Thread: TD5 head moves , why?

Originally Posted by Pedro_The_Swift

I've read quite a few threads on the TD5 head problems ,,

and it seems easy to blame the plastic dowels,,

but if the head is loose enough to move,,

would steel dowels actually make any difference?

go cut a plastic dowel with some side cutters then try the same with the steel dowel. the steel dowles make ALL the differance.

btw, every diesel ive ever worked on has steel dowles or flange bolts to stop heads moving.
only land rover can wreck a good motor for the sake of a .30c part!! or, maybe they read a dissimlar metals thread somewhere

cheers phil

thats not really a reason,, Phil,,

why do the heads move?

I'm guessing that aluminum (head) and cast iron (block) have different thermal expansion rates.

I tried to ask this question in another post
I guess the point is do the steel dowels prevent the head from moving?
If they do then I would of thought that the effect would be minimal something somewhere has to give.
How many people have still blown head gaskets with steel dowels?
Is the steel dowel replacement an old wives tale that makes TD5 owners feel more comfortable?

Originally Posted by djam1

I tried to ask this question in another post
I guess the point is do the steel dowels prevent the head from moving?
If they do then I would of thought that the effect would be minimal something somewhere has to give.
How many people have still blown head gaskets with steel dowels?
Is the steel dowel replacement an old wives tale that makes TD5 owners feel more comfortable?

or, and bear with me here,,

should we be talking vertical movement here,, regardless of materials?,,

I can only assume that plastic is softer than steel, so repeated sideways movement is a concern ?

but if the head doesnt move at all,,
(and most heads dont--)
why does it matter?

You could also ask why the heads crack and leak diesel into the engine oil. Is this only the case on earlier TD5's with plastic dowels? The jury's still out as to if mine is leaking fuel into the oil. Mine is a 2004 TD5 classic country manual with steel dowel pins suposedly.
Regards
Robbo.

Originally Posted by TimNZ

I'm guessing that aluminum (head) and cast iron (block) have different thermal expansion rates.

Correct,and many engines are like this & have no problems for over 500k.The TD5 will often need head work at less than 250k,even if it has been serviced correctly & never overheated.Dunno if the dowels are the problem or whether it is something else with the design?


Earth to JC...or Blknight.....or the other guru's around.....that work on these all day

I'm probably off base here, but aren't there only problems after an overheat situation, and the plastic dowels allow side movement causing damage to the valves against the top of the pistons?(but the head gasket has already gone bu then?)
So they only fail after a problem anyway?
However, the steel ones would reduce the damage.


Fraser