OK iv been searching on head gasket replacing...and not much result.

SO, can anyone who has replaced or knows how to, give me a step by step guide to replaceng my head gasket for the ol TM.... I got a mitsu service manual and it shows how to take it all off, and not much else...

Thanks in advance

Andrew

It's pretty easy. You can do it with the inlet manifold and exhaust manifold attached but I think it is easier to do it with these off.

Unbot the exhaust manifold, water pump and inlet manifold (make sure you label any hoses). Once that is all out of the way mark where the distributor is pointing and pull it out. Pull the rocker cover off and take the sproket off at the passenger end (front) of the engine. Move this out of the way. Then undo the head bolts working your way out from the center e.g.:
3 1 5
4 2 6

Once that is done you should be able to lift the head off the engine. If it sticks, be careful prying it up as a nick out of a head can be bad :)

Once it is off pull the gasket off the block or head (most of it will still be stuck there) and clean the head gently with a gasket scraper. Inspect for cracks and use a straight edge to make sure that it is not warped (across the centre, front, back diagonals and then along front to back in centre and either end). The distortion allowed should be in your manual. If it exceeds this you will need to get it machined.

Clean the gasket surface on the block with your gasket scraper, inspect this and also check it with a straight edge.

If you are happy that the head and block are OK, place the head gasket gently on the block and lower your head down onto it. DO NOT SLIDE THE HEAD AROUND ON THE GASKET!

Then tighten the head bolts to the torques specified on the head gasket package in the sequence specified. Normally you have to tighten each 3 times (once you have finisahed one tension, tighten them to the next).

Put the rest together and you should be all good.

While you have the head off I would also change the valve stem seals (if you buy a VRS kit they will come with it)

OK
Thanks this is great...but how on earth do you get the intake manifold off??? its imbloodypossible!! the bolts on the top row of the flange can be done for sure, but the ones underneath??

I kinda stopped here cos if i unplug all the fuel lines and heater hoses its cool, but the lil vacuum lines are gonna get a bit mixed up if i dont label them..... so is it easier to find out a way to unbolt the whole manifold? :nuts:

oh yeah... changing the valve seals... do i have to put the head in an oven or something to get them out/in??? and the y definitely need replacing cos when the engine is running exhaust comes out the holes and out the oil filler cap if i open it.... yay :doubt:

Thanks........ I'll get this cruise missile back on its way across the Euphrates in no time!!! :badgrin:

The ones underneath the manifold are very fiddly but it can be done. You need to use a spanner in some pretty strange and wonderful positions.

I would definantly mark your vacuum hoses, Magna carbies and their emission systems are a *****.

You can do it with the manifold on if everything is clear, but I prefer (personally) doing it off there.

As for the valve stem seals, the only thing you will need is a valve spring compressor. You do them one at a time and press the spring, pop the collets out and change the seal (try not to move the valve itself).

now you are a brave person
cant say i would want to have to replace a head gasket
i can pull things apart /but getting them to start again ..no way
i always stuff up the valve timing and have to get racq to fix it

you deserve a magna medal
Hehehe thanks.
Actually what I used to work on quite often were the old Nissan/Datsun L Series engines. They were a bugger to do a head gasket on because if you werent careful you'd drop the sprocket and timing chain down into the timing case and pull that off as well!!! At least the mighty Astron has a guide to stop the sprocket from dropping.

As for setting the valve timing, it's not that bad - just need to remember to set both the block and the head at TDC before you pull it apart, then make sure the head is at TDC when you put it back on!!!

you need good tools to do fiddely work like this, stubby ratchet spanners are the bomb for this job, at very least stubby 12mm and 14mm spanners.

i got it all done now....

while the head was off it got new valves, seals guides re grinded valve seats, a service regrind(head shave) and all cleaned up in a chemical bath...

and its stapmed as 1991 TP too cool!!!

noew im figuring out how to get the frikken vaccum lines done AND the exhaust return **** greeny recycle emmission theing sorted out, in the end i just plugged it all up but i dont think its gonna work...

Your head sounds good mate :)
As for the emissions lines, if they are all there replace them one by one. If they arent (which I am guessing by you saying they're blocked up) then have fun with vacuum diagrams.

mag 86 how much did the head work cost you approx looks like i am up for the same thing
Just a suggestion - try and get your hands on a second gen head - roller rockers and higher compression.