float_6969 wrote: ↑

Fri Jan 06, 2023 5:57 am

Well damn. That sucks man. I haven't tried to get a KA for a while. Are they still dirt cheap?

No.

Aaron has a head he's offered but I feel like I did what I wanted to do with this platform. I've been a 'KA guy' for as long as I've owned an S chassis. Going on 20 years now, man time flies. There's a lot of time and money into the build but I'm at peace with the fact that I wanted to make solid 400 streetable HP and find where the weaknesses were on this drivetrain, expose them, and make it solid reliable and fun. I did that and I can let it go. I am going to do a boroscope inspection of the cylinder before I pull it. It's possible I got a bad spark plug and the insulator self destructed but that seems unlikely. The top of the piston has some pitting and damage but it's way beyond what detonation would be and, why only 1 cylinder? I was gutted when it happened but now that I've had time to step back and re-evaluate there's another path I want to go that I'd always mused about so now's my chance. The car will always be my project. The chassis is solid and where I want it. I still really enjoy driving it. It'll continue to evolve as long as I have the capacity to support that. Just, the Si and Cobra will be getting some love in the interim while I save up (maybe a couple of years for what I want to do) in order to do the build I know I'm capable of.

I'll probably post the whole drivetrain up for sale this spring to see if someone wants a SOLID setup to work off of as opposed to peace-mealing it out but we'll see where that ends up. I have a lot of nice proven parts on this thing.

I kinda figured, but it was worth the ask. I realized after I posted that, dirt isn't really cheap anymore either, LOL!

I get taking something to it's limit and then wanting to explore something different. I'm not sure I'll keep this chassis long term... though I only seem to think that when I can't drive it, and then as soon as it's working again, I realize why I've been messing with these things for over 20 years. When everything is right, they're just soooo much fun.

I am bummed that we never got to meet up/race/cruise with that engine. I think the low end tq vs. high RPM power matchup would have been fun. But life is like that sometimes. Maybe I'll actually get mine done this winter. It's been in the garage for over a month and I've done more to it in the last month than I have in the last two years. I might actually get it "done" (they're never done) this winter, assuming the Mrs. doesn't get sick of my piddling and ask me to start doing all the house projects I said I'd get done this winter too

Anyway, if I get mine going and you need to scratch the S-Chassis itch, just LMK. I'd like to see that Cobra anyway, so we can meet up swap cars

float_6969 wrote: ↑

Fri Jan 06, 2023 9:10 am

I realized after I posted that, dirt isn't really cheap anymore either, LOL!

float_6969 wrote: ↑

Fri Jan 06, 2023 9:10 am

I kinda figured, but it was worth the ask. I realized after I posted that, dirt isn't really cheap anymore either, LOL!

I get taking something to it's limit and then wanting to explore something different. I'm not sure I'll keep this chassis long term... though I only seem to think that when I can't drive it, and then as soon as it's working again, I realize why I've been messing with these things for over 20 years. When everything is right, they're just soooo much fun.

I am bummed that we never got to meet up/race/cruise with that engine. I think the low end tq vs. high RPM power matchup would have been fun. But life is like that sometimes. Maybe I'll actually get mine done this winter. It's been in the garage for over a month and I've done more to it in the last month than I have in the last two years. I might actually get it "done" (they're never done) this winter, assuming the Mrs. doesn't get sick of my piddling and ask me to start doing all the house projects I said I'd get done this winter too

Anyway, if I get mine going and you need to scratch the S-Chassis itch, just LMK. I'd like to see that Cobra anyway, so we can meet up swap cars

Heck yeah, I'd be up for that. I'm swapping to a new carb (one that has a choke) on the Cobra this spring. I think you'd like a spin in the Si too if you haven't driven one before. For a decent HP FWD car it is extremely balanced. When I'm done I should be REALLY doubling down on my low end torque so I'm still game to play around in Mexico.

VStar650CL wrote: ↑

Fri Jan 06, 2023 10:16 am

I did that

NukeKS14 wrote: ↑

Thu Jan 05, 2023 7:42 pm

I believe I floated a valve into a piston last fall on the #3 cylinder.

