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-   -   Perkins 4-108 oil leaks solved (https://www.cruisersforum.com/forums/f54/perkins-4-108-oil-leaks-solved-188370.html)

sv.antea 27-07-2017 11:40

Perkins 4-108 oil leaks solved
 
My friend's Perkins 4-108 always leaked oil. Two years ago he took it to a yard, they pulled the engine and replaced all the gaskets and seals. It started leaking badly again in few months. I have installed a nice fiberglass pan under the engine, so the oil doesn't end up in the bilge. Oh my hubris. I pulled the engine again, replaced all the seals and gaskets. Looked beautiful. Started leaking all over the front few months later. I don't give up. Pulled it again.

Aside. I put myself through college fixing MG at the local British Leyland dealership. I have rebuilt few Perkinses over the years since I switched to sailing and sailboats and always noticed how superficially similar the design of the 4-108 was to an MGB motor. The relevant similarity is that the front motor mounts are attached to the front plate. When I disassembled the 4-108 this time, it finally struck me. The front plate on the MGB went on the front of the block over two big locating pins. The Perkolator has no such pins. It weighs twice as much and (some owner refer to them as "rock crunchers"): add shock loads and vibration. What really drove the concept in was noticing the Perkins engine block had provision for hefty motor mounts brackets, forward and aft, unused in the marine version. I bet the famous London cabs use THOSE to mount the engine. Not the front plate.

Before you install the timing cover, the front plate is held to the block by five or six measly 5/16" bolts. A bunch of 1/4" and 5/16" bolts go through with the installation of the timing cover, but the torque specs and common sense prevents you from honking down on those. The timing cover is easily distorted and leaks would be all but guaranteed. The gasket set you get these days is all of one material and it is foam of some kind. So, as the engine bounces around and shakes, the block starts twisting behind the front plate coming to stops on the threads of those measly five bolts.

The proper answer would be to install sturdy locating pins. A machine shop could probably do that. You would need to find suitable location as not to compromise the block.
As I didn't have the time or money for the machine shop, I came up with different solution. First I made a hard paper gaskets instead of the foam one in the gasket set to go between the block and the front plate and one for the timing cover. I used hard setting Permatex on the block to plate gasket. Tightened the aforementioned 5 or 6 measly bolts, but temporarily added all the timing cover bolts as well without the timing cover and tightened everything lightly and evenly and in a fanciful sequence, so the gasket got compressed evenly. Let it set overnight.

Before installing the timing gear and cover, I tightened the 5 bolts properly.
Now the hard part. Out of some high tensile Al alloy plate, I cut and drilled a frame in the shape of the timing cover gasket, but narrower. I used 1/4" plate and made it in two pieces because I didn't have enough material for the complete circuit. Thicker and one piece would be better. I used it instead of the good-for-nothing original oval washers when installing the timing cover.

Anyone confident enough to install the timing gear and set the backlash probably knows the timing cover is made to float a little and has to be positioned just so, so the front crank shaft seal is concentric with the shaft. There was a special tool for that operation for the MGB, A ring, temporarily installed instead of the oil seal, before the bolts of the timing cover were tightened. Now to be sure, after centering the timing cover by feel and tightening few of the bolts lightly, I drilled and tapped two #10-24 locating screws through the timing cover into the front plate.

With the proper paper gasket and the stiff aluminum frame instead of the handful of oval flat washers, the timing cover can be tightened down (with longer bolts of course) as much as the bolts and threads can handle, providing the extra needed support for the plate to block joint. To say nothing of the now leakproof timing cover gasket.

sv.antea 27-07-2017 12:11

Re: Perkins 4-108 oil leaks solved
 
Let me try to ad photos. Ooops, windows 10 doesn't let you resize photos.

sv.antea 27-07-2017 12:32

Re: Perkins 4-108 oil leaks solved
 
2 Attachment(s)
photos, one of bedding down the front plate, the other: after the timing cover went on

zeehag 27-07-2017 13:07

Re: Perkins 4-108 oil leaks solved
 
perkins are brit engines. brit engines always leak. leaks make em run. pretend it is a diesel mg B. hahahahaha
even brand newly rebuilt will leak. buy oil absorbant engine diapers and place one under engine. run engine.
breathe and live life. engine will leak oil.
if it stops leaking, it will blow up.,

sv.antea 27-07-2017 13:31

Re: Perkins 4-108 oil leaks solved
 
ZeeHag, you are completely right. But I can't help myself, I got the engineering bug and a Zen and the Art of Sailboat Maintenance complications. I occasionally manage to sail somewhere, too.

