rockcrawler31 wrote:hi guys
i need someone to help me change the head gasket on my 1HZ. I want to learn how to do it myself so i would need someone who can do a cash job, and doesnt mind letting me watch or help.
Is anyone here interested in a little after hours money, or do you know anyone who might be?
I am in the brisbane area, so in the SE queensland area would be good
Cheers
if you can do it on a petrol engine, you can do it on a diesel, don't be afraid to rip into it yourself if you're a decent home mechanic. However, what symptoms make you think the head gasket is bad? The 1HZ isn't known for throwing head gaskets, unfortunately head cracking is far more likely and the symptoms are often indistinguishable until the head is off. look for cracks between the valves. the precombustion chambers are also likely to be cracked. If it is the head gasket then the likelihood of head warpage is high (the spec is generous for warpage however). if the head is warped, it must be replaced.
some things to be aware of:
the head is HEAVY - take the bonnet off for access, and unless you have 4 steady-handed mates, use a hoist to lift it on and off.
there are 5 different head gasket thicknesses for the 1HZ, three of which are available as spare parts from toyota. you have to use the same thickness as the one that comes off or the next thicker. do not use an aftermarket gasket.
you will probably need to replace the precombustion chambers. use aftermarket ones, the price of toyota ones will kill you.
cam and fuel pump timing is done at #1 BOTTOM dead centre to avoid the possibility of crashing the pistons into the valves and to avoid trying to line up the pump at the top of its compression stroke where it won't stay still.
replace the timing belt and tensioner while you're in there. they're cheap and it's easy.
if you re-lap the valves you will need to have the valve lash shims adjusted, take it to a shop for this part once you have it running again. it's just not worth dicking around with unless you have the tools and shim set. check the clearances while the rocker cover off anyway.
Can't remember if there are any other tricks required to do a 1HZ head, it's a pretty easy motor to work on really, everything pretty much falls apart and back together without too many skinned knuckles or swears. If you have a Gregorys manual it covers all the major pitafalls, the only special tool you'll need is a torque wrench.
good luck
Brian