I have an 84 5 speed, it shifts good and runs fine, oil pressure is good , but theres a knocking noise coming from somewhere in the engine bay. I noticed every time i press the brake pedal down even slightly it goes away..take my foot off..starts knocking again. Any suggestions on what to look for? It doesnt blow any type of smoke or hesitate or leak any fluids btw.

 

If you have one of the cheap HF harbor freight mechanic stethoscopes you could poke around.

Try to isolate the knock. If it is in the cam tower, maybe a lifter.

If it sounds deeper in the engine, NO. 2 rod bearing

https://rennlist.com/forums/924-931-...cam-tower.html

Could be a loose bolt in the PS pump or alternator bolts.

GL
John

 

If it is coming from the engine, why would pressing on the brake pedal stop the noise?

 

I read about tightening the big bolt down when you take the distributor cap and rotor out?

 

The cam gear bolt cannot be retorqued.
It has to be replaced ~$6 on Pelican.

It is designed to stretch upon initial installation.

Yes, this is a very serious condition if the bolt is loose.

I do not know why this would be your noise if it goes away when you press the brake pedal????

GL
John

 

Sorry, missed the "brake pedal stop the noise" part....
John

 

Ill do more loooking around in the engine bay tonight, i have stethoscope.

 

So i start it and look for the knocking sound, its coming from the bottom of the engine in the back. I went inside the car and pressed on the brake pedal..knocking stops..let off the pedal..knocking repeats etc. Any thoughts? There are no metal flakes in the engine oil at all.

 

Also while it was knocking, i raised the idle smoothly and the knocking went faster. It sounds to me like a rod bearing but i don't know why that would effect brakes?

 

Camsti,

Look for "firewall fatique" around the pedal cluster.

http://forums.pelicanparts.com/porsc...cabriolet.html

Is the clutch pedal "freeplay" set correctly to 2-3mm?

Is the pedal assembly worn?

GL
John

 

I just drove it around for awhile and i can hear the knocking when im rolling out of 1st gear then it goes away. The oil pressure is a steady 2-3 at idle and 4-5 when driving normally, Sometimes it hits 1.5-1.75 mark..is that good? It doesnt blow any smoke either.

 

What happens when you push in the clutch?

 

When I press the clutch in, It still knocks.

 

Is it ok for my oil pressure gauge to idle at 1.5?

 

Have you checked oil pressure with a mechanical gauge? Dash gauges aren't necessarily reliable.