Cars / e32 / Engine / M30 to S38 Engine Block Conversion

M30 to S38 Engine Block Conversion

Re-posted By: Green Lagoon

Article applies to: applies to all BMW M30 engine blocks.

Disclaimer: This valuable information is getting lost on the internet as time goes on. I am not the original author of this content.

It was posted in various threads on and I am just making a summary of this procedure, to make it more clear to understand and posting it again in 2020.

S38 engine blocks are hard to get these days, not mentioning the price. Technology isn’t there yet to 3D print them 🙂

The solution is to use the M30 block, since the S38 originates from it or at least is its close relative, and convert it to S38 block.


1. Drill 5 additional holes at the top where the head comes on (use a S38 head gasket as reference) . . .

…. and insert two oil injectors into these two oil feed holes (OEM # 11111306874)

2. Bore out the cylinders to 93.4mm (S38B36 spec) and check piston stroke, if its bored deep enough.

3. Drill an additional hole into the seat of the first main bearing. This is used for timing chain lubrication. Hole diameter is 4mm.

Drilling angle needs to be such, that you drill into the hole for the timing chain guide dowel pin.

4. Bore out the hole for the timing chain guide dowel pin from d=8mm to d=10mm (S38B36 dowel pin OEM # 11111308657) and drill an additional hole for the dowel pin of the oil pump chain tensioner (S38B36 dowel pin OEM # 11111706500).

Both are press-fit, so be careful with your choice of drill bit diameter!

5. Add a hole for the head oil return pipe. You can make an adapter plate for the connection.

A small portion of the block needs to be brushed away at the top where the head comes on, in order for the pipe to clear.

6. You can also engrave the S38 number on the block where the water pump comes on.

. . . also, one hole for the water pump is not threaded on the S38 block. Its the one behind this engraving. You will see what I mean when you will try to fit the S38 water pump.

The procedure above is for S38B36. For S38B38 you need to add additional oil squirters at the bottom of each cylinder (piston cooling/lubrication) and bore cylinders to 94.6mm.

Note: M30 blocks differ from one version to another in build material, various connections, bores….. M30B35 block from the E34 535i is sufficient for standard non-boosted use.

Hope this helps someone in the future.

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