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1.8 BP5W engine rebuild

I’ve got a 10ae with ~112000 miles which previously had a jrsc mp62 mounted. After noticed signs of head gasket failure, the blower was removed and an engine rebuild was put on top of my priorities. I was planning on only machining the head, while replacing most of the top end (valve stem seal, head studs, gaskets, etc). I was not even thinking of a bore or hone until I noticed a low oil level earlier today. Now this was the first time in a while that I myself checked my oil ~10000 miles. After realizing my unforgivable negligence I just performed an oil change. Now should I machine the cylinders along with purchasing new pistons. I just do not want to spend ~$800 on a job that really doesn’t need to be performed.

-P.S. head gasket blew do to overheating.

You sort of need to take a class in Automobile Engines 101. Not checking your oil, allowing your car to overheat, don't bode well for managing a rebuild.
Yes, if you install new pistons, you need to machine your cylinders. Seriously, do a search on engine rebuilding as it seems that you don't really have an idea where to begin. One quick and easy solution might be to have your head shaved and put in a new gasket and see where everything is at. If you routinely go 10,000 miles without checking your oil, your engine probably is pretty tired out anyway. You don't have much to lose.

Or buy a Honda.

Paul

Your on the fence I think. Over heating CAN cause the rings to loose tension. That's not good for oil consumption. If you want ultimate performance, then you are looking at a full rebuild. At that point, its cost efficient to just buy a long block from TSE. I've priced it out. It's only like 300 bucks more to buy a motor from them, built by professionals, as opposed to building it yourself. I sure as hell ran around more than 300 bucks worth, building my engine.

Quote:

Originally Posted by ryansmoneypit (Post 1495971)

I'm wondering how you arrived at that number? By the time you include core charge and shipping, you're looking at a pretty big number. Thumbs up on the motor built by professionals if you're not experienced in doing it yourself.

Paul

Sounds like you want to do the minimum to keep it running. If that is true, then just replace the head gasket. You have to be super honest with yourself in order to do the right thing. An "engine rebuild" means you must remove the entire engine (not just the head) and get the block completely taken apart in order to hot tank (clean), replace all seals, bearings, address any crank issues (polishing, maybe grinding), resurface the block (decking) and of course all the issues with the head.

You have to carefully assess where you want to land. If I were a betting man, I'd say you are landing in the camp of 'replace the head gasket' and keep going. Then, at a later date, buy a JDM replacement engine (used from Japan) and swap it. Lots of people have had great success going that route and it is really cost effective if you are relatively lucky and get a decent engine with no real problems.

BTW, you really should have a shop evaluate what "needs to be done" if you don't know what you are doing. How do you even know the head gasket is blown? What are the symptoms?

You forgot having a shop measure everything. That's extraordinarily important.

How do you go 10k without checking oil levels? I mean, I know the new synthetics are all snazzy and all, but how do you go 10k without an oil change on a blown Miata?

Quote:

Originally Posted by pmhellings (Post 1496000)

Because I have rebuilt a few Miata engines lately. After all the bits, pieces, machine work etc..it adds up fast.