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Another dead piston!!!
Another dead piston!!!
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Old 08-04-08, 06:44 AM   #1
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Default Another dead piston!!!

Went autoxing yesterday for this first time since May. I have been doing more road course stuff lately with it.

The autox was going well. Car was being two driven by another local driver who is very good. We got about 12 runs in and the car started to idle very roughly. Turned the car off and back on and we were greeted with a spy hunter cloud of smoke out the exhaust. (the left side of the exhaust flows much better than the right btw) This was followed by a missfire code on #2.

Great!! Sounds like all the classic signs. Get it back to the shop and pull the plugs. They all look very good. Do a compressor test with the results of 125-130 on 1,3 & 4.....all normal. We did #2 last.....35psi. Sounds like another cracked ringland.

We are pulling the motor today to take a look at the condition of the block and other bits. New pistons at least are going in...possibly a sleeved block.

Pics to come.

Tony
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Old 08-04-08, 08:27 AM   #2
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Default Re: Another dead piston!!!

Sorry for the late reply. Been taking the motor out. Everything is ready to go, just have to get the engine hoist on and remove it from the car. Been working slowly taking mental note of everything and inspecting as I go.

As far as the condition of the car. It had 633 miles with the stock tune. During that time the motor never went above 4500 and never went WOT. I could tell the tune was crappy from the start and didn't want to chance it. Car is a pre-stop sale engine. It was purchased in the middle of Feb and was one of the first in the mid west.

At 633 miles it received a stage 1 tune from P&L Motorsports. At 3500 or so it got a stage 2 tune. At 11000 or so it got a P&L Intake and another tune. Car has run flawlessly during this time. Problem ocurred at 17011.

The car has seen 4 or 5 track days and a few autox's. Most of the street driving has been pretty easy for gas mileage concerns.

I am fanatical about maintenance!!!! The oil was changed at 400 miles with regular dino oil. It was changed again at 3000 to synthetic. Since then it has been changed every 2500 - 3000 miles or before a track day. Oil was last changed 500 miles ago using Motul 300V 5W40. Before that the car has always had Castrol 5W40 starting at 3000. The engine did not burn any oil between changes....not a drop!!

By the fact that it is piston #2 that seems to have died, I really see this as being an issue with crappy pistons. If it were 3 or 4 I could see heat being an issue as everyone for years has talked about (not saying I completely agree with this or not).

As far as the plugs and O2 sensor goes, they all look perfect. They are all a light tan color and show no signs of detonation. I also have not felt any det while driving the car on the street or track. In no way do I feel this is a tune issue. Jorge is a great tuner and has always done well with the car.

I would never even consider taking it to the dealer to have them fix this. What would be the point of having them put in crappy cast pistons again? Plus I know I do better work than the techs that would be rebuilding it.

More to come as I start the tear down.

Tony
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Old 08-04-08, 08:28 AM   #3
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Default Re: Another dead piston!!!

Sorry to hear about this guys. It was a great performing car.

Were you using the Stage 2 Protune for autox? If so, that kind of puts holes in the theory that it's the tune that makes the engines pop.
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Old 08-04-08, 08:35 AM   #4
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Default Re: Another dead piston!!!

Thanks for the update Tony - that's pretty much the scenario I was afraid of. I only had the stock tune on my pre-stop sale car for ~200 miles, never went WOT, and changed the oil at 2000 miles to be safe. Now I'm thinking stage 2 will have to wait until I can pull the block and do the cams as well. Awaiting news on whether the cylinder walls are ok.

Frank
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Old 08-04-08, 09:19 AM   #5
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Default Re: Another dead piston!!!

You know Tony, thinking about this, if the compression is THAT low, it's almost like there's something major like a hole burned into the piston. Or a dropped valve. Usually ring lands drop 30-40 PSI... Not RUN 30-40 PSI.

Regardless, if it IS a piston, I say just toss in some good forged units (with the mileage, you could probably get a way with it).

Interesting to see what you find when you tear it open.

-Jorge

Last edited by La Mer; 08-04-08 at 10:35 AM.
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Old 08-04-08, 10:28 AM   #6
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Default Re: Another dead piston!!!

So - to go back on topic.

Motor is out of the car. Tony is continuing the breakdown. Jorge, I had thought of the cracked piston. We'll see once we get it out. Overall I'm just curious. Either way, I hope we didn't drop a valve, as that would be major suckage.


The car had FTD before retirement from the event.
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Old 08-04-08, 11:48 AM   #7
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Default Re: Another dead piston!!!

Quote:
Originally Posted by Garrett View Post
Can we get some pics, just to hold us over, while your break the boxer down..?
pics of the pull out are coming. Tony has been taking a few along the way. As for me - I'm off to the post office for now...
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Old 08-04-08, 12:02 PM   #8
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Default Re: Another dead piston!!!

Hi,

Sorry to hear about your trouble. Can you post pics of the rings and pistons , please. We have seen a similar issue before but would like to see some different incident.
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Old 08-04-08, 12:08 PM   #9
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Default Re: Another dead piston!!!

Quote:
Originally Posted by Methodbuilt.com View Post
Hi,

Sorry to hear about your trouble. Can you post pics of the rings and pistons , please. We have seen a similar issue before but would like to see some different incident.
Oh believe me - we'll be throwing up pics of those in great detail.

We also need to figure out what pistons and rings to go with. And then it goes on to the question of the bearings....

And then we need to wonder if we should have the heads flowed and ported.....

We seem to go through a huge decision tree on all of this whenever we end up pulling one of the motors on our own cars...
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Old 08-04-08, 01:14 PM   #10
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Default Re: Another dead piston!!!

Quote:
Originally Posted by mattjk View Post
Sure is nice to have your own shop to be able to do these things!

Much luck to you guys!
Yes. Yes it is.

Sad part is we're suspension guys, but we've had more motors out of scoobies since we've moved to this new location than we've had suspensions out of scoobies.
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