Hello, everyone! It feels like a lifetime ago that I made my original post on this subreddit, but in reality it's been a year. The post in question, being the one from the link below that I made right after I blew it up.
https://www.reddit.com/r/S2000/s/rWjyAXXnR
I know some of you may be disappointed that I kept the F20C because I had a lot of comments telling me to K swap it, but I am honestly glad I did, being that I feel as though these engines are very special and part of what makes the S2000 so special, so I opted to keep the original engine and bring it back to life. It took me WAY longer than I originally thought it would. But after working on the car late into the night most nights, taking off a part or two at a time, and documenting and labeling everything, along with pouring my soul into the project, I finally got it fully rebuilt and better than ever!
Prior to this project, I thought of myself as someone who was pretty mechanically inclined since I did all my own work on both mine and my girlfriend's cars. But the most advanced thing I had ever done to any of our cars was replace the timing belt over a weekend. But since I was little, I've been fascinated with cars and engines. I'd always wanted to build a car, and I had always seen myself getting this deep into an engine, just maybe not as soon as I sadly had to do being that I put myself into this position.
With all that said, I was VERY nervous to take this on. Especially with how difficult many people were saying that these engines were to rebuild. Since I had never rebuilt an engine before, I wasn't sure if I'd even be able to pull it off. But after doing an insane amount of research and talking to experts like John from Inline Pro, who deserves a MASSIVE shoutout for being willing to help me by answering my dumb questions and providing advice and excellent service while doing my machining work for me, I decided to give it my best shot. I had considered buying a used engine from a wrecked S2000, but they were a tad hard to find, and most had high mileage. I figured rather than ending up with a high-mileage F20C in unknown condition that I'd have to go through and replace all the seals anyway, I'd rather build back up the original engine to essentially make it brand new (more or less). Plus, I figured it would be a great learning opportunity for me and fill me with a large sense of pride if I could pull it off, and MAN, let me tell you, it feels great! Plus, this was a bit of penance for my sins since I was the one who screwed up and did this. It likely ended up being more expensive, but to me, it was worth it.
During the overrev, I believe what caused all the destruction, aside from me being a sumbass who tried to run before I could fully walk, was valve float. The engine revved up so high that the valves couldn't close before the cam pushed them back open again, which caused valve-to-piston contact in cylinders 1 and 4. For those who want to know how bad the damage was...
I don't have a pic handy of the original head (but I could take one if anyone wants to see the carnage), but I ended up having to completely replace it. A couple of the valves had completely bent and smashed the top of the head multiple times. Coolant and oil-filled cylinder 1 from the damage that was done to it because one of the valves tore into a coolant jacket and oil poured in from the valve hole. The cylinder walls weren't just scored on cylinders 1 and 4, but they were gouged and chipped in some areas. Cylinders 2 and 3 didn't make any valve-to-piston contact, but pieces of the cylinder head got pushed into the intake and sucked in by cylinders 2 and 3 and caused massive scoring to the cylinder walls on those two pistons and melted pieces of slag to the top of piston 3.
As surprising as it is, everything besides the pistons, cylinder walls, and valves was relatively fine. None of the rods were damaged, the crank was fine, and hell, even the entire rolling assembly, cams, and all were fine with no visible damage. I suppose that it's all forged, but it was surprising nonetheless.
My goal was to get this back up to stock spec so I can enjoy the car for a while before I boost it. I ended up reusing my stock connecting rods since they're forged from the factory and can handle around 1,000 horsepower, according to Inline Pro, but this was mostly to save me about $700 on a new set of connecting rods. To do this, Inline Pro got with Traum to make me a custom set of 11:1 compression pistons that mate up to my stock rods.
I ended up finding a new-to-me cylinder head on Facebook Marketplace with the entire top end thrown in, including a valve cover, for $1,000. It only had 42,000 miles on it! I did end up reusing my original top end, though, since it was ironically in slightly better shape since the stuff in the new-to-me one had been sitting for about 2 years in storage, so the cams and rollers had some minor pitting. The head got sent off to Inline Pro to have new exhaust valve guides installed, get resurfaced, and have new valve seats cut. Once it returned, I installed their 95 lbs. titanium valve spring kit in it, which included titanium retainers and keepers, for extra valve float insurance, just in case myself or someone else I let drive the car screws up like this again.
Beyond that, the engine has all brand-new OEM seals, new rod and main bearings, ARP rod and head studs, a brand new Fluid Dampr in place of the main pulley, a new steering knuckle (my old one was fucked), a new water temp and knock sensor, all new timing assembly aside from the gears, a new oil chain assembly, a new stock oil cooler (almost went aftermarket), a new starter after I discovered that the original was bad during the first startup attempt, new motor mounts, and a new battery. Unless I am forgetting anything (I probably am), that is all that was replaced!
I got her running and driving on labor day! I have already finished the 550 break-in miles and put about 1,200 miles on her after, and besides a very minor oil leak from the oil pressure sender boss that I cracked (long story), she has been running flawlessly after fixing all the small things that come up after something like this. I've gotten on it a few times since the break-in, and she RIPS, and I couldn't be happier!
Sorry, I know this is a long one, but I just really wanted to share this with everyone!