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Old 24-02-2013, 20:06   #31
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Re: Perkins 4.108 compression

I do appreciate everybody's comments & effort,
but I still need the figures,( min / max ) for the compression.
I've written to Perkins but still waiting for an answer.
thanks everybody,
Walter
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Old 27-02-2013, 20:45   #32
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Re: Perkins 4.108 compression

my compression is 22Bar, 323 PSI.
Still smoking on cold (25 deg. C.) start. I will have to get used to it!
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Old 27-02-2013, 21:02   #33
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Re: Perkins 4.108 compression

How old is your fuel?
Mine smoked quite a bit until I ran new clean fuel through it for about 50 hours after I finished off the 8 year old fuel.
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Old 28-02-2013, 02:15   #34
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my compression is 22Bar, 323 PSI.
Still smoking on cold (25 deg. C.) start. I will have to get used to it!
Try rotating the Pump. My 4108 was rebuilt with Folley parts. It smoked cold. I played with the pump and it went away but eventually came back. Now I just live with it and just warm up the engine and go.
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Old 28-02-2013, 03:57   #35
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Re: Perkins 4.108 compression

Any diesel engine with a mechanically governed fuel system will smoke when cold, the reason is because you haven't reached sufficient engine temperature for the fuel to burn efficiently, the smoke you see is unburnt fuel. Take the boat for a cruise and then check for smoke when the engine temp is 85/90 degs. To obtain optimum performance from your engine don't mess around with the injector pump timing once it's set up correctly.
Modern diesels with electronic fuel management don't smoke because the systems sensors continually feed back temps, loads etc to the microprocessor and adjust the fuel flow automatically.
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Old 01-03-2013, 01:25   #36
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Any diesel engine with a mechanically governed fuel system will smoke when cold, the reason is because you haven't reached sufficient engine temperature for the fuel to burn efficiently, the smoke you see is unburnt fuel. Take the boat for a cruise and then check for smoke when the engine temp is 85/90 degs. To obtain optimum performance from your engine don't mess around with the injector pump timing once it's set up correctly.
Modern diesels with electronic fuel management don't smoke because the systems sensors continually feed back temps, loads etc to the microprocessor and adjust the fuel flow automatically.
Then why some 4108's smoke upon startup and some dont?
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Old 01-03-2013, 10:57   #37
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Re: Perkins 4.108 compression

avazquez, Injector pump set too lean, possibly retarded timing, either way the engine underperforming.
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Old 14-03-2013, 21:14   #38
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Re: Perkins 4.108 compression

The Perkins engine manual specifically warns against braking-in an engine and claims it may actually harm it by not bedding the rings properly. Just start using it the way you normally do.
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Old 14-03-2013, 22:09   #39
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Re: Perkins 4.108 compression

Thre are some rebild gasket kits out there, with a little different valve stem seals for the 4-108. These seals will allow a little oil to seep into the cylinders. This of course will cause smoking to happen on startup! nothing to worry about unless it do not stop after a little bit of running ! Just something I picked up the hard way LOL don't ask how long it took me to figure it out lol
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Old 15-03-2013, 18:14   #40
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Thre are some rebild gasket kits out there, with a little different valve stem seals for the 4-108. These seals will allow a little oil to seep into the cylinders. This of course will cause smoking to happen on startup! nothing to worry about unless it do not stop after a little bit of running ! Just something I picked up the hard way LOL don't ask how long it took me to figure it out lol
Is Foley one of them? I have the same exact situation.
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Old 15-03-2013, 19:28   #41
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Re: Perkins 4.108 compression

I don't really remember the brands of gaskets that contain these seals, sorry been to long LOL but if they are different looking then your old ones it could well be one of those sets !! Im sure they don't come in the factory parts kits, so they would most likely be in a after market set!! It mostly only smokes on startup and go's away quickly! not a real problem ! a little extra oil on startup not;s really a bad thing !
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Old 04-04-2013, 04:06   #42
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Re: Perkins 4.108 compression

White smoke is a lack of compression. Black smoke is over fuelling. A little grey smoke is normal on a cold engine. Blue smoke is engine oil getting where it shouldn't.

It is very unlikely that a problem with the injector pump would cause blue smoke.

A bit of blue smoke is common when a rebuilt engine is first run but it should clear within a few minutes. Anything longer should be looked int seriously.

First check the easy things.

Oil Level. Is it too high.
Crankcase breather. If that is blocked then crankcase pressure could be pushing oil into the intake system.

Why was the engine rebuilt in the first place? Is there any oil sitting in the exhaust system?

