Changing manifold gasket on VH

[VS_Wagon_Baby]

Ok, so the old VH is sitting in the front yard unregistered at the moment and my younger bro will be getting it soon. It still starts first pop everytime, but it is running pretty rough on 5 cylinders, but is still very driveable when it is moving (although it sounds like a giant lawn mower).

Anyway, my dad reckons it is the manifold gasket causing it and i am going to have a crack at changing it. Does anyone here have any experience with changing one on this model, and could you give me a rough idea of whats involved and how difficult it will be.

Thanks

[DANNY8]

Is it a 6 cylinder?

If so, remove the throttle cable (2 bolts holding the bracket on), undo the fuel line, remove all vacuum lines (take note of where they go), then unbolt the carby which is done by the 4 bolts at the base. The carby should pull off, followed by a large plate and a thick gasket thingo.

Then undo all the bolts holding the intake/exhaust on, either a 12 or 13mm socket should do the trick.....then the exhaust and intake should just come off.

[VS_Wagon_Baby]

^Yeah, she's a 6. Thanks a lot for that man, ill report back with my progress when i get around to doing it.

[VS_Wagon_Baby]

I just found this thread i started a little while ago and thought i'd update it.

I got hold of a compression tester and tested it, turns out the second plug closest to the steering wheel (no.2) is putting out nothing at all, and no.3 is putting out about 30ish, and all the others are good, putting out 150ish. So, does this mean it is a head gasket? If so, how hard and time consuming is that to take apart and change?

[Tom_1569]

Normally if its a cracked headgasket it will be one cylinder, and if its two, they are normally even, or very close to even (i.e mine had about 32 and 35 which was a crack between cylinder 1 and 2).

If you squirt abit of oil down the bore and see if the compression comes up this will tell you if its the gasket or the piston ring. If it comes up its your rings, if it doesnt then its most likely your head gasket, could even be a valve.

Changing the head gasket isnt that hard, just time consuming and will depend on your mechanic knowledge.
But a white marker pen, and mark everything when you pull it off especially vacuume lines.

Start by removing the carby (i normally just sit them to one side) remove the Manifold, remove the exhaust headers.
You may have to unbolt your air-con or power steering bracket.
Remove brake vacuum and other vacuum lines going to it.
Take off Rocker cover, and timing cover.
Wind the motor off to TDC (make sure top and bottem are both at TDC)
Then remove Dissy
Unbolt head, do this in a sequence, dont just rip one bolt out at a time.
Remove the head, see if you can find where its cracked, if its obvious then full stem ahead. You can get it machined and crack tested etc, its up to you.

Clean both surfaces, and prepare to put it all back together.
I use a chemical sealent on the gasket and on all head bolts, I cant remember what its called my mate brang it round for me to use, but Im sure someone else will know what its called.
Torque all bolts up in correct sequence and stages, and then start piecing everything back together, again I used the sealent on most gaskets as I went along.
You will have to make sure the timing is still correct and replace the dissy back in also at TDC, once its all back together you can redo your timing.

Ive probly missed heaps of what needs to be done, but see if you can find someone to help you do this if your in doubt. and you will need a torque wrench, dont attempt it, if you dont have one.

[elegance]

gm sealant and it smells crap

[Tree cutter]

Drain the coolant out of the block before you unbolt the head so you dont get coolant in the cylinders and lifters. Keep the pushrods in the same order as they came out by cutting little crosses in a piece of cardboard so you can poke the pushrods into the cardboard as you pull them out of the engine and write on the cardboard front and rear so you can put them back in the same order. You don't have to pull the distributor off but you will have to unbolt the coil.