To Head Gasket or Not To Head Gasket?

[carsounds_dan]

its done 36000 miles, i have no service history and im dropping the engine out anyway to do all manner of other servicing. so... what do u recon? if i choose to do i need to use new stretch bolts aswell? or reuse the old ones as the gasket hasnt blown?
cheers
dan

[deviant]

My attitude would be:

If it aint broke, and you don't need to have the head off for anything else, then why bother. It's only going to cost you time and money. For all you know the existing one might go on another 20k miles.

It's not something like the camchain where the engine will instantly self destruct if it lets go.

[Caz]

where on the service schedule does it say "replace head gasket"?

im with deviant on this one, if it aint broke dont fix it

[zimm]

where on the service schedule does it say "replace head gasket"?

im with deviant on this one, if it aint broke dont fix it

+1

oh, if you do go ahead and do it you wont need new bolts, but you will need a new base gasket (or chuck it, use silicon to seal the block to the cases and gain a bit of compression) and you may as well fit new rings as they get a hard life in high revving engines.

[carsounds_dan]

right well im 3 doors down from the felbridge store of http://www.motorcyclecentre.com and spoke to the lad in there.
he used to race them aparently and he seems to think it would be worth doing whilst i have the engine out. How much harder is it to change the rings? and what on earth is the base gasket? i've rebuilt the mini A series engine before so chances are that i know what they are, just called different things.
cheers
dan

[zimm]

unlike a car engine, the bolts that hold the head on pass straight through the block and screw into threads in the upper crankcase sandwiching the block. The base gasket goes between the block and the upper crankcase. Consequently, its good practice to replace the base gasket as once the heads off this seal is disturbed and you run a risk of crankcase pressure escaping at the join. Disposing of the base gasket effectively shortens the block by oooh .5mm (?) same as a mild head skim but free !! its a common tweak on zxr400 engines. Ive done it myself on 2 engines this year alone.

It also means replacing the rings is dead easy as you will be pulling the block off the pistons anyway. Just prise them off the pistons carefully and replace with new ones paying close attention to which way up they are (they are slightly tapered.. no you cant see it, but they should be marked)

only fiddly bit is persuading shiny new rings to squish up neatly and slide back into the block without going all over the place.

[masterofinsanity]

as said before if it aint broke then why bother?

[rene]

as were using silly sayings...

prevention is better than cure

why not change it why its easy? other wise if it dos go while you still own it you've got to skim the head ect

so easy job now or harder job later? seems like a no brainer to me

[carsounds_dan]

to those who care it turns out that it has blown since the new cam chain was fitted. so engine out on wednesday and hopefully get the gaskets and rings changed on sunday and put the engine back in... sounds like i've got fun ahead.
any hint/tips on head gasket change or any special tools that i'll need for it and will I need to replace the head bolts.. anyone who wants to come and take pictures/help is more than welcome btw
cheers
dan

[masterofinsanity]

you can take pics yourself and do a write up while your at it. good luck! getting the head skimmed?

[carsounds_dan]

i'll skim it myself, the gf's grandad used to run microdean engineering so more milling/lathes/big machines than anyone could shake a stick at.
I was wondering if it actually has gone though, theres no oil in the water, the water hasnt dropped anything and theres only the smallest amount of mayo in the oil... i wonder if it could have been condensation from where it was left standing without any fluids in it for about 4 months?
what you recon?
if i do do it i'll see what pictures i can take whilst at it.. i wont bother with fairing removal etc.. just the main work involved.
cheers
dan

[RedexRobB]

The mayo on the oil cap is more than likely just condensation from standing about. What makes you think its gone?

[rover220]

itll be condensation. mine builds up quite bad on the oil level sight glass.

bes bet is to get it real hot thenturn it off and take the oil cap off

[carsounds_dan]

well nothing fool proof but the rad has lost probably an inch of fluid since she was topped up (engines been run about half an hour since then in 8 or so little blasts, none of which reving her up much and only one up to running temp).
I just noticed aswell that the clutch has a rattle which it didnt have before, so new plates it is for that and also its got a little bit of a rattle from the top left of the engine, where piston 1 sits so i'm wondering wether i should be looking at doing the valve clearances (never heard a zxr400 before mine so no idea what they should sound like) . Anyone else's views/experiences please let me know.
Cheers
dan

[RedexRobB]

dunno if this video helps mate but this is what mine sounds like

http://www.youtube.com/watch?v=oc_AawMkJR4