Perkins 4108 - oil leak!

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neil1967

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Our recently acquired Oyster 406 is fitted with a Perkins 4108. We took her out for the first time in our ownership today (very exciting!). During our short shake-down trip I noticed that the raw water pump was dripping water; however after the trip I discovered that there was a fair amount of oil in the engine bilge. Given that there was also water from the raw water pump, it was difficult to judge how much oil had leaked out - perhaps 100-200ml? There is no obvious leaks, but given that the bilge slopes, it is evident that the leak comes somewhere from the front of the engine (ie the other end from the propshaft/gearbox). I am aware that Perkins are considered to be a bit like older land rovers - you start worrying about them when they stop dripping oil - but I felt the amount of oil was excessive. Are there any obvious areas I should be looking at, or is this normal? The boat has been ashore for nearly 2 years so could it be a case of shrunken seals and if so, are they likely to expand again with use?

Thanks

Neil
 
Rocker gasket? Cheap easy fix.

Water pump seal and gasket set, good chance to replace the impeller too. Worth just doing that first, so find the oil leak.

Perhaps the timing case gasket? Not the end of the world, nor is the water pump gasket (Change the whole pump if it's off...)

Finally, the front crank seal? Are you sure it's not overfilled? It's easy to do on a 4108, as the level seems to be too low or too high, tricky to get bang on!! :confused:
 
Mine leaks oil. I've made a drip tray to go underneath it, and have started to clean the bilges (which obviously the previous owner hadn't done. Ever. Not surprising, as I've already decided that he's an idiot who should never have been allowed to have a boat!).
A little bit of oil on top of the water goes a very long way, and being diesel black it looks worse than it really is.
I think mine leaks from 2 or 3 different places - definitely the front and rear crank seals. The front is easy to deal with as it is accessible (at least on mine it is), so I may do that in the near future. The rear one is obviously an 'engine out' job, so it's going to have to wait. In the meantime, some Bilgex, absorbent socks and a few trips to the local tip are my answer.
 
Mines dry as a bone :eek:

Doesn't use oil either :eek::eek:

Great little engine. Mind you, had a £4000 rebuild at Brooms around 9 years ago :eek::eek::eek:
 
No Regrets said:
Great little engine. Mind you, had a £4000 rebuild at Brooms around 9 years ago :eek::eek::eek:
Click to expand...

I think that deserves more :eek:'s !!

I must say that I am rather impressed with mine, even though it needs a bit of work to bring it up to scratch (dodgy wiring bodges, a bad diy alternator mounting setup, some badly bent injector pipes etc). Plenty of power and sounds rather impressive too.
 
Check the timing chain cover, mine corroded under the thermostat housing, a steady drip of salty water over thirty years and I had engine oil in the bilge, it took a bit of finding as it was hidden under the thermostat housing.

Good news is that replacement covers are available from Diperk in Peterborough, not cheap (around £200 if my memory is correct).

No reason for it to leak oil, once I'd replaced t/c cover mine was fine.
 
I think the Perkins 4.108 fitted to Oyster 406 were the same basic engines as the '87 Land Rovers! I enjoyed 9 lovely years cruising mine. It eventually started dripping oil from both front and back crankshaft seals; very little out of the front, rather more out of the back. Also from the rocker case, but that was easily fixed.

The back seal leakage shows as drips from a small drain hole in the gear box adapter bell housing. We eventually replaced both seals. It was two days work in situ for a mechanic familiar with Perkins engines.

However, when we bought the boat, it was obvious that poor engine access made annual maintenance (tappet adjustment and injector removal) very difficult. So I took a chain saw to the galley to make the whole galley side and top removable for servicing. Never regretted that move. Whole port side an top of the engine easy access, and engine removal without chainsaw now possible.
 
Jim

Do you happen to remember how long it took to do the front seal - from the workshop manual it doesn't look too bad a job, even in situ. The rear seal on the other hand looks a real pain!

Neil
 
Front was only about an hour in itself, but preparing to do the work (removing fan belts, pulley wheels etc) and re-assembling took up a whole morning.

