I have a 1990 240sx s13, relatively stock, with about 163000 miles on it. Ok here's the deal. I have spent countless hours going over threads involving the apparent problem with our timing chains. What I can't figure out is why the problem is intermittent. When I first start up my car, it will 98% of the time makes that horrible noise of timing chain slapping again something. I have found 1 way, and only 1 way, to make it stop. If I jump on the interstate and drive at least 4 or 5 miles, when I get off, the noise is gone. If i start my car and still there, giving it a little bit of gas, while it makes the noise it runs like real crap. It feels like its missing, until it stops, then it runs fine.
My first question, what makes the noise intermittent like that? Second, what should be my next course of action? Im fairly familar with mechanics and have done a lot of work to my nissan myself. I am confident that I can tackle a timing chain replacement by myself in a weekend. I am ready to fix this problem, but i dont want to just go out and start buying parts. Any help from you guys will be much much appreciated. Especially if maybe you have had the same problem in the past. Thanks guys.
RichHampton - VA
Timing chain.
Re: Timing chain. (burba1269)
The 89-90 SOHC motors had oil pumps that became marginal early in their life. Low oil pressure will cause the hydraulic valve lifters and the timing chain tensioner not to work correctly.
After the motor warms up and the RPMs go up, the oil pressure goes up and things quiet down.
You can check the pressure very easily by installing a temporary mechanical oil pressure gauge. You would remove the oil sensor which is located next to the oil filter and install the mechanical oil pressure gauge in it's place; you may need to get an 1/8 BSPT to 1/8 NPT adapter to hook up the gauge. With the engine fully warmed up, the pressure should be as follows:idle - at least 11 psi3000 RPM - 60 to 70 psi
If the oil pump needs to be replaced, it's easy to do so on a '90 as it bolts on externally.
After the motor warms up and the RPMs go up, the oil pressure goes up and things quiet down.
You can check the pressure very easily by installing a temporary mechanical oil pressure gauge. You would remove the oil sensor which is located next to the oil filter and install the mechanical oil pressure gauge in it's place; you may need to get an 1/8 BSPT to 1/8 NPT adapter to hook up the gauge. With the engine fully warmed up, the pressure should be as follows:idle - at least 11 psi3000 RPM - 60 to 70 psi
If the oil pump needs to be replaced, it's easy to do so on a '90 as it bolts on externally.
Re: Timing chain. (rogoman)
You ever find a solution to this? Or even figure out the problem?
