Rockin engine problem

derekhay316

Registered User
Since i bought the car its always bin kind of a rough idler. I can feel it rockin back and forth when i'm sittin in the thing. I noticed the other day that the idler pulleys look pretty bumpy. Would new idler pulleys make it a lot smoother? Is this a usual problem?
 
Idle Problems

There are many reasons an engine will "rock." If you have a lot of mods, and from the photo it appears that you do, it may be the price for going fast. Some would even say it's a small price to pay for improved performance. If your cam is such that it has more lift and duration, and your injectors are larger, you MAF and TB are larger, you've moved into rumpty rumpty land. Great for midrange and top end, but a little hard on the lower RPM band. The only way to compensate for such mods is to bring engine idle slightly above the loping if possible. If you don't have any mods that would affect idle, then I would suggest the basics, a tune up, check and adjust all the intake components, and make sure the fuel system is working properly. If still a problem, check valve adjustments for equal settings on all lifters.
 
Have you changed the engine mounts? If not, watch the engine under the hood while you rapidly open the throttle. If it lifts on one side you need new mounts ungently. Most people opt for the solid replacement (SOB job to do, but very important) which are available for SCP, MN12, etc. I would say every SC over 100,000m or 5years needs new mounts. If you don't replace them the engine drops about 1/2" towards the cross member & the sump pan rubs on the power steering pipes; initially causing a power steering fluid leak and finally it'll cut right thru the sump pan itself. WORTH CHECKING.
 
I'll be watching this one. Having the same problem in my 95 and I have had the engine and transmission mount changed within the last year to solids and my harmonic balancer is not wobbling. Anything else it could be?
 
I'll be watching this one.

Me too. My engine "rocks", and I'm guessing it may be for the reasons discipled1 posted. With my mods, it only started doing it after the rebuild and heads/cam addition. But I do also have a ticking sound in the valvetrain, which I'm thinking is either a loose rocker, or noisy lifter, so I wonder if that could be the cause instead? I'm going to try adjusting the idle a little higher via the tb set screw, and see if that "solves" the problem.
 
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