Yea it's a bummer but we will get it going soon

 

Damn that sucks guys. Was that still on 4lbs or had you upped it a bit? With all these pistons going out, I'm tempted to build the motor before I turbo it. The only thing that has me thinking otherwise is that a TL3.2 or MDX 3.5 is such a cheap motor, I can toss another one in 4 or 5 times before it costs the same as building the motor. But who wants to do that that many times?

Any indication of the root cause?

 

Another Turbo J bites the dust. Thats unfortunate ;(. it was getting interesting

 

Terrible news. I was hoping that what happened to my pistons was a fluke and you would be going strong. Sorry to see that the pistons in the Type S are just fatally weak and can't withstand boost.

 

will do. Ill send you pics when we get them out.

 

I was hitting 8 lb at 3500 and tapering down to about 6. The cause was just a cheap piston. The skirt was thin and made of a cheap cast material.

 

That's too bad. That's pretty much 100% failure rate. The only one who may have survived is HiSpeed but he was getting tons of blowby which was my issue as well.

It makes sense that Rodney went with forged pistons and stock rods right away. He must have known all along.

 

I think what Rodney figured out early on was the importance of running the car very rich. I had 50k trouble free turbo miles after about 30k with the SC and primitive management. All the new turbo guys didn't know to tune so rich. Also refusing to use methanol in a high comp turbo build was a poor idea. I also don't see the point in running the same compression ratio as stock in a forged build for boost.

 

MADDOGZ28 broke his on meth injection and 10 PSI we broke at 8 PSI and very rich mid 11's fuel mixture and safe timing, what kind of boost pressure was the super charger making ? I think it's a very low boost only thing for stock pistons

 

I wonder if the different pistons between the 3.2L and 3.5L engines makes any difference in their abilities to handle boost? I was running water/meth the final time that my pistons cracked. I haven't been by the shop to see which pistons cracked and whether or not the skirts of any broke off.

I guess forged pistons are just a requirement for boosting the 3.5L Type S...

 

The SC was low boost at 3 -5 psi but , my point was more the lack of proper engine management that could have harmed the engine. I don't know much about the type-s pistons but they seem to be more delicate that those in the 3.2 or the tune used is more aggressive. Is Vit take any responsibility for the failure. ( reduced tuning cost ). The J&R turbo guys also have knock indicators that might have saved our engines when the engine began to knock. I know my blow by happened after some heavy knock I never heard only saw the LED flashing.

 

The motor survived ~25 hard WOT pulls during tuning at various boost levels (as well as his normal day to day drives he was doing), I even had Dean using the Hondata app to monitor ECU feedback so he could get out of it in case of anything fishy (anything at all). Fueling & timing were in a very happy place and every time I viewed a log (whether WOT pull or driving/fun) everything came back clean -- I'm as sad and disappointed we had a failure as anyone else reading this thread.

I'm in contact with Scott & Dean on a regular basis and am waiting on the engine tear down -- the information I have so far is the engine was actually running, no smoke (blow by, ie signs of melted pistons, cracked ring lands, etc), and very noisy (due to the dropped skirts). Spark plugs even check out fine -- the motor's been running clean.

Once they have the motor torn down we'll known more -- and you can be assured I'll be there along the way to make sure we get the car back up and running.

 

Wow, well great build man and outstanding work! I hope you can get her going again soon so we can allow follow our dream builds on your an your dads footsteps. Hopeful to see a powerful Turbo TL going strong soon!!


Sean

 

Well this is a set back, I wonder if the larger stroke as anything to do with it?? Probably not.. Just thinking out loud.

 

That might not be a bad thought. The J32 has a high rod/stroke ratio - 1.8:1. I forget what it is on the J35, but I think it's in the 1.6x:1, and I'm too lazy to go look up the rod length right now.

I don't know if that would be the sole cause of the issue outright though. I do think there must be an inherent difference between the J32 and J35 as far as strength is concerned though.

LSthatch ran tons of passes (granted on 110 octane) @ 700+whp and 20psi from an S372 without issue on a J32A2 motor. Yes, he had one drop a valve, and he overboosted one, but those do not qualify as 'blowing the motor' to me.

