ok no update for a while but I've been trying my best to move it all on, the baby is now here but they are both asleep so here is my chance!
right the engine came out, I've left that heavy box there its happy and out the way!
A quick jet wash of the bay has cleaned it up a treat, not done in this photo
I think I've worked out what went wrong now and how to fix it
its all to do with these 3 bolts, you can see two types here, the fucked ones and the correct ones with the m6 nut on the end. my car didn't have any nuts?! why I don't know so the whole lot was moving back and forth.
The consequences of the swarf going around mill isn't great.
a few of right and wrong as such.
onto the bottom end then.
A few shots of the main bits, the crank is pretty tasty and, very small webs and its light, slugs are small and light along with the rods.
This is the ultimate 24v non M power bottom end, or a very exotic one as its all unique to this engine. Crank is used in the 3.3 version but the pistons are 3.4 only and 87mm.
This is where it get interesting or expensive..........
I inspected the shells. The main ends were mint, nearly zero wear to shells. Great.
main ends, shes pretty clean inside, so much that you can still see the paint dab on these shells for the different classification. BMW use standard size shell from new, then either paint them white, yellow or green and they are ever so slightly different in size. 0.01 of a mm to keep the tolerances with the crank journals right.
A stock bmw engine uses a set as such so they are all the same colours. Not on this hand built beauty. Alpina obviously measure each journal and vary which colour shells they use. It all adds up in the end and shows the hand built nature of the engines.
Big ends not so, they were worn and there was scoring on a couple. Not good, the wear is expected at that milege and performance nature of the engine also so no surpise there
Crank is ok and not needing a grind, so just a really good clean and blow out of the oil ways and shes good to go
new big end shells, standard size
an original big end shell, its gone dark grey indicating the wear, the cap end gets the harder time that this upper shell.
Onto the oil pump.....
you see again some swarf has come up through the pump. The housing looked fine
So a new gear and matching bit should restore any lost oil pressure.
I've ended up having the block and head acid dipped cleaned to try and make sure all swarf it removed. Or anythats left. So the block needs painting again
I've had the block re honed or glaze busted, the old honing was still visible still but there was some vertical scoring on the bores. This was the worst. Machine shop looked at it and declared it ok. No 6 pot picture here was the worst and you could feel it with your finger nail. Not good, but none of the scores come right to the top of the bores which is good. Meaning a total seal as such on the rings on the compression stroke
Now onto the piston rings.........alpina part number got me frightened as non of this was budgeted for but that's cars.
Stilling down the price was £108 per set. I need 6 sets........
Machine shop to the rescue, they deal with a German company called SM for their in house rebuilds they do. All they make is piston rings that's it.
I gave him old rings which were measured and he mentioned the pistons are more like something out of a race engine! the rings are very thin and exotic basically. Anyhow he measured them all up and rang to see if he could get them. The answer was yes and they confirmed these piston rings are only fitted to this engine! The 87mm bore size isn't an odd size but the thickness of the rings are being 1.2mm 1.5 and 1.2 irrc
Short of it yes they could supply for £38 per set! I bit there arm off and I sourced a full set for a third of the dealer £660 odd they'd want.
I know i'm going on but Alpina list only ONE piston size and rings for these engines. Theres NO over size rings are slugs listed. Meaning the bottom end is as far as it could be taken. No over boring if you block ends up damaged, or sleeving either I think.
So with some effort it can be done! So heart attack was avoided and the engine saved imo.
Onto the head now
seats were in fab condition and lapped in nicely, as were the valves themselves. A good diet of super judging by the minimal carbon build up
My dads as always has given the head a re face. He took off 5 thou so nothing to worry that's just over the thickness of a human hair.
Again alpina don't list an over size gasket for heavily skimmed heads! More worry.
This is another issue I've looked into as the head gasket is a stupid price of £424 plus VAT. I've ordered one from BMW and it turned up in an elring box. My machine shop deal with elring, so I've got them on the case to see if I can get one like the rings and avoiding the sheer greed that BMW/Alpina have in their margins. So watch this space, they've ordered one in and its £60 plus VAT if its correct. I'm not holding my breath but worth a try?
Valves all going back in, the valve springs are unique to this engine as are the camshafts.
head built up ready to bolt down.
So its ended up being a full engine overhaul really. Not what I wanted or expected but that's cars. At least she should be good for another 100k if the gasket lasts! Plus i'll have to run it in now with new rings. But no.104 shall be good again!
I've not quite worked out how i'm going to build/fit the engine now my little girl has been born! but its the baby tram so even an hour a day will help
Looks like the nuts have come loose and the sprocket has worked its way forward? Take the cover/piston off the housing and see what the state of the bore is, could be ok to go again with some new bolts and seal. Its possible that exhaust cam has slipped, thats the same bad running problem I was hunting for weeks, but it wasnt half that bad!
Le Mans Classic 2006
Just to help me later on if I get a sensor fault
