Re: tracking down ticking noise

Posted by Tim Cole On 2019/6/6 19:42:26

There is a limit as to how much those cylinder heads can be milled. It may be a different head than original as well.

If all that is desired is to stop the valve from hitting the head the valve head can be cut back (chamfered). This is used to increase flow as well.

Although Packard manuals specify torque for dry threads, the modern practice is for lubricated threads given clamping force is increased 40%. However, some of those old motors start to yield and lose clamping force. Pierce-Arrows are good for that.

The tendency of those low compression motors to blow through head gaskets when they get old is an engineering problem the first step of which is to determine the operating pressures inside the cylinder. My suspicion is those thick gaskets don't work, given modern cars use essentially a spacer package and run much higher compression ratios.

An example using anti-seize provides a good example. We do a lot of lab testing for EPA purposes. Some of these cars have exhaust studs in difficult places and I've seen some big guys struggle. I had one of these that called for a torque of 45 NM dry. I put anti-seize of the studs and torqued it to 30 NM to account for the anti-seize. Well they blew the engine running it at 10,000 rpm with a supercharger on it. When it came back the fella said "Gee these exhaust bolts aren't even tight." I told him that is because I put anti-seize on them which increases the clamping force and showed him the gaskets which showed no indication of leakage under those extreme conditions.