Detroit Diesel

[Jrmcnabb9]

Thanks for reply lepke.
I have removed and tested the oil cooler and hydro tested the head with injectors out to check injector cups. That was all good. She got hot about 2 yrs ago but didn’t show signs of cracked head Then. It sat up for about 3 mo before it showed water in oil. Now I’m hoping head gasket kit. But I can’t seam to get it off. On each end of the 471 there is hardly no tolerance I’m thinking it’s rusted in but not sure I want to make sure there’s no bolt somewhere before I get to rough w it.

[GordMay]

Greetings and welcome aboard the CF, Jrmcnabb.

Is it an In-Line, or V-Series engine?
FWIW: In Line (1993) 71 Series Maintenance (workshop, repair) Manual
➥ https://avtec.edu/sites/default/file..._srv_man_0.pdf

[oldcal46skipper]

A friend who has only been a commercial shrimper his entire life got cancer and can no longer go to sea. He had a classic 35' wood shrimp boat with the DD 4-53. I have the engine now and it is available. Runs perfectly with BW Velvet Drive 3 to 1 Redux & forward PTO to pull nets.
Here she is setting next to a Perky


I fix engines, but can't figure out how to post pictures??? Can someone turn this picture over for me?



If I were younger than 81, I would get a boat it fit and run it just so I could hear that sweet DD sound. Reminds me of the gensets we had in the USMC in the 50's.


A neighbor here on Bayou Chico has a converted wooden hull with twin 6-71's. Whenever he is backing into his slip, I always stop and go listen.



Life is good!

[drcot3]

Try using starter motor with all injectors in place just head bolts loosened ie using compression to lift the head, hopes this helps
Otherwise try lifting the head with overhead gantry.
or use rubber hammer to move the head sideways / or any direction.

Just make sure it's the head problem and not somewhere else causing loss of coolant. Have you done a compression test

Good luck David

[Sailmonkey]

Originally Posted by Jrmcnabb9

Hello.

I need alittle Help. I have one of these ole early 70’s Detroit. It’s a n471. I have it in a small 32’ shrimp boat. Single screw. Love it it’s the best. “If there’s no oil under them there’s no oil in em”.Lol

How ever the 471 is down rn with water in oil. I tested the oil cooler, test for leaking injector cup. That was not the prob.

Today I attempted to remove my head and it would not budge. I removed obviously the head bolts, the two bolts at the front of the motor and two bolts in the rear of the head. Has anyone here ever had such a problem w the head stuck to the top of the block?

. Anybody’s words of wisdom would be appreciated.

Are you saying you’ve only pulled four head bolts?

I want to say there’s something like ten that hold that head on.

[Jrmcnabb9]

Hey thx for that gordmay I needed one I’ve been referring back to an old 53 series manual but it’s so old looks like incests got a hold to a lot of the pages. Unfortunately for me they are very vague when it comes to this part.

[newhaul]

Originally Posted by Jrmcnabb9

Thanks for reply lepke.
I have removed and tested the oil cooler and hydro tested the head with injectors out to check injector cups. That was all good. She got hot about 2 yrs ago but didn’t show signs of cracked head Then. It sat up for about 3 mo before it showed water in oil. Now I’m hoping head gasket kit. But I can’t seam to get it off. On each end of the 471 there is hardly no tolerance I’m thinking it’s rusted in but not sure I want to make sure there’s no bolt somewhere before I get to rough w it.

hope the pictures were before you removed head bolts.
I can see at least 2 that are still in the head . Should be a minimum of 10 bolts ( going from memory here can't find my torque specs book)

[Jrmcnabb9]

Yes pic was taking before I tore it down. I am going to play w it more this am. I’ll post a few more hopefully w the head off.

After sleeping on it The only thing I can think to look at is under the two lifting eye. I’m sure there’s nothing there but I may be able to spay some lube in that crack.

[Jrmcnabb9]

Oh yea nice looks like it’s ready to get back to work. They were fit for battle that’s for sure. We have a bayou Chico here in la. Thought we were neighbors.

