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-   -   tell me something good... (https://www.miataturbo.net/engine-performance-56/tell-me-something-good-55570/)

rigidbigelsworth 02-12-2011 04:16 PM

tell me something good...
 
2 Attachment(s)
so during a spirited drive yesterday, my cars "charge battery" light came on intermittently, the steering got stiff, and my engine starting making a loud knocking noise. so i thought, great both my belts just broke? (super wishful thinking) luckily i was only a minute from my house so i basically coasted the rest of the way. i was told to check the "key" on the end of the crank. i removed the pulley, and this is what i found:

im pretty sure since the edge of the crank keyway is rounded off, this means the crank will need to be replaced huh?
Im secretly hoping someone says "no it looks fine, thats how its supposed to look, get a new key and put it back together!"
but basically im just checking to make sure there is no other solution than to pull the engine, and install a new crankshaft. on a side note, anyone selling a 1.6 crankshaft?

Thanks for any feedback

curly 02-12-2011 04:46 PM

Time to replace. If you have a skilled machinist available, Theres a few options, most of them still require pulling the engine and crank. So you might as well replace. Sorry.

golftdibrad 02-12-2011 05:19 PM

"tell me something good... "

While your changing the motor you might as well upgrade to a 1.8l?

saedrin 02-12-2011 05:28 PM

Well, the engine had a good 20 year run. About time something broke.

Hot_Wheels 02-12-2011 10:15 PM

quick question, i hear alot of talk about small crank nose failure, is this what there referring to? are the large nose motors prone to this damage too?

magnamx-5 02-12-2011 11:16 PM

you have a 93 if the car its native engine than this is not the shortnose crank failuer however the crank failure does look much like this when it occurs in the later cars. Most likely someone did not tighten the crank bolt tight enough allowing the keyway to move and eventualy tear up the crank. I have yet to see a failure on a later model crank that did not involve this.

rigidbigelsworth 02-13-2011 09:39 AM

well luckily i managed to find a engine and trans for a steal, so i picked those up yesterday and got it onto a stand. i was told the engine had a "burnt cylinder" which im assuming he means a burnt exhaust valve. so i think for now, since this is my DD and i need to have it back up and running asap, im going to put my head,valves, and cams from my engine, onto his block, to avoid having to mess with the internals too much. then ill just take my time rebuilding the bad block from my car, and refreshing everything else in my spare time so ill have a fresh start for when i finally bite the bullet, stop lurking around a turbo forum without being turbo, and finally go turbo haha

thanks for the quick response curly

is there anything i should know before starting? i bought and read a haynes manual already but i didnt know if there were any "tricks of the trade" that may not be mentioned in the book that could make things easier/harder. other than replacing the head gasket, and valve cover seal, is there anything else that will need replacing?im not doing anything with the bottom end, just leaving it together and hoping its in good shape. i turned the crank over by hand, everything seemed smooth, and wasnt siezed. are there any other checks i can do on the bottom end without taking out the crankshaft, and having to replace all the bearings and piston rings? I know im taking quite a gamble here just slapping in a bottom end of unknown quality but it only has 125k on it vs my 191k so i figure at least for now, its worth a try, and i could always take it back out and rebuild it if it turns out to be junk, so either way, im stuck rebulding an engine..

any comments,or feedback would be appreciated since this will be my first engine removal/disassembly. (yikes!)

curly 02-13-2011 05:35 PM

If you're pulling the engine, don't bother removing the intake manifold. Although it does help with access to the wiring harness below it. Same with alternator, it stays on. Look at some old FM pics, there engines never look like they'd fit in and engine bay.

hysteria411 02-14-2011 10:34 AM

For what it's worth, I've been able to repair a few cranks like that on Hondas by machining a brass key for them, then welding the crank with the key in place. You'll have to grind the weld back down when you're done, but the brass key will keep the keyway clear and you don't have to remove the crank.

rigidbigelsworth 02-14-2011 11:10 AM

hmm sounds like it could have potential. at this point, i already have the engine out, and a new engine ready to go in, so i figure ill end up taking out the crankshaft anyways when i rebuild the old engine, replace bearings, rings, and clean up the valves, but i might offer that as a suggestion to a machine shop, if they dont know how to fix it.

rigidbigelsworth 02-15-2011 06:54 PM

ok hopefully last question for a while, where do yall order good OEM replacement parts? im going to need a replacement exhaust valve asap, and autozone and advance both dont have them available for order. any good websites that offer pretty quick delivery times?

Thanks

rigidbigelsworth 02-19-2011 10:00 PM

1 Attachment(s)
turns out my replacement engine isnt the same as my current engine. im not super sure about the whole "long nose" vs "short nose" thing, but below is a picture of the crank pulley/timing gear on my replacement engine. the pulley and timing gear are one piece. its not the same as the stock pulley from my current engine which is not one piece with the timing gear. the inner diameter of the pulley is smaller on the replacement. is this the "long nose" people talk about? also, how many of the parts can i plan on being interchangeable? i was hoping on reusing my whole head from my current engine, on the replacement engine, to avoid having to do all the valve work on top of new rings, rod bearings, and main bearing.

cliff notes: is this new pulley from a "long nose?
how many parts are interchangeable from a long nose 1.6 and a short nose 1.6?

Thanks as always


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