Restoring Perkins 4.108 after years of disuse

[stormalong]

Originally Posted by Finalee

All in $3500. That included $1200 machine shop and a $500 donor engine .
I supplied the labor. It got new pistons,bearings,crank,rebuilt injection pump, oil pump, cam, and pumps.

Thanks, do you have an estimate of how much time it took?

[Finalee]

Originally Posted by stormalong

Thanks, do you have an estimate of how much time it took?

I work slow. Probably 100 hours over 2 months.

[stormalong]

Originally Posted by Finalee

I work slow. Probably 100 hours over 2 months.

Thanks again. I work slow too. I take my time and make sure everything is right.

So, assuming a pro mechanic would do the job in 40 hrs and charges at least $100 per hour, the price would have been about $4000 for the labor.

[Finalee]

That's if you could find someone. I was figuring 150 per hour.

[doog]

Originally Posted by ttex

Doesn't sound like my engine. I have a 4108 as well. Yours has a lot more higher pitched rattling sounds. If that makes sense. Mine is a deeper more consistent sound.

Edit: If everyone elses sounds like this and mine is the weird one maybe mine is broken, lol.

HA< HA>>Yes, I agree. Thanks for lending your ear.
Very high-pitched ringing and almost a scraping, clattery sound like a bad alternator bearing but I cant locate the source by placing a rod against the motor or working around it, and it goes away at very low speeds. (although it does seem to be in the top end and from the rear) Ive even recorded the engine with my phone in slow motion mode to try to break down the noise to figure out what it may be. It really sounds more like gear noise than an engine knock, so I checked the idler gear to be sure its tight and other than the cam and the fuel pump thats all there is on this engine, to my knowledge.
And I also ran the engine without my exhaust silencer or the vetus waterlock and it sounded totally different and had the lower, more engine-like sound and far less clattery. It occurred to me it could be a back-pressure issue because the exhaust is fairly long and has a high goose-neck to prevent siphoning.

Just getting an oil analysis lined up to see if that offers any clues.

[Rumrace]

I’d hate to be accused of being able to fix by sound but tinkle tinkle says valve lash, lifter wear, weak old springs,leaking guides, rocker arm wear, cam bearing, gear wear..
All upper end stuff.

[doog]

Originally Posted by Rumrace

I’d hate to be accused of being able to fix by sound but tinkle tinkle says valve lash, lifter wear, weak old springs,leaking guides, rocker arm wear, cam bearing, gear wear..
All upper end stuff.

Thanks Rumrace, and Im running an oil analysis and yes that tinkly top-end clatter suggests to me the sound of a motor with a potato stuffed in the tailpipe, you know? And on installing after pulling the trans to change the damper plate, I hit the starter with my wrench (oops) and started the engine accidentally without the exhaust connected and it sounded totally different. Fortunately got to the fuel control and stopped it but with my long, wet exhaust and water lock and gooseneck I wonder about backpressure which is now much more with a freshly rebuilt water pump and all new impeller and cleaned out heat exchanger. These engines sound so different with a dry exhaust.
Thanks again everyone for the input and personal details! You cant pay people for this but for free, the best information can be had through mutuality, for want of a better word.

[doog]

Anyway no, regarding the potato in the tailpipe idea. I just ran with the exhaust system disconnected and sounds the same. Tinny/clattery, no difference due to back pressure/wet exhaust. Next, the oil analysis results.

[doog]

Originally Posted by W32Glorious

Looks and sounds just like mine and mine is over 40 years old. Just keep the fuel clean and change the oil and trans. Fluid regularly.

Can anyone tell me where to get some Perkins Marine Blue paint, so I can freshen up my engine? It is hard to find.

