Perkins 4107: Rebuild or Replace??

[atmartin]

Girlfriend and I are doing the Baja Ha-Ha and Bash this coming fall in our mariner 31. So we'll be bashing 800 miles to windward under motor.

Our 4107 hasn't managed to gain my trust yet and developed a knocking in the top end at idle. It requires a bit of throttle on start-up. I had the injectors rebuilt, to no avail. I jury-rigged a compression tester and got 390 on one cylinder and ~200 on the others. I questioned those numbers, but took the head off to discover that the gasket was blown and the head cracked, with a great deal of pitting in the #3 cylinder face and valves. Oil pressure is good (~50, I think), most of the peripherals are in fair shape, nothing amazing.

I'm looking at a minimum of maybe $2k to sort out the top end and some other minor issues (tranny leak, for example). $1500 of this is for a new head, I haven't been able to find a used one. There's some scoring, but re-doing the liners ($100/ea) and the whole bottom, aside from the labor (which I'll do) is certainly not cheap.

Block doesn't look cracked, but I haven't run it by a machinist. My other option is to repower, say with a beta 20-25HP. I hate to junk a classic motor (with only 1900 hours), but I don't want to sink money into an antique that seems a little difficult to find parts for.

I'm shocked the perkins ran as well as it did given it's condition, I'm not sure what caused the crack, temp or oil pressure has been solid all through my use. Although some raw water made it into the crankcase for a day after the water pump seal went.

Survey says? I was all set to rebuild until I discovered the cracked head and pitting, which really surprised me. Now I'm not too sure.

Some pics:

[SimonV]

Hunt around for a reconditioned 4.108 and bolt it in you should be able to do it for less than 7k US if you do it yourself, rebuild at less than 3k.

[Richard Jordan]

Replace.

[S/V_Surya]

Hello,
I am in the process of reassembling my 4107 after injection pump rebuild and head rebuild. My head had cracks in it also and to rebuild head cost me about $350. I do not know what constitutes a head that is not rebuild-able but 2k sounds high. Yeah parts are getting scarce but so far I have not had a problem. To repower will cost you $6k-$10K. It is difficult to decide whether to junk or go for it. It is a gamble for sure.

[zeehag]

you only have 1900 hours on a diesel???? is nothing.
if there is a knock topside--check the injectors and fuel lines. mine were a tad leaky after i installed mine-just found the reason for the slight lil air knock--is good and perfect now--dont be in such a hurry to dispo a perfectly good engine.
your sail south will be all down hill--isnt a difficult run. has a lot of rocky coastline--once away from coast is a lot breezier-- go there and use sails.
do your 2k repair and see if it works--mine was awesome even with airknock all the way to la cruz de huanacaxtle..... now is fixed.
there are engines and repairmen for 4-107 and 4-108 all over mexico. lots less pricey than 2k--can get entire rebuild here for that. just havve to know where to look.
if only 1900 hours, will last a lot longer-- fix and sail.

[atmartin]

Originally Posted by S/V_Surya

Hello,
I am in the process of reassembling my 4107 after injection pump rebuild and head rebuild. My head had cracks in it also and to rebuild head cost me about $350. I do not know what constitutes a head that is not rebuild-able but 2k sounds high. Yeah parts are getting scarce but so far I have not had a problem. To repower will cost you $6k-$10K. It is difficult to decide whether to junk or go for it. It is a gamble for sure.

Is repairing a cracked cast iron head a viable option? All my previous experience is on gas engines with aluminium heads. The opinions I've been gettin from machinists/machenics around has been that cracked head=game over.

In fact, the machinist who i had take a look said something along the lines of "this head is junk". Considering the pitting and crack, im inclined to agreed. His advice was to throw the head back on and "run it til it won't run anymore". Then i mentioned that we were headed to Mexico. "Well, I wouldn't do that".

My girlfriend is on a schedule and a major engine failure means her going home and me rebuilding and fighting my way north alone. Fun fun

[beneteau-500]

parts are plentiful for this engine go to Parts4Engines: Perkins Diesel Engine Overhaul Kits and Spares

[Tranquilo]

Replaced mine with another perkins from TAD. Could not be happier and with proper care, should have no issues for thousants of hours.

