Mr.Matchbox

Gentlemen,
one more question: It seems that the S2000 engine suffer often from damage on cylinder 4 and the rod bearing of cylinder 4.
My impression is that this was adressed by changing the oil jet bolts. But is there annother reason for this specific damage on Cyl. 4?

In the german S2000 Forum, sadly a member reportetd about annother damaged engine. Cylinder 4 (almost) seized, FRM gone, rod bearing in pieces, piston hit the head lightly, crankshaft on rod bearing 4 damaged.
Car was driven for 15 Kilometers - 10 Miles with top Speed on the autobahn, hitting 260 Km/H - 162 MPH. While deaccelerating, back to cruising speed, the engine starts to knock and the damage was done.

The owner reported that he discoverd, while dissaembling the engine, that the chain tensioner of the oil pump was gone but he never see the red oil light on at the dash.
It was a 2006 modell, RHD, imported from UK (Much cheaper this way in Germany) but it should have the better oil jet bolts installed from factory. It was the original engine. The owner used 5w-50 Oil.

Any thoughts about this? I know for sure, as tempting as it is, i dont want to press the car to the limit on the Autobahn.

WarrenW

I wonder if it could be related to the grade of oil. Is 5W-50 recommended for use in Germany or the UK? My owner's manual says 10W-30 so 5W-50 would be a good bit heavier oil than what's recommended.

Mr.Matchbox

No. Also in Germany only 10w-30 and 5w-40 is recomended. As 10w-30 is a extremly uncommon grade here in Germany, most owners here use 5w-40.
There is a opinion in the german S2000 Community that you should use xxW-50 Viscostiy for extra protection. I dont belive this. I think using this viscosity will maybe do more harm than good, but as allways with Engine oil, this is extremly controversial.

starchland

Hard to say without knowing the history of the car. But what leads you to believe cylinder 4 is persistent?

Utah S2K

The #4 cylinder failure was first identified here on the board by a gentleman known as WyomingBarry(sp). The issue is directly related to the banjo bolts. Honda corrected it but no field action was taken. Problem is well known. If you run an early series car under boost or extended high rpm speed (number I recall was 105mph) you may starve the #4 journal.
Utah

rpg51

Just keep it under 100mph and you should be ok.

miloking

Sounds like oil pump failure, also there are known problems with cooling of 4th cylinder. The 4 hole banjo upgrade from late 2002 was a fix but not sure how effective in these extreme circumstances.
Is the engine original to the car? or maybe it has had earlier engine replacement

Mr.Matchbox

@ Utah S2k: Thanks, that was the information i was looking for. I heard / read it, but i dont know for sure. I was also under the impression that the updated banjo bolts have adressed this problem.

@ rpg51: So i should let all these BMW - Audi pass me? This is hard!
Seriously, i allways try to keep it around 5.000 RPM -150 km/h - 93 Mph while cruising on the autobahn, beside the occasional short sprint to higher speeds.

@ Miloking: I asked the owner the same question, it was the original engine. But it is of course a pre-owned car, so who knows what maybe happend before..


The more i think about it, the more i came to the conclusion that a xxW-50 oil that is roughly twice as viscous at operating temperature as a xxw-30 Oil maybe really does more harm then good.

Car Analogy

50W, under that extreme load, sustained near redline at highest load possible, could certainly be the cause.

On an old school motor with loose tolerances, higher weight can equal better protection. But on a motor like ours with tight tolerances, weight that high can easily be too thick to flow sufficiently.

I am not saying that 50 weight oil IS the cause here, but it certainly COULD be the cause.

cosmomiller

I wish I could find the source but I recall a 25 second limit on WOT in any gear.
Not sure if this applies in this case.