Well that sucks. You hate to see it.
Does it still run on all 4 cylinders or is there no compression in one?
Interested to see pics if you just pull a valve cover and the plug first.

PapaSmurf2k3 wrote: ↑

Fri Jan 06, 2023 7:04 pm

Well that sucks. You hate to see it.
Does it still run on all 4 cylinders or is there no compression in one?
Interested to see pics if you just pull a valve cover and the plug first.

Yeah, it still runs. I got it home and backed it in the garage and stepped back to clear my head and re-evaluate things. I'll pull the plugs and grab compression numbers and boroscope everything this spring and figure out where to go with the engine itself, whether I'll take Aaron up on the head and get that piston replaced or whether I just want to sell it as-is.

Here's what came out of cylinder 3. That isn't melted, my phone didn't want to focus but the insulator is shattered and something was traveling around the cylinder. I suspect it was either the ceramic insulator or a piece of valve. I'll keep you posted when I find out for certain.


I shut it down as soon as it happened and coasted to the shoulder. With the plugs out at home I could rotate it by hand with no indications of interference so I said f*** it and put a new plug in and it fired up, no noise no issues, but the exhaust doesn't smell right and I can tell it isn't running properly so it hasn't been out past the driveway and I didn't idle it at length. I also observed some damage to the piston top but just on #3. The rest of the plugs were just fine. Work did get in the way a bit too as I was working ~73 hours/week for about 6 weeks there last fall while we refueled our reactor.

It was a perfect storm because I was gearing up to drive it down to FL to hang out w/ a close friend and I'd been working up to get ready for that for long time. I have TONS of OEM BNIB parts I was going to stash in my trunk as back-ups for the ~20 hour drive too. I'll have a nice fire-sale this spring when everyone else is getting back out to it too

Man, that ceramic is hard stuff. Can't be good when its floating around in there.

PapaSmurf2k3 wrote: ↑

Sun Jan 08, 2023 10:04 am

Man, that ceramic is hard stuff. Can't be good when its floating around in there.

Knock is an invisible b#%&h, that's usually where busted ceramic comes from.

VStar650CL wrote: ↑

Sun Jan 08, 2023 11:26 am

PapaSmurf2k3 wrote: ↑

Sun Jan 08, 2023 10:04 am

Man, that ceramic is hard stuff. Can't be good when its floating around in there.

Knock is an invisible b#%&h, that's usually where busted ceramic comes from.

Fair enough but just on the lone cylinder? That's what's got me stumped. All 3 of the other piston tops are perfect. What has me wrapped around the axle is that I had JUST bought these plugs from the local O'Reilleys and installed them a day or two before this happened. Same heat range (BKR7ES) that I had before. Same gap that I had before. Maybe I'm connecting invisible threads that don't really exist. The new plugs had the clear plastic 'collars' around the threads, I looked and bought them from the local parts store because I'm weary of the NGK knock-offs sold on Amazon.

I'll know more with a boroscope in there.

Yeah, strange.
An injector can always take a s*** and lean out 1 cylinder though.

PapaSmurf2k3 wrote: ↑

Sun Jan 08, 2023 5:56 pm

Yeah, strange.
An injector can always take a s*** and lean out 1 cylinder though.

+1. Unless it was just a defective plug, the cylinder going lean would be the most likely culprit for spontaneous detonation. It wouldn't take knocking for very long to cause a failure at the hp level you're running.

It's really hard to tell unless it's apart. Once the plug does that, it's even harder to tell because that ceramic goes EVERYWHERE in the engine. I wouldn't be surprised if you have damage to the other cylinders. I had dumb thing going on with an engine that I won't plug this post up with, but the TL;DR is I kept having plugs break like that. When they fail, the little pieces of ceramic go back up into the intake to get sucked into the other cylinders. I had it happen 3 times before I figured out what was happening. Unfortunately, pieces of ceramic going though an engine can look a lot like knock because they only tend to damage the area under the quench pads... which is the same place that knock tends to damage.

All good stuff to consider. Thanks for the info/input guys. I'll definitely follow up once I have things apart. Live, learn, rebuild it better.

We've all been there man. Its a crappy club to be in.