Ticking Under Load- SOLVED

[Indiana80]

That does not look like same plug, seen in first picture.

Exhaust and combustion gasses leaks/ticks. Tend to be present at all RPMs. The most notable difference, is when head/exhaust is cold or hot. Heat results in expansion, sealing minor leaks and reducing larger ones.

But hearing leak, is another issue. I put my ear in fender well at cold start, then again during warm up and then when engine hot.

Another way I hear the leak. Is standing at the curb, as someone else drivers off stepping on gas hard as they pull from curb. I'll the hear the POP POP POP.

Yet another is driving next to a wall. Sound bounces off the wall. Like retainer wall on HWY.

Personally once new plugs in, if still hearing the underload tick. I put a torque wrench on a few of new exhaust nuts, while engine cold. Or you can take to shop and see if they hear. They can check torque and or use a smoke leak tester.

I checked all my exhaust manifold nuts. All torqued about where they should be. In the process, I separated steering shaft at the yoke to get better access to manifold. Figured I’d slip in my new, lubed up firewall donut seal since my old one was toast. That was my problem- for sure. Super quiet in the cab now- no more tick! Add firewall steering shaft seal to possible cause of ticking / engine noise- in addition to cracked manifold / manifold gasket and loose spark plugs. The new seal is helping to keep the cold draft / excess heat off my legs and feet. Maybe $15 fix + some bloody knuckles and a beer or two. Well worth it. Now I need to replace this same seal on my 80.