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Need input about reason of failure - cracked cylinder walls
Hey guys just wondering what coulda caused this. Some context on the build, scat rods with 81mm nippon low compression pistons,nippon racing rings with 1st ring gapped to .016 and second ring was .020. Ran 15 psi and afr's were on the richer side, 11.6-11.8ish and conservative timing tables. My initial guess was the rings expanded too much and hit each other but with this being the first engine I've built I can't say for certain. Any input from people a little more experienced?
re: Need input about reason of failure - cracked cylinder walls
What block? What turbo? What fuel? 11.6-11.8 is actually a touch on the lean side. What's your injector size and duty cycle at this range? I would *so far* agree to the ring issue, but without a little more info, it's a toss up.
Last edited by TheShodan; Jun 9, 2020 at 07:04 PM.
re: Need input about reason of failure - cracked cylinder walls
Originally Posted by Txdragon
What block? What turbo? What fuel? 11.6-11.8 is actually a touch on the lean side. What's your injector size and duty cycle at this range? I would *so far* agree to the ring issue, but without a little more info, it's a toss up.
its a b18b1 block with a ebay gt35 and 91 pump gas. What would be a good afr to target for that boost level or would that be a little too ambitious of a boost level for pump gas? Injectors are 775 ID's and im not sure of duty cycle. I guess one important thing to note is that it wasnt tuned on a dyno or by a reputable tuner, just some guy off of the facebook groups. Maybe this played a bigger role than any kind of part failure?
Originally Posted by TheShodan
Co-Sign
Originally Posted by NVturbo
that **** would have never happened if he used those ARP/Wiseco ring compressor tool
Originally Posted by NVturbo
Looks more like poor install than product failure...
Like i said this was my first attempt at a build so I'm open to input. I followed this
re: Need input about reason of failure - cracked cylinder walls
Originally Posted by yazarpm
its a b18b1 block with a ebay gt35 and 91 pump gas. What would be a good afr to target for that boost level or would that be a little too ambitious of a boost level for pump gas? Injectors are 775 ID's and im not sure of duty cycle. I guess one important thing to note is that it wasnt tuned on a dyno or by a reputable tuner, just some guy off of the facebook groups. Maybe this played a bigger role than any kind of part failure?
Like i said this was my first attempt at a build so I'm open to input. I followed this video as a guide but if there's something different you'd like to add or change I'd be happy to hear. I did use this style of ring compressor, are you talking about this instead?
The no-name facebook tuner could have lots to do with it, but I'm still leaning toward a ring malfunction of sorts. I have also had some bad luck with Nippon pistons.
as for the ring compressors, This one is inexpensive and will get the job done. The downside is that it is somewhat "clunky" and like a pissed off ex, WILL cut you. Lol!
Need input about reason of failure - cracked cylinder walls
