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M20 Engine Build Options

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e21Keith
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M20 Engine Build Options

Post by e21Keith » Wed Oct 16, 2019 8:21 pm

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?



e21Keith
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Re: M20 Engine Build Options

Post by e21Keith » Sun Oct 20, 2019 6:34 pm

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?

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Jeroen
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Re: M20 Engine Build Options

Post by Jeroen » Sun Oct 20, 2019 10:14 pm

Uwbuurman may be able to provide some info on this
Regards/groeten, Jeroen

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uwbuurman
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Re: M20 Engine Build Options

Post by uwbuurman » Sun Oct 20, 2019 11:43 pm

Well, we do have a 2.7 topic in the pinned tech topics. I'll try to write some stuff up, tomorrow
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Duracel79
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Re: M20 Engine Build Options

Post by Duracel79 » Mon Oct 21, 2019 9:10 am

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
1982 323i (S54 "Test Mule" - to be rebuilt into M20 powered track car)
1983 316 (Taiga Thunder - The refined S54 Race car)
2004 330d Touring (The Daily Hack / Tow Car / Load lugger)

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