Thread: urgent td5 head advice please!!!

If they have done a good job, they would have measured the valve depths and re-cut the seats to suit. Was that not done?

How does the hardness of the face compare with the rest of the head? This is more important than how much was removed.

No not to my knowledge Paul. So are you saying they should of measured before the shave and then set the values to the same measurement to the face after the shave??

Thanks Jim

i assume you are concerned with valve to piston clearances ?.
i am no engineer here, but IMO 9 though shave on a head should not cause any clearance issues with the valves needing recessing. also it would increase the compression a miniscule amount and not a concern for me. i would be more concerned about the hardness of the head myself.
certainly if the valve clearances were that close that a 9 though shave is going to cause issue, then surely we would have seen td5's with bent valves by now?

Originally Posted by jimbob

No not to my knowledge Paul. So are you saying they should of measured before the shave and then set the values to the same measurement to the face after the shave??

Yes. When my head was done this is exactly what my machinist did.

Originally Posted by Rosscoe68

i assume you are concerned with valve to piston clearances ?

Not just the piston to valve clearances but also the compression ratio will be increased. A 9 thou skim equates to approximately 0.5cc reduction in combustion chamber volume due to valve intrusion.

Yes i am concerned with the valve to piston clearance mainly. I have gone from the 2 hole gasket to the 3 hole gasket. Not sure what the thickness difference is, but this should assist in the clearance and compression situation.

In regards to the hardness, the machine shop said the minimum hardness you need is 67 brinel. But i fail to see how they can say that when they know nothing about these engines eg. the high boost pressure they run and the stress that must put on the head gasket.

Cheers Jim

I have read that you can get the head re-hardened. Is it the machine shop that normally does this? How long a proceedure is it?

So any one lnow how i can work out the clearance issue??? Measure how far the piston comes out the top of the block, measure how far the valves come past the face of the head , find out how thick the 3 hole gasket ends up being once compressed and from this work out if the pistons will hit the valves.

Does this sound right???

pretty please all td5 GURU'S!!!