I recently bought a beautiful 1 owner 1981 300sd with 155k miles. I’ve been slowly going through it to make sure its engine and transmission will keep going another couple hundred thousand miles.
Did a compression test, ranging from 380 to 410 psi across all cylinders both hot and cold, so I feel good about spending some money on her.
Today I pulled off the injectors to have them tested. Went relatively seamlessly, heat shields stayed in the head. I was hooking them out and discovered that the opening into the prechamber is much wider on cylinder 5 than on all the others. Is this normal?? Seemed to weird to not reach out to the community.
Please advise!!
Attaching some pics. The smaller opening (approx 7mm)represents cylinders 1-4, the bigger one is cylinder 5 (approx 10-12mm).

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