Perkins 4-108 50HP Fix or Replace

[johnar]

Hello All,

I am at a point i have to deside if i should repower or repair the engine (1979 Perkins 4-108 50HP) I see on here that the price has a very wide range. There must be something i am missing because the cost $10,000 or above is very high to me. I have looked online and found a number of replacement engines ranging $2,000 to $4,000 rebuilt.

In my case i have never worked on a Diesal but have rebuilt a Chev years ago. Myself i wish it was a simple 350 Chev in there.

ok back to the subject, i have a mechanic coming to go over the engine and give me a price to what i would call freshen the motor. What i am unsure of is at what point (cost) should i just repower? I plan to take some classes soon on Diesal.

John

[Alan Wheeler]

If you are in the US, I find it hard to believe it would cost you $10K. Consider the 4.108 as half the Chev. It is actually a very simple to work on engine. Rebuild and actual cost is also a little like the chev.
The actual cost however, is the same length as a piece of blue string. It depends on what is actually wrong in the first place. Worse case is the block and head have to be removed and sent away for machining. This then means you will need new over size pistons. Then maybe you need a new Crank and new Cam. This is worst case remember, slightly better maybe a simple grind and oversize bearings used. The injector Pump and Injectors will need work as well and they need to go to a specialist.
Then you have the add ons, like Heat exchanger and exhaust manifold and so on. So it kinda depends in the end.
For repowering, that is a length of red string. The rule of thumb is double what the engine cost you. It does depend on the engine you are replacing with. You will have engine mounts and bearer work to do. You may gave to repitch or buy a new prop. Shaft coulings, exhaust outlet being different and the list goes on.

[johnar]

Thank you so much for your post i fully agree

John

[lannen]

My Perkins 4-108 was finally beyond repair.

I replaced it with a Yanmar 4JH. I get giddy every time I get to start the Yanmar. What a sweeeeet engine.

Expensive, yes. $9,800 USD, and yep, about another 10 grand by the time all was said and done. Since the engine was coming out, so was the transmission, and what the heck, can't use that old shaft, or prop, or cutlass bearing...

I'm happy with my decision and wish I would have re-powered sooner. I wasted money trying to fix an engine where rigor had set in.

All situations are different, this was how I did it.

[Boracay]

If your engine is 1979 and in poor condition then everything else is probably going to be 1979 and in poor condition.

Oil pump, water pump, hoses, heat exchanger, injectors, gearbox, instruments, cables, wiring, starter... The list goes on.

In my case misleading surveyor and mechanics reports had me $3k into repairs before it became clear that it was just not practicable to fix the engine.

Fixing old engines is expensive. If you are planning to keep the boat only a short time or are not going to be using it much then it may be practicable. You could possibly do much of the work yourself if you have the time.

If you need to get some serious use out of the engine then consider a repower.

[easterly]

My boat was repowered in the 1990s with a Perkins. Perkins are great engines, they use them in Bobcats. If you have a Perkins and replace it with a rebuilt Perkins the cost is much less than repowering with some other make of engine. You won't need a transmission plate or different transmission, coupling, shaft, mounts or any other associated hardware.
How many hours on your current Perkins 4.108?

[Chief Engineer]

Call Sherrie at TAD for perkins engines, perkins diesel, perkins marine, perkins parts, perkins generators, perkins service don't know where you are but they may have a rebuit one in stock

[johnar]

Thank you for your post,

I am unsure of the hours no meter, i agree anumber of other things need replaced also, At this point i dont know alot on the motor when i got the boat last month i ran it 15 minutes it had a oil leak but ran. its on the hard so i didnt want to run it that long. My thinking was if it ran at all i could dump around $4,000 into it and be ok.

I got the boat at a price i can still put another $20,000 into a refit but i would like to get it moved to Jacksonville from Sarasota before the major work is done.

I plan to make it back to the boat late this week, at that time i am setting up a meeting with a mechanic to get a bid on the work, i also have to deal with the Nav. Lights while im there.

John

[Sea Maid]

I had a bad perkins 4-108. So I called Sherrie at TAD (Trans Atlantic Diesel). Sherrie was wonderful and they were great to work with. I payed $4,200 for a total rebuild with a warranty. But I asked for new fuel injectors and had them install my new rebuilt fuel injection pump. Otherwise it would have been $3,800 for a total rebuild. I put on a all new hoses, heat exchanger, exhaust elbow, wires, had the starter rebuilt and various other parts replaced. Anyway I have basically all new stuff and I am at $6,300. Best of all it was very easy to do and took very little time, pulled out the old and put in the new. I went this route because me and the previous owner took out the transmission and he payed to have it completely rebuilt, along with a new shaft, cutlass bearing and prop and I did not want to change out perfectly good glassed in motor mounts. I highly recommed TAD. They

[johnar]

wow Mike to me that is a nice price, sound like what i will do myself I know one thing for sure i want a motor i can depend on before i take off in Feb. Yes i will contact them thenk you so much for the info.

John

[Sea Maid]

John, Keep in mind that I gave them my old and they gave me a new with nothing on it, except what I asked for and that was my fuel system. Wanted it all tested, timed with my fuel injection pump that I sent them. Everything else I put on myself. They payed for shipping to them and I payed for shipping back to me. At the time, that was a year ago, it was $340 to have it shipped by ground. Told the shipper it weighed 340lb and that covered it. For me the cost of shipping was WELL worth my time of not having to run around with an engine, probally would have had to make a few trips to the mechanic, you know how it goes. I felt the $340 more than payed for itself. I had my starter rebuilt, fuel injection rebuilt ($860), new heat exchanger, new exhaust elbow, all new hoses and wire, new oil hoses. Also I kept every old cooling system, hose clamp, fuel lines anything I felt I may need in an emergency. And I cleaned and inspected everthing and repainted what needed repainted. I know %&(@ happens, but I really love the peace of mind I now have.

[Davwu]

After looking at replacement costs, I pulled my 1986 4.108M engine on 40.5 Beneteau with unknown hours and brought it home for a rebuild. It smoked, shook, vibrated and leaked oil everywhere, but did start every time.

I had not done an engine in many many years (ok, high school on an old Volvo B-18) Turned out great. Did not need a lower end rebuild after pulling pistons and inspecting. Did valves, all rubbbers (heat exchanger parts from ASAP supply in UK for $25 each US delivered in 3 days), injector rebuilds, injector pump and pipes, fuel lift pump, full gasket and seal set, water pump, mounts, torque plate, and hoses. Lots of good info in the Service Manual and on the Web.

It was a great decision. No smoke, no oil leaks, no vibrations, more power (have to add more pitch to the MaxProp), great fuel economy took about a month of nights and weekends and I have about $2300 into it. Suggest going to genuine Perkins distr. for parts - only genuine PERKINS. They were a lot cheaper overall for the valves, springs, injector pipes.

Good luck!

[capttman]

Oh my word the workhorse should be rebuilt... they just don't make em like they did...