter setting comes into play as it physically restrains the fuel pump rack from allowing to much extra fuel to be injected during acceleration however as soon as the engine reaches 1000 rpm then the rack backs off and the governor is back in full control.

We never control the running power with the rack stop as this would limit acceleration drastically at all speeds.

There are other settings on governors such as droop which I have deliberately ignored here to save confusion however in different engine applications it may sometimes be required that the engine speeds up slightly as load is applied ie diesel alternators. Where as in other applications the engine may be set up to slow down a few % when load is applied. In actuall fact if you study some of the older Volvo engines you will see they readily run to 3600 RPM light but even on a free floating governor the same engine will probably only achieve 3000 RPM under light load and even less if tied up to the pontoon. This is due to the droop designed into the governors. Not all marine diesels have this fail safe feature.

To reduce the power output the easiest way is to reduce the propeller pitch
so that the engine has to absorb less power however every effort should be made to ensure it still reaches full operating temperature.

You certainly do not try to de power by throttling air etc.

Having played with various Ruston engines up to 5000 HP running in pairs to a single propeller this is a topic close to my heart as it involved balancing governor characteristics to ensure that when we gunned those two roaring tigers they shared the load equally right through the rev range. It used to be amusing to see the skipper ring full away after dropping the pilot at some distant port then stumbling off the compass platform as the unexpected acceleration took him by surprise. Not many cargo ships of 25000 tons could do that but occasionally one of my third engineers would show off however he had to have all conditions correct and of course no cargo in the ship

Get it wrong with almost stalled turbos then the smoke tumbled out of the funnel like a black river onto all those on the bridge wings if a following wind.

 

[Heckler]

With respect Stu, not opening the throttle is not a good solution. You end up with a very limited range of throttle to use. In my case, with a 55hp in a 12m, 8.8t sailing boat, at 800rpm idling it does 2.5 to 3kts, 1500rpm 6kts, 2000rpm 7.5kts. With more power at idling I would be doing 4 to 5kts and hull speed at somewhere near 1200 to 1500rpm. You have to loose power somewhere else and it will become uneconomical.

I am not that familiar car car diesels but is not the xud a turbo. If so removing the turbo would reduce the power considerably. There's probably some reason why this can't be done easily (different head?) but it seems the way forward to me. In a marine environment, I do not like the idea of adding turbos to the 2003 or 2030 to give the extra 10hp of the 2003T or 2040
Roy

Roy
You cant just remove the turbo, the injection system is set up to use the turbo. (been there to pick up the pieces on a D8 Cat when someone did that in Angola) Going on from there, the throttle sets the revs, the governor sets the power output. More load trys to slow the revs, the governor responds by putting more fuel in. If you have ever driven a diesel car there can be a slightly scary moment when the throttle is being slightly opened and the load comes on, the governor opens up and the car APPEARS to accelerate without any movement of the throttle.
So if the OP wants to put a "big" engine in a small boat, he can use the throttle to control the power, if he has a small prop the engine wont slow down and the governor wont open up, so he isnt using full power.
Stu

 

[tinkicker0]

OOPS Bilgediver is correct in part. It would depend on the type of governor fitted. Max Min or constant speed. It is twenty years since I taught this. However I am pretty sure Max Min governors are rare nowadays. Restricting the throttle movement on a constant speed set up would not reduce the power the engine could produce at that restricted rpm.

The way to do that is to reduce the max fuel delivery.

Sorry, don't see where the bilgediver is correct in part. Have I missed something?

 

[pappaecho]

Your posting is not as daft as some seem to think. The Ford XLD 418 diesel engine was capable of 64BHP, but one of mine came from a Fork Lift Truck and is derated to 49 BHP, produces more torque apparently ( which is good for a boat) and uses less fuel (which is also good for a boat)
The bad news is that I have no idea of how the reduction in power output is achieved. On more modern diesel engines with an engine management system, this is done by remapping the timing, and is done with a PROM chip. However older diesels dont have an engine management system, so clearly they must be retimed by possibly having a different injector pump, or a different rack

 

[pappaecho]

Having re read earlier postings the easiest way of restricting the revs on a marine engine is to fit a larger propellor to hold the engine back

 

[Heckler]

Your posting is not as daft as some seem to think. The Ford XLD 418 diesel engine was capable of 64BHP, but one of mine came from a Fork Lift Truck and is derated to 49 BHP, produces more torque apparently ( which is good for a boat) and uses less fuel (which is also good for a boat)
The bad news is that I have no idea of how the reduction in power output is achieved. On more modern diesel engines with an engine management system, this is done by remapping the timing, and is done with a PROM chip. However older diesels dont have an engine management system, so clearly they must be retimed by possibly having a different injector pump, or a different rack

It used to be done on the rack stop screw if I remember right.
Stu

 

[colvic987]

cheap method of detuning the engine..????

put a block of wood under the accelorator....

 

[Bilgediver]

It used to be done on the rack stop screw if I remember right.
Stu

The rack screw stop is not a way of limiting running power as its purpose is to specifically allow a correct amount of excess fuel for acceleration! This might serve as a get you home measure but not as a permanent set up.


If you are an engine builder and want to derate a range of engines to a lower r power setting then if it is an old fashioned system you just spec out a lower capacity pump and smaller injectors and if a common rail electronic system then probably can chip it. Maybe aalter cams too!

Some engines when wanting increased power they have just altered the max speed setting
as with some Beta's.

