Perkins diesel engine maintenance questions

[Water Dragon]

I'm quite accustomed to working on engines in cars, trucks, tractors, airplanes, and helicopters, but I'm pretty new to boat engines. I have a Perkins 4.108 that I'm fixing up, and there are a few seemingly simple things that I'm not clear on.

• There is a small plug on the bottom-front of the oil pan. The engine is tilted up at the front, so if I drain the oil that way there will still be a lot of oil remaining in the pan. How do I get this out?
• How do I drain the coolant? Ordinarily I would drain the radiator, but of course marine engines don't have those. Nor do I see any obvious drain plugs on the engine block.
• Are there zincs on the engine, in the raw water system? How does one differentiate a zinc from an ordinary bolt or plug?

[Captain Randy]

Well to answer your question on oil extraction I just did my 4108 yesterday. I got a 6.25 quart extractor from Westmarine (spring sale). It comes with al the tubes. You will use the smallest diameter and enter through the dip stick tube and suck it out. Worked great but did take about 45 mins but pretty much sucked it all out.

[RobTryon]

I have an old Perkins M-60. Bought a manual on amazon that covered everything from simple maintenance to complete rebuild. Now that old rusty unreliable piece of crap looks like this and runs as new, plus I did all the work myself except the machine work.

[BozSail]

Regarding zincs, there is a zinc in the heat exchanger at the end where the raw water enters. You may have to cut off the tip of the new zinc to allow it to screw in all the way. I had to cut off almost one inch off the zinc on mine. Still good, just not quite as long lasting. There may also be a smaller zinc at the other end of the heat exchanger, depending on your heat exchanger. If it's like mine, you don't have to shorten that one. Draining the antifreeze can be done by removing the hoses from the indirect cooling hoses on the heat exchanger. It's good to flush the system with fresh water before filling with new antifreeze mix.

[deblen]

http://www.fujiyachts.net/manuals/Pe...p%20Manual.pdf



https://www.youtube.com/results?sear...e+perkins+4108

[DougR]

There is a coolant drain plug on both sides of the block, one inboard of the starter motor and the other to the rear of the lift pump. These will typically have a hex head plug in them or might have a small petcock. Then you will normally find a drain plug on the bottom of the heat exchanger, and there might be a drain plug on the combination oil/gearbox oil cooler.

If the 4-108 engine is sitting level in the boat, the oil pan will be deepest at the front and slope upward toward the flywheel. So even if the engine is mounted with the flywheel end lower than the front, the bottom of the oil pan may be fairly level. This will allow almost all of the oil to drain out the front drain plug during an oil change.

BozSail is spot on regarding zincs.

DougR

[rbk]

Just to clarify, there may or may not be zincs in the heat exchanger depending on which hx you have. Some of the Bowman’s do not have or require zincs. Seems wrong but you could end up searching for something that’s not there.

[michaelratinter]

Originally Posted by Captain Randy

Well to answer your question on oil extraction I just did my 4108 yesterday. I got a 6.25 quart extractor from Westmarine (spring sale). It comes with al the tubes. You will use the smallest diameter and enter through the dip stick tube and suck it out. Worked great but did take about 45 mins but pretty much sucked it all out.

I find that extractors work better if the engine is warm.

[FionaJC]

I replaced (well my marine engineer did at my cost) my Peugeot XD2 with a Perkins 4107 which is almost identical to the 4108. There are a variety of setups for these engines, with loads of different solutions depending on the purpose of the original engine.

Everyone above is right. I have a Bowman without a Zinc anode, I drain warm, not hot, oil out the dipstick hole which I swapped over sides, using a Pela oil extractor, its easy and no mess. I have a tap for draining coolant on the side of the engine which had to be replaced.

The manuals are easy to obtain as are spares, apparently if you rebuild a Perkins its only good for another 1,000,000 hours to the next rebuild. Frequent oil and filter changes are the key.

[KadeyKrogen38]

I was under the impression that most 4-108 were equipped with an oil sump pump just below fuel secondary filter. At least mine is so fitted.

[Maka]

The Perkins 4-108 has a water pump like an automotive water pump. When it goes bad it drips 1st. Unlike your car dripping on your driveway where you can see the puddle,,,the 4-108 drips into your bilge and is easy to go undetected.
This was the cause of my overheating last summer.
Good news is the Perkins survived the overheating with no negative consequences.

[Mikado]

Originally Posted by Water Dragon

I'm quite accustomed to working on engines in cars, trucks, tractors, airplanes, and helicopters, but I'm pretty new to boat engines. I have a Perkins 4.108 that I'm fixing up, and there are a few seemingly simple things that I'm not clear on.

• There is a small plug on the bottom-front of the oil pan. The engine is tilted up at the front, so if I drain the oil that way there will still be a lot of oil remaining in the pan. How do I get this out?
• How do I drain the coolant? Ordinarily I would drain the radiator, but of course marine engines don't have those. Nor do I see any obvious drain plugs on the engine block.
• Are there zincs on the engine, in the raw water system? How does one differentiate a zinc from an ordinary bolt or plug?

My boat came with a Perkins 4.108 that ran the generator. I no longer have the eng/gen but I'm pretty sure I have all the original manuals.

Send me a PM and I'll be happy to send them to you if I can track them down.

Jeff

[Maka]

Originally Posted by Mikado

My boat came with a Perkins 4.108 that ran the generator. I no longer have the eng/gen but I'm pretty sure I have all the original manuals.

Send me a PM and I'll be happy to send them to you if I can track them down.

Jeff

Jeff

I sent you a PM regarding the manuals

Fair Winds
Maka

[LLCoolDave]

Second dibs for the manuals!

[Argyle38]

I drain the oil from that front plug. I'm sure there is a little bit of old oil left in the pan, but I don't worry about it, the percentage of old oil in the new oil after re-filling is going to be pretty small in any case.

Coolant/Zincs question. It seems that whether or not you will have zincs depends on what kind of header tank you have. Remember, being a 4-108 defines the block, and in most cases, the cylinder head. How the rest of the assembly is put together depends on who made it a marine engine, and when it was done.

I have a Bowman manifold on mine and it doesn't have any zincs at all. Others seem to have zincs, so it will depend on what you have. The Bowman manifold has a drain on the aft end on the side away from the block. This will drain the header tank/manifold, but will leave some coolant in the block. To drain this there are plugs, or sometimes a drain, at the aft end of the block, on either side I believe.