The aft end was a pig. Had to be done out of the water. Prop shaft pulled aft (left the ceramic sea seal open), Halyard UJ disconnected and lifted out, gear box bell housing disconnected (engine mounts had to be loosened to get access), bell housing and gearbox lifted clear, then get to work. The seal itself similar to the front job.

Easier if you don't have a UJ and a sea seal stern gland, but then you have fiddly engine alignment issues, vibration when the engine is running, and a dripping gland!
 
Pete735 said:
Good news is that replacement covers are available from Diperk in Peterborough, not cheap (around £200 if my memory is correct).
Click to expand...

200 beer tokens for a bit of bent tin!?

jimbaerselman said:
I think the Perkins 4.108 fitted to Oyster 406 were the same basic engines as the '87 Land Rovers!
Click to expand...

Definitely not the same engine; similar propensity for oil leaks though.
 
neil1967 said:
I noticed that the raw water pump was dripping water
Click to expand...

If you're going to replace the seals in it, make sure you've got a decent gasket between it and the engine body. My last one apparently did not, and after 2 seasons the shaft on the pump (the slotted bit on the end, more accurately) failed due to fatigue leaving us in a 'slightly' inconvenient location with no engine about 4 weeks ago.

According to my mechanic friend, you should be able to feel some backlash when you manually try to move the impeller end of it once re-installed. If you can't, that's probably bad news. Good thing we had Uncle Ben's rice boxes on board, and all used to watch Blue Peter.

Great practice for sailing back for 2 days with no engine to get spares. Also great practice for anchoring in the dark in an unfamiliar place with 35+ knots of wind!

Apologies if this is teaching your granny etc...
 
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The raw water pump alignment problem is not the gasket - it's the position of the adapter ring between the pump and the timing cover.
That's why the pump instructions tell you the dimensions of the alignment tool, and warn about shaft damage if suitable care is not taken.
I get round the problem by tightening the securing studs while the engine is being cranked - that way the pump self-centres.
The addition of the pump fixing is probably why they think they can charge so much for the 'tin cover'.
If mine leaks, I'll glass it.
 
Reading the manual, it appears that you can remove the pump from the timing chain cover and the timing chain cover from the engine without having to remove the adaptor plate, and in those circumstances the alignment tool is not required - it is only needed if you remove the adaptor plate. Is this correct? And under what circumstances would you want/need to remove the adaptor plate?

Thanks

Neil
 
Billjratt said:
The raw water pump alignment problem is not the gasket - it's the position of the adapter ring between the pump and the timing cover.
That's why the pump instructions tell you the dimensions of the alignment tool, and warn about shaft damage if suitable care is not taken.
I get round the problem by tightening the securing studs while the engine is being cranked - that way the pump self-centres.
The addition of the pump fixing is probably why they think they can charge so much for the 'tin cover'.
If mine leaks, I'll glass it.
Click to expand...

Ah - that throws a whole new light on it! And there was me thinking I was being clever too... I don't suppose you've got the pump instructions handy? It would be useful either to know what they say. Either that, or could you please elaborate on the tightening-while-cranking procedure? Many thanks. Apologies for thread hijack.
 
My pump had been spraying water everywhere for years under the 'care' of it's last owner, so there was rust and tight components.
The pump flange bolts were inaccessible as they were a bit behind the body of the pump, so I took off the adapter flange and pump as one assembly. The studs came out, so I just greound off the protruding bits and created 'bolts'.
When I rebuilt the pump and bought a spare, it came with the instructions as they had a lot of returns with broken shafts.
The tool can be made with a bit of pipe and some tape to get an idea of alignment (and paint some guide marks if required) but you should still be cautious and turn the engine over while allowing the pump and flange(bolted together tightly) to centre
You can feel the pump chattering on the shaft until it is aligned.
I have been trying to copy/paste the drawing, but can't do it here, I'll see if it can be PM'd. The drawing is on page M4 of the 4108 manual I downloaded for free, you may also have it already.
 
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