zeehag 27-07-2017 13:34

Re: Perkins 4-108 oil leaks solved
 
i keep the dideez under engine while sailing. is only time my gorgeous perkins needs em. ha ha ha

are you new at the fine art of oil containment???
helped that i had vws and other drippy cars so i know how to cruise with a spare set of all fuel and oil line bits and oil absorbant dideez.
ha ha ha ha

model 10 27-07-2017 14:14

Re: Perkins 4-108 oil leaks solved
 
I don't think what you did is necessary. I see what you are saying but I think you need to up grade your gasket sealant to something more modern. The real problem area is behind the mount plate with the front pan gasket.

jamhass 27-07-2017 17:09

Re: Perkins 4-108 oil leaks solved
 
Quote:

Originally Posted by sv.antea (Post 2442892)
What really drove the concept in was noticing the Perkins engine block had provision for hefty motor mounts brackets, forward and aft, unused in the marine version. I bet the famous London cabs use THOSE to mount the engine. Not the front plate.

Might it have been easier to engineer mounts using the "hefty" locations?

My MGA forward mounts do use 2 bolts directly to the block, along with 2 on the front plate, but most of the load is directed to the block. Any chance that the Perkins has a similar provision?

coloradohi1 28-07-2017 08:49

Re: Perkins 4-108 oil leaks solved
 
I always thought Perkins were externally lubricated!

SVTwilight 28-07-2017 08:57

Re: Perkins 4-108 oil leaks solved
 
Quote:

Originally Posted by coloradohi1 (Post 2443478)
I always thought Perkins were externally lubricated!


Hilarious!

DennisRyan 28-07-2017 09:25

Re: Perkins 4-108 oil leaks solved
 
Yeah, but they run and run and run. Due to the low compression, that engine is just about bulletproof, IMHO. I loved that 4-108 on my Irwin 52.

model 10 28-07-2017 09:44

Re: Perkins 4-108 oil leaks solved
 
Quote:

Originally Posted by DennisRyan (Post 2443515)
Yeah, but they run and run and run. Due to the low compression, that engine is just about bulletproof, IMHO. I loved that 4-108 on my Irwin 52.

I think the Perkins has a high comprssion ratio, like 22:1 Some other engines have ratios down around 18:1.

Qayaq 28-07-2017 12:47

Re: Perkins 4-108 oil leaks solved
 
Hiya. That should kill the leak. Nice one. You got the tool to centre the raw water pump drive flange so the drive doesn't snap.

model 10 28-07-2017 14:57

Re: Perkins 4-108 oil leaks solved
 
Quote:

Originally Posted by Qayaq (Post 2443657)
. You got the tool to centre the raw water pump drive flange so the drive doesn't snap.

Just about nobody does because it isn't needed. That kind of drive is pretty much self aligning.

Qayaq 28-07-2017 15:12

Re: Perkins 4-108 oil leaks solved
 
Quote:

Originally Posted by Guy (Post 2443711)
Just about nobody does because it isn't needed. That kind of drive is pretty much self aligning.

Really. You got a 4108. After re fitting my timing cover and not aligning the raw water pump flange, the ear snapped off the impeller shaft and dropped into the drive gears. Fortunately the gears survived but it did stick a hole in the timing cover.Which is when I found out about the need to align. So in my mind I would say to not bother aligning is somewhat fool hardy. Nobody needs that T shirt, I certainly didn't.

model 10 28-07-2017 15:25

Re: Perkins 4-108 oil leaks solved
 
Maybe everybody shouldn't try to re-assemble an engine. There are basic things you need to do and making sure the water pump slides into place is one of them. You didn't.

Deltasailor 28-07-2017 15:49

Re: Perkins 4-108 oil leaks solved
 
Quote:

Originally Posted by Qayaq (Post 2443721)
Really. You got a 4108. After re fitting my timing cover and not aligning the raw water pump flange, the ear snapped off the impeller shaft and dropped into the drive gears. Fortunately the gears survived but it did stick a hole in the timing cover.Which is when I found out about the need to align. So in my mind I would say to not bother aligning is somewhat fool hardy. Nobody needs that T shirt, I certainly didn't.

