N43 Oil pump, a handy hint...

Andystobbs · 10-24-2021, 04:21 PM

So if like me you own an N43 engined car, I sympathise.

My other half's one series started having a persistent issue with 3C01 which initially was cured by a new PWM valve. However after months further trouble free operation, eventually the issue came back, with a vengance.

I stripped the entire engine, had the crank re-ground due to some scoring and built it from the bottom up with new rings, shells, seals etc etc.

The oil pump was knackered though, it had deep scores internally that would allow pressurised oil to escape back into the suction side. A replacement was needed.
However BMW only sell it with the balance shaft assy. at over £800 - more than the rest of the rebuild put together, by a fair margin.

So I did some research and found another pump that is similar and seems to be fitted to the N43 without balance shafts - I've never seen such an engine in the UK, perhaps its a foreign market application.

Part number 11415A12274

It is a shade over £300 from BMW.

It does require modifications to fit to the balance shafts, I suppose you could run it without them all together if you had such a mind, but I decided to keep them and modified the pump to fit.
Brackets need cutting off and some holes drilling out and the original drive shaft from the old oil pump (with balance shaft drive gear) must be re-used in the new one.

I have a machine shop at my disposal and milled away much of the surplus metal, however its nothing that couldn't be done with a hacksaw, a file and some wet and dry paper taped to a glass sheet - for flattening.

Attached is a picture of the identical internals.

jwilalex · 10-25-2021, 05:39 AM

I'm afraid that's way out my league.. when my pump went warranty sorted it so not an issue. £100 excess to pay.

Costafortune · 02-27-2022, 01:28 PM

You can remove the balance shafts from the balance shaft housing and just block the oil supply hole. Balance shafts were not fitted to the N43 1.6 or the N45 1.6 used in the 04-07 116i.

Andystobbs · 02-27-2022, 04:19 PM

Wonder why not. Must be lower reciprocating mass of the smaller pistons.

Dormermike · 02-28-2022, 07:28 PM

Quote:

Originally Posted by Andystobbs

Wonder why not. Must be lower reciprocating mass of the smaller pistons.

More like the lower reciprocating mass of the wallet and something to differentiate the "bigger" models?

10-24-2021, 04:21 PM	#1
Andystobbs Captain 196 Rep 720 Posts Drives: E91 Lci, Vectra B V6 Join Date: Sep 2019 Location: Chester, South Wirral iTrader: (0)	N43 Oil pump, a handy hint... So if like me you own an N43 engined car, I sympathise. My other half's one series started having a persistent issue with 3C01 which initially was cured by a new PWM valve. However after months further trouble free operation, eventually the issue came back, with a vengance. I stripped the entire engine, had the crank re-ground due to some scoring and built it from the bottom up with new rings, shells, seals etc etc. The oil pump was knackered though, it had deep scores internally that would allow pressurised oil to escape back into the suction side. A replacement was needed. However BMW only sell it with the balance shaft assy. at over £800 - more than the rest of the rebuild put together, by a fair margin. So I did some research and found another pump that is similar and seems to be fitted to the N43 without balance shafts - I've never seen such an engine in the UK, perhaps its a foreign market application. Part number 11415A12274 It is a shade over £300 from BMW. It does require modifications to fit to the balance shafts, I suppose you could run it without them all together if you had such a mind, but I decided to keep them and modified the pump to fit. Brackets need cutting off and some holes drilling out and the original drive shaft from the old oil pump (with balance shaft drive gear) must be re-used in the new one. I have a machine shop at my disposal and milled away much of the surplus metal, however its nothing that couldn't be done with a hacksaw, a file and some wet and dry paper taped to a glass sheet - for flattening. Attached is a picture of the identical internals. Attached Images
	Appreciate 0 Tweet Quote

10-25-2021, 05:39 AM	#2
jwilalex Private First Class 34 Rep 128 Posts Drives: E90 318i LCI SE Business Edn Join Date: Jan 2016 Location: Glasgow iTrader: (0)	I'm afraid that's way out my league.. when my pump went warranty sorted it so not an issue. £100 excess to pay.
	Appreciate 0 Quote

02-27-2022, 01:28 PM	#3
Costafortune Registered 0 Rep 4 Posts Drives: BMW E36 Join Date: Feb 2022 Location: T'North iTrader: (0)	You can remove the balance shafts from the balance shaft housing and just block the oil supply hole. Balance shafts were not fitted to the N43 1.6 or the N45 1.6 used in the 04-07 116i.
	Appreciate 0 Quote

02-27-2022, 04:19 PM	#4
Andystobbs Captain 196 Rep 720 Posts Drives: E91 Lci, Vectra B V6 Join Date: Sep 2019 Location: Chester, South Wirral iTrader: (0)	Wonder why not. Must be lower reciprocating mass of the smaller pistons.
	Appreciate 0 Quote