87is M20 to 88is M20

[MattAvino]

I'm switching the M20 in my 87 325is to an M20 from my 88 325is. What are some details that I might overlook when swapping to the 88 motor? Small differences?
Thanks.

This motor:

Into this car:

[IRON-E]

Really?

[MrNatural]

Computer for one...

[MattAvino]

Computer for one...

Well yes. But, i'm asking if there is something small that I may over look, especially when wiring up.

[MattAvino]

Really?

Thanks for the help.

[jlevie]

The engine harness used on the 87 & 88 are different. There will be no problems if you use the harness from the 88 engine.

[MattAvino]

Ok. I will be switching the harness's so no problem there.

[TurboJake]

The cooling system might be different.

Other than that though. Nothing really.

[MattAvino]

Ok, thanks. I foresaw some wiring issues with late/early model differences.

[MR 325]

Use the car's harness and there will be no wiring issues.

As mentioned though, the 87 and 88 use different cooling systems. You'll either need to convert the engine to the early cooling system or the car to the late system. Both aren't too difficult.

[MattAvino]

Use the car's harness and there will be no wiring issues.

As mentioned though, the 87 and 88 use different cooling systems. You'll either need to convert the engine to the early cooling system or the car to the late system. Both aren't too difficult.

Ok thanks. I think I will opt to convert the early car to the late cooling system, after a quick read through the Cooling System section of the Bentley, the only mention of differences from 87 to 88 were clips in the process of radiator removal. But i will take a good look at both cars, i'm sure I can figure it out.

[MR 325]

Ok thanks. I think I will opt to convert the early car to the late cooling system, after a quick read through the Cooling System section of the Bentley, the only mention of differences from 87 to 88 were clips in the process of radiator removal. But i will take a good look at both cars, i'm sure I can figure it out.

No, all of the hoses are different, the radiators are different, the water pumps are different, and the late model has a coolant tube that the early model doesn't have.

[e30trooper]

o2 sensors are different.

[MattAvino]

No, all of the hoses are different, the radiators are different, the water pumps are different, and the late model has a coolant tube that the early model doesn't have.

Ok, thought so. I will be swapping everything anyways.

[MattAvino]

o2 sensors are different.

That will be swapped with harness