 

[Heckler]

The rack screw stop is not a way of limiting running power as its purpose is to specifically allow a correct amount of excess fuel for acceleration! This might serve as a get you home measure but not as a permanent set up.


If you are an engine builder and want to derate a range of engines to a lower r power setting then if it is an old fashioned system you just spec out a lower capacity pump and smaller injectors and if a common rail electronic system then probably can chip it. Maybe aalter cams too!

Some engines when wanting increased power they have just altered the max speed setting
as with some Beta's.

BD
sorry, but define "smaller injectors" and I think you will find that the excess fuel will give you more power!! In the older pumps the case dimensions were the same.
Think about it, you open the throttle fully, that allows the rack to go fully open, in this case full chat, more fuel goes from the pump. The engine revs rise, the governor takes over and when the revs get to where they should be everything is in equilibrium and the revs stay constant. Put more load on by punching a tidal stream, the governor senses a drop in revs and the rack opens again to give more power. You need to get your head around the 3 controls balancing each other. Throttle gives a rev position, in essence telling the governor what revs are needed, the governor "governs" the engine to those revs by controlling the position of the rack to allow enough fuel to the engine. That is why when a boat is overpropped you see loads of black smoke, the rack is wide open but the engine/fuel delivered cannot deliver enough power to get the engine revs up so that the governor can close the rack.
Stu

 

[TQA]

This is better than the excess oil thread.

I have just had my offer accepted on my new boat so am a little busy sorting out deposits contracts and surveys but will add my two pennyworth later.

 

[Heckler]

This is better than the excess oil thread.

I have just had my offer accepted on my new boat so am a little busy sorting out deposits contracts and surveys but will add my two pennyworth later.

good innit!

 

[Bilgediver]

Having re read earlier postings the easiest way of restricting the revs on a marine engine is to fit a larger propellor to hold the engine back

Which will have exactly the reverse effect by loading the engine in excess of design parameters.

In fact following your thoughts the reverse is actually true. Fit a smaller pitch propeller then the engine will be unloaded at all revs IE depowered

 

[TQA]

How can i detune a peugeot 1.7d xud??

OK the engine in question probably has a Bosch VE injector pump. The engine can be detuned by a simple adjustement to the pump.

The adjustment screw is located on the firewall end of the injection pump under a plastic cover that pops off. There is a lock nut that must be loosened and you may have to remove a collar tack welded on this screw to get enough movement.

Turn the power adjustment screw anticlockwise about 1 to 2 turns.

You may find the idle speed drops too low and becomes uneven. Readjust the idle speed.

You do not have to remove the pump from engine to perform these adjustments.

I have adjusted these to produce more power in the past, this is the first time I have been asked for less, guess it is a sign of the times.

This will not change the engines max rpm limit but might reduce it's ability to achieve that rpm depending on the prop fitted.

If you have another injector pump please specify manufacturer and model. I think Peugeot used an oddball maunufacturer from time to time.

 

[PCUK]

Bilge diver is 100% correct, fit a finer pitch propeller - job done!
Messing about with the engine will only cause problems.

 

[Bilgediver]

BD
sorry, but define "smaller injectors" and I think you will find that the excess fuel will give you more power!! In the older pumps the case dimensions were the same.
Think about it, you open the throttle fully, that allows the rack to go fully open, in this case full chat, more fuel goes from the pump. The engine revs rise, the governor takes over and when the revs get to where they should be everything is in equilibrium and the revs stay constant.
Stu

You are quite right in your thinking for a standard engine STU but the OP wanted a 65 HP engine derated. EG full chat was now to be 45 hp not 65 HP hence a requirement give or take of around 30% less fuel. The old injectors and pump barrels would be a waste of space as they were not being used to their full range under any circumstances...OP does not want 65 HP when accelerating! So the engine could be matched to more suitable pumps and injectors which are more suitably sized for the job required.

This is all highly theoretical as the easiest way to get the result as was said elsewhere is to either just reduce the max speed setting and reprop or fit a prop with finer pitch. The OP would then just have to be sure to keep the lump warm using reduced power all the time and maybe experience glazed liners in time but I doubt it. If the prop does not absorb 45 HP then the engine will not develope it!

 

[Heckler]

You are quite right in your thinking for a standard engine STU but the OP wanted a 65 HP engine derated. EG full chat was now to be 45 hp not 65 HP hence a requirement give or take of around 30% less fuel. The old injectors and pump barrels would be a waste of space as they were not being used to their full range under any circumstances...OP does not want 65 HP when accelerating! So the engine could be matched to more suitable pumps and injectors which are more suitably sized for the job required.

This is all highly theoretical as the easiest way to get the result as was said elsewhere is to either just reduce the max speed setting and reprop or fit a prop with finer pitch. The OP would then just have to be sure to keep the lump warm using reduced power all the time and maybe experience glazed liners in time but I doubt it. If the prop does not absorb 45 HP then the engine will not develope it!

AArgh
dont try to teach your granny to suck eggs §) Bottom line for the last time, why use a car engine unless it is for the cheapness! Changing pumps and injectors aint cheap!!
Just use the throttle!! As you say, if the prop doesnt want big hp then the engine wont develop it!!!
Stu

 

[DownWest]

After all this euridite advice, where is our original poster to explain what he is up to and why he needs to detune?
A

 

[Bilgediver]

After all this euridite advice, where is our original poster to explain what he is up to and why he needs to detune?
A

Like so many it was either a troll or he has gone away totally bemused