[David M]

They remind me so much of Seascouts back in the 70's. Almost all the boats back then had them....military surplus boats mostly. Many had never been rebuilt since they were manufactured in WW2. Military used them because of their reliabiliy. Modern Diesels now have wires, sensors and computers on them making them less reliable, but more efficient and quieter. Used to be that Diesels did not require 12VDC to keep running....to start, yes of course.

[a64pilot]

The DD was designed I believe in very much of a hurry, the drawn on a napkin type of design.
I believe it was designed to be modular in that many different engines could be built from the same parts, sort of a potato head engine, be easily built without expensive, fancy tooling, and be cheap to build, lightweight and compact, primary consideration was production rate, they wanted as many built as fast as possible.

On the lightweight and compact comment, remember it was 1939 and engines were huge and heavy, pressurized oil lubrication wasn’t common, and that greatly limited engine output, aircraft had oil pumps but not many other engines.

It was never meant to last a long time, that sort of just happened,but that was common for the time, most WWII aircraft were designed to last 25 missions, no longer, but many are still around today. A theory was that designers weren’t as smart as they are today and just couldn’t design to a life limit, so in fear of something not being strong enough they overbuilt.

Ever wonder why the vast majority of surviving aircraft from that era are US built aircraft?

[tkeithlu]

I run and maintain a surplus US Navy 4-53; love it, but you're right - fighting oil leaks is a way of life.

Idea for you. I keep two orginary wide blade wood chisels for this type of problem. They are sharp enough to get into those tiny gasket gaps, and tapped gently in at both ends will lift loose just about any glued down gasket.

[Jrmcnabb9]

The 471 head gasket consist of O ring and a parameter rubber gasket.i would hope there’s not Sealent in there but never know. I’m almost convinced that what is hanging this head from coming off is rust and crud on the sides of the head. There’s About a 2 sheets paper thin gap on front and rear of the head. I’m afraid the salt water is my enemy here. I have no history on this engine so no telling what Else I may find. Wish me luck

[Lepke]

If someone used sealer it can be like trying to split a 2x12. I've used steel wedges in the past on the really stuck heads, but carefully. The bottom of the head is smooth, no combustion chamber like a gas engine. You don't want scars on the surface. There are no hidden head bolts (studs).

The 71 series design started in the early 1930's when 2 one cylinder prototype engines were built. The smaller one became the 71 series and in 1938, 700 engines were built. The big prototype became submarine Winton engines. Neither were rushed in design because the war hadn't started. They were made to be long lasting engines, but in military service the 671 was run at 2800 rpm when the peacetime continuous rating was 1800. The 71s were made to be field rebuildable. Everything - blower, pumps, injectors were able to be rebuilt in primitive surroundings.

When I was a commercial fisherman, the 671 was the most common engine. Some were war surplus, still going in the 1970s and never overhauled. In the military they ran landing craft, generators, and Marine Sherman tanks. For some reason the army preferred gas engines in their Shermans. Some 671 powered Shermans were sent to the USSR and they copied the engine and manufactured a 671 copy into the 1950s. LCI (L), large infantry landing craft, were powered by 8 671s, 4 each on 2 shafts. Each engine group was known as quads. At the height of WWII production, 6000 671 engines were made each month. The 12v71s came in 1957 and that was the end of the quads.

Pic is Tongue Point, Astoria, Oregon - stored LCI (L) after WWII.

[oldcal46skipper]

Originally Posted by Jrmcnabb9

Oh yea nice looks like it’s ready to get back to work. They were fit for battle that’s for sure. We have a bayou Chico here in la. Thought we were neighbors.

Wow! I thought my Bayou Chico was the only one. N30 24 W 087 15
We are about half way between downtown Pensacola and Naval Air Station. After service in the USMC, then 30 years in SoCal we sailed away 1988 to 2002, cruising West coast of Mexico, Costa Rica & Panama. Then more roaming South America, Caribbean, east coast USA. We never found any place we liked better than Bayou Chico.


Don't want to de-rail the OP's thread. I still have that low hour DD 4-53 w/ BW Velvet Drive 3 to 1 Redux and PTO for pulling nets. I hope to roll it outside to my test area, run it,observing oil pressure, cooling etc. I will video tape and send to any interested persons.



I had two DD 3-53's that I sold to fishermen in Peru. Maybe I should get this one ready for South America