Rebuild progress vent session

[NC325iC]

So... I bought a $400 200k mile m42 for my 2002...

It was running when removed from the car so I figured it would be an ok starting point. I figured I'd pull the head to get a look at the cylinders, pull the oil pan, clean everything up a bit, replace the timing guides and seal it back up and be on my way without sinking thousands into it...

Well I'm at about $1500 in parts now, including the original $400, and my mindset has had to change.

It started when I found the cylinder 3 scuffing and crank endplay. Well that means I need a new crank and bearings at the very least. While I have it torn down I should get the block cleaned and honed, and might as well get new valve seals done too. I'll get rid of the idler wheel on the timing chain. New lifters all around because why not...

Checked my bearing clearance and it's in, but at the high side of the tolerance... In is in and that will be more oil flow.... Right? I couldn't tell what color the paint marks were, either yellow or white but it's not clear... I should have the machine shop measure them to be sure.... Can I return bearings... Didn't think so.

Checked my ring gaps yesterday and they're... A bit big... Well shit. I had the block honed... It didn't fix the scuffing but that was ok at the time... Now I'm not so sure it is. I think I'm gonna take it back and have them bore it to clean metal. Can I get away with this without new pistons? (I know it depends on how much they remove)

Vent session over for now

[NC325iC]

Forgot to mention the valve guides are sloppy and need to be replaced

[amcp]

Never fails. Sometimes its better to just slap it in than while we're here.

[bmwman91]

Haha well, such is the way of digging into old engines. If you go looking for the kind of wear that can be expected on a 200k mile engine, chances are you will find it, and the cash bonfire just keeps going at that point. What are your goals for the engine? If you just need a daily beater, it is probably OK, and will just burn some oil, not get amazing fuel economy and generally just work "OK." If you are looking to be able to drive it hard on a regular basis, maybe step back and start making plans out for a full performance build (which will, admittedly, cause your cash bonfire to be visible from space).

[NC325iC]

goals are pretty moderate, just want something to put in my 2002 for a while. Forgot to mention the $400 included a g240 and all of the ancillaries so there is a bit more value in there. If it werent for the stupid 180 thrus bearing....

sigh...

I think i will just go with what I have and keep the cash fire at a medium level. Hell my long term plans for the car are electric anyway, I just dont think the aftermarket electric industry is quite to my comfort level yet and my m10 is pretty well trashed.

On to the real question that is plaguing me today...

I did plastigage my bearings so i know my clearance is acceptable. How can I be sure about the bearing-cap and bearing-block fit? Should I even worry about it if the plastigage came out ok?

[TobyB]

Something to keep in mind is that the 'end' tolerance for parts is the 'last time you should put it back together' number,
NOT the 'hey, the rod just punched a window in the block' number.

So if you're at the end of the acceptable range, you're building a 50k motor, not a 200k motor.
Which is NOT the end of the world.

M42s are still showing up in the cheap junk yards around here.

N52s are starting to get plentiful, so I've changed focus!

t
it'll fit, if I trim a bit.