Miata Turbo Forum - Boost cars, acquire cats.

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-   -   Blew the motor! Rebuild time. (https://www.miataturbo.net/diy-turbo-discussion-14/blew-motor-rebuild-time-36483/)

240_to_miata 06-30-2009 10:04 PM

2 Attachment(s)
More info later but...

Cyl 3 and 4 (left to right)
Attachment 204959

Everything else looks amazing...

SEE...

Attachment 204960

curly 07-01-2009 12:04 AM

Dude have you found out what's wrong yet?

I have the uber 1.6 engine. I reved it to 7250rpm multiple times a minute for a couple weeks when it was still my dad's car and it spun a crank bearing. Made a clicking noise but seemed to run normally, granted I was easy on it since I knew something was up. We balanced the rotating assembly along with rebuilding it (rings, gaskets, honing, etc), but then my dad assembled it without tightening one of the rod cap nuts, so it came loose and started smacking the valves. It drove less than a 1/4 mile like this before we tore it apart again and rebuilt it. 30k later I turbo it, run it uber lean for a while before finding out (because of my WB) that my fuel pump is bad and am now running a fairly safe bandaid tune. I have no idea how you people keep blowing engines, they're obviously bullet proof. (knocking on wood).

dustinb 07-01-2009 01:23 AM


Originally Posted by curly (Post 425553)
Dude have you found out what's wrong yet?

I have the uber 1.6 engine. I reved it to 7250rpm multiple times a minute for a couple weeks when it was still my dad's car and it spun a crank bearing. Made a clicking noise but seemed to run normally, granted I was easy on it since I knew something was up. We balanced the rotating assembly along with rebuilding it (rings, gaskets, honing, etc), but then my dad assembled it without tightening one of the rod cap nuts, so it came loose and started smacking the valves. It drove less than a 1/4 mile like this before we tore it apart again and rebuilt it. 30k later I turbo it, run it uber lean for a while before finding out (because of my WB) that my fuel pump is bad and am now running a fairly safe bandaid tune. I have no idea how you people keep blowing engines, they're obviously bullet proof. (knocking on wood).

19lbs of boost (spike), 440cc injectors, on a 16g with a stock 1.6 fuel rail = failure. That's how you do it.

And interesting pics above, any ideas?

wayne_curr 07-01-2009 01:25 AM

Those cyl walls look great O_O. Our integra didn't look that good when I put a new head on it 10k miles ago. The pistons even wiggled back and forth in the cylinders :giggle:

Good luck man. I cannot believe you bent a rod on that kind of power...these rods must suck.

wayne_curr 07-01-2009 01:26 AM


Originally Posted by dustinb (Post 425572)
19lbs of boost (spike), 440cc injectors, on a 16g with a stock 1.6 fuel rail = failure. That's how you do it.

And interesting pics above, any ideas?


Lol, thats not his setup at all.

SKMetalworks 07-01-2009 01:52 AM

T25 ftw!

240_to_miata 07-01-2009 06:57 AM

Yeah, I was quite amazed at the condition of all the bearings and cylinder walls. The entire motor other than the rod (and the WEAKKK piston rings) seems to be in great shape.

I have been having some issues with noise in my CAS signal to megasquirt. It would randomly spike to like 65000 (yes sixty five thousand) RPMS...causing the rev limiter to blip for a millisecond and i would have a lean spike with no spark. I always had this happen on highway cruise but I'm thinking this may have been the one time it happened under boost and it just didn't make the rods too happy.

Either way I am excited to rebuild. The head looks decent and I should get away with new rods, bearings, ring, gaskets and a quick clean and hone. Stock pistons FTL, but I think I would rather have a coolant reroute, dual feed fuel rail, and bigger rad before I go bigger pistons and end up convincing myself to turn up the boost or something.

neogenesis2004 07-01-2009 07:26 AM

Sounds like a great plan!

That crosshatch is money, amazing for it to still be in that great of shape.

Measure your stock rings and order a set of matching moly rings from wiseco. Then you will have great rings that can stand a beating.

240_to_miata 07-31-2009 08:48 PM

5 Attachment(s)
Im putting the engine back together this weekend, getting it back from the shop 2morro i think.

Here are some pics of random progress:

Attachment 204431

Attachment 204432

Attachment 204433

And i got poking when i shouldnt have...
Attachment 204434

Attachment 204435
Pass side was hacked by me in the past and needs to be done right, drivers side was a supprise. Ill be fixing this soon.

mike_671 07-31-2009 09:42 PM

Engine bay looks clean :)

Stein 08-01-2009 12:03 AM

I thought that I was going to join you today. I had it running good at 10 psi. I had it at 11 psi and I heard some knock. This is on a 99 9.5 motor so I would guess that's about the same as 13 on a 9.0. Also a T25.

I need to get it back down to 10 before going into boost again.

hustler 08-01-2009 01:16 AM

its sooooooooooooooooooooo nice to have a forged 8.7 motor with 22-28* advance at 15psi. lol

FRT_Fun 08-01-2009 01:31 AM

Wow.. I'm def putting my engine rebuild before a few things now...

240_to_miata 08-01-2009 05:40 AM

Unfortunatly I chose to put a few things before pistons on my list, so my build only includes upgrading the rods and ARP head studs. I want to worry about cooling, wheels, tires, and sways before I bother with pistons. I figure before I reach that point I would need a bigger turbo and clutch anyway.

rrjwilson 08-01-2009 07:19 AM

That conrod doesn't look quite right :D
Kinda shocked you blew a rod at that tune. Something must of been real bad in there to do that.

240_to_miata 08-03-2009 05:24 PM

Found out why I have always had low compression and only dynoed 98 rwhp stock...

My head needed to be done. He did a leak test and found a few of my exhaust valves werent sealing...

Oh you gotta love the machine shop Bill :(

Fireindc 08-03-2009 08:04 PM

If you are spending all of the money on a rebuild etc, why the hell not throw in a set of forged pistons?

240_to_miata 08-03-2009 08:24 PM

Because I am a BROKE college student.. and i expected to run into some things that would already increase the price of my build..... aka my head needing work.

Plus, Ive thought it through, and I will need to upgrade my clutch LONG before I surpass what the stock pistons can hold... And i need new tires and wheels (runnin 205 crappy bald all seasons)

So i guess the question is:

Why not upgrade the turbo so you can then have to upgrade the clutch so you can then have to upgrade the pistons so you then should upgrade the head, but then you really need a coolant reroute and rad. and oh yeah... TIRES.
$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ $$$$$$$$$$$$$$$$$
Trust me I thought long and hard about where my limited funds should go.

Fireindc 08-03-2009 08:33 PM

Cool man, as long as you've thought it out.

Personally after spending a shitload of money on the expensive part of the build(the build/machine work part), I would without a doubt be putting in full forged internals.

Your argument is not the same, because you do not have to pull apart the motor in order to install a clutch, coolant reroute, tires, etc.

240_to_miata 08-03-2009 08:37 PM

trust me Im sorda regretting it, but I need to pay rent and insurance... and i just bought a winter beater because I really needed a second mode of transporation. You can always pull apart a clean motor and throw it back together as long as nothing is damaged. If I ever have the money for a turbo, clutch, reroute, and tires....... then I will probably have the money to redo the motor as well.


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