I know there are differences in an all out 1/4 mile pass vs. street driving, but if the motor can handle the stress of that much power and torque repeatedly, then it should be able to handle 8 or 10psi from these setups. Also, if we assume that detonation/tuning is not an issue in these instances since maddog had meth, and Utahs' logs were clean, there has to be another cause.

Utah - did you get the rest of the motor apart yet? Any damage to the tops of the pistons, or any other clues? I'm not apt to simply dismiss it as 'weak piston' yet.

maddog - you said it cracked a piston on the dyno with meth? Did a ring land crack, or was it elsewhere? Got any pics of the pistons?

My plan originally was to use an Odyssey 3.5 long block (added displacement and 10:1 CR), but if there is something weaker about these pistons, I may stay with the TL 3.2. Longblocks are cheap enough that's for sure.

As much as I hate to admit that Matt (I hate cars) was probably right the whole time, my initial suspicion now is that the ring end gap is REALLY tight on these, maybe tighter on the 3.5 than the 3.2, and the increased heat from the turbo (anyone have IAT logs?) and increased cylinder pressures are causing the rings to touch and break ring lands even easier than the 3.2s did.

 

In that situation I usually see the rods given up -- the Mazdaspeed3 platform is a good example. Easy to make lots of torque, long stroke, rods are twigs -- bend and then snap.

Some people just get all the luck -- there's a guy with a K20 in an EK running around making 700hp for 2years+ now, street racing the piss out of it and it has yet to break. Definitely not the norm... most guys are lucky if 500-600 lasts a year on those (rods break eventually).

That's an interesting theory, maybe Scott can measure the end gap on the pistons that are not damaged (FWIW).

IAT hasn't been a concern -- on the boost level the car was at we'd see at most a 10-15* IAT increase after spending time in boost.

 

I thought the pistons were forged in the j35a8 (TL type-S and RL)?

 

forge for light weight not for strength. Big different in material thickness.

 

I'm not sure what broke on the last dyno run with meth. I'll find out and post some pictures once I get them.

 

Is there anyway that the head design of the newer J engines (no headers) has anything to do with these failures? I've seen many J32A2 stock motors handle boost no problem.

 

I had thought of that as well. Perhaps the single exhaust port causes hot spots or something. However, that would then mean that these failures were not hp/torque limitations, but detonation incurred, and I was giving the benefit of the doubt on the tuning in these instances.

Also, I believe there are a couple/few other turbo TLs and some AV6s that just don't post that much on here that have not had issues.

 

The new TSX and Civic heads are the same way, we're doing 400whp+ on pump gas on those and not losing anything along the way, 500whp+ on E85 on stock bottom ends.

 

AV6 guys have our own issue with blowing up the ring lands before the piston go.

 

Well damn, just when shit started getting fun huh?!

Sorry to hear that this happened, really. In this case of low boost, I'm inclined to think that the ring lands broke due to there being no signs of wall damage. But then again, I usually don't see piston fragments in the oil pan unless there is evidence of cylinder wall scoring or piston seizure that occurred. The later generally involves fragmentation due to the rod pulverizing the piston once detached from one another. Some cases of land failure that cause fragmentation can be from extreme chamber heat or preignition.

What type of plugs (part number preferably) were you using?

Did the failure during a datalog recording and if so, any knock counts shown at any point?

I'm interesting in seeing tear down pics if you have them or plan on taking any. If possible, get some clear shots of the wall, piston (all pieces), rod and the chamber too on the cylinder that failed.

 

Interested in the pictures of the aftermath. I too think ring gap is a critical factor , LS motors can handle big power for a while with just a ring gap change. I was wondering about the stroke because of the piston skirt pieces that appeared in both turbo builds, it's puzzling.

 

Wow, I've been out of the loop on K series stuff too long. Makes me almost wish I had a 4 cylinder. The cast turbo manifolds that those cars use are pretty cool and seems incredibly easy to make.

But I digress. That makes me feel better that the single exhaust head is NOT a contributor to failure, just wish we had a better idea of what exactly is the main cause. I'm just not sold on it being that the pistons are too weak.