I bought a " re coned" 4108 in 1988 to install in my Endurance 37 that I was building on a shoe string. I drove from Liverpool to Peterborough to meet a man who told me it was a factory test engine. He said it was "factory re conditioned" (possibly with a can of spay paint) I knew "knowt", It looked OK so I took it back to Liverpool and installed it. We sailed "Mr Orion" to Greece in 40 days (Biblical?) and started a charter business, That boat ran for 10 years with little or no problems. I had no issues, it was a very dirty engine, you could tar the road with the oil after a few weeks, but it ran and ran. We took her back to the UK through the French canals with no problems. A great tough engine proud to be British.

Qayaq 28-07-2017 15:49

Re: Perkins 4-108 oil leaks solved
 
Quote:

Originally Posted by Guy (Post 2443729)
Maybe everybody shouldn't try to re-assemble an engine. There are basic things you need to do and making sure the water pump slides into place is one of them. You didn't.

Ho ho. Your funny. Those drives do damage if they are not set up correctly, which is why there is an alignment tool, though it is easy to make your own. Check the 4108 manual. I've been an apprenticeship served marine engineer for over 25 years so I was quite surprised when I damaged my own engine. And yes I did turn the engine over before final tightening of the flange bolts. Ho hum

Maka 28-07-2017 17:26

Re: Perkins 4-108 oil leaks solved
 
If my 4-108 stops leaking oil, I know I'm outa oil.

If I implemented this complicated fix... how would I ever know when the engine was out of oil?

Kekaimalu 28-07-2017 18:02

Re: Perkins 4-108 oil leaks solved
 
We have a Perkins 4-236 about 20 + years in our yacht. Compression ratio is 16:1. It cannot compare in noise & vibration to more modern engines such as the new Volvo Marine Diesels (which are about 23:1) but so far it has proved extremely reliable. We normally run it at 1000rpm for 5kn up to 1400rpm for 6.5kn and so far it has never let us down. After reading the posts about oil leaks on the 4-108 I thought I'd add that we haven't experienced any oil leak problems with this Perkins model.

Capt Gill 30-07-2017 00:30

Re: Perkins 4-108 oil leaks solved
 
Quote:

Originally Posted by sv.antea (Post 2442892)
My friend's Perkins 4-108 always leaked oil. Two years ago he took it to a yard, they pulled the engine and replaced all the gaskets and seals. It started leaking badly again in few months. I have installed a nice fiberglass pan under the engine, so the oil doesn't end up in the bilge. Oh my hubris. I pulled the engine again, replaced all the seals and gaskets. Looked beautiful. Started leaking all over the front few months later. I don't give up. Pulled it again.

Aside. I put myself through college fixing MG at the local British Leyland dealership. I have rebuilt few Perkinses over the years since I switched to sailing and sailboats and always noticed how superficially similar the design of the 4-108 was to an MGB motor. The relevant similarity is that the front motor mounts are attached to the front plate. When I disassembled the 4-108 this time, it finally struck me. The front plate on the MGB went on the front of the block over two big locating pins. The Perkolator has no such pins. It weighs twice as much and (some owner refer to them as "rock crunchers"): add shock loads and vibration. What really drove the concept in was noticing the Perkins engine block had provision for hefty motor mounts brackets, forward and aft, unused in the marine version. I bet the famous London cabs use THOSE to mount the engine. Not the front plate.

Before you install the timing cover, the front plate is held to the block by five or six measly 5/16" bolts. A bunch of 1/4" and 5/16" bolts go through with the installation of the timing cover, but the torque specs and common sense prevents you from honking down on those. The timing cover is easily distorted and leaks would be all but guaranteed. The gasket set you get these days is all of one material and it is foam of some kind. So, as the engine bounces around and shakes, the block starts twisting behind the front plate coming to stops on the threads of those measly five bolts.

The proper answer would be to install sturdy locating pins. A machine shop could probably do that. You would need to find suitable location as not to compromise the block.
As I didn't have the time or money for the machine shop, I came up with different solution. First I made a hard paper gaskets instead of the foam one in the gasket set to go between the block and the front plate and one for the timing cover. I used hard setting Permatex on the block to plate gasket. Tightened the aforementioned 5 or 6 measly bolts, but temporarily added all the timing cover bolts as well without the timing cover and tightened everything lightly and evenly and in a fanciful sequence, so the gasket got compressed evenly. Let it set overnight.

Before installing the timing gear and cover, I tightened the 5 bolts properly.
Now the hard part. Out of some high tensile Al alloy plate, I cut and drilled a frame in the shape of the timing cover gasket, but narrower. I used 1/4" plate and made it in two pieces because I didn't have enough material for the complete circuit. Thicker and one piece would be better. I used it instead of the good-for-nothing original oval washers when installing the timing cover.

