“100% guarantees” can be problematic…much like the words “always” and “never”
I find it plausible that some ultra fine particles might pass through a filter and, if running carbs, find their way into an engine. The passageways on a typical carb are large enough to let such fine particles travel along.
I’d be less worried on a typical F.I. engine as the filters in the injectors themselves are an additional backstop against particulates entering the engine.
If you were my brother I’d urge you to avoid gambling
With 6-cylinder XJs we see very few engine ‘failures’ or catastrophic engine damage. Blown head gaskets, yes. And damage related to overheating, yes, sometimes. Ages ago we’d hear of tappet guides walking up and crashing into cams but it seems that those have been repaired, often preemptively, or scrapped. In any case, not related to deposits on valves.
Engine failure with V12s is virtually always related to dropped valve seats…which in turn is related to overheating and/or poor coolant flow. This is well established. Occasional timing chain failures or head gasket failures. Again, not related to build-up on valves.
I’m not asserting you’re wrong by any means. You’re probably technically correct. But I think your predictions are a bit dramatic and describe a type of failure that, while possible, we just don’t typically see…even though rusty fuel systems are quite common.
On the other hand it may come down to how these cars are used in the present day. Vastly fewer are used for regular transportation nowadays. They see only week-end and sunny-day driving…so a problem with valve deposits may never develop to the point of being problematic.
And, when the cars were in daily use they virtually never suffered rusty fuel systems…as the rust problem typically occurs when the cars are left storage.
I’m somewhat reminded of a discussion maybe 15-18 years ago where a fellow had a holed piston (apparently) due to carbon build-up and hot-spots on the piston. He asserted, with great, huge, enormous, and very big emphasis, that the same failure WILL unquestionably befall all of us if we didn’t immediately pull our cylinder heads and clean the pistons. Anyone not willing to do so, immediately, was nothing less than a moron. It developed into quite a lively conversation :). Some of the old timers here might remember it.