Perkins 4.236 white smoke - time to overhaul?

[LobeliaBlue]

Hola Compañeros.

The Tub (ML48) has the original 1980 LD series UK Built 4.236. I've gone over all the accessories in the last few years, but i'm seeing more white smoke lately than before.
I'm like, 80% sure it's a dry valve guide because I haven't started it up weekly like I used to.

Buhhh... when do you throw in the towel and decide it's time? There's never enough $ for everything, but at 8000 hours before the panel broke,
and 2 neglectful previous owners, I wonder if I'm being needlessly stubborn.

I get dockside opinions from 'it'll be fine for another 20 years as is!" to "throw it away and get a 6cyl Lehman".
What says the CGF collective? I'm seeing overhaul kits are only $500ish, with months of free nightmares.

cheers, LB

[Kettlewell]

Keep it going--the engine will outlive you! Lots of possible causes of white smoke. Otherwise how is it running? https://learndiesels.com/the-causes-...t-to-look-for/

[LobeliaBlue]

That's a great read. I just had the injector pump and injectors rebuilt and had ruled it out of hand, but maybe it wasn't done/timed correctly.

It used to run so sweetly, vibration free and quiet, but it feels more clunky and noisy the last year.

[Kettlewell]

I'd think about a valve adjustment and compression test before you try too many other things.

[LobeliaBlue]

Completely reasonable. I'll do it with someone new as well.

[mvweebles]

I have a 4.236 and like the engine a lot. It's one of the few things I didn't replace during a massive refit, and it's been the most reliable system on my boat this far (currently sitting on Guatemala border - started California). I personally think it's a slightly better engine than the Ford Lehman 120. The only engine I'd consider above it is a Deere 4045 NA (around 85hp so similar to your Perkins).

But swapping engines and gears with a different brand complicates the repair. And it's not like Lehman's are new engines either.

I'd track down the white smoke issue - timing is a good guess, as would a head gasket. If it's unburned fuel, usually smells different than coolant.

I'm barely a shade tree mechanic, but there were some decent diesel savants on this forum (and even more on CFs sister site - TrawlerForum). "Lepke" is extremely knowledgeable, for example.

Good luck. I'd keep plugging away a bit longer on the Perkins.

[deblen]

Smoke color guide:


White smoke falling to water & causing film on water-raw,unburnt fuel due to non-combustion in one or more cylinders.


White smoke rising rapidly upwards-steam


Blue smoke n first start,then goes away-bad valve seals.
: continually-worn rings.


Black smoke: partially burnt fuel-due to overloaded engine.


http://www.sailingncruising.com/boat...smoke-exhaust/


https://www.cruisersforum.com/forums...er-279605.html

[Locquatious]

Our 4-236 Perkins was a 1982. It blew a head gasket. Or perhaps, it was the gasket that papers over some of the coolant channels in the head. Not all the coolant channels are used, or they were just trying to change flow direction in some areas of the engine. What happened is the paper of the gasket that covered the holes eventually softened enough that coolant water entered the cylinder.

The newer gaskets are highly engineered plastic-impregnated units. You have to make sure the gasket covers those same blocked off holes, by being careful to match engine serial numbers to the new gasket design.

In our case, the engine suddenly quit, of course just after launch in a crowded marina. Fortunately a pirogue came by just in time to save us from the rocks and tow us to a mooring.

The engine was still in great shape. We cleaned surfaces, removed carbon on the pistons and head, and put the head and valves back on as normal. It was very difficult to get rid of the water in the engine oil. After three oil changes, the oil was still milky. A mechanic suggested running the engine hot and hard for about an hour. This evaporated the water in the oil, which was changed a final time.

[LobeliaBlue]

https://imgur.com/a/mmnfe0J

Looks to me like a leaky valve guide on #1, Yogi.