This engine has had aftermarket sleeves put in, and OEM pistons. The sleeves and pistons have different expansion rates, the OEM pistons are designed to match the expansion rates of the OEM FRM sleeves. I want to agree with you, cylinder 4 seems to be the culprit, may be a result of slight rod knock. Next step is to check the rod bearings on #4, these engines are not easy to rebuild. I would only rebuild the cylinder if there's less than .25mm worth of damage, sleeving the block is never a long term solution.

My advice, find a used bare block that hasn't been sleeved, and transplant it into the car, if your crank is still ok that is.

http://www.ebay.com/itm/Honda-S2000-OEM-stock-ENGINE-MOTOR-BLOCK-CASE-AP2-2-2L-F22-F22c-F22c1-free-ship-/302131905652?hash=item4658770474:g:j84AAOSwcLxYIJV X&vxp=mtr

What kind of pistons does your engine have? A or B? It should be stamped on the block deck, in your case I can't tell because it looks like they shaved the block, they might have shaved the head as well, which can also cause a ticking noise. In short that thing's a disaster, but it's not the end of the world. Find out what kind of pistons you have, if they're B pistons, then you can grab that Ebay block and just transfer everything into it.

Here's a set of B pistons that can go with that block.
http://www.ebay.com/itm/OEM-Honda-s2...5Y4Y31&vxp=mtr

if the crank is fine, with this you can put it back together and not worry, although you may still have a little ticking from the decked head.

Also slightly off topic since this is beaucoup bux but here's a mint 0 mile OEM head
http://www.ebay.com/itm/HONDA-OEM-00-05-S2000-Engine-Cylinder-Head-12100PCX811/262763717581?_trksid=p2047675.c100005.m1851&_trkpa rms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D2%26asc%3 D41811%26meid%3D5d9d5d3636784fdd955142e2eabaf897%2 6pid%3D100005%26rk%3D4%26rkt%3D4%26sd%3D1624486079 73

Look in the WTB forums or the classified forum and see if anyone has what you need. You may need a new piston if #4 is scratched up. Just trying to give you some decent options man, I feel for you.

 

Hmm, this does sound about right. What is the solution to this? Or is the engine trashed?

 

Refresh the page I gave you some leads, that would be the best long term solution in my opinion. If you go this route you can get the thing back together and enjoy it for 100,000 worry free miles.

 

I really appreciate all of that information, now if only I could figure out how to remove these damn connecting rod bolts. I'm going to try and figure out which pistons I have so I can go from there, after all of this I'm really not sure how long I'm going to keep the car so longvity is important but I am a little more influenced by cash because I am already in way too deep to spend that much on this engine. Would throwing in an appropriate set of aftermarket Pistons and verifying the condition of the bearings be enough to get this car by for a good while? And i may very well have these steps done by a professional mechanic because I have gotten this far and I really don't want to mess anything up now.

 

The piston letter is also on the piston crown you may have to clean the crown to get a good look no marking = "A" piston, but can also have an A, "B" pistons obviously have a B, the A pistons are a tiny bit bigger than B pistons. The cylinder 4 bore looks like it has some scratches not sure how deep though if it doesn't catch your fingernail then you may be able to hone it, and if the measurements are ok put it back together. As for the rod bolts, it's crazy that trying to remove them stripped a 12 point socket. How did you try to remove them? Breaker bar?

Just for your info
A piston diameter measured at the skirt = 86.980(at service limit) - 87.006mm or 3.4244"(SL) - 3.4254"
B pistons are .0004" smaller, so same range but .0004" smaller

The matching bore is supposed to be ideally ~.0007" larger than the matching piston but no more than .002" larger, and no less than .0002"

In any case I think it's possible the builder overtightened the cam caps and may have caused the scratches on cylinder 4, however they do take quite a bit to tighten, I think it's 18ft lbs + 90 degrees.

Your next step would be to remove the rod caps to see how the bearings and rod journals look.

I mean I suppose you could put it back together if you verify the rod journals are in good shape, and the correct bearings have been used, you'd have to plastigauge the rod journals to find out provided the rod journals aren't scratched up. But there's no way of knowing how long the engine will last as is.

 

If it were mine i would put a known good used motor in it. I would pull the head apart and pistons out at the least. I have heard this car run and adjusted the valves on it. The noise should be obvious when you find the cause. What is on top of number 3 piston? Is it glare from camera flash or is it something actually abnormal with the piston? Motor had a lot of noise from #4 and maybe #3. Don't band aid it....in picture #4 is draging, scoring or whatever you call it and piston/ring lands are going to be trashed. Probably crank also. Put oem used motor in it or part ways. Lots of money/effort either way. Good luck mitch.

 

sorry for the discovery.

 

I'm pulling the pistons and then taking the car back to the nearby tuning shop Dynosty who happened to have been the first shop I took it to that instantly said there was deep internal problems and get their opinion again now that the engine is in pieces. Believe it or not, the cylinder walls seem to be in decent shape, the wear i pictured on cylinder #4 is completely surface damage only and isn't noticeable at all when rubbing my finger across the cylinder wall. Considering their track record with S2000's and engine building in general I know they are more than capable of getting this thing running again, just all comes down to numbers now.. If i cant find anything obvious on the pistons or rods that would be causing this noise and the scoring I am going to follow everyone's advice and trash the engine. Definitely not tearing any deeper into this thing.

 

Just wanted to provide a little update to anyone interested in how the car is doing, the Dynosty shop did not believe keeping the block was worthwhile and agreed that sleeving this engine is a very poor decision for any sort of longvity. At this point, I am finding everyone that has a broken s2k considers every part on them to be worth the equivalent of a brick of solid gold, so I do not believe it is economical for me to just buy a junkyard engine and slap it in considering my seats are trashed, my wheels aren't the prettiest, and the entire passenger side needs a significant amount of bodywork.

I am am looking into picking up a 2007 NFR S2000 with 88k miles that has good seats, good engine, and nearly every body panel I need already painted the proper color. I am starting to worry that buying a 3000+ engine that is over 17 years old to be a poor choice, which is what is pushing me towards the more reliable newer AP2 engines.

Would there be anything wrong with going ahead and doing a full AP2 conversion on my car? As in...
AP2 engine
AP2 transmission
AP2 diff
AP2 steering wheel/guage cluster
AP2 seats
AP2 bumpers
AP2 soft top
AP2 wheels
AP2 tail lights

 

If you really are in love with that particular car. Yes it is worth it. If you think you may sell it some day......sell it now for as much as you can. It's a lot of work. Good hobby and learning experience. You've seen my s2000 beater. I shouldn't have fixed it money wise but it is my buisness/hobby.