I have no idea what really happend to my motor. That is why I have brought my problems here to Honda tech. Ok here is my setup because I know everyone will ask.
B20 Block
Darton sleeves bored to 84.5mm
Wiseco 84.5 mm pistons 12:1 compression
Eagle rods with arp bolts
Arp head studs
LS crank and all brand new bearings.

I have a built b16 head, but the head was not damaged at all so that shouldnt matter. Basically what happened was I was out one night beating on the car a little and I heard what I thought was a rod knock. So I tore the motor down only to find all my bearings are perfect. I was a little confused so I pulled the head. No problems with the head. Then I looked at the cylinder walls all four cylinders where slightly scored. I thought that was weird. So I look a little closer and my number 3 cylinder is grooved to ****. I pulled the piston and this is what it looked like...



One side



same side no flash



Other side



That side again no flash


Top of piston.

So really I have no idea what happend. The car was always warmed up before driving to avoid extreme piston slap. I never lost oil pressure. There were absolutley no signs of detonation. The motor was tunned properly. So if anyone has any idea what the hell happend please let me know.

 

looks like the pistons wer getting too hot.. expanding and rubbing...


btw.. ur block is bored 84.5
and wiseco 84.5s
what was ur p/W clearance?

just curious..

lets w8t for the gurus to chime in...

 

was it tuned what so ever? either lean mixture or p/w clearnace was too tight...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by h2b_eg8 &raquo;</TD></TR><TR><TD CLASS="quote">either lean mixture or p/w clearnace was too tight...</TD></TR></TABLE>

x 2

 

x3

 

The car was tunned and it was a little rich. I broke the motor in on the dyno so after everything was seated it started to run a bit rich. I had nearly 5000 miles on the motor. The pistons are forged so they are supposed to expand. The p/w if anything i thought would be to loose since I know the piston was slapping around in the cylinder.

 

The motor was also assembled at a shop so Im not sure what the final clearances actually were.

 

could be piston slap.. the noise

or making the same sound as to when its too tight..

if u can contact the shop that assembled it it wud help... get all the info etc needed,

with builds like this, u should be on top of it all.. from p/w clarance to final bearing clearance etc... i know i would...

 

agreed ^^^

 

I know for sure the noise was piston slap. However what I dont understand is why the motor lasted 5,000 miles and suddenly the piston starts slapping around in the cylinder. When I had the motor sleeved the final bore and hone was set to the p/w clearance as per wiseco. The motor was built by Intec racing in washington, so I was fairly confident that the clearance were checked before the final assembly, however now Im not so sure. What I really need to know is if this is possibly an assembly error or was it something I could have done driving.

 

hmm....hows the cylinder wall look? cant be pretty.....

 

intec racing?

i think one of the guys there, is a member here, get in touch with him..

they sound like they know what their doing, im sure u can get answers from them...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by acid-burn &raquo;</TD></TR><TR><TD CLASS="quote">looks like the pistons wer getting too hot.. expanding and rubbing...</TD></TR></TABLE>

thats my first guess.

not sure about you guys but ive never experienced piston slap with my forged pistons. ive had 3 sets so far and none of my motors knocked upon startup.

 

This is just a question but were you spraying any nitrous at the time this happened? I know you didn't list it in your info but I've seen similar damage on nitrous engines that went lean.

 

You said you were sure there were no signs of detonation. How are you sure? Just because you can't hear it doesn't mean it isn't happening. Also, find out what the clearances were set at (obviously). A good shop will have all that stuff on record. Show a picture of the spark plugs that were in the motor when you tore it down.

Isn't number 3 the one that always runs the hottest?

Someone was posting the other day, he had a question about piston to wall clearances using Wiseco pistons and he was saying Wiseco recommended 0.0025". I have never used Wiseco, but that seems awfully tight unless its a 4032 type alloy like an SRP.

 

hmmm what interests me also is.. that it was dyno tuned a little rich? why.. and when everything was seated it started to run a bit rich...

i guess its no longer "a bit" rich...

running rich could potentially wash off oil from the sleeves too..

where was it dyno tuned , juz curious...

hopefully this doesnt happen again

 

Alright to answer all the questions.

I have never run nitrous on this motor.

There are no signs of detonation because I would have been able to tell on the top of the piston.

The motor was put together and tunned by intec racing basically they are just saying it is no their fault and there is no way it possibly could be. The motor was not tunned rich. The motor was tunned perfect, but after it was completly broken in it was slightly rich. It was not rich enough to wash out the rings however. I have already contacted Intec because I live like 20 minutes away, one of they employees there actually helped tear the motor down and they basically just told me Im S.O.L, but i really think that this is an assembly issue.

I will have pictures of the cylinder walls and spark plugs up soon.

 

the only thing i can think of is it went lean for whatever reason and heated the piston therefor expanding it too much for the cylinder walls.

 

It does look like the piston expanding to walls. Maybe your oil temp was consistently too high causing the pistons to expand too much whenever you drive your car hard.

I noted the bigger bore wiseco pistons tends to recommend a bigger p-w clearance.

The 85mm CP i have with me now recommends a 0.003" on the sheet and the other 85mm Wiseco i have recommends a 0.004". Thats quite alot if you ask me.

Where else my friends 81mm wiseco call for 0.0025".

This does tells me that the bigger bore wiseco does expand a little more than the smaller bore.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1 2 NV &raquo;</TD></TR><TR><TD CLASS="quote">the only thing i can think of is it went lean for whatever reason and heated the piston therefor expanding it too much for the cylinder walls.</TD></TR></TABLE>

Take this theory one step further and check the injector for that one cylinder. I think you mentioned it was cylinder #3.

 

Could you have gotten a bad tank of gas? Do you run a A/F gauge? Datalog? How sure were you that the engine was up to temp? Are you running a low temp t-stat?

What did the plugs look like?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1 2 NV &raquo;</TD></TR><TR><TD CLASS="quote">

thats my first guess.

not sure about you guys but ive never experienced piston slap with my forged pistons. ive had 3 sets so far and none of my motors knocked upon startup.</TD></TR></TABLE>

Strange, when I mentioned this problem to the OP, he got all butt hurt and wrote a reply indicating I didn't know what the hell I was talking about. The piston in the picture CLEARLY got hot. This is a little bit beyond a fuel issue also. I don't think you heard any noise from anything "slapping" around. That piston had a lack of clearance, not too much.

Here is a link to his OTHER post about the same problem. I guess one topic on it wasn't enough. Seems to me like he already knew the answer to begin with. Why as for our help?

https://honda-tech.com/zero...09877

 

Ok so if the noise i heard wasnt piston slap then what the hell was it? It wasnt a rod knock. This also did not happen on start up the car was warm. If the piston did get hot and over expand what could have caused this? Lack of oil would seem to be some what obvious answer to that, but why all of the sudden did it just happen after 5,000 miles?

 

just wondering, how does the top of a piston look when detonation happens?

 

Its not a put together problem, its a tuning problem

Those scars are from the piston expanding because of the heat, heat is created when a lean mixture is added, whoever tuned your car is the one you should go too..
Pistons dont expand on their own and thats some serious scaring you can even see the side of the piston towards the top, its being "melted" away reguardless of chipping it was getting way to hot in that motor..
What was the timing and AFR set at..thats some high compression.

Possible bad batch of gas?? What gas were you running.. Intec is a great trustworthy group of people i would suggest getting some more info from the guy who tuned it first.