4AGE Timing. Slightly raised compression.

[andrew_mx83]

Maj - You can shave the head for as much comp as you want, basically until you start smashing piston into valve. I went from 9.2 to 11.5:1 with just a head shave and a touch over 12:1 with a block shave as well. That said my 7m now sits about 2.5mm shorter than everyone else's

OP - put the motor together however you want, planned or can afford to then when its together advance the timing til it pings then back off a touch and do the bolt up. Dont root around with a timing light and numbers.... try it, drive it and adjust accordingly. Keep it just under the point where it starts pinging and you're sweet.

[maj]

I know it can be done and it's a common method, but the numbers we were talking about and the desired outcome it might not be the best avenue to be following.
Of course I am only offering my own thoughts on this, at the end of the day budget and requirements can be two separate things.

[justin_es]

so to repeat a previous question.
especially now the comment of pistons smacking valves come up.
How many mm off the head is a safe shave for a standard motor?

as long as the block and head has no cracks in it im doing this as cheap as possible head gasket kit and shaved head as it should be done anyway. Just taking a little more off for a little cheap gain while the head is already off.

[trdee]

Maj - You can shave the head for as much comp as you want, basically until you start smashing piston into valve. I went from 9.2 to 11.5:1 with just a head shave and a touch over 12:1 with a block shave as well. That said my 7m now sits about 2.5mm shorter than everyone else's

OP - put the motor together however you want, planned or can afford to then when its together advance the timing til it pings then back off a touch and do the bolt up. Dont root around with a timing light and numbers.... try it, drive it and adjust accordingly. Keep it just under the point where it starts pinging and you're sweet.

you realise an engine starts detonating long before you hear audible pinging right? thats why tuners use detcans

[andrew_mx83]

Yes, but remember not all detonating is a life threatening situation. A big ping, under full load is going to do damage sure, but there are plenty of engines of there that have plenty of detonation events (big and small) and are no worse for it.

I do see your point though.