head gasket life?

[griston64]

Originally Posted by Laird Scooby

http://dragonfly75.com/moto/SquishVelocity.html

That's fairly well written and reasonably accurate to explain it. In some engines it can promote better power due to being able to run higher compression and/or more advance due to reduced knock effect, i've no idea if it works in a red block though.

That said, there's no reason it shouldn't though.

For higher power with a turbo you want to lower the compression.

[griston64]

This goes on a bit but it's talking about tight squish

https://forums.tbforums.com/showthread.php?t=124192

[Laird Scooby]

Originally Posted by griston64

For higher power with a turbo you want to lower the compression.

There's obviously a way round that Mark as many new petrols turbos are running 18psi and 10:1 compression or similar. Yes, you read that right and yes, i queried it when i first heard it. I've still not got to the full facts about it so there's scope that it's incorrect but i daresay someone knows. It flies in the face of everything that has previously been known though.

[230ina245]

On our redblock engines tight squish means having the the outer circumference of the piston come to within 1mm of the cylinder head at TDC.
The idea is that the mixture of air and fuel is squeezed out of those areas at high velocity to increase the efficiency of the combustion process. There is a lot of info about this on line.
You would need to measure (very accurately obviously) the height of your pistons in the block compared to the deck of the block. In other words how much they stick up above the block or how far down in the bore they are.
Then using the compressed thickness of a head gasket one can work out how much needs to be skimmed off the block. (Skimming the head has no effect on this calculation.)
Alternatively, using a head gasket with a lower/higher compressed thickness would also acheive the same goal. As far as I know the only gaskets that are offered in varying thicknesses are Cometic multi layer steel gaskets and ironically they recommend having the head and deck skimmed to provide a suitably flat surface. Although I think it true to say that most cylinder heads now need some work to be re-used.
The thread quoted from tbforums includes a post from stealthfti (post #8) - the late, much respected Tom Fritz and includes much of the info you need to know. He was a proponent of tight squish and often posted regarding it.
Tim

[Jebus]

Originally Posted by Laird Scooby

There's obviously a way round that Mark as many new petrols turbos are running 18psi and 10:1 compression or similar. Yes, you read that right and yes, i queried it when i first heard it. I've still not got to the full facts about it so there's scope that it's incorrect but i daresay someone knows. It flies in the face of everything that has previously been known though.

Its not so much rewriting what was known just very carefully desgined port combustion chamber and piston designs, Direct injection and varied injection phases, they can control where the fuel is in the cylinder, what would have made an engine explode in a million bits a few decades ago or was only on delicate race engines now to many thousands of miles on the school run, nipping to tesco and buzzing up and down the motorway, it really is amazing when you think about it