I have come to a difficult decision. I either have to fix the IROC or sell it for parts. I cant afford to have the car and not drive it.

I will give you some back-story on it.

The engine has developed a knock. It sounds very much like it is coming from the back of the engine. Idle has not degraded, and it still runs. It just knocks. I replaced the spark plug cables and spark plugs, the rotor and cap is 1 year old. Everything else is stock. Though I cant totally rule out spark, it is unlikely at this point that it is spark knock.

From what I can see, I'm going to have to rebuild. that, although it is possible, its rather difficult as I have no garage to work in at the moment.

If anyone has any suggestions of what might be going on, I'd appreciate it.

 

I'd recommend checking for a loose/cracked torque converter/flexplate before you do something rash.

 

also make sure the dist cap is on tight, if its slightly cocked 2 the side the rotor will hit the side of it and make a ticking

 

its much too loud to be that. its quite loud, coming from the back of the engine, possibly the last cylinder on one of the sides.

 

Yeah, what he said. My friend had this happen to him. He thought for sure the motor was done for......

Also what is your oil pressure like?

 

Some flexplates make an awefull racket and sound like they are coming from the rear of the engine. A torque converter on the way south can also do that.

 

The stock flexplate on the 90 had a big crack around the bolt holes after my dad did a burnout and made some noises after that. But we could tell the sound was coming from under the console.

 

you ought to figure out what the problem is before you go blindly replacing parts and spending money

 

my old 84 Z did the same thing. Turned out to be the convertor bolts were loose and had backed way out. I would check that and for other loose bolts, etc. I'd hate to hear you get rid of your car or part it out just to find out it was something simple.

 

If you exhaust those options (flexplate, bolts, TC, trans input shaft) you might be able to identify the source by removing or shorting a spark plug on the running engine - one cylinder at a time, of course. This might identify a loose rod bearing, wrist pin, etc.

Even if you determine it is a main, you might be able to establish better oil flow with an engine flush. Don't quite give up on it yet.