destroyed supercharged '94.
 

Back story: built this for a local, he was complaining of a shitty running, leaking, nasty engine. It's running a worn out jackson racing supercharger with a power card and no wideband. JR header, otherwise stock r package. Ended up finding a piston with a small chunk missing, which I believe is on top of Shuiend's lamp currently.

I charged him $400, he dropped it off and I rebuilt it with some used steam cleaned pistons and rods from a member on here, new rings, bearings, seals, etc. It ran for all of a couple hundred miles, if that, before I started hearing him talk of certain death noises coming from engine.

It was brought back, torn out, and disassembled this morning:

https://www.miataturbo.net/attachmen...ine=1387220998

https://www.miataturbo.net/attachmen...ine=1387220998

https://www.miataturbo.net/attachmen...ine=1387220998

My back story: I've built my 1.6 twice, once after a rod bearing was crushed at 100,000 miles and 7500rpms, and again about 20,000 miles later when I decided to turbo, although I probably didn't need to replace the rings and bearings, but I did. I've also built a '96 with 10:1 pistons and a '99 head. All are working well currently, so I'm not sure what happened to this one, that's why I'm posting here. Because this customer and I need to figure out how to pay for the new pistons, bearings, head gasket, and rings.

Compression was checked to be at 160-160-0-160 immediately before disassembly, so the rest of the engine is "fine". I'm just curious as to what happened to #3. Map line to the powercard was found to be completely pinched, so I'm not sure it was getting any extra fuel for boost.

Any idea what could of grenaded the piston?

I think you hit it on the head, the power card wasn't working like it should. Looks like there was alot of detonation happening. It looks like it was rattling rod bearings causing the top layer to flake loose and gall, and the busted piston skirt. Things were really rattling inside, surprised he didn't hear it, maybe his exhaust was too loud.

Did you look at the spark plugs to see if #3 was a lot leaner than the rest? is there damage to the other pistons? I dunno, seems the Map line being pinched is going to have an effect on it either way.

If #3 is a lot leaner, or all the pistons had some det. signs (it just so happned than #3 failed first...) then its probably due to the powercard...

:brain:

3/4 plugs show light brown/white tips, obviously #3 is black and wet with oil.

Here's the twist in the story: When I brought the engine back to his place and I helped him install it, I installed the shifter. The vacuum line runs the length of the center console, and I can't remember if I installed the center console or not with the shifter, but it sounds like he's putting that blame on me. Obviously any one of us on here with a boosted engine and a wind band would have noticed the issue immediately with anything over ~12.0 afr in boost. Plus I would think a little boost would open up the map line fairly easily, although it was difficult to tell what it was even pinched on.

What say the MT brains to that?

I say you sit down and have a talk with him about why they're called "band-aids".

Which piston had a chunk missing out of it before you rebuilt the engine the first time? If he's running boost with no AFR gauge, questionable piggy-backs, and his car already ate a piston once......

Doesn't seem at all unreasonable that whatever did it the first time just did it again.

Honestly man, you hooked that guy up. $400 to rebuild a motor is a friggin steal, in fact - if you were near me i'd pay you that in a second to build mine.

besides the point, if he is too dumb to NOT be running a wideband, he deserves to go through motors. I know, because I was there at one point (band aids+ no wbo2), and as soon as i got a WB02 on the car finally, i almost shat myself with mid 13's afrs in boost.

He has no ground to stand on, it sounds like you built him a motor for a good deal AND helped him install it! Then he detonates a piston in half with his shitty ass setup and tries to blame you.

17s myself. Found out the coupler between the FP and pickup tube was split. Wide bands tell a lot. I'll see what he says, I've been thinking the same things as you have, just wanted to make sure I wasn't trying to be a weasel.

Det destroyed the first engine. The issue wasn't addressed and det destroyed the second engine. Seems pretty clear.

