Jimmy vs. Perkins

One advantage of the larger Detroits is the air box covers.

Removing them does allow cylinder and piston inspection ,

but for seasonal boaters the access to the cylinders allows fogging fluid to simply be sprayed into each cylinder.

This prevents the cylinders from rusting , and is impossible to do on other engine brands.

This is one reason there are so many OLD Detroits still running strong,

Most diesels have a dished piston crown and I've often wondered how one would get a good dose of the carbon eating stuff called "Sea Foam" down around the rings. A slant or a V type engine may be helpful but w a vertical engine I would think the Sea Foam fluid/oil would just sit in the depression on the piston crown. Anybody addressed this and managed to get the fluid down to the rings where it needs to be?

I sat with Billy Proctor (a Broughton legend) and discussed DD. He has a 471 in his trawler Ocean Dawn. Been fishing and logging for many years with it. He claims close to 100k hours. Said he used to change the oil every few hundred hours but now does it very few years. He figures that since he is always adding that it is being changed all the time! Probably going to rebuild it this Winter and wouldn't think of any other make. All the while we were talking the motor was running and sounded great.

I love it when someone starts a discussion about a Jimmy against anything else!

"saltcod" as you're seeing from the replies, all engines have tradeoffs, but one thing that I can tell you from first-hand is that if you have the DDs in your bilge, and you expect to live for another 50 years, then you will be running the same engines until your end of days… and that's with poor maintenance

Mine were 50 years old and the worst problem was that the aluminum blocks had suffered from electrolytic corrosion on the seats of the water seals between block/head. I cleaned them up, squared them up with JB Weld, new gaskets, dropped the heads back on, and continued cruising without anymore problems.

Don't get scared away about comments about dripping oil. Place a small tin can under the breather tubes and wipe down you engine every now and then (like a good sailor should anyway).

Yes you can recycle engine oil back into your fuel tanks but I don't remember what the ratio was. If you're long range cruising and have to change two engines every 200 hrs then you might investigate those Puradyn or similar units that eliminate oil changes. Anyone have experience with those?

However, you should think about replacing the air boxes with air intake silencers (perhaps something from the trucking industry) and then upgrade the engine room sound absorption. Guy I knew ripped up his decorative sole, laid down a dense layer of 1/2" rubber matting and then another layer of 3/4" ply on top of that. Triple layer floor helped wonders.

Good luck on your purchase.

Thanks for all the opinions, guys. I finally was able to talk to my friend Tom, who has 40 years experience as a diesel mechanic, a lot of it on boats. Not to hurt anybodies feelings but having extensive experience with both DD's and Perks, he recommended the DD's. Cheaper and more plentiful parts, more reliable, easier to work on and last forever. He also said they were noisy, that they leak, and if you start using ether the start them, you'll never stop. Just waiting to hear on an offer we made for the CC41.

This conversation has changed my view of DD......thanks guys..

Yes you can recycle engine oil back into your fuel tanks but I don't remember what the ratio was.

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Actually, DD goes out of their way to specifically prohibit this in their manual.

I wonder how a 2-53 would fly in Willy?

I know a few old fishermen who love the sound of screaming Jimmies,none of them will say anything against them.

I have a pair of 8v71n's in my current boat,they are the very models of reliability.
About the only thing I have to add to the discussion is don't fill them more than half way between the marks on the dipstick,keeps the oil loss down a lot.

My second favourite engine is the old 6 cylinder Ford Lehman,great motor that with normal TLC goes a long way.

I grew up with Gardners which go forever and are probably the most economical diesel engines you can get, mindblowingly expensive to overhaul though.
The sort of engines you leave to your kids in your will.

Both over the road and commercial boaters know the fuel penalty of a DD. It is not significant for a recreational slow boat though. There are valid reasons the 2 strokers fell by the wayside. Emissions, weight and fuel economy being the primary ones.

My experience with the DDs includes side by side operations with Cummins and Cat in heavy earth moving. Engines were routinely seeing +3000 hours per year and careful tracking of fuel and maintenance costs a must for the large fleets.

By the late 70s stationary pumps and gensets had pretty well switched to 4 strokers with very significant fuel savings the reason. By the late eighties emissions issues ended the DDs long and glorious run in most NA applications. That didn't stop them from being dropped into large yachts though as emissions were not relevant and the 2 strokers reliability and familiarity carried the day in low hour usage.

My favorites were the lower HP 8V 71s. During the eighties we were able to get NAPA to rebuild them for about 2/3 the cost as compared to the DD guys and offer an equal warranty. But in those applications though we got rid of most of the DDs as down time for engine rebuilds was too expensive for the 24/7 applications.

Like one's favorite hunting dog, the DD mystique lives on, especially for the mechanics who don't have to buy fuel. Art DeFever was never a DD fan as he world cruised his designs and needed the 4 stroke fuel, size, and weight advantage.

The difference between a perfect 16 Hp per gal and perhaps 20 Hp per gal is a huge difference for 24/7 high power use.

At 3gph for most boaters with only 200 hours a year , the difference is almost meaningless.

The difference in reliability , and service life easily pays for the 1/2 gph penalty.

