jamesd2

Hello all

I have, for my sins, been bitten by the Honda 'bug'.

Here is my story, so far, of my experience in buying a project S2000 in need of engine work.

I have finally bought a 02 car as a project with the engine provided in several boxes The engine suffered from a big end failure on one cylinder and damaged the crankshaft and connecting rod beyond repair. Having a engineering background, I thought that this sounded like a nice project and a challenge to get it going in time for the summer (not sure which one just yet).

In the lead-up to buying the car I now own, I almost bought another (which fell through - seller was a bit of a muppet). The engine in this car had dropped a valve and was now just a large, interesting paperweight. During the maligned purchase process I had the opportunity to get a brand new zero miles out-of-the-crate K24 engine. Knowing that the F20C were difficult to repair, and in big demand by the rally fraternity, my idea was to get this into the 'S'. So I bought it, but then I ended up not buying the car. However, this process lit the S2000 fire under me and I searched for another car. After a few weeks I found the one I now own. So I had a car, with a broken engine (I bought it unseen so didn't know how broken it was) and a transplantable engine. When the car and boxes arrived I set about looking over the damaged engine to see if could be recovered. I guessed that a new crank, rod and some refurbished bits would be sorted and away we go.

I am currently embarking on the project to get it back together. The original engine had done 6 figure mileage when it expired, so I was expecting some refurbishments in addition to the known issues. If it all went awry, I always had the K24 to fall back on. But, really, I wanted to keep the original if possible. The first thing to do was to check to see if the original crank was salvageable, but unfortunately it was not. So I managed to source a used unit which needed a polish. This has been done and is ready to fit.

I examined the existing cylinder block for wear and tear. There were some signs of light scoring (to the extent that they were detectable by the 'finger nail' test) on the thrust face of the cylinders. I was faced with the problem of honing the FRM bores. After some research in the factory manual, I discovered the process and spoke with a local engine builder who had the correct honing equipment (machine and stones), and an appreciation of what was required. He did a great job and the bores are now good to go.

Next, I stripped the cylinder head and checked the valve train for wear. The valve guides had considerable wear and needed to be replaced. The valves were measured for wear and were all well within factory spec. The guides were replaced, reamed and the valves/seats were cut in. Next up was the much vaunted problem of the valve retainer (or valve spring caps). I had read a lot about the F20C dropping valves due to the retainers cracking and splitting (the theory being that this is caused by over revving). I guess this is what may have happened with the first vehicle I looked at. I didn't want my new build engine to suffer this fate, so I set about checking them (visually and more scientifically). I used a process of non destructive testing which is employed to check for cracks and surface discontinuities in metals (Magnaflux). The retainers passed this testing without issue, and were refitted yesterday when I built the head. Prior to reassembly, I polished the exhaust ports and the combustion chambers to ensure the best possible performance from this engine when it is put back together.

I was interested to discover the root cause of the original engine failure, and my focus shifted to the oil pump. The root cause of the failure could have been down to poor servicing (very old oil or a lack of oil). The guy I bought the car from had replaced the knock sensor, and the cam chain, due to trying to firstly cure a fault code, and then cure a 'noise'. I'm guessing the problem was big end bearing wear, gradual, but it was misdiagnosed and the car was driven until the noise got so bad that it was obvious what was wrong. After I completed the cylinder head build I stripped the oil pump and examined it in detail. The strainer was full of metallic particles, emanating from the disintegrating big end bearing. I split the pump to check it for wear (the rotor and the rotor to housing gaps), all of which were, once again, well within the 'new' specs. The only issue within the oil pump is a score mark on the housing where the rotor sits against the casing. This evidence suggests that the root cause of the failure is likely to be a lack of servicing. My next job is to have this surface faced (via a milling machine) to remove the scoring, and to restore the pump to 'as new' condition.

The condition of the original con rod was so bad that it was not salvageable. I sourced a new one, complete with piston, from the same supplier as the crankshaft. The original pistons are showing minor signs of scuffing, so I was keen to source a replacement set. I investigated new Honda (v.expensive), new aftermarket (v.expensive x 2; only one manufacturer makes FRM bore compatible pistons, and these have a different gudgeon/wrist pin internal diameter which require new con rods to be fitted as well). I have settled on the idea of sourcing a good used set, and replacing the rings. I have imported a set from the USA which should arrive next week. This is the second replacement set, as I bought a set from a UK breaker, who, despite being asked, sent a used set that were much worse than my originals. These were returned and I was refunded, but it just goes to show one mans idea of knackered is another mans idea of being OK. The new rings should arrive next week as should the pistons. Then I am onto the home straight for the engine rebuild.

Ill try to get some images up next week so that you can see what I'm up to.

Thanks for reading,

James,

Nick Graves

Very interesting read James. Thanks for posting. It's good to read a considered technical report on the detailed damage, as many have already got to the rod-throwing stage and diagnosis can then become a bit more difficult.

My money would be on oil starvation, either from running it too long between level checks or track day surge. A lot of people were caught out by VTEC blow-by on these engines in the early days.

s2konroids

Christ you haven't had the best of luck, hope your next build goes more smoothly.

mikey k

excellent work and good luck!

Vtechead

Has it crossed your mind to use the k24 crank in the f20c to create a stroker engine ? I'm thinking about doing it in the future.

Mortlach

Will be following this with interest. Best of luck James

tobyCHIPPO

I thought that was only possible with the k20?

Interesting read though, will be cool to see how it all pans out.

Vtechead

Definitely possible see link.

http://www.superstreetonline.com/how...stroker-build/

jamesd2

Definitely possible see link.

http://www.superstreetonline.com/how...stroker-build/
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I have had several thoughts about options for rebuilding. I read much about a stroker kits, one of which used K24 crank and H22 rods amd piston (FRM compatible), but I put that on the back burner. There was some concern about rod ratios and accelerated piston/bore thrust face wear. Also you have to machine the liners to take the increased sweep of the crank/rods. I think that I'll probable get the F20 together and running first. Then, I do fancy building the K24, perhaps for forced induction. But not wanting to run before I can walk, I want to get the F20C going first.

Ultra_Nexus

Yeah sounds like you have fought a bit of an uphill battle!! I'd like to see the pics though.