Anyone confident enough to install the timing gear and set the backlash probably knows the timing cover is made to float a little and has to be positioned just so, so the front crank shaft seal is concentric with the shaft. There was a special tool for that operation for the MGB, A ring, temporarily installed instead of the oil seal, before the bolts of the timing cover were tightened. Now to be sure, after centering the timing cover by feel and tightening few of the bolts lightly, I drilled and tapped two #10-24 locating screws through the timing cover into the front plate.

With the proper paper gasket and the stiff aluminum frame instead of the handful of oval flat washers, the timing cover can be tightened down (with longer bolts of course) as much as the bolts and threads can handle, providing the extra needed support for the plate to block joint. To say nothing of the now leakproof timing cover gasket.

Well done, I suspect you've also reread and edited making your's an easy read, too often not done here leading to much head scratching.
My 4-108 has similar,but minor issues. Understand that these are Gremlins of the British sort and they DO NOT go away they simply move to another place. Having much experience with British vehicles of all sorts I've learned it's better to live with them than fight them. In this case,as long as it's manageable, I will do as zeehag does, keep a supply of nappies & drip pan, this way I know where the Gremlin is and not have to be concerned about it relocating and causing havoc, usually at the most inconvenient time. A reasonable accommodation I believe.

cottonsail 30-07-2017 12:24

Re: Perkins 4-108 oil leaks solved
 
Why don't the British build computers? Because they can not figure out how to make them leak oil.

UNCIVILIZED 30-07-2017 13:38

Re: Perkins 4-108 oil leaks solved
 
So then the same people that built fighter planes out of wood, & came up with a positive ground wire system for cars, that nobody on the planet understands, also build boat engines? No wonder they leak oil. ;)

Regarding gasket material, are we referring to using Admiralty nav charts type paper? And might there be a better location on the engine to attach engine mounts to? Ones not directly connected to any sealing plates on the engine.

Capt Gill 30-07-2017 17:31

Re: Perkins 4-108 oil leaks solved
 
[QUOTE=UNCIVILIZED;2445026]So then the same people that built fighter planes out of wood, & came up with a positive ground wire system for cars, that nobody on the planet understands, also build boat engines? No wonder they leak oil. ;)

Kinda begs the question, why would anyone buy such things ? Beauty, a sense of uniqueness and finally seduction. Critical thinking takes a back seat; this is how it was for me and I don't believe I was alone in that regard, it's similar to romantic love. Take a E type Jag ,which I had for awhile, first it catches your eye, get closer enter the cockpit, the aroma of the leather is first to disarm your critical thinking then the bucket seats they fit you as a fine kidskin glove fits your hand, then gently laying your hand on the s/wheel inlaid w/fine wood one notices the highly polished walnut dashboard sporting a multitude of Lucas (AKA The Prince of Darkness) gauges; you feel as if you're in another realm, a contemporary Camelot ,you not only want it you need it :smitten:and if not totally seduced by now peering through the windshield there's this v. long front hood that must surely house a powerful engine, so you get out, lift the bonnet which exposes all, since it's the entire front enclosure, but v. light. The engine is brilliant, all but the block is highly polished aluminum including the three carbs.
Oops, sorry got caught up in the reverie of a past love affair, in any case it's how infatuation can trump logic. :peace:

model 10 30-07-2017 19:01

Re: Perkins 4-108 oil leaks solved
 
[QUOTE=UNCIVILIZED;2445026]So then the same people that built fighter planes out of wood.


They were not fighter planes, they were bombers. They had 2, a big bomber and the Mosquito. Just about biggest plane we ever built was wood. Wood is just about the strongest composit there is. The oil leak is not the mounting plate, it's the timing gear cover.

sv.antea 30-07-2017 19:23

Re: Perkins 4-108 oil leaks solved
 
You are right, Jamhass, it's been a while since the MGs, I remember now one bolt per side went to the block, two to the front plate. Perkins 4-108, three 5/16" bolts through the plate only. So on top of everything, thrust tries to bend the plate.
Quayaq, did not have any problems with misalignment of the raw water pump before, strangely enough just discovered that problem on my Universal M25. One time however when I had to fit a new timing cover, as the old rusted through, the new part was so poorly made that the front seal could not be aligned because the crank timing gear would touch the cover and keep it from moving any higher. Had to take a torch and a ball peen hammer to it to make room for the teeth. Your problem may have been due to poorly made timing cover, too.

sv.antea 30-07-2017 19:33

Re: Perkins 4-108 oil leaks solved
 
Uncivilised. There are the four bolt bases machined and threaded I mentioned, and some kind of weldment could be designed to fit these, but lot of other stuff would probably have to be shifted around. They probably opted for the plate because it is further forward for better mount load distribution.

