My 200sx with a ca18det has a knock only over 2000 rpm. what could cause that?
Answers:
The knock is the connecting rod bearings giving you audible notice of their impending TERMINAL failure.
This engine is a highly tuned performance engine and is under a lot of stress.
You may have already noticed that many 200 sx's are sold with engine damage for small money, as they are quite expensive to repair properly.
It is now time to sell the car as is,
or give the engine a 2000 Euro (3000 US dollar) engine overhaul.
I personally think that giving the engine a professional overhaul is the best route ( and the cheapest in the long term ) as all the second hand engines for this particular Nissan are similarly worn, unless guaranteed to be below 30,000 miles.
A professionally overhauled engine will also have the latest modifications for reliability that the Engines Remanufacturer Federation deem to be in the best interests of engine reliability.
the guy locked in your boot trying to get yor attention
Unfortunately a knock is a knock is a knock. Knocks are not good! I'm assuming that ca18det is the engine designation, but it doesn't matter. Knocks do not just appear and disappear. I would assume that the engine has a slight knock at lower rpm, you just can't hear it until after the 2k mark. I'm also assuming that you realize what the next sound will be if repairs are not made. A knock is caused by excessive clearance between two parts of the rotating assembly. When main bearing wear, they knock. When connecting rod bearings wear, they knock. Wrist pins can also cause knocking. Low oil pressure can or blocked oil passages can cause these parts to wear prematurely. So I would suggest you rebuild it or get a rebuilt unit. The one you don't want is those parts on the inside to wind up on the outside. Make sure you are hearing a metalic knock (metal on metal) and not a pinging noise that could a bad knock sensor or bad fuel, or timing problem. Good luck.
That sounds like your crankshaft, have you changed your oil to fully synthetic? or semi - synthetic? you might need to have your crank reground. it wont get any worse but just sounds bad.
your spark timing may need to be advanced, to check this try a lower octane fuel
does it have good oil pressure? it could be spark knock
bad
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