Green engine fixer question

[goldenbb]

So my head gasket is going out. The car is parked, I don't need it right away. It has just north of 145K miles. I kind of figured the PO was selling it due to something major going on it, so this comes as no surprise to me. Maybe what is surprising is that the coolant in the oil took almost a year to show up.

Anyhow, what I am asking about is what to do next. I obviously want to at least install a new head gasket, new head bolts, all the various "while you're in there" plugs and seals, and also install a new timing belt and water pump even though it had those replaced at around 110K according to the PO. I will also likely take the head to a local shop and have it gone over and cleaned up, machined, if necessary, and so on. Is that enough? I have read that putting a new or refurbished head on a high miles bottom end basically means you will kill the bottom end due to the increase in compression. Should I pull the whole engine and rebuild it?

I have also considered performance upgrades--a hotter cam and a header, although I'm not sure I want that because I enjoy the car as it is and just want it to run reliably. It needs some cosmetic fixes and a couple of other little things, so I might better spend money on those first.

TL/DR: Is just replacing the head gasket and refurbishing the head sufficient or will I bomb the short block?

[NoM54me]

New head kill the bottom end? I say no way. Especially if you only have 145k. You're only bringing it back to spec, and even if you mill the head to the minimum, you won't be significantly raising compression. I replaced the head on my 533 at 275k, all I did to the bottom end was clean off the piston crowns. New gaskets, head bolts, oil, and coolant....fun weekend project.

[jlevie]

145k or therebouts is not really high mileage on an M20 engine. Unless grossly mis-maintained there should be no worries about the rest of the engine.

Pull the head and take it to a machine shop. At a minimum it needs to be surfaced, valves ground, and new valve seals installed. It could possibly need new exhaust valves and guides.

[goldenbb]

Thanks for the advice! It sounds like those trying to sell complete engines to me are full of you know what. I do plan to take the head to a local shop and will have it gone over.

I am also going to refurbish the injectors, I don't think I included that in my list of things on the original post.

[jlevie]

Thanks for the advice! It sounds like those trying to sell complete engines to me are full of you know what. I do plan to take the head to a local shop and will have it gone over.

I am also going to refurbish the injectors, I don't think I included that in my list of things on the original post.

I highly recommend having the injectors cleaned, rebuilt, and flow tested by a pro shop. I use RC Engineering.