Mistress Sirena 01-08-2017 20:09

Re: Perkins 4-108 oil leaks solved
 
well my solution to most of the oil leaks was to simply tighten all the nuts and bolts back down starting at the oil pan on up to the valve cover. just snugged them "all" up surprised how slack they all were.

TKDSailor 24-11-2019 13:55

Re: Perkins 4-108 oil leaks solved
 
Quote:

Originally Posted by zeehag (Post 2442976)
perkins are brit engines. brit engines always leak. leaks make em run. pretend it is a diesel mg B. hahahahaha
even brand newly rebuilt will leak. buy oil absorbant engine diapers and place one under engine. run engine.
breathe and live life. engine will leak oil.
if it stops leaking, it will blow up.,

Sorry, Zeehag, but not true!! I've had a Perkins 4-108 in our Roberts Spray 38 "Ark" since 1995, and it NEVER leaked a drop, having motor/sailed the ICW 3 times (along with other sailing), until 2017. It was a PERFECT engine (except I had problems bleeding it...). Then, in 2017, on our 4th trip up the ICW, she developed a leak. 1 quart every 8 hours. The pan caught it, and (much to the admiral's dismay) I would suck it out with a turkey baster, and put it back in the engine. Turned out, Perkins, in their infinite wisdom, made a plastic cover for the mechanical tachometer hole, which I did not use. The plastic cracked, and, after putting on a cap from a medicine bottle and hose clamp, it stopped leaking. Unfortunately, now it started leaking from elsewhere, but only 1/4 quart per 8 hours motoring... I have plenty of diapers now for this senior engine, and it's still awesome!!
(1993- last year they were made)!

Capt Gill 25-11-2019 01:36

Re: Perkins 4-108 oil leaks solved
 
Quote:

Originally Posted by TKDSailor (Post 3022627)
Sorry, Zeehag, but not true!! I've had a Perkins 4-108 in our Roberts Spray 38 "Ark" since 1995, and it NEVER leaked a drop, having motor/sailed the ICW 3 times (along with other sailing), until 2017. It was a PERFECT engine (except I had problems bleeding it...). Then, in 2017, on our 4th trip up the ICW, she developed a leak. 1 quart every 8 hours. The pan caught it, and (much to the admiral's dismay) I would suck it out with a turkey baster, and put it back in the engine. Turned out, Perkins, in their infinite wisdom, made a plastic cover for the mechanical tachometer hole, which I did not use. The plastic cracked, and, after putting on a cap from a medicine bottle and hose clamp, it stopped leaking. Unfortunately, now it started leaking from elsewhere, but only 1/4 quart per 8 hours motoring... I have plenty of diapers now for this senior engine, and it's still awesome!!
(1993- last year they were made)!

I agree with Z, maybe not all Perkins leak, however, when 99%(anecdotally) of those Brit engines leak to say "all" is ok. Maybe you had one of the exceptions for awhile! I've had many Brit cars and one m/cycle, a Norton, in my time and can't recall a one that didn't leak oil; I used to have an auto shop and one of the quips we'd make re. Brit engines is, "if it's not leaking it's probably out of oil", one even tends to supernaturalize to explain the issue as I have with my Perkins 4-108, this can also apply to you, it's the Gremlin theory, i.e. the Gremlin(s) is/are embedded in the boat, one can't get rid of it w/o destroying the boat so you learn to live with it and appease it, e.g. in our case, the Gremlin is residing in the Perkins, so ya fix the leak, however the Gremlin relocates and the engine leaks elsewhere (remember, can't get rid of the Gremlin it only relocates). In my case, I've resigned to accept this as fact, so we get along ok as long as I appease the Gremlin, although the engine still leaks it's v. little and manageable; you may ask, "how does one appease the Gremlin?" well, this works for me: the Gremlin is at its best behaviour when given a clean, tidy environment and proper maintenance. Of course, since perfection is not possible, the Gremlin will let its presence be known, e.g. the same oil leak that wasn't fixed properly the first time or something else that has been neglected. The Gremlin also has times when it's evil, vindictive or just out of sorts and will cause problems that have nothing to do with you, in that case, it's best to take a deep breath then go about what needs to be done to remedy the issue, try to refrain from getting angry, yelling at your mate or kicking the dog as this will provoke the Gremlin, it sees this as a weakness so steps up the game, perhaps by sabotaging the work such as allowing a unique piece of hardware to slip from your hand into the hinterland of the bilge,but the trick is to maintain a calm attitude take a break if need be, that will keep the Gremlin at bay as you're no longer any fun. If this all sounds a bit anthropomorphic so be it, however, I think most of us can recall a time when we struck, banged on or spewed epitaphs at the object of our frustration, if so you're being Anthropomorphic.
Seems like you've come to terms with your "awesome" Perkins as I have, so much so that I'm going to give it a first name, any ideas? Maybe Anthony?

