hey
looks like my valve in the 1st cylinder has been burnt...
so i was thinking while the head's off i might look into getting it bored aswell.
it's a stock 1098 and i'm prob just looking at getting +20 thru....
dose anyone have any idea of how much i should expect to pay??
and what power gains would you get?

Cheers James

_________________
'75 windowless van
~LOLA~

Your about to spend a lot of money
To bore the motor means that it has to be taken out and stripped down. The actually boring is about $25 per cylinder but new pistons to suit the bigger bore is about $200 a set but then you might as well get new bearings. The crank will need linishing (as a minimum) and so it goes. Then you need a new oil pump, seals etc.

The cost will be about $1000. More if you emply labour for engine building etc.

Add $200 for a full balance, and what the heck, throw in a sports cam.

In the end of the day - the power gain from a rebore by .020 is so little that the second time you take it around the block you wont notice it at.

Better carburettion and exhaust system and the car will be quite different with noticable improvement. A whole lot cheaper as well.

Unless you have other reasons to rebuild the motor (like its stuffed) then dont go that direction as you are about to spend lots of money. To some a couple of thousand is not much though !!!!

THANK YOU VERY MUCHLY

_________________
'75 windowless van
~LOLA~

You're assuming you'd notice any difference at all! The .020 over is not really going to make it go noticably faster, it would simply be having a fresh motor that would make the difference. Going +60 might make a bit of a difference, but as stated it's not really worth the cash unless you're rebuilding your motor anyway.

James, Just took my 998 block to Repco - West Gosford.. $300 for a 0.060" bore and hone, and a crank grind to 0.010" undersize...

Pistons, about $200, bearings and gaskets about $150, Oil pump $50 and water pump / thermostat, water neck etc.. another $100 ....

So you can get away pretty cheap if everything else is pretty good...

J

_________________

thanks guys

i'll c how much it's going to cost me to get this burnt valve done and see how much more it will be for a bore...

o and what causes a burnt valve?

cheers

_________________
'75 windowless van
~LOLA~

It will cost you about $250 to have the head reconditioned - that is a chemical clean, new guides, one new valve, a head skim (to make sure its perfectly flat) and have all the valves reseated. For about an extra $100 you can have hardened exhaust valve seats fitted which will allow you to run unleaded petrol.

Your machinist may advise that one or more valve may need replacing and valves are less than $20 each for standard and normal sized valves.

The costs may vary from place to place but the above is a pretty good guide. An option is to go to a wreckers - or a mate- and but a second hand head that looks good. You could take it to a machinist and have it pressure tested and skimmed (about $50) and just stick it on. Chances are it will be a reasonable quick fix. I am sure any number of ausmini will sell you a small bore head for a very reasonable cost. If your engine is large bore then the head cost is very different.

Now, exhaust valves take an enormous amount of heat and stress and it doesn't need much of a gap between the seat and the valve for super hot gases to pour past under compression. Once that starts the valve will very quickly burn. The cause may be crap built up on the valve seat, valve not closing properly, a valve sticking slightly open in the valve guide or the valve simply starting to break up due to age.

Haha I got mine for free and it was all done by the engine recoers (work experience)


monkey pm me if you are interested int he head I can sell you it if you are interested


Pat

_________________
_______________________________________________
Team MADMAN/Pat Rogers

took the head off today and had a bloke look at it - theres already been somework done to it and he has some spare heads so he's gonna use some of the useable parts from them so everything looks pretty good

thanks anyway Pat

cheers

_________________
'75 windowless van
~LOLA~