Hello Grease Monkeys, I have a problem with a knocking sound coming from the distributor and front timing chain cover when at idle. If the idle is bumped up higher, the noise goes away. This does not start happening until engine warms up. Engine ran fine a few years ago and I wanted the nova back on the road again so changing oil, gaskets, water pump, starter, etc so as not to have any problems when it got back on the road. The old distributor was rusty inside and had an external coil with it so I put a EFI distributor in it. Fired it up and heard the knocking from the distributor so ordered another one. Installed that and same noise. Added a second gasket under dist, no change. Added another gasket, still no change. back to one gasket. Changed cap and rotor hoping maybe something hitting, again no difference. Keeping my fingers crossed! Thanks in advance for your help!!
Distributor and front timing cover knock
- Thread starter lowtower
- Start date
I'm sorry that I left out that Important info. Yes your right, HEI distributor on a 1974 SBC 350. Not sure about the milage but when I pulled the oil pan off everything looked good, removing the valve cover showed signs of some miles. Lets say 70,000 miles. I have a stethoscope for checking the engine and heard the knocking from the dist and timing cover. Oil pressure was 20 at idle and went up with rpm.
Yes, checked everything that moves with the stethoscope and all sounds good, only noise is coming from dist and front cover. Checked my El Camino for noises for comparison. If it is the cam walking back and forth, would a cam button take care of the problem?
So this would make the cam float up and back making the noise at idle? But when I bring the rpm's up the noises go away.
zora
Staff member
- Joined
- Apr 24, 2012
- Messages
- 5,518
- Reaction score
- 139
- Points
- 63
On a stock set up the cam goes back only, does not move back and forth. I'm not there and can only guess. If you are unsure take it to a professional.
G
G-262140
I am able to do the work, it’s just not knowing what the cause is so I don’t start tearing things down for no reason. I know it’s difficult to diagnose a problem when all you have is texting but give me your professional opinion and we’ll go from there.
zora
Staff member
- Joined
- Apr 24, 2012
- Messages
- 5,518
- Reaction score
- 139
- Points
- 63
A bad fuel pump, broken spring on arm, can cause the pump rod to knock. I also mentioned the cam gear. Only thing front to rear/distributor is the camshaft.
The fuel pump is new and I heard no noise with the stethoscope from it. I agree that the only thing front to rear/distributor is the cam.
The cover has never been off, so I guess thats the next step. Thanks ZORA