TKDSailor 25-11-2019 06:51

Re: Perkins 4-108 oil leaks solved
 
Quote:

Originally Posted by Capt Gill (Post 3022948)
I agree with Z, maybe not all Perkins leak, however, when 99%(anecdotally) of those Brit engines leak to say "all" is ok. Maybe you had one of the exceptions for awhile! I've had many Brit cars and one m/cycle, a Norton, in my time and can't recall a one that didn't leak oil; I used to have an auto shop and one of the quips we'd make re. Brit engines is, "if it's not leaking it's probably out of oil", one even tends to supernaturalize to explain the issue as I have with my Perkins 4-108, this can also apply to you, it's the Gremlin theory, i.e. the Gremlin(s) is/are embedded in the boat, one can't get rid of it w/o destroying the boat so you learn to live with it and appease it, e.g. in our case, the Gremlin is residing in the Perkins, so ya fix the leak, however the Gremlin relocates and the engine leaks elsewhere (remember, can't get rid of the Gremlin it only relocates). In my case, I've resigned to accept this as fact, so we get along ok as long as I appease the Gremlin, although the engine still leaks it's v. little and manageable; you may ask, "how does one appease the Gremlin?" well, this works for me: the Gremlin is at its best behaviour when given a clean, tidy environment and proper maintenance. Of course, since perfection is not possible, the Gremlin will let its presence be known, e.g. the same oil leak that wasn't fixed properly the first time or something else that has been neglected. The Gremlin also has times when it's evil, vindictive or just out of sorts and will cause problems that have nothing to do with you, in that case, it's best to take a deep breath then go about what needs to be done to remedy the issue, try to refrain from getting angry, yelling at your mate or kicking the dog as this will provoke the Gremlin, it sees this as a weakness so steps up the game, perhaps by sabotaging the work such as allowing a unique piece of hardware to slip from your hand into the hinterland of the bilge,but the trick is to maintain a calm attitude take a break if need be, that will keep the Gremlin at bay as you're no longer any fun. If this all sounds a bit anthropomorphic so be it, however, I think most of us can recall a time when we struck, banged on or spewed epitaphs at the object of our frustration, if so you're being Anthropomorphic.
Seems like you've come to terms with your "awesome" Perkins as I have, so much so that I'm going to give it a first name, any ideas? Maybe Anthony?

LOL! Good luck with Anthony! We've followed similar paths; my first bike was a Norton Atlas, with that wonderful Featherbed frame... I used to use it as a scrambler off road, as it handled so well. Unfortunately, as the pistons both went up and down at the same time, it vibrated so bad that things would fall off it as I went down the road... I went to school and became a motorcycle mechanic, fixing rice burners and brits (yeah- 3 sets of tools- Whitworth, Metric and English...). Our 1974 MGB did leak, but the saying was,"Lucas igintion, home before dark..." And, living on the island of Gloucester, MA, it eventually rusted so bad that the Unibody sagged in the middle...

I'm definitely going to try re-bedding the timing cover, to see if that helps... I have really beat up that engine, overheating her a few times, putting gas in the diesel tank (not my fault), etc. and she still runs beautifully. I think I'll name mine Sheila...

