Rattle when hot.

[jeremywatco]

Hi there,

Been a while. When my ‘73 gets hot and then is under load and I hear a loud rattle from somewhere that I can’t figure out.

Only when it’s hot

I know…. Vague question. Any ideas? Definitely a mechanical rattle.

 

[Broncobowsher]

Detonation.
Too much timing, too little fuel, not enough octane, carbon buildup, even the wrong spark plugs can do it.

 

[DirtDonk]

Under what exact, precise conditions does it rattle?
At all times after it gets hot? Or just under certain circumstances?

 

[jeremywatco]

Hot and under load.. hard acceleration or climbing a grade.

 

[73azbronco]

Detonation, retard time, increase octane.

 

[DirtDonk]

What they said. Also commonly referred to as “pinging” by many.
If it didn’t do this before, then you need to check a few things. Maybe something has changed in your distributor or a fuel delivery.

 

[jeremywatco]

Detonation, retard time, increase octane.

Thank you. I’ll throw some 100LL in and see what happens.