New Zealand Datsun Club

Hey guys,

my datsun blew a headgasket a month or two ago, z18et.

I have it in at CHS getting it resurfaced and pressure tested, but am wanting to up the compression ratio to give her a wee bit more.
Can anyone point me in the right direction if its worth skimming it a bit more to up the compression ratio and would it cause any issues eg valves hitting pistons?

And if any knows the CC in the chamber i should be aiming for?

Thanks!!!

KA

With an OHC datsun motor, if you skim the head it will affect the valve timing.
Since it's turbo, just increase the boost slightly.
Maybe try fitting a "boost bottle" to it.
Get a container like a small empty aerosol. Drill out where the nozzle used to come out, and fit a hose tail/nipple. Run this hose to a tee in your wastegate line. Then before the wastegate can open, the turbo will also need to fill the new vessel with pressure. This will give you a boost spike in the lower-mid rpm, giving a power increase. (in the lower rpms you still have plenty of spare injector duty cycle/AFM range)
The bigger the vessel, the bigger and longer the boost spike.
I haven't tried it myself, but I read it in a book written by a clever bloke.

Bartman wrote:With an OHC datsun motor, if you skim the head it will affect the valve timing.
Since it's turbo, just increase the boost slightly.
Maybe try fitting a "boost bottle" to it.
Get a container like a small empty aerosol. Drill out where the nozzle used to come out, and fit a hose tail/nipple. Run this hose to a tee in your wastegate line. Then before the wastegate can open, the turbo will also need to fill the new vessel with pressure. This will give you a boost spike in the lower-mid rpm, giving a power increase. (in the lower rpms you still have plenty of spare injector duty cycle/AFM range)
The bigger the vessel, the bigger and longer the boost spike.
I haven't tried it myself, but I read it in a book written by a clever bloke.

sounds like a recipe on how to make a bomb lol, although I must concede It should work quite well.

Bartman wrote:Since it's turbo, just increase the boost slightly.

I'm with Bart, are you after driveability or power, increased compression will mean you can run less boost safely, thus less potential for Horsepower.
Add boost, not compression I'd say

Spray cans run much higher pressure than your manifold will ever see. I've seen my dad "repressurising" cans that have gone flat with a duster gun. (Don't tray that with a can of engine start though!)