It was mentioned that when the heat exchanger is disconnected the smoke is grey. Is this the water heat exchanger or the oil heat exchanger? Oil getting into the raw water and then the exhaust maybe?

Mechanically, it is possibly oil scraper rings not fitted properly, problem with valve guides or seals. Some seals will actually pump oil down the guides if they are too tight on the stems and too loose on the guides. I'm not familiar with this particular engine but it may also be a problem with the oil spray nozzles that spray oil on the underside of the pistons and cylinder walls. They are normally holes in the conrod big-ends that point upwards. If different / wrong conrods have been fitted, the nozzles may be too big or pointing in the wrong area.

Where are the injectors fitted on this engine? If they are under the rocker cover then check that they are all tight and that the copper washers that seal them to the head are all fitted and in good condition.

The only other thing it may be is a problem with the head gasket or rocker cover gasket or manifold gasket. As I have mentioned, I'm not familiar with this engine but I have seen cases where there is an integral intake manifold built into the rocker cover. The rocker cover gasket can leak and allow engine oil into the intake.

I would be very concerned about finding the cause of the blue smoke. It could be an indication of a serious problem that could happen at any time. You don't want to find out what the problem is when something gives and the engine starts running on the engine oil instead of diesel.

If it happens, the engine stop will not work and the engine will just rev faster and faster until it self destructs. The only way you can stop it is to block the air intake. You need to use something that is substantially solid. I have seen a Detroit 6V53 engine run away while on the dyno. Someone grabbed a 3" thick workshop manual and put over the intake. It just swallowed it, chewed it up and spat it out the exhaust. They now keep a 1" thick steel plate handy just in case...

If you have nothing to stop it immediately then get out of the way and wait for the inevitable. It won't take long. Bits that are supposed to remain on the inside very quickly find their way to the outside.

Roger.
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Old 04-04-2013, 06:40   #43
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Re: Perkins 4.108 compression

Quote:
Originally Posted by FlyingCloud1937 View Post
Also the injector pump timing is critical, and can only be set properly by bringing the #1 cylinder up to top dead center on the compression stroke. Then drop the valve spring on the #1 intake vale, let it sit on the top of the piston, Then set up a dial indicator and move the engine by hand to get the reading to top dead cent by measuring the top of the valve stem. Then counter rotate the engine back, about 1/4 turn, look up in the work shop manual degrees BTDC set the pump timing, rotate the engine forward until the dial indicator moves to the required point, the adjust the injector pump to the timing marks.
This wont give you an accurate crankshaft position as the piston doesn't move enough when close to tdc to get an accurate reading and you have no way of actually measuring the angle.

There are possibly timing marks on the flywheel or crankshaft pulley that will indicate tdc and / or the injection point or a range of degree marks. If there are then check these are in the right place when No. 1 is at tdc and use these. It is possible that the flywheel has been mounted wrong so the marks may line up on a different cylinder tdc or not at all. Some engines also have a plug in the side of the block that can be removed and a pin inserted which will locate in a hole in the crankshaft when it is in the correct position.

If neither are the case then you will need to find tdc manually.

This is the method we always used when building engines where the timing marks were not reliable.

Firstly, make sure everything around the area is spotlessly clean. You will have parts of the fuel sustem open and any dirt can cause major problems.

You need a large diameter circular protractor and a dial gauge. All of the injectors should be removed so that the engine can be turned easily.

The protractor is mounted on the flywheel or crankshaft pulley, depending on what is accessible. The angle is not important, as long as it is centered on the crankshaft and doesn't move on it's own.

A pointer is mounted on the engine block somewhere and points at the degree marks on the protractor.

Turn the engine until No 1 piston is near tdc. Lloyds method of using one of the valves with the spring removed will work well but the rocker gear will need to be removed and it can sometimes be difficult to remove the valve spring while the head is in place. If the dial gauge has a long extension that will reach down the injector hole and touch the top of the piston then that would be an easier method. You need to make sure that the dial gauge plunger does not jam as the piston moves up and down.

If using the valve then something needs to be wrapped around the stem to stop the valve dropping down the guide and into the cylinder if the engine is turned too far. An o-ring in he collet groove works well or a piece of tape wrapped around the stem after the oil has been cleaned off. if the valve does drop into the cylinder then the cylinder head will most likely need to be removed to retrieve it.

Once it is set up, turn the engine back and fourth over tdc and watch the dial gauge. set it somewhere close to the highest reading on the gauge. Lift the gauge pin a little to make sure it is not at the end of it's travel. Most dial gauges travel about 1/2" or 10mm and it will be extending as the piston moves away from tdc. Set the gauge so that it can move out at least 5/16" or 8mm from where it is at tdc.