Foley has it, 47.00 per can. Just looking into their Perkins upgrades which might also repair my worn valve train. https://www.foleyengines.com/brands/...nes-and-parts/

Im convinced on continuing to work on it that its got critical wear in something due to its oil starvation history or perhaps in injection issues which can also make crazy sounds like this, I find in certain cases. Now as I am running to test a new alternator its increasingly clattery at all RPM.https://www.youtube.com/shorts/_DakweU4eXE

[stormalong]

Originally Posted by doog

Foley has it, 47.00 per can. Just looking into their Perkins upgrades which might also repair my worn valve train. https://www.foleyengines.com/brands/...nes-and-parts/

Im convinced on continuing to work on it that its got critical wear in something due to its oil starvation history or perhaps in injection issues which can also make crazy sounds like this, I find in certain cases. Now as I am running to test a new alternator its increasingly clattery at all RPM.https://www.youtube.com/shorts/_DakweU4eXE

Tread carefully when dealing with Foley. I have read many posts on many discussion boards detailing a history of him ripping people off. I have not been one of his victims but I have spoken with him on the phone and his attitude said to me STAY AWAY. Ask Skip Gundlatch about him before buying anything from him.

PS. This is my OPINION, libel lawyers stay away.

[doog]

Thanks for the tip, (I see Im not the first to cross paths with Foley!) and I like some of his ideas but this outfit seems like the $47 can of paint, ridiculously overpriced, like so much in boating. But I think an honest, hardworking Perkins upgrade would be a great idea with hydraulic lifters and improved, variable injection timing and a balanced engine

I find I can get an alternator belt upgrade to grooved for a hundred bucks elsewhere and Im learning my engine rattle is likely the rocker assy having excessive wear and easily repaired. And recently going to lighter weight oil on advice of the manual is likely the reason its noisier now, so with a rebuild of the rocker assy. and good multi-vis oil Im hopeful the clatter-bang can be reversed.

[doog]

So on inspecting the rocker assy, yes its worn but no way it could be responsible for this noise which is more like gear lash. Ive heard this in reduction gear aircraft and sounds just the same. not rhythmic but just a gnashing sound...

[doog]

Getting to the bottom of this! Running with the clatter louder now, still runs beautifully but sounds like a can of rocks rattling.

https://www.youtube.com/shorts/_DakweU4eXE

But really doesnt sound like rod knock and compression is excellent. No broken rings or cracked pistons nor does it use oil.
I removed the injectors which all look fine, a little sooty from cool operation, and then removed the rocker arms to free up the camshaft from the valve spring pressure. And turning over by hand it makes this zipper sound like loose chain on a sprocket. Almost sings. Zeeeiiii...Here it is and there is only one gear internal to the engine, the oil pump which has a sort of slanted spiral gear driven off the camshaft. And that must be the bugger that is becoming critically worn. You can hear it in this clip. And I guess my option is to now pull the engine and the oil pan and check this thing directly and Ive got room to do it. And with the oil pan off I can make a much closer check for possibly bad bearings at the rods but hopefully won't need to remove the head and do a full tear down. And thanks again for the helpful input from everyone with experience on these engines. https://www.youtube.com/shorts/qLZMbUqh6Ek

Im seeing the nice little 3 cyl Perkins online for just over $2K right now and its tempting but their fuel economy is not any better and the refit work would be substantial. So Im keeping old knocky and doing whatever it takes to make it purr again.

[Finalee]

Your logic sounds right. IMHO tearing her all the way down is the only sure fire way to find the problem.

[doog]

Yes, but I found that zipper sound was the starter gear hanging up. Removed the starter on good advice and found the gear failed to retract and when the engine revved it melted the bushing. Its an aftermarket Wilson geared starter and works great but has an engagement issue. And now with the starter out and all the rocker arm forces off the engine it turns over without a tick or tap anywhere. TDC and BDC all cylinders and if there were a spun bearing, it'd knock at least a little.

Will see what oil analysis shows but I think Im okay for now! (once I find a proper starter) I traded in the original starter as a core exchange when it was in fact a problem with a bad ground wire connection on the starting battery. But that massive thing was a beast. You almost need a hoist to lift it out of the boat!)