Which Engine Would You Use ?

[sww914]

I just bought a boat with a Perkins 4-107 that had water enter the cylinders about 3 years ago and the PO let it sit like that. It appears to be rebuildable. I've removed the head and all the pistons and cylinders are junk but the bottom end is OK, no water down there. The engine has 400 hours since the last rebuild. I can repair this engine for about $1000.00 in parts and machine work. I am a mechanic.
My other choice is a Yanmar 3JH5E with about 20 hours on it for 5K.
Most things leading to & from the existing engine need to be replaced either way, so there isn't a huge difference in price or time between the repower and the rebuild as far as exhaust, fuel lines, gauges, etc.
The thing is, I don't have the 5K. I have about 2-3K.
If I go with the Yanmar I'll need to work to earn that other money and work is slow right now. If I go with the Perkins rebuild I can get the boat going 2-3 months sooner.
What would you do?

[zeehag]

changin gfrom perkins to yanmar was estimated to me to be 20-25000 dollars--yipes-(incl engine)-they said they had to change the stringers, motor mounts, lots of things.
as for the perkins, find a replacement for really cheap and use many parts for spares. you will need them. most of the parts are even usable in the 4-108.
i just repowered with a 4-108 from 4-107. i looked at yanmar first---wanted it, but was prohibitive , price-wise. i go the perkins 4-108 for 2500 and installed for 3 loaves of fresh bread. cant beat that.

[SkiprJohn]

4-107 and 4-108 are good engines. If you will spend a lot of time and cash reconfiguring to replace the Perkins with a Yanmar I'd say it wouldn't be worth it.
regards,

[fishwife]

Rebuild the Perkins, looked after it will still be doing fine when you sell the boat, even if that's in 20 years time

P,

[sww914]

The Yanmar is looking better. I got the parts quote today for the Perkins. I was expecting $700.00 - $800.00, it's $1900.00. I might be able to trim it down here & there but maybe not enough.
Boats are fun.

[markpierce]

Originally Posted by sww914

Boats are fun.

Keep smiling.

[MichaelC]

Figure up the hours you have worked to earn that rebuild money, then figure the hours you must work to buy the new parts. Put it all together. How many days could you have been sailing if you did without the engine altogether? That is your true cost.

[Chief Engineer]

Get a parts quote from www.tadiesels.com ask for Sherry Moon

[never monday]

I'd do the repower just because the parts are newer

[goboatingnow]

Figure up the hours you have worked to earn that rebuild money, then figure the hours you must work to buy the new parts. Put it all together. How many days could you have been sailing if you did without the engine altogether? That is your true cost

This "opportunity coat" stuff is often trotted out. By its based on the assumption that a) you have no time thats your own, (b) your self employed and (c) you can get paid work for all the hours that you want.

Otherwise its an apples and oranges comparison. In essence your time off from work is free labour.

[sabray]

Ive seen some Yanmars installed using cradles off the existing beds. You could slice the pie differently.But I would think with periferial gear and other labor your looking at 20k plus for a repower.I replaced a 4-154 with a Cummins from TAD. Cash out I think it was in the 12k but Im ruffing that I think I posted a real number once. Of course there were also all the while Im here things. Like the sole of the cockpit the fuel tank exhaust parts hose clamps yaddahdahh it goes on. My engine was blowing oil and lots of these parts needed the upgrade. The turning point for me was all the work I had to do anyway. The engine was coming out the sole was spent the wiring sucked etc... I had a rebuild cost of maybe $2500 guess and I put a new engine in for 6000 more. for all of that work the 6k looked like a good choice. Im happy you need to weigh those other components. I did the work myself so I got off work and spent a cold winter putting it all together but ohh what fun.

[barnakiel]

All other things equal, I would always pick a Perkins.

Rebuilding can be a success if your Perkins mechanic is the man. A failure in all other cases.

b.

[Ex-Calif]

Originally Posted by sww914

I just bought a boat with a Perkins 4-107 that had water enter the cylinders about 3 years ago and the PO let it sit like that. It appears to be rebuildable. I've removed the head and all the pistons and cylinders are junk but the bottom end is OK, no water down there.

I don't know the Perkins block. Are the cylinders sleeved? Or are you saying that even with the water damage the cylinders can be oversized?

In my opinion this is about the machine work. The good news is it's all free until you have to decide. Get it apart and evaluate the block, crank and head.

Get the head zyglowed for cracks and then measured. Evaluate the valve seats etc.

get the block measured to make sure it's true and straight or can be made so. Evaluate the cooling jacket and whether the cylinders can be oversized.

Get the crank maganfluxed and measured.

At this point you have your labor and maybe a couple of hundred in machine shop costs.

If anything is an issue, go with the Yanmar. Otherwise keep what you got.

Even with the higher than predicted parts bill you are still coming up a couple of thousand cheaper. Don't forget the externals - engine panel, engine controls, wiring, etc, etc, etc that go with the repower.

[Steve Pope]

If you are considering a new replacement Beta marinise Kubota engines that are around the best you can get, at reasonable prices too. I believe they have a 4107 / 4108 replacement, take out / drop in.

[beneteau-500]

ssw19 i don't know where you got your prices for your parts for but i have recently totally rebuilt my perkins 4.236 engine from top to bottom i fitted new main bearings piston's and piston liner's and completely stripped down cylinder head and replaced all parts , the total amout for the parts which i got from a parts guy in the uk came to £530 or about $837 us dollars