yenadar

MSM, FM2 conversion.

So I was driving late last night in the middle of no where, pulled up to a stop sign to hear banging noises, it could barely idle, and i then noticed my oil pressure gauge was full left. Bad news. Shut it down, checked the oil, dipstick wet but no level on it. Poured in 1/4th of a quart of oil, immediately saw it draining out the bottom of the engine. Well **** beans.

Took 3 hours to get it towed back to my house, and in the morning light I went looking for the problem...

and there is no oil pan drain bolt in the pan. Great. I'm an idiot somewhere. I torqued the bolt last oil change (last week, but ~2,300miles ago), but i also used a new washer from the auto parts store. I usually use a nylon washer, used a metal one this time. Dunno if that is why. Whatever, my fault in one direction or another, and definitely need to rebuild the engine.

My question is mostly around what I can expect.

Spun bearing for sure, so bottom end all around, new bearings, likely new pistons and rods (might as well support more power!).

Is Valvetrain damage likely? What about turbo damage? Anything else?

It will probably take a month ish before i actually pull the engine and start disassembling it, Tax time bills are a bitch. Just looking to baseline my expectations.

Thanks.

shuiend

iTrader: (24)

Plan on needing a full new motor. Turbo could possibly be fine. Head is iffy. Until motor is out and starts getting taken apart you can't really know though.

yenadar

By "full new motor", do you mean replacing everything, re-honing/boring/etc...? Or literally junk this one and get another?

codrus

You can probably reuse the block after boring out to the larger size, might be possible to cut the crank and reuse it but those are cheap so why bother? The head is likely trash because the cams spin in the bare aluminum.

--Ian

shuiend

iTrader: (24)

It depends on how long it ran without oil. You may be able to reuse some things, you may not.

Block is probably good, but yeah crank and head are the worrisome parts.

Savington

iTrader: (31)

Head might be salvageable, depending on how long the motor ran. Crank/rods are garbage, pistons are likely garbage too. Best case, you need a crank and rotating assembly and can use your block/head. Worst case, nothing but the bare block is salvageable.

mmmjesse

may be easier to just get another bottom end to have done. It all depends on how bad it is. Crank will be fucked probably. pull your valve cover and then some cam caps. inspect the cams and caps for damage. if those are ok, you can probably reuse your head. Get a Boundary Engineering pump while you are at it also.

yenadar

The engine was running smooth 2 miles (~@40mph) earlier at a prior stop sign. I know it ran long enough to do damage, but not like it was 30 miles of no oil or whatever.


Thanks guys.

Pistons/Rods/Bearings/BE Oil pump are already a given for me. Looks like I can assume to add a crank (best option for one? Are all 1.8's the same?) at a minimum.

If the head is done I'll have to figure out if I want to go VVT or not.

It sounds like the turbo is likely fine? Would end play be the means of determining damage there? Another method? It's the GT2560.



I'll be able to turn up the power post-rebuild as the stock block was the only thing not upgraded before, but will stay sub 300whp. I street it for weekend excursions with the girl at about 210-220, and turn that down for track stuff, but haven't had it on track in 2 years. I don't know that I want another 50%.

I'm 90% sure I'll be going with 9.5:1 or 10:1 pistons. I don't like low compression motors for normal driving stuff. This motor is also fairly likely to make it into an Exocet one day...

yenadar

Or put in a 13b. I'm a rotorhead at heart, this is my 3rd BP engine failure (albiet this is my fault), none have lasted longer than my RX-8's motor which is renown for shitty reliability. There is an emotional side that just yes to screw the BP engine.

codrus

A 13b does not fit very well in a Miata, LS3 would be easier.

--Ian

shuiend

iTrader: (24)

If you are running pump gas ever you want 8.6:1 Supertech pistons. Miata motors like timing, and the higher compression pistons will limit that. Once you overbore a bit for the larger pistons you won't notice.