Newly Rebuilt Perkins 4-108 Break in Procedure

[lifeofreilly57]

Greetings
My newly rebuilt Perkins 4108 is back in the boat and we're ready to head south to warmer waters. Event though I rebuilt it myself and it has run quite well since start up I couldn't find any good info on the break in procedure n the perkins manual.
I've built and broken in many motors over the years, both gas and diesel this is the first Perkins I've built.
any suggestions on properly running it through the break in period?
Vary speed? Run at fixed speeds? Vary loads? Limits loads?
How many hours before changing the break in oil? Etc, etc.
all suggestions are appreciated.

[Lepke]

Maintenance page from a 1978 manual. Too big to post the whole manual. The continuous rating is 3000 and I'd stay under that for a few hours and make sure the oil psi and coolant temp is steady. When you change the filter I'd open it up and see what it's been catching.

[coopec43]

I'd go along with Lepke's advice.


Here is an articles which explains the procedure quite simply.


https://www.boosttown.com/engine/running_in_engine.php


Clive

[Wotname]

Have a look at posts #33 and 36 by a64pilot in this thread for his viewpoint on breaking in.
http://www.cruisersforum.com/forums/...-205252-3.html

IMO, it is good advice.

[a64pilot]

Link doesn’t work for me, and I don’t know what I wrote, but in new motors I like to first pre-lube the engine meaning spin it over with starter without compression until oil pressure is well established, then crank it.
I run one long enough at high idle for it to completely warm up, maybe shifting into fwd and reverse to add a little load and ensure xmsn works.
The shut down and dump oil immediately, and cut open and inspect oil filter, there should be little to no metal. Vast majority of wear in the breaking in process occurs almost immediately, the rest of the time your polishing so to speak, so I want the wear metal out fast, and inspect the filter to get a good feeling nothing bad is going on.
No need for expensive synthetic oils during break in, a decent straight grade oil is fine, or 15W-40 is OK too, but use a good premium filter.
Then run her pretty much normally for the next 100 hours or so, varying load and RPM, going to higher RPM as the time accumulates, and after 50 hours or so don’t be afraid to run her hard, don’t baby the engine now, that’s actually bad in the break in process, but after broken in, then you can baby her.

[Rick Williams]

I just had my Yanmar 4JH4E 4 cylinder, 54 hp diesel rebuilt by the Yanmar mechanic in our yard and while I thought the engine had to be babied, on our seatrial on the new engine he asked me to get us in gear and run the RPMs up to max for a few minutes. I thought this was cruel but he assured me that the only unusual thing I needed to do was change the oil and filter at 50 hours which we did.
So far except for burning a little more oil than normal (explained in the article that was attached as the rings aren't properly seated yet) the engine seems happy so I am as well.
When I called Yanmar to ask about the duty level of the 20 year old 8 hp single cylinder raw water cooled Yanmar 1GM diesel I had in my previous Bayfield 25, they told me those engines were made to run at 3200 RPM all day long. I was shocked but they confirmed it.
I never did that but that's what they told me and if I can believe that the fishing boats I've been on are any indication, it's probably true.
Possibly the worst thing you can do is idle them for too long, run them without a load or run them slowly for too long. They like to work hard.

[a64pilot]

Most modern compression rings have an angle cut on the inside of them, this angle uses cylinder compression to “Blow” the rings open, this is why there is an up on rings and why you ensure you don’t put them on upside down.
Anyway higher power of course comes from increased cylinder pressures and RPM, this higher pressure forces the rings against the cylinder wall and makes them wear in or seat as it’s called.
Modern tolerances are so good now that a new motor usually seats the rings very fast, so you never notice any oil consumption.
Anyway if rings don’t seat in the run in period, it’s likely they never will, this leads to excess oil consumption, excess blow-by that overheats the oil, and soots it up quicker, and slightly lower power.
The aircraft piston engines I have overhauled, after a couple of ground runs to ensure everything is good and an oil change, I take off at max power and climb at max continuous power to 10,000 ft and hold it at full throttle while up there, of course that higher altitude reduces power so it’s the same as backing off the throttle.

I’ve seen more than one engine broken in gently and babied, that the only way to stop the oil consumption was to disassemble and re-hone the cylinders and start over.
https://www.hastingspistonrings.com/...g-installation

[lifeofreilly57]

Thanks for the information.
I've built and modified many engines over the years, hot rod engines, performance motorcycle engines and diesels in my previous boats, this was the first 4-108 I've rebuilt, I found it to be a fairly basic but reliable, stout piece, which is why I decided to keep and rebuild it rather than replace it with a more modern but also more delicate piece.
So far she's running just fine, I'm just about up to the break in oil change and will sample the oil and filter,
So far, so good, the engine runs smooth, the temps are consistent, and the oil pressure at between 50 - 60 psi at 2800 rpm, starting out at 60 psi
and dropping to 55 psi after an all day run. Nothing to complain about so far.
Thanks guys.

[Wotname]

^^ thanks for the update - good to see it is working out as planned!

[rbk]

Specific to the 4108, you MUST re-tourque the head bolts (in sequence of course) after 15-30hours.

[phorvati]

I had rebuild a westerbeake 4-108 myself and had a break-in period. Firing that baby up for the first time was a very nice feeling. Besides following the manuals etc, one thing i would say is that these blocks are notorious leakers. I hope u used good gasket sealer when assembling major parts. What i noticed is that all those bolts ended up needing a bit more tightening after some time of the initial use. Unless you dont might oil in the tray or bilge, I suggest you get used to reaching out to those bolts that hold oil pan and block together, especially back at the flywheel housing. Timing gear cover was also always in need to tightening its bolts. Once I got used to getting to them, I found that leaks went away if i kept up with tightening procedure.