m42 replacement engine.. questions on what to replace

[smashed s4]

hey guys so i picked up a very clean 91 alpine a few weeks back. m42 was seized. interior and exterior are near flawless..

anyway, i just picked up a running m42 with 170k miles. gonna start prepping the replacement swap. what do you guys recommend i replace to keep this m42 running strong? valve cover gasket, spark plugs, any sensors? anything that is common to fail on these motors? sorry i dont know much about these guys yet.
ive heard upper and lower oil pan bolts. i know the upper is hard to get to when its in the car, will definitely change that too..
oil pump?

any help is appreciated! ill just start making a list of things to look at/replace

thanks!

[///digitalme]

define strong??
gaskets, make sure the sprockets are in good shape...if you want to go further, complete timing overhaul(which by the way is expensive)

[///digitalme]

mess under the intake is a must....

[smashed s4]

mess under the intake is a must....

can you expand on this?

[getouth]

^^^all the vacum connections under the intake manifold there is a pretty extensive thread here dedicated to it. Timing tensioner and a full cooling system overhaul are some major things to consider.

[irish44j]

replace the front and rear crank seals. They're cheap and easy to replace while the engine is out of the car, but a PITA to replace if they start leaking with the engine in the car.

Also worth pulling the oil pan to make sure none of the upper pan bolts have fallen out, as seems to happen to everyone. if not, take them out, clean them up, and loctite (blue) them and then put back in torque to spec.

[smashed s4]

parts ordered! gonna fix the cooling mess under the intake along with a bunch of seals and gaskets and h20 pump!

[bmwm42]

id suggest replacing the timing chain tensioner unless you have documenation as to when last replaced and i would also remove the vc to inspect the cam gears and also removing the lower oil pan to inspect bolts

[jrobie79]

check your spark plug holes...if there's oil in there I'd do the VC gasket and plug gaskets

[smashed s4]

hmmm.. timing tensioner too? how hard will that be to do while its in the car?

[Ryann]

^Search this sub forum, it's covered extensively here. If you want to dig deeper replacing the crank thrust bearing with the updated m50 360 degree version would be a good idea. I'd also definitely change your thermostat and pull the timing covers so you can inspect the chain guides.

[series88]

learn from me, I didnt get to change a bunch of seals and she leaks like hell...Were you the one that picked up Jericho's m42?

[smashed s4]

learn from me, I didnt get to change a bunch of seals and she leaks like hell...Were you the one that picked up Jericho's m42?

im replacing a crap ton of seals and gaskets! but yes i picked that one up!

[series88]

lol forsure. just put 2 and 2 tohether....The SJ car sold, his engine sold and that post on e30 pcs

[AndrewBird]

Check for crank endplay. The 180º main bearing can wear on the crank causing a lot of excess play. You can replace it with a full 360º bearing. Well worth it IMO since you will have the pan off. Prevents damage to the crank (which will be very expensive to fix later), unless the crank is already worn.