One of these is not alike lol



That hole reveals the ring!


Im going to guess this happened after my car was overheating and then died during my last race. I still havent figured out why I was overheating, but I hope to find it as I continue to tear it down and pull it out.

RS machine pistons, anyone else ever done this?

 

Nice kill

 

Yikes.. Was that the D16?

 

top of piston says pr3... pr3 = b16.

 

B16 pistons in my B18B

The D15B7 isnt ready to go in yet, Im hoping that one doesnt grenade too.

So far I have 2 B series kills right around the same track hours on, ~8 hrs,

Im not doing something right when I build these things or Im too hard on them! Im just waiting on my HPD order to come in so I can rebuild this D.

 

tune......????

 

Old gsr motor was tuned by phearable, this motor was a phearable basemap I had tuned by a local guy.

 

I think thats your answer

 

i'd also think it might be the tune. not enough fuel/too much timing, things got hot, and it nuked a piston. that or u have a fuel delivery issue causing a cylinder to lean out ie-pump, filter, injector, etc.

i can't see it being a build issue unless the piston to wall clearance was too tight and the piston broke when it swelled. but you'd have severe cyl bore scoring, the piston skirts would be trashed, and i don't think those cast pistons swell all that much.

just my.02

-drew

 

Yeah, looks like that cylinder was running leaner than the others. Is that #3?

 

 

that was 3.

I was running rc 310s also...

I guess it could have been a tuning issue this time.

 

 

The other cylinders were perfect, rc injectors were brand new.

Whats the possibility of the injector failing? I just think its odd only 1 cylinder had an issue. The rest look fine.

 

You mentioned these are RS machine pistons not OEM am I correct? Could be a production flaw in the piston, if the injector didnt fail or got debris in it. Have you tested the injector?

The piston, if the cylinder was leaning out, would have expanded and scored the cylinder wall as well as the piston. That would be a good visual to eliminate any guesswork if it leaned out because more than likely you would have more than one wall scored which you don't; unless the #3 injector got clogged or it failed itself or failed to get a signal. If the walls are clean, and only the piston is melted, I would be suspect of the cheap piston.

 

You can send the injectors out to RC to see if one is flowing poorly. Doesn't #3 burn a bit leaner than the others anyhow? What were your a/f numbers for the tune?

 

meh. i've done better than that
if there are no mechanical issues (valve hit the piston or osmething cool like that), look for a tune up problem or an injector going.
mine was an existing crack from piston to valve contact that eventually failed after a few heat cycles.

 

Exactly what I was gonna say. Cyl 3 will be the first to lean out when everything else but the tune are good. That's why it is recommended that a pyrometer be installed in cyl 3 when using one.

 

Injectors were brand new and flow tested before they were sent. Im not sending them back, but I can test them to see if they were firing.

RS pistons, yes.

No contact with anything else, just silver shavings from the piston.

A/F was always around 14, I had an AEM gauge on it.

I'm going to check the wiring, maybe a wire came loose and it wasn't firing.

 

14 afr under wot throttle?

 

And that's your answer.

Running 14:1, I melted a piston (looked exactly like yours), popped 2 head gaskets and broke ring lands twice and that's on a D16!

Several thousand dollars later I visited a dyno with a guage and an adj FPR.

 

Really? I think I was around 14.3 ish wot.

I'm done with this crap, going to run all oem parts on my d motor and make 100 reliable ponies.

 

Ya that is a really lean assuming you are on gas

 

Is it recommended to run an A/F meter on the dash for this reason? I would think by the time u datalog on a kpro the damage has been done???

 

Just make sure increase the fuel pressure for those 100 ponies! lol


I'm not the best person to ask. I did the poor man's tuning (or the OBD0 man's tuning) and by that I mean all I did was adjust fuel pressure and distributor timing while on the dyno. I didn't touch my computer. I have 3 printed dyno graphs which include my AFR for the powerband at 43, 44 and 45 psi (my 3 ranges). I can simply look under the hood at my fuel pressure gauge with the vacuum disconnected and see what WOT pressure I'm at. Then, when I shut off the engine, if the systems holds pressure I know the injectors are sealing and the FPR is still good. Simple and easy.