[Jesse]

The 4107 and 4108 engines have a well deserved good reputation. A rebuilt version of either one will bolt right up and serve you for years for a lot less $pondoolix than buying a new replacement and going through all the changes a different brand will require.

[casual]

Originally Posted by atmartin

Girlfriend and I are doing the Baja Ha-Ha and Bash this coming fall in our mariner 31. So we'll be bashing 800 miles to windward under motor.

Our 4107 hasn't managed to gain my trust yet and developed a knocking in the top end at idle. It requires a bit of throttle on start-up. I had the injectors rebuilt, to no avail. I jury-rigged a compression tester and got 390 on one cylinder and ~200 on the others. I questioned those numbers, but took the head off to discover that the gasket was blown and the head cracked, with a great deal of pitting in the #3 cylinder face and valves. Oil pressure is good (~50, I think), most of the peripherals are in fair shape, nothing amazing.

I'm looking at a minimum of maybe $2k to sort out the top end and some other minor issues (tranny leak, for example). $1500 of this is for a new head, I haven't been able to find a used one. There's some scoring, but re-doing the liners ($100/ea) and the whole bottom, aside from the labor (which I'll do) is certainly not cheap.

Block doesn't look cracked, but I haven't run it by a machinist. My other option is to repower, say with a beta 20-25HP. I hate to junk a classic motor (with only 1900 hours), but I don't want to sink money into an antique that seems a little difficult to find parts for.

I'm shocked the perkins ran as well as it did given it's condition, I'm not sure what caused the crack, temp or oil pressure has been solid all through my use. Although some raw water made it into the crankcase for a day after the water pump seal went.

Survey says? I was all set to rebuild until I discovered the cracked head and pitting, which really surprised me. Now I'm not too sure.

Some pics:

Check clasified's there is a 4 107 for sale

[capttman]

Rebuild

[martinjrichter]

You might want to look on Ebay, I saw a Perkins 4 108 rebuilt for 2150 plus core.

[atmartin]

Thanks for all the replies. We're really wrestling with this decision and are under a bit of a time crunch (other projects pending).

The westerbeke 4107 listed here seems to be in good condition, I'll look into it. Different accessory layout tho, but should fit. I have heard, in general, bad things about the westerbeke vs perkins. Is this reputation deserved?

Also, there is a 27hp yanmar listed. I'm getting the impression from many here that changing engine models is a poor idea. Clearly, the perkins has a good rep, but is it really that difficult to switch out motors? I understand that the prop will need to be changed from LH to RH (or is it the other way around?), exhaust size might need to be changed. etc.

I should mention that we can easily (and the girlfriend isn't fond of the current noise) accommodate a smaller motor. We're a 6 ton boat, 25' on the waterline, 9.5' beam (cutaway keel tho). I shock most people when I tell them we have a 4107 in such a small boat. Lol, even with all it's problems we easily make hull speed upwind in 15 knots, at sea, at 1700 RPM.

[SimonV]

The Perkins 4.107/8 and the westerbeke are identical in the early mods, depending on regions there were some changes in the bolt on bits. Later when Perkins sold their 4.108sin the US under the Perkins brand, Westerbeke not wanting to source the whole motor from Perkins out sourced the bolt on bits and this was where their reputation started to fail.

[roverhi]

I've just done a reinstall of a Yanmar 3GM30 in my boat. Engine was originally an Atomic 4. PO's install of the Yanmar was crap and engine could not be aligned. Pulling the engine, changing the mounts, restructuring the beds, etc. etc. took me and a competent boat mechanic most of a week to redo the installation.

Figure that re-engining with another diesel will take you and/or a mechanic at least that long to change over. Add the cost of a different engine and it makes rebuilding your 4-107 look very attractive. The Perkins is a reliable engine, though reported to be a bit of an oil leaker, that should give you more than a decade of reliable power once rebuilt.