Thread: Td5 - to steel dowel or to not steel dowel

Originally Posted by spudboy

Have a read of this thread....

Who has fitted Steel head locating dowels (Td5)

Cheers
David


> > All td5 derivatives within VIN range
> > ds2 02 my 2A736340 - 3A793895
> > def 02 my 2A622424 - 3A647705
> >
> > Cylinder head locating dowels.
> >
> > Td5 engines fitted to vehicles within the above VIN range are fitted with
> > plastic dowels to locate the cylinder head onto the cylinder block.
> >
> >
> > LRE has intrduced steel locating dowels from the following VINs.
> > ds2 - 3A793895
> > def - 3A647705
> >
> > IMPORTANT
> > If a cylinder head is removed from a vehicle in the above VIN range, the
> > plastic dowels must be replaced with new spec steel dowels, which are now
> > available from LR parts.
> >
> >
> > CAUTION
> > TD5's 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!
> >

So how does this (potential) head cracking occur?

It could only be if the metal dowels are too long for the holes in the head, or the diameter of the dowel holes in the head are too small???

Either way it seems simple to remedy unless the earlier heads are too different to modify.

Originally Posted by isuzurover

or the diameter of the dowel holes in the head are too small???

Unlikely to be that if my physics are correct. A ring (or a hole in a piece of metal) expands as temperature rises. Aluminium (i.e., the cylinder head) expands at a greater rate than steel so the dowel should become loose in the hole.

Mines in the earlier non metal dowel range and since the rebuild it hasn't had any problems, and that includes crossing the Simpson Desert!

The dowels are a split hollow steel tube so the fractional differences in the expansion rates should really make no difference.

The Vin number range where you supposedly can use the steel dowels I think ties up with the external fuel return to the regulator, as opposed to the head drilling.

Originally Posted by Psimpson7

The dowels are a split hollow steel tube so the fractional differences in the expansion rates should really make no difference.

Dowel pins?

Yep, they look like them!

Originally Posted by p38arover

Dowel pins?

Originally Posted by Psimpson7

Yep, they look like them!

yep x2

I guess they'd expand to fit the hole as the hole expanded. I wonder if there more an issue on cool down as the hole contracts fater than the steel?

Originally Posted by Psimpson7

The Vin number range where you supposedly can use the steel dowels I think ties up with the external fuel return to the regulator, as opposed to the head drilling.

I wonder what changed? The holes too close to the fuel reg?

"Does your mechanic know something no one else does "sealed injector harness" AFAIK there is no such thing, just the supposedlly upgraded unit, which in all honesty I could see no difference. People have tried to seal the unit with limited success.
Cheers
Craig "

Apparently.... I also sealed one myself, easy to do. The plug end has a cover that can be taken off, then washer of soughts with holes for eaCh wire can be moved out along the wires. Sealant (non corrosive sensor safe) is then squeezed in around the wires the washer put back in and then the cover. A smear over the top to seal the whole thing and no more oil running down the wires in the plug to the connection on the harness and into the wires to the ECU, works perfectly and has done for 4 years now. Might want to try it yourself. or see a better mechanic.!!