Detroit 6/71 - Work required

Thanks for the update Alf, I had forgotten about the injury and the subsequent work stoppage. Nice to see and hear the DD's rumble again!
Hope the hand injury repairs quickly, cheers!
 
Divemaster1 said:
Oh ... and in respect to your own situation, please do not worry .... if you run the engines gently and reduce the time spent above 1800 RPM, give them good oil, clean(ish) air and fuel, they will last for 10's of K hours without anything else than a tune-up etc.... not accounting for impellors and items that may stand to death rather than lasting when used...
Click to expand...

Hello Divemaster1
When you inspected the rings at the beginning, you saw that one fire ring was loose, then when you opened the engine, you saw the piston head broken on a side and a nick on the liner. If I understand correctly, one cause of the problem could be the fire ring : do you know if was it a factory mounted ring or if it was an unproper (or maladjusted) fire ring mounted by a previous owner ?
Thanks
 
OCEAN I said:
Hello Divemaster1
When you inspected the rings at the beginning, you saw that one fire ring was loose, then when you opened the engine, you saw the piston head broken on a side and a nick on the liner. If I understand correctly, one cause of the problem could be the fire ring : do you know if was it a factory mounted ring or if it was an unproper (or maladjusted) fire ring mounted by a previous owner ?
Thanks
Click to expand...

Old thread... needed to skim through it again ... brings up memories linked to my scar.. :)

I suspect that the engine was assembled like this .... the engines was supplied from factory as 325 HP units, but before install in the boat, the injectors were up-rated to larger ones and brought up to to around 385 which is in a higher rating band for the type of Fire Ring which was installed on that cylinder. All other cylinders had the newer fire ring installed. All In-Line 6, 71 series engines rated above 385hp were delivered with the new type fire rings.
... and I believe that lessons were learned and brought in as standard for the higher ratings of the V6 - V24 92 series engines.
 
Thanks a lot for your reply, and sorry to bring you up memories liked to your scar, (hope you fully recovered your tendon).

Maybe old thread for you, but very new for me, as my experience on diesel engines repairs is limited to my very loved 30yo Land Rover !

To be honest, I spend time, gripping and instructive time, reading your posts, particularly those regarding the DD's.

DD's is old fashionned for Europ, but it seems to be the engine that may suit me here (I live in Madagascar where diesel workshops, in the few places where they exist, are not very reliable...).

So an engine without main injection pump, with liners, it sounds like a dream to me !

For the moment I am looking for good old unit available from Italy (following your advises on other threads...).

If by chance my project can finalize, what happened to your engine will happen to me, soon or late, and I'll have to go trough heavy mechanics like you did, in the same conditions.

But at least I know that it is possible with good documentation, courage, few Stella Artois and a tendon sacrifice!

Please Alf, tell me if the injectors could be properly tuned by following scrupulously the documentation, or does it require high qualification ? (I have seen 8V92 TI LP, 558 hp, 1540 hours, which seem to have been nicely maintened).

Thanks.
Phil
 
OCEAN I said:
......

Please Alf, tell me if the injectors could be properly tuned by following scrupulously the documentation, or does it require high qualification ? (I have seen 8V92 TI LP, 558 hp, 1540 hours, which seem to have been nicely maintened). ....
Click to expand...

Phil, following the step-by step instructions in a service manual and with access to a £20 DD injector timing gauge, imperial sized spanner set, some feeler gauges and a couple of screwdrivers, and with some element of mechanical knowledge (lets for argument sake use "can change break pads on a car"), should be able of doing a engine tune-up (injectors, exhaust valves, fuel rack and idle). You will take a lot more time than a trained mechanic (particularly with the V engines' fuel rack), but follow the step-by-step guide it is pretty simple and logical really... Only mechanical bits fitting into other mechanical bits ... do it in wrong sequence and the bits won't go into place.... No shortcuts allowed :)
 
Divemaster1 said:
Phil, following the step-by step instructions in a service manual and with access to a £20 DD injector timing gauge, imperial sized spanner set, some feeler gauges and a couple of screwdrivers, and with some element of mechanical knowledge (lets for argument sake use "can change break pads on a car"), should be able of doing a engine tune-up (injectors, exhaust valves, fuel rack and idle). You will take a lot more time than a trained mechanic (particularly with the V engines' fuel rack), but follow the step-by-step guide it is pretty simple and logical really... Only mechanical bits fitting into other mechanical bits ... do it in wrong sequence and the bits won't go into place.... No shortcuts allowed :)
Click to expand...

Thanks Alf !

So DD's injection can be ''humanly'' tuned.

The prespective to leap to a nice unit may get closer then :rolleyes: (and my tools completed with imperial's :encouragement:), because beautiful big V's with common-rail and plenty of electronic are scaring to me, a problem with such sophisticated engines occurs here, and I can do nothing...

I understand that DD's pistons/conrods can be pulled of from the top, without dropping the crank (same for the V's, correct me if I am wong) : did you have to replace the conrod bearing shells by standard size or by ''plus something'' ?

Was your oil pump presenting any sign of wear ?

I learned from you that in all cases I'd better focus on units whose engines have never been rated in the higher band.

Luckily you take care at your engines; most of usual owners seeing an unusual smoke at cold that disappears when hot, cannot even imagine that something is happening inside the engine, and just run for hours, quietly, towards ''Big Bill''...

Thanks Alf,
Regards.
Phil
 
You would like my 16V 71 then Phil, its in a Pacific truck as one of the standard fitments and is well over 40 years old and still running perfectly.
 
Collected and restored cars for more years than I will admit too, her indoors told me I had enough and not to get any more cars so I didn't, I got a Scammell (scammer) then an AEC Militant (Milly) followed by the Pacific which I came onto by chance, and it was a right hand drive model.

It isnt the biggest engine option either as there is an optional 24V 71 which is a V24 engine with over 2000 BHP. Mine doesn't have the optional driven front axle, they were designed as logging trucks working on logging trails and even without the optional driven front axle it has phenomenal traction off road.
 
Nice trucks !
Should be really phenomenal in mud, what about sand ?
I don't have trucks, I am about to finish a total ''refit'' of my Land Rover, and I am starting a VW Bug.
Seems indoors'opinions are same, everywhere, so I am about to leap for a 50-60' boat...:rolleyes:
Do you have a boat with DD's also ?
 
No, I am aware what a good engine they are and how they were and still are underrated due to the fact they are a 2 stroke unit and make a lovely sound.
 
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