Ok I have a 2000 GS-R with about 138000 miles. For the last 40k i noticed there is a build up of black soot around my rear bumper after a few hundred miles of washing it. Also noticed i am burning more than a qt of oil less than 500 miles. If I rev it hard while its stopped I notice some blue smoke come out nothing crazy like clouds of blue smoke. At start up nothing maybe a little white smoke when its cold but goes away once warmed up. Cant tell if anything comes out when driving at least not noticeable in rear view.

So I did a compresion test results below:
Dist to Timing Belt side
250 180 250 250

Added some oil to the 180 cylinder and redid comp test and it went up to 245.

Also the plug from the 180 cylinder was really caked up and blackish compared to the others who were more grayish and not oily.

What does this mean? Is my piston ring shot? How do i know what it is exactly? Can you replace the one cylinder or would you have to bore all 4 and do them all new? Need some advice.


Facts
Original Cat Conver
Original O2 Sensor
New PCV Valve
Dist Cap changed about 30k ago
Dist Rotor 30k ago
Wires 30k ago
Plugs 20k ago
Air Filter 50k ago
No CEL

Mods
RS-R Exhaust
AEM Short Ram

 

sounds like bad rings id do a leak down test to comfirm. Unussual for one one cyc to be that bad and the rest ok. hmm anyway do a leak down

 

id definately say the rings are leaking only other options are cracked piston. its time for a rebuild you should be able to take out one piston and replace the rings but it sounds like alot of trouble not to do the whole shebang

 

Few questions

1) Where should I be listening for the air to come out, what are some of the key areas to look for?

2) Can I do it with the valve cover off? It just seems easier to find TDC for each piston that way instead of having to pull it off set TDC and then put back on before doing test.

3) If we do determine its the piston rings can i just use the same piston and add new rings to it?

4) Do I need to get the cylinder walls machined a little to accept the new rings?

 

1)you would want to listen to air coming from the dipstick for the rings, intake manifold for intake valves and tail pipe for the exhaust valves.

2)you can do it with the valve cover off.

3)you might as well change as a whole set

4)yes you would want to rehone the cylinder

 

what do u mean you added oil to the 180 cylinder?

 

because adding oil will cause the ring seal to go up if the rings are bad/

 

oic