Perkins 4-108 Nightmare

[ssullivan]

Originally Posted by speedoo

My 4-108 has been terrific. Definitely worth a rebuild if it's really that much less expensive than a repower, IMHO.

I agree. I have 2005 Yanmars now. They look pretty, but they aren't built as well as that old Perkins I had last. Stupid things like:

*coolant hose to close to belts and was knicked
*coolant pump seal leaking a drip or two (on 2005 engines!!)
*must suck oil through dipstick tube

That coolant pump thing realy says a lot to me. If a 2005 engine can have seals go bad that quickly, with 400 hours on it, how well is the rest built? Ahhh... the era of selling cheap crap for lots of money.

[hellosailor]

Joe, I suspect there's a lot of FUD about synthetics partly because they are "different" and in some cases that makes a difference (old engines, bad seals, aviation use, etc.) but also because, let's face it, a lot of cheap auto oil change business gets done and those folks don't want you to stay away for a year at a time.

On the other hand, Mobil and everyone else in the synoil business put their terms and tech notes out to the world and usually give you the same written warranty that their regular oil carries: If there is any damage to your engine from their product, they'll warranty it and pay for it. They started that policy ages ago (1950s? 60s?) when Detroit car dealers said "If you use anyone else's oil, we won't warranty the engine" and eventually that went to court--and they no longer make that threat.

What you have is a "new old stock" diesel engine. While there may be some continuing questions about break-in time with conventional oil, after 80 hours that is also behind you. Using synoil in a newly broken-in diesel engine is fine, just get a diesel-rated oil. Yes, it is that simple. Check with Mobil, Shell, Penzoil, Chevron, etc. to find a product you like.

Yes, they really work. When Mobil1 was something brand new, terribly expensive, and unique on the market, I put it in my high-revving car after the first break-in change. Have had it for almost 100kmiles and the engine still has full compression and no oiling problem, no leaks, just hums like new.

Yes, Shell(?) had problems insome aviation uses in supercharged engines, but that relates to the special conditions aircraft engines encounter at altitude.

Yes, if you put synoil in an old tired engine, it may actually clean out the crud that is holding some cracks together where gaskets used to be, and they may leak, or burn more oil as itslides past loose pistons. And then again--I know a friend who had one of those old engines, he swore he picked up fuel mileage because it also lowered internal friction. Go figure.

The oils aren't cheap, but the are warrantied in writing, and you can always have oil testing done (about $22-25 per test) to REALLY see how your engine oil is doing, once or twice a year till you get a baseline.

[avazquez]

I have a 22,000 # vessel with a rebuilt 4108. It took a while for me to solve some smoke problems after the rebuild but it runs solid and have no complaints. In my case I would have tried to replace it with a more powerful Yanmar.

[Alan Wheeler]

I'm told I should avoid synthetic oils, does anyone know why?

HS has offered some good info. To add, often in older high hrs engines, the piston rings are being sealed by gunk build up. A good synth will clean the rings and the thing starts to burn oil. Not a fault of the synth as such. It's an age issue. Never use synth additives to mineral oils. I am sure there are a few good ones out there, but out of 9 major additive companies in the US, 9 currently have law suits against them.
One of the big issues to be very careful of is the weight when it has a wide ratio. Very common in synth oils to find ratings like 10w50 or the biggest I have seen is Penzoil with their 5w60. Bad news for older engines like Perkens and Fords. They will burn oil bad and you will get terrible oil pressure. These old low tolerance engines regiure a Mono grade 30w oil and that is hard to find in synths, so as smaller variance in the rating and as close to the 30w as possible.
In am coming up to a full year of running Amzoil in my Perkins 6.354 engine now and have noticed a lot quiter running engine. It has not lowered the normal smoking. I am about to do a test as to how much oil it has used though. I have just clocked 1020hrs and the oil went in at 800hrs. I will let you all know what results I find.

[CharlieCobra]

I use Rotella T in mine.

[Pelagic]

All the advice above is spot on and in hindsight, the big lesson is to ask more questions and get a worst case scenario before committing to getting work done.

You seem to be more in favour of a repower versus re-build.

Is it because you don’t trust the mechanic?

Will the mechanic warrant all of the work he does for you for 1 year (parts and labour?)

Will he give you a complete fixed price painted and installed/tested?

Is he open to any discounts?

Is he interested in supplying you a new Engine at discounted price, by taking in the old one as a trade-in…. so that he can rebuild for re-sale?

This last point will tell you a lot about the wisdom of rebuilding with this mechanic.

Good luck!

[Pelagic]

Sorry guys I only saw the first page before posting. will read the rest now

[marc2012]

Previous post correct boat next to me when on shipyard did same as you.Had to change intake lines prop exhaust.Has to red line under power or void warranty,better ck on that.

[David_Old_Jersey]

I have a Perkins 4107 from circa 1970 - no major work required since buying a couple of years ago.

But past experiances of my Father with long term ownership of an elderly 4107 it ate a bit of money drip by drip due to PO's not being as fastidious as they could / should have been and was replaced by a 4108 which never had a major problem during 10 years of ownership and 99% self maintanence.

I would be happier with a newer engine longterm - my first pick would be a brand spanking new 4108 due to my complete confidence in them and being a (fairly) staright swap, but alas not to be

My next preffered option is something Japanese using a Kubota block - but the big PITA with a whole new engine is the cost of installation. One of the local Marine Engineers has a very good reputation and works as a one man band - the only problem is getting hold of him!.....I ended up working in a firm with his Missus who also runs the paperwork side of the Marine Biz so has a very good understanding of the Biz - her estimate was that installation of a new engine type cost much the same as the engine itself if not more) once you add in all the bits and bobs it would be a good idea to replace when the engine is out / brand new......Jersey prices are kinda Steep, so experiances may vary.


Excellent E-bay link above on the re-furbished / re-manufactured Perkins (4108 and 4107).....makes me tempted to think about one.......but I still struggle with the fact that essentially I do still have an old engine......but of course wayyyyy cheaper on purchase and more importantly installations costs.........anyone had any experiances on a re-furb engine? or advice? - I am guessing yer need complete confidence in the firm to use more than a coat of paint........

Plan A is to stick with the current engine (albeit it does need a bloody good clean and some paint!).....but if nothing else would be nice to be able to compete with Father's boat engines. His 4108 looked like it came straight from the factory 10 years after installation and the twin Volvos he now has in his Mobo look better than new after a similar time frame.....

[powrpacks]

I have a friend with a newly rebuilt Perkins 4108 4 cylinder diesel engine, tagged reman by Detroit diesel. It does not have intake or exhaust manifolds, nor the starter or flywheel (bare crankshaft end). It does include new injectors and has complete fuel system with injection pump. Here are the other tagged numbers;
perkins 108 red70207 ser 04ed001519 code c104. He is asking $3500.00 for it, plus shipping. Send me an email if interested..
Thanks,
Kevin