Engine re-build - Detroit - Desicion made - Start 03 Nov 2011

[omega2]

head refitting

I do not envy you that job, our Fords sit up straight, and it's a three man job, two lowering and one guiding. in the ford lorries they are fitted on an angle like yours are and the book recommends "blind head bolts" one in each corner, with slots for screwdriver extraction, maybe you can find four spares to cut, or threaded rod to fit.

 

[Divemaster1]

Similar suggestions are from the workshop manual and Assassin in here gave more advise...

"Obtain a length of threaded bar of the same thread as the head bolts and cut this into 6 lengths, fit these to the end 4 stud holes and two centre holes with the gasket fitted.

Fit a nut onto each piece of bar and put a washer on top of the nut so the washer is in contact with the head face and not the gasket. This will allow you to lower the head into place and guide it down, you just wind the nuts down a little at a time to lower the head nearly into place. Make sure the nuts are not wound down far enough to contact the head gasket.

Support the head with your rope and frame assembly and remove one threaded bar at a time by unscrewing it and remove the nut and washer from the bottom. Refit the bar without the nut, and repeat with all the bars, just lower the head exactly into place with the rope. Fit all of the head studs to locate the head then remove the threaded bar and replace these head studs."

Was worried that I'd bore people in here with such a thread, but people seems interested.... Thanks to all who have offered advise, support and encouragement...... or simply looking for something to go wrong ...

Cheers, Alf

 

[Latestarter1]

So piston crown and skirt are separate parts? Unusual.

How are you typing with broken arm!

Many modern engines have articulated pistons. However I did not know DD used them on strokers.

 

[Divemaster1]

Every day you learn something new ...

....... However I did not know DD used them on strokers.

Not quite sure if I get away with it though ...

 

[longjohnsilver]

How are you typing with broken arm!

Many modern engines have articulated pistons. However I did not know DD used them on strokers.

What is an articulated pisto?

 

[Divemaster1]

articulated pistons:

Two-piece pistons incorporating an entirely separate piston crown or dome with a separate skirt, and linking the two together with the piston pin. Many 1994 and later engines incorporate steel crown/aluminum skirt articulated pistons.

From http://www.motorera.com/dictionary/ar.htm

 

[longjohnsilver]

articulated pistons:

Two-piece pistons incorporating an entirely separate piston crown or dome with a separate skirt, and linking the two together with the piston pin. Many 1994 and later engines incorporate steel crown/aluminum skirt articulated pistons.

From http://www.motorera.com/dictionary/ar.htm

Thanks, guess that makes life easier when repairs are needed. Any downsides?

 

[Divemaster1]

........
When you have that engine room all cleaned up and back together I'll come for a beer

Good luck with the project and keep the photos coming.

All the best

Little Ship and her crew.

Cheers Tom... you'll have to do another trip up to Scotchland or perhaps the Canal ....to meet us .... but you'll always be welcome!! ...but I doubt I'll manage to rival your Gin Cabinet though....

 

[burgundyben]

How are you typing with broken arm!

Many modern engines have articulated pistons. However I did not know DD used them on strokers.

Slowly.

I never knew of such things, interesting stuff.

 

[Latestarter1]

Thanks, guess that makes life easier when repairs are needed. Any downsides?

Steel articulated pistons came out in early 90's.

Liner and piston crown both expand at the same rate enabling very tight tolerances.

You can get juce the brains out of the jug with no risk of burning the crown.

Alloy skirt contains cocktail shaker arrangement to keep cooling lube oil up in the crown area.

Downside, greater reciprocating mass, cost, and a bit of a biggie, if you drop a valve, all ends in tears. Steel piston, steel valve no room for everybody, so if they get half a chance they exit to atmosphere..........Out the side of the block.

Concept gradually being replaced with iron pistons.

 

[Nauti Fox]

Great work Alf, well done.

 

[jfm]

Great thread Alf. Loving it

Scuse my ignorance, but I've been looking at the pic of the liner and piston. The ports in the liner are air intakes. Is the bit of the liner above these intake ports water jacket cooled? If so, how does the water jacket seal? I can't see any kind of shoulder on the liner. Is there kind of a big o ring or what? Or is there no water jacket here?

 

[Divemaster1]

Cylinder Liner ..

Great thread Alf. Loving it

Scuse my ignorance, but I've been looking at the pic of the liner and piston. The ports in the liner are air intakes. Is the bit of the liner above these intake ports water jacket cooled? If so, how does the water jacket seal? I can't see any kind of shoulder on the liner. Is there kind of a big o ring or what? Or is there no water jacket here?

Thanks !!

The Detroit 71 series engine has dry liners ... so water jacket in block..... simples !! Picture not the best one, but may give an indication ...

 

[jfm]

Thanks !!

The Detroit 71 series engine has dry liners ... so water jacket in block..... simples !! Picture not the best one, but may give an indication ...

Ah, thanks, all understood. Nice design of engine in terms of ease of rebuild

 

[Divemaster1]

So piston crown and skirt are separate parts? Unusual.

Changed my mind I think .... DD recommended full cylinder kit (Liner, Piston crown & skirt, Rod, Clamshell bearings etc.) as "best practice" ...so asked for price + new seals etc...

Also piece of piston and ring probably thrown out through scavenging port in liner and into airbox ... (where I first confirmed the cylinder failure), and is probably somewhere in the sump.... so will go fishing with a magnet on a stick through the oil pan access hatch.... or open the rear (lower) access hatch....

 

[jfm]

Also piece of piston and ring probably thrown out through scavenging port in liner and into airbox ...

But is there a route to the sump from anywhere in the air inlet system Alf? I can't see that there is

 

[sarabande]

Alf

as a confirmed raggie, may I say that this is a really good, intriguing, post, and many thanks. I must rush out and buy a mobo !

Hope the putting together and testing goes well for you.

 

[Divemaster1]

But is there a route to the sump from anywhere in the air inlet system Alf? I can't see that there is

During operation, there will be water vapour from the air charge ... and some oil/fuel vapour fumes etc., whch will settle at the bottom of the air box. This condensation is removed by the airbox pressure through drain outlets in the side of the block...

Now there are at least two configurations for these drain outlets, and I am not quite sure which we have... One was closed and drained to sump.... other open to drain to collector tank (or bilge).... I'll look at this and see what can be found ...

 

[Divemaster1]

Alf

as a confirmed raggie, may I say that this is a really good, intriguing, post, and many thanks. I must rush out and buy a mobo !

Hope the putting together and testing goes well for you.

A pleasure .... and do I detact a small hint of sarcasm ?? .... main thing here may be that on a "simple" diesel, you can do quite a lot yourself....

...Well... putting it together again and testing is another issue....

 

[sarabande]

Alf - no sarcasm. I am just happy that everything seems to be going well- if slowly - and wish I had your skills and knowledge. It is a seriously good post, and will encourage someone else to have a go at a simpler repair perhaps, and that will make them a better sailor.


The pics in particular are excellent but a bit daunting for someone who just normally deals with Landrovers