Hi folks,
I managed to slightly pop my head gasket a few weekends ago, 100 miles from home.. Managed to get the car home with a LOT of replacement water for the radiator, pulled the head off, and it's just popped over slightly (no holes or missing pieces, just signs of blow-by between cylinders), so I shoved a new head gasket on, re-did the valve clearances (after mentioning to anto that I was down on power.. d'oh should have thought to re-do the clearances after putting a new head gasket on), and she's running just like she used to.. except after backing off and putting the foot back down, it now blows lots of smoke.. OH, also sitting idling for more than 1-2 minutes causes it to very badly gunk up the plugs.. Compression test done, we've decided I've probably detempered the valve guides or something and it's sucking oil down them, so a head job was in order..
Then I got to and actually tested the engine in my parts car (much to anto's dismay, he's been 'meaning to' test it for a while to put it in his..), and found the compressions are awesome compared to what mine have always been (I've always had 130'ish, this has 190'ish). So decided to use that engine.. But since the gearbox is cactus (doesn't go into second, and the other gears aren't much better), I bought a gearbox off makka. Only problem there is I have rubber uni-joints, and the gearbox from makka has cooper drives (or so we think? round plate with four bolts?).
Since my mini does 100km/h at 3000rpm in 4th gear, which I'm told is quite unusual, I wanted to keep my diff (4.4L/100km on a trip to melbourne and back is awesome++) so I figured the easiest way to solve both problems was to simply unbolt the rear housing and remove the existing diff, and then do the same with mine and drop mine in.. Which Anto quite happily (grin) pointed out this weekend wasn't quite so simple, as I'd have to swap the gear that drives the diff (the one inside the gearbox) as well.. While that's not a HUGE problem, it does mean I actually have to pull the engine off the top of my gearbox, which means my car will actually be off the road for more than a few hours (i.e. it's not just pull old engine out, swap diffs, drop new engine in..)
So I'm wondering a) what diff ratio my car must have to be doing 100k/h at around 3000rpm on the highway), and b) how to identify what the diff ratio on the gearbox I bought from makka is.. I'm hoping (big hope, I know) that it's actually the same ratio, so I can just drop my diff straight on and save a whole lot of trouble..
Any thoughts?
Cheers,
Damien
