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-   -   Crankshaft end play? (https://www.miataturbo.net/engine-performance-56/crankshaft-end-play-27834/)

dima88 11-06-2008 01:49 AM

Crankshaft end play?
 
What are the specs for the crankshaft end play on a 1.8L?
Max?
Min?
And what are good replacement bearings for a turbo with about 300+whp?

18psi 11-06-2008 02:31 AM

a turbo with about 300whp? wtf does that mean? that is so broad I dont even know where to start....perhaps you should list what kind of turbo it is and the specs and what not

dima88 11-06-2008 03:36 AM

ha ha that is not what i meant.:giggle:

I need to know the specs for the crankshaft end play in a 1.8L engine, BP.

And I need to know what (performance)-> brand of rod and main bearings would work good in an engine that will make more the 300 whp.

Thanks

olderguy 11-06-2008 08:10 AM

On a 1.6 the specs are 0.0031" - 0.0111" Maximum of .012" I would suppose that the 1.8 is very similiar.

dima88 11-06-2008 02:46 PM

I have about .020, I can i get away with only replacing the thrust bearing? or do i need to replace all the bearings?

olderguy 11-06-2008 02:50 PM

I would open it up and look at them. Book says to grind the crank and replace the thrust bearing with an oversize one. Personally, if there is no gauling(sp) on the crank, I would get an oversize thrust bearing and grind it down to fit.

dima88 11-06-2008 03:26 PM

The engine is out of the car and opened, that is how i checked the end play, i think that the crankshaft is good so can i just put in a new thrust bearing or all new bearings, why do i have to put in an over sized one? the engine has about 25,000 miles after rebuild.

patsmx5 11-06-2008 03:34 PM


Originally Posted by dima88 (Post 327978)
The engine is out of the car and opened, that is how i checked the end play, i think that the crankshaft is good so can i just put in a new thrust bearing or all new bearings, why do i have to put in an over sized one? the engine has about 25,000 miles after rebuild.

You can't just throw bearings at an engine. Everything in it has to be perfect and to strict tolerances. There are even special methods of measuring pieces, and reassembling them, etc. If you're not extremely knowledgeable on building engines, I wouldn't try as odds are you'll fuck it up. You're gonna have to get a machine shop to do a lot anyways. Just let them do it all. That way they assemble it and if they're a good shop, it should be right.

Also, there's a $20 Haynes manaul available for your year car that has all the engine specs in it.

dima88 11-06-2008 04:47 PM

Dam i knew it wasent going to be easy. Do you think that i can get away with leaving the .020 end play? most likely not

patsmx5 11-06-2008 06:44 PM

Is everything else about this engine perfect? If it needs a rebuild, you could just swap in a good used engine instead for cheap. The 1.8 BP came in a lot of other cars besides a miata.

I wouldn't leave .020 end play. That's not right.

dima88 11-06-2008 07:50 PM

The engine has je oversized pistons, pauter rods, arp main caps. so i cant get a new one. and it has 25000 miles on it....is it too soon for it to have .020 end play?
I didnt buid it so i dont know if it was built right. so i have to take to an engine shop and have them fix the end play? i cant do it myself?

olderguy 11-06-2008 08:23 PM


Originally Posted by dima88 (Post 327978)
The engine is out of the car and opened, that is how i checked the end play, i think that the crankshaft is good so can i just put in a new thrust bearing or all new bearings, why do i have to put in an over sized one? the engine has about 25,000 miles after rebuild.

The thrust bearing is only half a bearing, trapped between the journal and the side of the crank. You would go oversize to fill the space that has either worn off the crank or that you grind off to flatten it. The side against the journal doesn't wear.

Check the actual allowance for a 1.8 before you do anything except pull out the old one. The spec MAY be more open.


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