For a modest trawler the 2-71 or 3-71 (60 or 90hp cruise)would be a realistic choice , even today , if the Air Police would allow it.

The WWII mine sweepers used aluminum blocks for their boats , that might help with the usual weight hassle . Talk about hens teeth!!!

We have 4 of the 8v71's aboard the tug. 2 have 40,000 + hours with rebuilds around 20,000 hrs.

FF said:

The WWII mine sweepers used aluminum blocks for their boats , that might help with the usual weight hassle . Talk about hens teeth!!!

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The two aluminum block 6-71s in my old boat were gensets in a WWII minesweeper. If I recall correctly, they were actually manufactured in the late-30's.

Weight aside, I prefer cast iron blocks. Since personally I'll never have twin engines on one of my boats again, that shouldn't be an issue.

BTW, it always freakin' amazed me that no matter how cold it was, that they would start within a a 1/2 second of hitting the starter. Zero problems in this regard!

The issue at hand is which old engine to buy.

To answer that we might want to look ahead ten years to see which engine would require repower or just be repairable. My guess is the same discussion would happen then except the perkins parts would be harder to find while the detroits would still be leaking away with parts and mechanics everywhere..

bayview,
I would buy the boat that had the engine in the best condition.

Ordinarily I woukd agree but assuming both run ok at that age you need to consider what happens in the future. Tempis fugit and all that.

It is all speculation on us TF ites as to the current condition of the boat and engine. Fact is though the Perkins factories are still around and owned by Caterpillar. No shortage of base engine parts but mani coolers have been an issue, go MESA! Water pumps are Jabsco and transmissions still made by ZF. Point me towards a DD factory.

As said earlier, let the best overall boat win. This Jimmy vs the world fight was lost decades ago. Even the Old Lehman came about as a Jimmy replacement, forty or so years ago!

Richard on Dauntless is sure happy he had a thrifty 4 cycle. If he'd a Jimmy his boat would have gasped several hundred miles short.

I bleed CF2 40w oil, making me a Detroit, man, but I would not hesitate to buy a Perkins powered boat with engines in good condition. Like DD's and Mark Twain, reports of their demise are greatly exaggerated.

In the end, the boat with Detroits was better laid out and better maintained. That and the fact that the broker for the DD boat started the engines for us without asking, and the diesel genset as well. When my wife asked the broker with the Perkins boat to start the engines, he said we would have to make an offer first. In my head I said to myself "I would never make an offer on a boat without knowing if the thing will even start"
Our offer was accepted! Now for all the inspections. I'm not expecting any problems.

That's great! Good luck on the surveys and then happy cruizin! (from a Detroit owner)

Ah yes makobuilders,starting a DD is one of life's pleasures.
As a mechanic I love an engine that starts instantly.Not to mention the sound of a twostroke V8.

stornoway7-

not just that… had manual oil pressure gauges… manual stop (fuel cutoff cable)… manual tachometers. The only thing electric was the starter motor (but easy enough to replace with a manual spring starter).

can you imagine anything more reliable on earth?

can you imagine anything more reliable on earth?

Death and TAXES

FF said:

can you imagine anything more reliable on earth?

Death and TAXES

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Ughhh, you had to go and ruin a perfectly good moment

WELL with just a National Sales Tax , we could repeal the second plank of the Commy manifesto

(a graduated income tax) ,,,AKA the 16 amendment ,

and just pay whatever taxes you desire , depending on what you consume.

Just think how the price of everything would GO DOWN with no billion dollars a year just for compliance.

Death will be harder to escape , but with time ????

Back to your area of perfection FF....boats....

Ski in NC said:

The noise may be the biggest downside of the DD. A good exhaust system and good engine room isolation/insulation can control the noise. But not all boats did a good job with this. It is hard to kill that exhaust drone on a DD.

Make absolutely sure you can live with the noise.

I did some work on a Hatteras LRC with 4-53n, it had mufflers but was still too loud for my tastes. Kind of like a Harley: The noise is fun. For five minutes.

My vote is for the Perkins. Much quieter, and a lower frequency tone. Love me some old Detroit iron, but I have paid with some hearing loss.

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I have owned the 8V DD on a Canoe 37, the 6.453 on a fishboat, and had a Cummins 330 on Hercules. And a Saviem 210 on a 31 Enno. The latter slobbered, had a shrill turbo tone, and blew white smoke enough to raise a fire party on every starting.

The Cummins sounded like the trucks that pull up to you at stoplights, for some reason, and eventually I didn't want to hear it anymore. Gimme a Gardner to listen to.

The 6.454 "Green Leaker" didn't and howled like a 2-stroke. Hit above its weight and hummed. Dean at Saltspring straightened me out on soundproofing and for $400 worth of soundproofing I knocked it down low, where I operate. ;-)

The DD 8V's did leak, somewhere high onto the valley, but a gravity leak I mopped up. They too performed up to spec and beyond, and I could stand to listen to them. Absolutely the way to go given the WWW, especially, I feel. In Craigslist we trust.

And I agree, knowing their provenance helps. My DD's always professionally prepped each season.