Turn the crankshaft backwards until the dial gauge is at or near the end of its travel.

Carefully turn the crankshaft forward towards tdc until the dial gauge reads about 1/4" (6mm) from the tdc reading. At this point, note the readings on dial gauge and on the protractor.

Carefully turn the crankshaft forward and past tdc until the dial gauge reads the same value as it did before tdc. Note the protractor reading.

True tdc will be the halfway point between both readings.

Check 2 or 3 times and make sure you get the same reading each time. Always turn the engine back past the start point and take both readings when turning in the same direction. When you have an accurate tdc angle, set the crankshaft at that point and permanently mark it for future reference with a hacksaw blade or center punch mark on the crank pulley or flywheel and a corresponding mark on the engine block or timing cover.

Once you have tdc then refer to the engine service manual for the injector timing angle and set the crankshaft to that angle on the protractor from the tdc angle. Mark this position as well.

Spill timing the injector pump is the most accurate method but if the injector pump has timing marks that can be trusted then you should be able to align the pum to these and that will be all that is needed to get the engine running reasonably well. If there is any doubt in the marks or there are none then the pump will need to be spill timed.

Most good engine service manuals or injector pump service manuals should have instructions for spill timing and the method may differ between different types of pumps. It involves removing the injector pipe for No 1 cylinder and fitting a short pipe with the injector end open and angled so it will drip. An old injector pipe with the end cut at 45 deg and bent so that the end points slightly downwards works well. Place a container under the pipe to catch the fuel.

Most injector pumps will have a delivery valve in the fitting that the injector pipe fits to. This is used to keep pressure in the injector pipe when the engine is running so that as soon as the pump starts delivering, the injector starts delivery immediately. This valve needs to be removed to do the test. Remove the pipe fitting and remove the valve and spring and refit the pipe fitting.

Inline pumps have a plunger that moves up and down in a barrel in the side of the barrel, is a port that is uncovered when the plunger is at the bottom of it travel. The lift pump is used to provide enough pressure to fill the barrel above the plunger. When the delivery valve is removed, fuel will flow freely from the pipe.

When spill timing, the pump is moved until the fuel is just dripping out of the pipe at about 1 drip every 5 - 10 seconds. When the pump is just before the injection point, fuel will run freely from the pipe and when it is after the injection point there will be no fuel running out of the pipe. The correct position is just as the plunger covers the port in the barrel and this is the point that delivery to the injector is started. Depending on the lift pump, it may need to be operated continuously to keep the fuel flowing. If the delivery valve cannot be removed then this will definitely be the case or an electric pump will need to be used.

With the crankshaft at the injection angle, loosen the pump mounting bolts until the pump housing can just be rotated. If it is too loose then it will be difficult to get the position accurately. It is better to have the pump firm and tap it to move it a little at a time.

Rotate the pump housing in the direction that the pump shaft rotates until fuel is flowing out of the pipe. Rotate the pump back the other way a little at a time until the flow turns into drips and there is 1 drip every 5 - 10 seconds. At this point, tighten the pump mounting bolts. If the rate of the drips changes then the pump has moved as the bolts are tightened. You will need to make very small adjustments and tighten each time until the drip rate is correct when the pump is tight.

As a final check, turn the crankshaft backwards a few degrees until the fuel is flowing from the pipe and then turn it forward until the fule is dripping at the correct rate. At this point, the crankshaft timing marks set before or the protractor pointer should line up with the correct angle for injection. Again, check 2 or 3 times.

If possible, mark the pump shaft in relation to the pump body. This way, if the pump ever needs to be removed, it can be refitted reasonably accurately.

Remove the spill pipe, refit the delivery valve and spring, tightening the valve housing to the correct torque listed in the service manual. Refit the injectors and pipes, again, referring to the service manual for torque settings and if the valve spring was removed, refit this and refit the pushrods or rockers, which ever was removed to access the valves. Check the valve clearances if necessary.

Roger.
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Old 05-04-2013, 03:12   #44
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Re: Perkins 4.108 compression

Thank you very much for your input, Roger.
We had the pump adjusted whilst the head was off.
The motor is running well but still smoking badly for about 30 seconds.
I will get used to the smoke.

Thanks again,
Walter
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Old 05-04-2013, 08:03   #45
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Re: Perkins 4.108 compression

Perkins have a depression in the back of the crankshaft pulley and one of the timing cover nuts is a lock that when unscrews into that depression, holding the engine at TDC. Of course, it's up to you to figure which TDC but with the valve cover off you can see that the two #4 rockers are going up & down at the same time and that tells you that you're at #1 TDC
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