Thread: urgent td5 head advice please!!!

Thats Great news thanks JC. I am a little concerned with the hardness, but if 9 thou had to come off then the head was stuffed any way. My main concern was the valve clearances to pistons, But if they are ok then i have nothing to loose by putting it back together except a few gaskets and a few hours.

To be sure can i put it all back togther then turn the motor by hand? Will this give me an indication or not?

2 hole is the thinnest then 1 then 3.
I am at work at the moment so cant give you the exact sizes, however there is about 6 thou between each gasket and strangely AFAIK 2 holes is the thinnests then 1 then 3.

Ok so going off that, I had a 2 hole to start with and am getting a 3 hole, then i have increased head gasket thickness by 12 thou. So because i have lost 9 thou off my head i have still increased the distance between the valves and the pistons by 3 thou.

Ive just checked the info I have. Paddock Spares, Rover Parts and Turner engineering all have the same data
I always found it odd that their info said thickness went 2, 1, 3. anyhow....
1 Hole - 1.27mm
2 Hole - 1.20mm
3 Hole - 1.35mm

There is a 0.0059" difference between thinest to thickest. (say 6 thou)
1 inch equals 25.4 mm

So you have only have 3 thou to be concerned with and in my opinion this shouldnt be a problem, but others may differ here.

I cant answer the hardness question with any certainty so better off being quiet.

hope this is some help.

Originally Posted by strangy

The TD5 compression wont change with a head machine. The combustion chambers are in the piston.

There is more valve head in the space between the piston and head so it will increase the compression ratio by reducing the total combustion chamber volume by (approx) 0.5cc

Not a huge change, but something to be aware of.

I wouldn't be to concerned.
My old engine's head was welded and then skimmed. The water galeries had become part of the combustion chamber when we took the head of. I never knew how much of a skim they did. It went 100,000km before the turbo jamed for max boost and coupled with an over fuel killed itself.

sorry to thread steal.
dropped my head off today, they reckon it will need about 15-20 thou to take the head gasket ridge away, but assured me that the head hardness is good still.
the head is pressure tested and holds no probs, and there is obvious signs that the gasket itself was leaking thus the blown headgasket fault, not a cracked head.

is this too much to take off ?
they will only do it if i agree for them to reseat the valves to compensate for the valve/piston clearance, which i agree is fine, but just not sure if thats too much to take off the head

Originally Posted by Rosscoe68

sorry to thread steal.
dropped my head off today, they reckon it will need about 15-20 thou to take the head gasket ridge away, but assured me that the head hardness is good still.
the head is pressure tested and holds no probs, and there is obvious signs that the gasket itself was leaking thus the blown headgasket fault, not a cracked head.

is this too much to take off ?
they will only do it if i agree for them to reseat the valves to compensate for the valve/piston clearance, which i agree is fine, but just not sure if thats too much to take off the head

In my opinion, that is almost through the actual hardfacing, and is sailing very close to the wind for reliablility.
I am not a head reconditioner though, and that measurement is information given to me previously about the depth of hardfacing of the factory head. I can't give you a 100% guarantee if this will be a problem or not.


JC

Thank you all, I feel much more at ease about bolting it together. I have had a bit of a family emergency so it will not get done untill the weekend. I will do some measurments before it is put together.

Will keep all informed on how it goes..

Thanks for all the help.

Jim