Shorty40 wrote:I have prob with the 253 atm
When it has been running for a while (usually stationary) and I switch it off, I can hear a knocking noise (I can also feel it through the car itself).
I lifted the bonnet yesterday while it was making this noise and the water hose leading - into or out of - the intake manifold was "pulsing" in time with the banging noise.
The engine temp gauge was reading a little higher than usual.
Any thoughts ???????
on a holden v8 there are two things that cause this the number one cause is the water pump, you have to run a cast impellor pump the pressed steel ones are just crap and cavitate far to much, the other thing is the thermostat has given up and needs replacing, from experience i would say its the water pump. there are some other mods to do to holden v8's to help keep them cool here it is.
have you got a good clutch fan and shroud or thermofan setup,
next you can put coolant/steam bleeds from the high point on the manifold at the back by drilling and taping the manifold (one each side) and run it forward to the top of the thermostat or in to the top radiator hose (on the radiator side of the thermostat) each line only needs to be about 5/16, this works well i've done it on a 60thou overbored 351 cleveland with great results.
next underneath where the small hoses come out of the thermostat housing you need to get a piece of copper pipe that fits neat in the hole in the manifold and flare the end 45 degrees and countersink the hole in the manifold so the pipe will go unflared end first in to the manifold and the flare sit in the countersunk bit so when the housing goes on it holds the pipe there the pipe should be long enough so it is about 6mm from the bottom of the manifold.
the next thing you can get is a ECOtrans thermostat conversion system it moves the thermostat to the bottom hose and makes the cooling system more efficent the person you want to speak to about this is John Bennett at ECOtrans ph- (03) 9335 4344 at 23 webb road airport west victoria
i have read articles about this system that say it can keep a big block cool with a two core radiator. hope this helps.
