an interesting vid.

https://www.youtube.com/watch?v=-e-2CAcgPnQ

wondering if STP was one of the villains?
not at americans, but you guys used to love that stuff.

According to STP:
"Some after-market oil additives contain corrosive chemicals, including chlorine-based lubricating compounds that may be harmful to internal engine parts. STP® products do not contain any corrosive components and are safe for use in all engines."

I've never used it.

Marvel Mystery Oil, has phosphorus in it. That could do it being an acid

250 hours restoring a 914 that sat for 30 years and you do not take the engine apart?

Water gets into the oul from condensation on cylinder walls during cold running. That can be the statr of acid formation. An oil analysis woyld have shown that.

First used STP in my '51 Ford Crestliner flathead V8 in 1964 to reduce oil usage - and it worked. Used it many times in old cars & trucks, and once in a '73 Triumph Trident motorcycle.

It does help reduce oil consumption in old vehicles with bad rings......

GN

Lots of things could be root cause. Hopefully the doc posts followup engine teardown video. No way to find root cause without a teardown.

Cars don’t usually get parked for 35 years without some underlying problem that led to it being parked in the first place. Not saying it doesn’t happen occasionally, but it’s not the norm.

They all “ran when parked”.

https://www.youtube.com/watch?v=Ctin21yrfcA

I add a can of STP with every oil change in both my teener and Cayman. After running my bugeye Sprite for 278K miles I became a believer that maybe STP was a worthwhile addition to the oil mixture.

Better to wear out a car than let things decay. Nice video from the Doc!

Thank you for the feedback. A TRUE 50 thousand mile car, one owner, perfect compression and leakdown, old oil looked ok when we drained it, nothing in the strainer, engine had never been apart before, still has its colored vacuum lines. Dream come true for anyone (one would think). Took about 150 miles for the knock to start, so now the teardown to see exactly what happened. Sounds just like a rod knock to me, and the only thing that could have caused it in my opinion was the oil turning to acid

thanks for the video. This is the #1 reason we rebuild our motors as part of every restoration. The #2 reason is that we don’t want to revisit a restoration after completion, we just want to enjoy them and forget about the years of challenge restoring them

thanks for the vid. it was very interesting.
i resurected mine after 16 years asleep. you had me out there listening for rod knocks.

wonder what clutch you are going to find in there when you drop the motor. rubber core? but it probably would have exploded already!
35 years is a long time - pushing it in the storage stakes.
if the old guy had gone out and started it every now and then during the first few years of garaging it, which he might have, it would never have gotten properly warm and driven condensation out, which might also have made the oil problem worse? he might have created a moisture cycle situation?

what i heard about STP is that it was not very friendly to air cooled engines - which run hotter. i got the story years ago. STP can go acidic after exposure to high heat. people used to pour it into their worn out fords, holdens etc back in the 70s like there was no tomorrow.