Guest 240Rob Posted January 24, 2004 Share Posted January 24, 2004 Alright I got this 1980 280zx for my project car from my friend. I'm having a little problem diag a problem at idle it sounds like a rod is knocking real bad with the clutch pushed in when you let off the clutch it goes away alittle bit and when you rev it it goes away. Is this a tranny problem or could it be a bearing in the motor? Also it is fuel injected and i'm looking for a HKS 3 2bbl intake manifold. Where could i find this or something similiar? Is there like a guide to take off my efi and to go carb? Or could you point me in the right direction? thanks Quote Link to comment Share on other sites More sharing options...
JMortensen Posted January 24, 2004 Share Posted January 24, 2004 Sounds like piston slap to me. Probably goes away entirely under load, but if you drive at a cruise it is there, and quieter when hot than cold. Jon Quote Link to comment Share on other sites More sharing options...
Guest 240Rob Posted January 24, 2004 Share Posted January 24, 2004 what would cause this bad rods wrist pins and what could fix this? is it so bad that the motor can not be rebuilt? thanks Quote Link to comment Share on other sites More sharing options...
Guest ON3GO Posted January 24, 2004 Share Posted January 24, 2004 no it should be rebuildable. i have this same problem on my truck but its the lifters. mike Quote Link to comment Share on other sites More sharing options...
EvilRufusKay Posted January 24, 2004 Share Posted January 24, 2004 Sounds more like a bad through out bearing (the bearing the clutch fork rides on)...If it only does it with the clutch in it is not the engine. Can you feel it in the pedal? Rufus Quote Link to comment Share on other sites More sharing options...
technicalninja Posted January 24, 2004 Share Posted January 24, 2004 Some possibilities- Thrust bearings- when thrust bearings are worn out or damaged the endplay of the crank is to large (ie the crank can move in and out of the engine) and noise can be generated. This is easily checked by applying a pry bar behind the crank pully and forcing the pully outward then apply bar to front of pully (use sway bar as push point) and move pully back into engine. Acceptable thrust is .005 inch (which you cannot see). If you can see front pully move then thrust is an issue. The thrust bearings are located on the center main bearing and require major dissembly to repair. More likley is an issue with the clutch. Bad throw out bearing or incorrect pressure plate (maybe badly worn out pp) could also cause your symptoms. You need to purchase a automotive stethoscope to help diagnose your problem. These can be purchased at local automotive parts house (ie Pep Boys)and should cost 10-20 dollars. These look like a normal stethoscope with a long metal prob at the business end. you place probe on oil pan and bell housing while some one pushes in the clutch (car on jack stands,engine running,in nuetral). Where the noise is loudest is probably where you problem lives. Be careful with you new steth. It can magnify noises far better that you would expect and can damage your hearing if you make mistakes (do not allow probe to hit a moving part- ie moving fan belt-most painful) I am a betting man and I would put my money on a clutch issue but checking thrust is easy and cost no money- do thrust check first. If you have thrust issue the engine will be coming out of car and you will get to see clutch anyways. If a thrust issue exists and you don't catch it you will get to do a clutch job that was not necessary. Another minor diagnostic trick is to remove all V belts from engine and see if this changes or eliminates your noise. This is also free and eliminates all external possible noise makers on front of engine. Quote Link to comment Share on other sites More sharing options...
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