While my engine is out, what should I do to it?

[AlexMaldonado]

Hello, so I recently came across an M20 from a 525i with about 100k miles on it. I'm getting a pretty good deal, so I think I'm going to buy it along with a transmission and diff. and swap it into my 318is. While I still have the engine out, I plan on changing the timing belt and maybe a headgasket kit. What else should I consider doing to refresh it for a long, healthy life while I still have it out? I've not got a huge budget, but I may be able to toss a couple performance parts on, but I'm mostly hoping for longevity.

[Kershaw]

Oil pan gasket. Rear main seal. Cam seals. And don't use Victor Reinz.

[TobyB]

I would not pull the head at 100k IF there was no obvious reason to.

jus me,
t

[e30davie]

I wouldn't touch the rear main if it is not leaking.

[pandaboo911]

Follow the prime directive. If it ain't broke don't fix it.

[digger]

Does the m20b25 from 525i mount differently to the m20b25 from an e30? I know there are differences but they escape me at the moment.

[AlexMaldonado]

From what I understand, it might need a different oil pan, but I haven't heard of any other differences. And I was thinking of doing a rear main seal, but then again the old if it ain't broke mantra is a solid piece of wisdom to live by.

[digger]

i recall something about dipstick and engine mount differences, but as long as the block mounting holes are the same and its just the brakcets that are modified then it should not be a problem

[BUDNUNTA]

You need to swap the sump for a e30 one

Tap the holes for the e30 motor mount arms

Drive the plug out of the block for the dipstick tube

Best to get an e30 harness too

I did a e34 M20 2.5 in to a 83 318i last year

[peterman]

Not sure about your situation, but those 318is are going up in value quicker than any other non M e30. If it were me, I would keep that M42 in there and get a cheap 325e to swap the m20b25 into... I think you will be devaluing you car by doing this swap - if the car is in ok condition.
I know you didnt ask for it, but that is just my .02.

Edit: But yes I would pull the caps on the rods to check bearings at least and do all the gaskets and any vacuum lines.. Once that rear main goes - its a pain in the arse
.
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[ThatOneEuroE30]

Personally. Would do all gaskets and the bearings.

[SkiFree]

Not sure about your situation, but those 318is are going up in value quicker than any other non M e30.

They might be catching up, but as far as I've seen, they are not yet at comparable 325i/is pricing. My .02 cents.


OP...
I'm assuming you are also swapping out the idler pulley and water pump with that timing belt? You are also going to want to do a simple valve-lash adjustment.


Beyond that, I see good arguments for both leaving it alone..or replacing bearings,etc. Your call.

[mr2peak]

Keep the 318is a 318is, or put something much greater in it's place. All you're doing is driving down the value of the car.

You can probably sell it or trade it directly for a 325 car in as good or better shape

[Sail Boat]

Keep the 318is a 318is, or put something much greater in it's place. All you're doing is driving down the value of the car.

You can probably sell it or trade it directly for a 325 car in as good or better shape

Agree, keep it a 318.