TD5 head moves , why?

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Originally Posted by fraser130

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

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That was my understanding too.

Guys think about it there are limits to the steel dowels not allowing side movement.
The alloy head just cant be under more pressure without consequences.
Maybe I am wrong

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Originally Posted by scarry

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

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SO...If I have an early Td5 ( 2000 + plastic dowels?) but have owned it from new ....without overheating and it has only 135k on the speedo....

Given the various comments..Is there any "service" attention needed to the head? eg checking of head bolt tension etc

Bob

this is worth a read.

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Originally Posted by bellmore

this is worth a read.

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DETAIL:
Td5 engines fitted to vehicles in the above VIN range are fitted with plastic dowels
to locate the cylinder head onto the cylinder block.
Land Rover Engineering has introduced steel locating dowels from the following
VIN numbers:
Discovery Series II: 3A 793895
Defender: 3A 647705

INFORMATION:

If a cylinder head is removed from a vehicle in the above VIN range, the plastic
dowels must be replaced with new specification steel dowels, which are now
available from Land Rover Parts.
CAUTION: Td5 derivatives prior to the above VIN ranges must not, under any
circumstances, be fitted with the new steel dowels. If steel dowels are fitted to

earlier engines, cylinder head cracking may result.

that is interesting

Quote:

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Originally Posted by one_iota

DETAIL:
Td5 engines fitted to vehicles in the above VIN range are fitted with plastic dowels
to locate the cylinder head onto the cylinder block.
Land Rover Engineering has introduced steel locating dowels from the following
VIN numbers:
Discovery Series II: 3A 793895
Defender: 3A 647705

INFORMATION:

If a cylinder head is removed from a vehicle in the above VIN range, the plastic
dowels must be replaced with new specification steel dowels, which are now
available from Land Rover Parts.
CAUTION: Td5 derivatives prior to the above VIN ranges must not, under any
circumstances, be fitted with the new steel dowels. If steel dowels are fitted to

earlier engines, cylinder head cracking may result.

that is interesting

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It is also wrong. In my experience over the last however many we have done, the early heads have all been refitted with steel dowels, to no consequence. On one in particular, a 2000 MY Defender, I measured the hole depths in the block and head and the length etc of the dowel, and there is NO WAY it can expand OR elongate enough to cause a problem. Not sure why they have said this, I will keep using steel dowels in ALL of them.

JC

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Originally Posted by justinc

It is also wrong. In my experience over the last however many we have done, the early heads have all been refitted with steel dowels, to no consequence. On one in particular, a 2000 MY Defender, I measured the hole depths in the block and head and the length etc of the dowel, and there is NO WAY it can expand OR elongate enough to cause a problem. Not sure why they have said this, I will keep using steel dowels in ALL of them.

JC

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Justin

There is also the choice to use a "hollow" tubular steel dowel... As used in Holden V8s...

These cannot expand as they have the slot in them...

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Originally Posted by Tombie2

Justin

There is also the choice to use a "hollow" tubular steel dowel... As used in Holden V8s...

These cannot expand as they have the slot in them...

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Good point too Mike. The 'Coefficient of linear expansion' (:p I love that expression, sounds Soooo officious) of certain steels dictates the length change when heated, and a small amount of diameter change is to be expected. Most of the dimensional alteration (Another silly way of saying expansion:p) takes place longitudinally though, and as you know there is heaps of space for the dowel to expand...
I'll give you a call during the week...


JC

IMHO I think most problems vehicles have these days is caused by the way they are used.People are lazy and drive 2k to the shops instead of walking so the engine doesn't heat up causing wear,the EGR valves fill up with soot because the engines don't get hot enough for total combustion etc etc.On a Td5 the head would get hot after 3mins but the block wouldn't so when it heats up and cools down it wants to move but the block won't go with it so it forces the headgasket to do what it doesn't want to do. Pat