Capt Gill 25-11-2019 14:49

Re: Perkins 4-108 oil leaks solved
 
Quote:

Originally Posted by TKDSailor (Post 3023036)
LOL! Good luck with Anthony! We've followed similar paths; my first bike was a Norton Atlas, with that wonderful Featherbed frame... I used to use it as a scrambler off road, as it handled so well. Unfortunately, as the pistons both went up and down at the same time, it vibrated so bad that things would fall off it as I went down the road... I went to school and became a motorcycle mechanic, fixing rice burners and brits (yeah- 3 sets of tools- Whitworth, Metric and English...). Our 1974 MGB did leak, but the saying was, "Lucas ignition, home before dark..." And, living on the island of Gloucester, MA, it eventually rusted so bad that the Unibody sagged in the middle...

I'm definitely going to try re-bedding the timing cover, to see if that helps... I have really beat up that engine, overheating her a few times, putting gas in the diesel tank (not my fault), etc. and she still runs beautifully. I think I'll name mine Sheila...

Sheila, I like that <https://youtu.be/5xb1z2V1z7k>, think I'll go with Tony because of the dark role TP played in the film Psycho.
The Commando somewhat cured the vibration problem with the Isolastic anti-vibration system developed by a former Rolls-Royce engineer, all the same, I blame that bike with its 10:1 compression and occasional cranky refusal to kickstart for the onset of my sciatica. My next bike was an "84 BMW R100 (which I still have)- push the button, starts every time. All the same, I did love the thrill of the Commando's torque when opening the throttle! The 850 introduced an elect. "assist" starter, assist meaning don't count on it. Yeah, Lucas AKA "The Prince of Darkness".
A novel approach to solving Perkins oil leaking, assuming the obvious leak issues are resolved, is a kit that works somewhat like a cars gas engine's PVC system, except the vacuum hose is connected to the crankcase, not the v/cover i.e. if the crankcase has positive pressure (checking at the dipstick tube) at cruising RPM then by installing this system it will create a neutral or negative pressure and ,in theory, prevent oil from being forced out through seals and gaskets. West Marine used to sell the kit. My friend has it on his Perkins and says it solved the oil leaks.

SSgtPitt 25-11-2019 18:55

Re: Perkins 4-108 oil leaks solved
 
The more I read this the better I feel. My 4108 leaks like all the rest. The diapers help but the leaky stuffing box eventually fills the sump which then eventually overflows into the bilge which eventually means Im vacuuming, disposing of nasty oiley salt water and scrubbing everything w 409.....only to have to start all over again in a few weeks.....frustrating. The longer Im on the boat the better I get at figuring it out.

jfhspike 09-02-2020 14:03

Re: Perkins 4-108 oil leaks solved
 
Here's a tip if you're thinking (or someone else reading this later is thinking) about replacing the rear oil seal...(which is where almost ALL 4-107 and 4-108 engines leak). You might say to yourself "maybe I should get something that doesn't depend on a cotton-asbestos(?) thing wrapped around a stiff wire, which has to be trimmer to exactly the right length to make things work," and decide to go with Foley's fancy fix at a cost of about $120 (!) -- https://www.foleyengines.com/product/...rear-seal-kit/.

You could, instead, order a similar upgrade kit from parts4engines, namely
https://www.parts4engines.com/perkins...l-upgrade-kit/ for $32.

which you'll notice comes with the gasket for the seal-housing (which you're going to destroy when you try to remove the old seal anyhow), not to mention the tab-washer you'll need when you want to replace the flywheel.

While you're at it, you can buy a full bottom-gasket set (which you'll need if you go all-out and drop the pan in an attempt to fix further leaks): https://www.parts4engines.com/search....ection=product. That's $45.

Pick 2-day shipping for $24, and even with the VAT, your total is $101, and if you're as lucky as I was, the parts will be on your doorstep 1.5 days after you order them.

Compare this to the Westerbeke cost for just the pan gasket ($118 from Marine Diesel Direct, who aren't allowed to sell it to me because they're in the wrong "region"...sigh), and suddenly that price looks pretty darned good.

ronieboy91 10-02-2020 15:27

Re: Perkins 4-108 diesel or water in sump
 
Hi.
Iv got a big problem with either water or oil entering the oil pan in my Perkins 4108 engine. The oil is a milky sort of colour and very thick. I have been trying to sort the problem for about a week now and still can't resolve it. Iv got the oil cooler tested, it was sound and even put a new one in and it's still leaking in. Iv tested the lift pump, it was sound also. Iv bipassed the oil cooler just to double check it it's still mixing. I have a fairly experienced mechanic working on it and he is even puzzled. The fresh water in header tank level is not going down so I think this rules out the head gasket does it? I'm just wondering if anyone could give me any other suggestions as to what the problem might be?
Any help would be greatly appreciated.

