Killed my PTO piston

[Shonuff]

Installed my new ADA head and blew 190 psi front hole, 155 rear.

Reinstalled my milled stock head and got the same thing.

Running 190 psi on 93 octane on my big bore with a bad, single line in, dual out cooling setup resulted in a little detonation and overheating.

Crap.

 

[Shonuff]

The last photo shows it covered in fogging oil.

 

[ATS_Aaron]

Bummer. I haven't seen one detonated like that. We usually snag rings and REALLY do se damage.

Aaron

 

[XFT LOU]

O no say it isn't so. Can the bore be saved.

 

[Shonuff]

Got new 84.5 pistons en route. Hone, replace, reassemble, ride.

 

[Scorn800]

Sucks, but not that bad.
this the boat with solas pump? what prop & ecit nozzle size?

 

[Cliff]

welcome to the club buddy.

 

[Shonuff]

Sucks, but not that bad.
this the boat with solas pump? what prop & ecit nozzle size?

yes, 13/21 and 81

 

[WFO Speedracer]

Yep you shonuff did.

 

[Scorn800]

yes, 13/21 and 81

Are you rpms under 7100?
When did it let go?
let me guess..going into wind at about 3/4 thottle?

 

[Shonuff]

I never noticed anything. I just finally tested the compression and found it thattaway.

 

[Big Kahuna]

what base gasket are you running?

 

[Shonuff]

The one Group K installed when they built the engine.

(?)

 

[Rickster]

What kind of oil are you running?

Both those pistons sure look like they were running a tad bit lean...

:spank:

 

[ATS_Aaron]

Both those pistons sure look like they were running a tad bit lean...

I was previously viewing the pictures on a iphone. Now with my laptop I can see better. I t looks like it got overheated, causing the pistons to grow and score up the cylinder/sides of the pistons.

The overheating could have been caused by being too lean or by too little cooling water flow.

Aaron

 

[Rickster]

I was previously viewing the pictures on a iphone. Now with my laptop I can see better. I t looks like it got overheated, causing the pistons to grow and score up the cylinder/sides of the pistons.

The overheating could have been caused by being too lean or by too little cooling water flow.

Aaron

Look at the picture showing both pictures, and the front piston is showing a lot of carbon buildup also, with very little/poor piston wash...

We all know that Shonuff is soooo... poor that he had to befriend Gill :shhh: that I was curious as to the kind of oil he ran...

I know on my bigbore that gets 927 I can still see the shine of the pistons through the plug holes...

Just curious is all...

:beerchug:

***Of course the above post is somewhat in jest****

 

[FyrHazard]

That sucks man. I hate cooking pistons!

 

[wsuwrhr]

Just so I understand,

You ran the engine after you knew one hole was 35 PSI less, with the other hole close to the limit of pump gas, and you could have destroyed the engine?

Brian

Installed my new ADA head and blew 190 psi front hole, 155 rear.

Reinstalled my milled stock head and got the same thing.

Running 190 psi on 93 octane on my big bore with a bad, single line in, dual out cooling setup resulted in a little detonation and overheating.

Crap.

 

[Scorn800]

The overheating could have been caused by being too lean or by too little cooling water flow.

Aaron

Or it could have been caused by over proping.
too much load will cause deto
:bananalama:

 

[SUPERJET-113]

Ya, sounds like a recipe for destruction.
You knew it had a prob with the weaker cylinder pressure!:trink26:

:biggrin: