27 replies to this topic

[Rusty1182]

It's MUCH easier and a lot less destructive to simply sink the 4 exhaust valves into the head by 40 thou. That's IF it needs it - measure up first...... With a standard lift cam/standard rockers you need 320 thou clearance. Some 940 heads already have that clearance due to valve seat recession.......

You mentioned 40thou here

To me that meens as I'm using a mg metro cam I don't need to go thurther than 40thou if any

Edited by Rusty1182, 06 February 2012 - 10:12 PM.

[bmcecosse]

MG Metro cam is perfect for the job - same lift as standard cam. So yes - 40 thou will be very safe - but in fact you may not need to do anything! The lift on that cam is 8mm (320 thou) - so if you have 320 thou from the head of the exhaust valve to the face of the head - that's enough. There is still the thickness of the gasket as a safety margin - intrude into that space at your own risk..... If say you only have 300 thou - then you would need to sink the valve by 20 thou to get to that magic 320 figure. Best to measure them all - and then sink them all to the same level. Instead of sinking - you can do the pockets if you wish - same measurements as above to determine the depth of pocket.

Edited by bmcecosse, 06 February 2012 - 10:39 PM.

[Rusty1182]

MG Metro cam is perfect for the job - same lift as standard cam. So yes - 40 thou will be very safe - but in fact you may not need to do anything! The lift on that cam is 8mm (320 thou) - so if you have 320 thou from the head of the exhaust valve to the face of the head - that's enough. There is still the thickness of the gasket as a safety margin - intrude into that space at your own risk..... If say you only have 300 thou - then you would need to sink the valve by 20 thou to get to that magic 320 figure. Best to measure them all - and then sink them all to the same level. Instead of sinking - you can do the pockets if you wish - same measurements as above to determine the depth of pocket.

Thank you very much
If I have to I'm tempted to pocket my self to keep cost down to sink I will have to pay to get it done
Also I have a knackered block I could practice on

[Frisco]

The valves are easily sunk into the head - 5 minute job with a 45 degree countersink in a pillar drill

Cutting valve seats with a countersink in a pillar drill? No thanks.

[Rusty1182]

I'm tempted to pocket using my dremel with router attachment with a grinding bit

[Rusty1182]

I've been told that if I just put the 1275 head gasket on the 1098 block I will be able too see exactly were to pocket
Or is there a more simple way to do it

The template just has numbers on them are they mm cm ???

[Tupers]

Has anyone got any of the pictures that where posted a while ago of a pocketed block where a crescent moon type section had been taken out the top of each cylinder instead of the normal semi circle? I've been searching and searching but haven't found it yet.

[Rusty1182]

http://www.theminifo...pocket-a-block/

[Sam Walters]

The valves are easily sunk into the head - 5 minute job with a 45 degree countersink in a pillar drill

Cutting valve seats with a countersink in a pillar drill? No thanks.

I dont know why he still gives out advice. Shocking.

[Rusty1182]

When using the 1275 head gasket on a 998 apparently you need to block of water passeges

[Sam Walters]

When using the 1275 head gasket on a 998 apparently you need to block of water passeges

Can be a little hit and miss, sometimes water leaks out the front of the block.

[Rusty1182]

Ok I'm guessing I will only find that out once it's together and running

[booton]

when i did all my calculations with my cam, skimmed head. etc i need 3mm, into the block.

this did not touch the piston rings.

like some of u said u can not just guess you need to work it out. every combination would be different.
please dont do 3mm just because mine is.