bmwe21.net forums

So I rebuilt the engine in my 323i as part of the resto but it's gone all rattly so I need to start again. Can anyone help me with what the options are using the original B23 block?

I could go stock but my bore on #6 doesn't look so great, I'm into around £1000 for linering and standard pistons or I can have oversize pistons made at about the same cost, this isn't very appealing!

Help please with alternatives? I have a 324d crank (same as the ETA but forged), and a whole selection of B20, B23 and B25 parts, so I could go for a larger capacity. I want to keep the car at least looking stock so the original numbers matching block plus the K-Jet. What combination of crank/pistons/rods can I use, what capacity could I end up with.

Sorry this is such a woolly question but I don't really know what the options are or where to start?

OK, nobody knows the answer to that one!

So I'll probably have to go stock which means a new set of pistons. Ireland Engineering list these for the e30 but not for the e21, and upon checking the ETK I find they have different part numbers.

Does anybody have experience of having pistons made by Ireland Engineering or indeed anyone else?

Uwbuurman may be able to provide some info on this

Well, we do have a 2.7 topic in the pinned tech topics. I'll try to write some stuff up, tomorrow

There are some many different ways of skinning the M20 cat. none of them really cheap.

Using your 81mm crank would need the block boring out to ø84mm and pistons & head to suit.
Then depending what CR you are happy with or what pistons you use, decking the block and a vernier cam gear may be needed.
To use your 200 casting head and the Diesel crank would need ETA pistons (or new custom ones).

There is a lot of info around about M20 build just have a search.

HTH

Ben

I think I might have found the answer to my engine rebuild conundrum, a NOS rebuilt short engine, rebored with new genuine oversize pistons. It will take a while to be delivered.

I'm used to cars with more horses, but in my E21 I'm quite happy with the stock 2.3 setup. There's always something that's faster...

I have 8 horses in the stable and they all have more power than my e21. The e39 M5 is usually enough to satisfy my need for power

At last the engine is back from the machine shop, only took them three months!

Now I have 6 new pistons at first oversize, one of the bores still needed a new liner, crank is also at first oversize. The head was done not that long ago because the original was cracked, this time I'm adding a new camshaft and all new valve gear.

Today I started to remove the engine from the car, taking it with the gearbox. Everything is removed from up top, tomorrow I'll get underneath, I expect to pull the engine on Saturday.

Good news, swap time! Pictures please!

After some problems with parts suppliers:
Recon PAS pump took 2 weeks to arrive.
New rockers took 2 weeks to arrive, when I fitted them 2 looked the same but the hole for the shaft was too small.
Wrong oil filter supplied.
I started the engine for the first time yesterday. First issue during startup was dumping the contents of the sump due to the incorrect oil filter (luckily before I started the engine). It's all quiet, so I'm happy. Need to adjust the timing and mixture.
Need to refit the bonnet and book an MOT, then I can drive it for the first time in nearly 12 months.
The list of new parts (excluding the obvious gaskets etc).

New Oversize pistons
Camshaft
Rockers + eccentrics
Camshaft spray bar
PAS pump
Injectors
Radiator

Machining work
Rebore to first oversize + liner for cylinder no6
Reface block
Chemical clean block
Crank was reground to first oversize

This is in addition to the machining work on the head at the last rebuild.

but you got there in the end!