 

Got home last night and tear down has begun (he won't let me help because I will just take over he says)

 

We had a little roll race the other night and my TSX k24 on 14 PSI is faster but after he turns the boost up to 12 PSI I think he will be faster

 

Was searching my notes for some specs on engine I am building for someone and came across these measurements I took a while back between several pistons. Though it gives critical area thicknesses, it really says nothing about material quality, design, etc. Surprisingly the j35y pistons (IMO) were some of the stoutest I've seen from Honda yet though it's one of the "thinnest" shown below. The ring lands were one of its strongest points by far because of how far down they were from the top which makes things easier for the rings themselves in regards to detonation/heat. Also, the crown thickness they had would give me less worries if installed in a boosted engine.

PGE (j32a2)
Skirt thickness (thrust side) 3.20mm
Skirt thickness (non-thrust) 3.20mm
Piston pin bore thickness (lower) 5.00mm
Crown to upper ring land 5.20mm
Crown to middle ring land 10.20mm

RGL (j35a6)
Skirt thickness (thrust side) 3.20mm
Skirt thickness (non-thrust) 3.00mm
Piston pin bore thickness (lower) 5.20mm
Crown to upper ring land 5.20mm
Crown to middle ring land 10.20mm

RKG (j37a4)
Skirt thickness (thrust side) 4.95mm
Skirt thickness (non-thrust) 2.20mm
Piston pin bore thickness (lower) 5.10mm
Crown to upper ring land 5.20mm
Crown to middle ring land 10.20mm

RJA (j35a8)
Skirt thickness (thrust side) 4.01mm
Skirt thickness (non-thrust) 2.05mm
Piston pin bore thickness (lower) 6.00mm
Crown to upper ring land 5.20mm
Crown to middle ring land 10.20mm

R9P (j35y)
Skirt thickness (thrust side) 2.87mm
Skirt thickness (non-thrust) 1.85mm
Piston pin bore thickness (lower) 5.41mm
Crown to upper ring land 6.00mm
Crown to middle ring land 11.50mm

Wiseco PN-6568M89
Skirt thickness (thrust side) 3.01mm
Skirt thickness (non-thrust) 3.01mm
Piston pin bore thickness (lower) 5.38mm
Crown to upper ring land 7.00mm
Crown to middle ring land 12.40mm

 

My sons first broken piston next to one of my favorites so special I wan't to cry

 

Brutal yet still amazing. You boys do good work!

 

Which was his and which was yours? I'm thinking yours on the left, his on the right?

 

Yeah mine on the left, we found three pistons with the skirts broken no broken ring lands on any pistons and no signs of detonation and it was on the non thrust side (inside of pistons )

 

how bad is the block?

 

Was the car purchased new? If not, I wonder if the prior owner had a habit of driving on a cold engine, maybe causing cracks in the skirt?

Or, could it just be a compounding of tolerances leading to too large of a bore for those pistons? (I think that is unlikely though.)

Good to see no signs of detonation or any broken ring lands. Still stucks that it happened though.

Are you guys going full pistons and rods or just pistons?

 

The block has a couple dings underneath. But the cylinder walls are flawless. Not a scratch, which is kinda wierd. Vit said that the clearance from the cylinder wall to the piston might be a little loose. Were gonna measure them in a day or two

 

The car was used. But the guy i bough it from loved this car dearly and i cant see him beating on it cold.
Were going to measure the diameter of the piston and the cylinder wall to see what the clearance was.
Yeah our tuner knew what he was doing so no signs of detonation. On top our pistons were in good shape.
Got 4 new pistons from JandE and 2 more on the way. Ill be ordering Pauter rods pretty soon. Just waiting on my tax returns.
Maybe valves further down the road.

 

no real knock.
i had ngk 2 step colder spark plugs i think part is NGK (5464) BKR5EIX but dont quote me on it. still looking for the receipt. lol

 

The piston on the left (OEM) looks cast to me but I guess people says it's forged?? With the shorter connecting rod length and longer stroke of the J35, it makes sense that you would see higher side loads on the piston and then adding a notch at the bottom of the skirt for what ever reason, doesn't help.

Stroke:
J32: 86mm
J35: 93mm

Connecting Rod Length
J32:161.8mm
J32:158.5mm

^ just pulled these off the interwebz, correct me if they are wrong.

 

I would recommend putting in supertech valves springs just for extra safety measure since you already have the engine apart. That way you don't have a O shit moment of dropping a valve on to your new pistons.