Pto cylinder blown up

[Florin]

Im trying to figure out what could cause these 4 tecs to completely obliverate their pto pistons. Last fall i bought a gti 130 with a blown rear piston,. Tore it apart, found no evidence of oil starvation, no heat marks, bearings were essentially new, nothing stared me in the face where i could say for sure what caused it. Heres where it gets interesting. I just picked up a 2002 gtx 155. It had just had a motor put in, maybe has 15 mins of idle time and maybe a minute of on throttle time. I bought it with the exact same damage as my gti. Same piston, same exact failure.

I really dont wanna build this motor twice.lol

Anyone know what causes these things to blow like this?

[SplishSplash]

The non SC machines are usually bullet proof, lot of rental places use them and rack up easily 800 to 1000 hrs with just standard service.
For a piston to come apart after just 15 min lead one to consider a defective piston/wrong piston
If your rebuilding it, I would only use OEM pistons.
Being in Windsor, I assume both machines were fresh water used only.
How many hrs were on the gti 130 though, your talking about 20 year old machines here.
Can you post any pictures of the pistons and block?

[Florin]

The gti had 93 hrs. The gti had never been opened before to my knowledge, as everything in that motor looked oem. Nothing was aftermarket. I beleive the gtx had a sbt long block droped in, or af least the head was sbt. I beleive this because it looks gone through. I havent had a chance to crack open the gtx motor yet, but the head is off. Both machines were fresh water machines. Im thinking that maybe an injector was clogged or bad on both of them or something along the lines of fuel. Ill post picks of the blowups later today when i get home.

[SplishSplash]

SBT, typical, wonder why they didn't do a waranty claim on it.

[Florin]

so I got those pic of the blowout. again, im not 100% sure exactly what engine the 02' gtx has. i know it had engine work of some kind, i know the head looked gone through, and i know the camshaft had no stampings on it, which leads me to beleive that maybe it had a sbt head, maybe block, the guy i bought it from didn't say much. I'm 99% sure the gti had an oem engine when it blew. it weird how on both, the damage is so similar and on the same piston.

[SplishSplash]

Wow, what a mess. Sadly crank may be twisted too
Is the oil restrictor missing in the second block?

[Florin]

Second block is an 06+ block for the 2013 gti, the updated block did not have the restrictor. Honestly, the crank feels good, it spins well, it plasti guaged in spec and has no damage as far as i can see "at least on the 2013 gti engine"

[Florin]

So i found the issue with the 02 gtx engine, the shop that rebuilt the motor decided it would be a good idea to reuse the torque to yeild bolts, and used loctite, took 15 mijutes of idling to losen those bolts lol. As for the gti motor, still no idea.