So the issue really is: do you want to fight this guy or help him. Is he being a dick? He must (or should) know that the definition of insanity is to keep doing the same thing but magically expect a different result. I know that you want to help him because that's who you are, but you want to be treated fairly too. How that resolves will ultimately be between the two of you.

It won't.

Gotcha.

I sent off a quote to the guy a few days ago, he hasn't gotten back yet. I'm deleting his EGR (including fabbing the plates), cleaned his car inside and out (I was disgusted), and offered to have him borrow a friends wide band that hasn't been installed yet to at least make sure it's running well N/A before he destroys it again. I quoted something around $350 for a second "rebuild".

Curly, you're a good friend.

Seriously, especially as it seems this guy is trying to take you for a ride...

So the owner and I have settled on an agreeable agreement. I get to pull the engine, rebuild it, reinstall it on my own labor, and he pays for all the parts. I'm ok with this since I get to do it my way, and don't have to worry about this happening again. He's also having me buy and install a wideband. And after driving him home in my 185hp 1.6, he's choosing to go the megasquirt and turbo route eventually. I told him the first step is the wideband, thank god he agreed.

So far we've bought a new head gasket, rod bearings, main bearings, front and rear main seals, break in oil, filter, and piston rings.

The block has been ball honed, and it along with the valve cover, oil pump, and oil pan have all been hot tanked. I just painted the block metallic black today, along with fixing a mangled piston squirter and installing them, along with reassembling the oil pump.

I recently built this with brand new 10:1 pistons in it:

https://www.miataturbo.net/attachmen...ine=1387856185

So I'll be using the used ones we replaced for this engine:

https://www.miataturbo.net/attachmen...ine=1387856185

My next concern is the head, #2 and 3 combustion chambers took a beating. I'm not too concerned, except for the slight markings on the gasket surface between #1&2 and between #3&4.

Does the collective MT brain think a head gasket will seal on this?

https://www.miataturbo.net/attachmen...ine=1387856185
https://www.miataturbo.net/attachmen...ine=1387856185
https://www.miataturbo.net/attachmen...ine=1387856185
https://www.miataturbo.net/attachmen...ine=1387856185
https://www.miataturbo.net/attachmen...ine=1387856185
https://www.miataturbo.net/attachmen...ine=1387856185

Holy moly that thing looks like it was detonating more than it was combusting.

You truly are being more than generous for doing this a second time after he was too stupid to run a wideband on a band AIDz supercharger setup

Provided the mating surface is flat, I'd say it'll be fine.

That head needs to be milled. All those rough surfaces in the combustion chamber need to be smoothed out as well. There is NO WAY I would have any warranty written or implied on a motor in a boosted car. You are being MORE than fair.

I agree. no chance in hell I'd be doing any work for free on this one.

maybe the owner could have heard the popcorn being popped in his motor if he didnt have a stupid ass SCer making whiney RC-car noise that you couldn't hear over.

This is another story, but this car and owner is probably something I should not of gotten involved with. I was naive about engine rebuild costs, and after disposables such as shop towels, simple green, purple power, zip lock bags, gas, and a $130 HF work bench with vise, I probably made about $100 true profit. But a good learning experience.

That also includes driving half an hour and helping him install it, along with going over a second time to help diagnosis some rough running, which was most likely the start of this destruction.

The weight on my shoulders has been heavy though. I'll just be glad to finish it and have it running well for a while before returning it. This saga has been going on since Summer.

And about the head, I'll have it milled, not worth the potential risk for ~$50. Plus the best head guy in the Portland area is my neighbor.

On another note, if I'm reading these instructions right, he had the power card hooked up pre supercharger, not post. Pinched line or not, I don't think the power card was ever going to see boost.

I'm not looking at the engine bay, but if I remember correctly it was connected at the 180* pipe. Not sure why I didn't catch that before.
https://www.miataturbo.net/attachmen...ine=1387897726

http://www.mossmotors.com/graphics/p...ns/999-170.pdf