jfhspike 10-02-2020 15:44

Re: Perkins 4-108 diesel or water in sump
 
Quote:

Originally Posted by ronieboy91 (Post 3072133)
Hi.
Iv got a big problem with either water or oil entering the oil pan in my Perkins 4108 engine. The oil is a milky sort of colour and very thick. I have been trying to sort the problem for about a week now and still can't resolve it. Iv got the oil cooler tested, it was sound and even put a new one in and it's still leaking in. Iv tested the lift pump, it was sound also. Iv bipassed the oil cooler just to double check it it's still mixing. I have a fairly experienced mechanic working on it and he is even puzzled. The fresh water in header tank level is not going down so I think this rules out the head gasket does it? I'm just wondering if anyone could give me any other suggestions as to what the problem might be?
Any help would be greatly appreciated.

Well...milky oil sure suggests water in it. There doesn't need to be a lot to turn it milky. There are two kinds of water around (assuming your boat's in the ocean): salt and fresh. Salt water comes into the raw-water pump, up through the oil-cooler, into the heat exchanger, and out the exhaust. I suppose that if the raw water pump seal is completely shot, you could be getting lots of salt water running from the back of the pump into the engine...but it should be coming out the "weep hole" in the bottom of the raw-water pump before then and be really obvious. You could check that the weep hole isn't somehow clogged --- take a drill-bit and run it up into the hole gently turning by hand to clear out any muck.

Salt water getting in at the oil cooler? You've eliminated that.

At the heat exchanger? There's only salt and coolant in there, no oil, so presumably that's not a problem.

AFTER the heat exchanger? I suppose that where it gets pissed into the exhaust loop might be somehow backed up or otherwise messed up so that you're getting salt water back into the exhaust, which then runs down the cylinder walls into the engine sump. But you'd expect that to be a problem that might cause a water-lock so that you couldn't turn over the engine, etc., so it seems unlikely.

So now I'm thinking "it's probably coolant." Maybe just a little, maybe a lot. But one quick check is to loosen the oil-drain plug and let just a few drops of stuff come out. Even if there's coolant emulsified in the oil, there'll probably be some sitting at the bottom of the sump, too, and it'll drip out first, because oil floats on water. So put a paper towel or 20 under the sump, ease out that screw until a few drops come out, and see what's there.
(example: see this video: https://www.youtube.com/watch?v=2tNYb0V5-U8) If what comes out looks greenish (assuming that's the color of your coolant!) you've got your answer.

It sure seems as if coolant is the more likely culprit, now that you've decided it's not the oil cooler.

Best of luck on this.

ronieboy91 10-02-2020 15:52

Re: Perkins 4-108 diesel or water in sump
 
Thanks very much.
Yes I thought about that but the engine is turning fine and is running very smoothly aswell so if there was water getting in up around the Pistons she wudnt turn as well ryt? And she wudnt be running so well. Ok if it's coolant then wudnt it be emptying the header tank? The level hasn't dropped at all and the sump is filling up at a very fast rate, like it goes from the min mark on dipstick to the top after running it for 20 mins?! It's an awful headache this.
Thanks again for your help.

ronieboy91 10-02-2020 15:54

Re: Perkins 4-108 diesel or water in sump
 
Sorry also I can't get to my sump plug because it's too tight to the bottom of the boat. Iv had to drain it with a vacuum pump and even crank it out through the filter cos the stuff that's coming out is too thick to suck out

MarkSF 10-02-2020 16:27

Re: Perkins 4-108 oil leaks solved
 
[QUOTE=Ecos;2445245]
Quote:

Originally Posted by UNCIVILIZED (Post 2445026)
So then the same people that built fighter planes out of wood.


They were not fighter planes, they were bombers. They had 2, a big bomber and the Mosquito. Just about biggest plane we ever built was wood. Wood is just about the strongest composit there is. The oil leak is not the mounting plate, it's the timing gear cover.

The salient point about wood there, is not about it's quality as a material for building planes out of.

The point was that, at the time, all the factories capable of making metal planes were running at full capacity. The Mosquito etc. could be made by workers that were experienced in working with wood - thus it was extra, bonus, manufacturing capacity.

rbk 10-02-2020 16:36

Re: Perkins 4-108 oil leaks solved
 
Most likely culprit to check is your raw water pump (front of the engine and either bronze and shinny or that large mass of green and white fuzz youre not really sure what it is). The double bearings end up leaking water back into your timing cover and mixing with your oil.


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