remachine the head?

[OldBMR1]

i have an '89 325i with 221,000. I got the car from my uncle, last i saw him he mentioned getting the head remachined.

i am curious to know when is (or most likely in this case, was) the head supposed to be pulled and refurbished.

i am south of chicago and I am looking for a good place to do this work for me
any hints would be welcome

thanks
k koning

email me
soccerun06@aol.com

[iXer]

I don't live remotely close to Chicago so can't help you out with finding a good machine shop.. But I thought I'd recommend things to take a look at while the head is off..
I would check: Valve guides/seals, valves, cam shaft, rockers, rocker arm shafts and seals.

Before you take the head off, check the compression. If you have bad compression it could be because of worn valves or valve seats. If you decide to machine the valves and do a 3-angle valve grind job to have better sealing it could still be the piston rings that cause the low compression, with the kind of mileage you have on the engine it's hard to tell and I'm not experienced enough to say what the most likely cause would be on an M20 engine.

Replace the small tube that runs between and above the rocker shafts, it supplies oil and gets clogged with time - especially if the previous owners haven't replaced the oil on a regular basis. They're cheap, so do it. You risk replacing a lot if this tube fails to supply oil.

For good pictures of the head, take a look at the pictures in this thread over at E30Tech:

http://www.e30tech.com/index.php?name=PNphpBB2&file=viewtopic&t=13

/Mattias

[OldBMR1]

sweden, huh? no not so close to me . . .

thanks for the advice. i am positive the previous owner replaced the oil quite regularly, as do i. if the compression test proves to be fine and normal, does this mean that i need not worry about the head? should i just do a valve and gasket job and go on my way?

[iXer]

Replace the tube anyway, or let it soak in a bath of diesel fuel while the head is left to the machine shop.
If the compression test shows about the same compression on all cylinders (about 150 psi or higher) you're okay. If there is too much variation, say one cylinder is down 20 psi it's usually deposits on the valve seats that makes the valve seal poorly. If this is the case, check the spark plugs and the fuel injectors, this could be a warning sign!
A smooth valve grind could be very useful if you suspect poor valve seal across the board, the engine will run stronger for years to come.

Oh yeah, adjust the valve clearances when you're done mounting the head back again.

/Mattias

[BavarianBimmer]

Me neither I can't help you
But as you mention you've a cracked or wharped head ?????

[OldBMR1]

the head is fine, it is just getting on in years. i am trying to make sure that it will last me as long as possible and i want to make sure that the correct steps are taken to maintain the engine.

thanks for the advice, folks

[OldBMR1]

I might forego the head project and drop in an entirely different and much much younger engine. Any thoughts on that?

[iXer]

That's a project on an entirely different scale but doable of course. It depends on what you're looking to achieve.

/Mattias

[OldBMR1]

first, I am looking to get myself the manul trans, second, i like the way the eta pulls off the line, third, gas mileage is killing me with the i engine, i am college student and i drive a lot