The most expensive mistake you’ve made on a project car?

In reply to GameboyRMH :

It's almost like insurance companies are out to make money or something 

I also lost my shirt on the only reman engine I ever bought instead of built.  I had a 73 Impala wagon with a 454.  The old man put 58k on it taking his two boys to and from college back in the 70s and then he parked it.  When I bought it, it still had nylon bias-ply tires.  I drove it 1300 miles home, and sure enough, the cam wiped a lobe.  I took advantage of some credit card points and a sale and bought a fresh reman longblock from Blueprint Engines.  I kinda thought it was weird that it had one 049 head and one 781, but they're close enough that I didn't stress.  I got the top end finished up (they hadn't set valve lash) and did a cam break-in.  After the first 13 mile trip it was misfiring and ticking.  Turns out they used about 5 different part numbers of pushrod - some from a 440 mopar, some from a Ford application, but only about 5 of them were hardened and the guideplates lathed them down.  The oil was full of a fine steel powder.  There were other problems like mismatched valves and two different part numbers of pistons.  I raised hell and Blueprint claimed that I never bought an engine from them.  They couldn't find my invoice number, my phone number, and the rep I bought it from was suddenly "we've never had a Jonas working here," despite their website clearly showing a sales rep by the name of Jonas.  He even had an extension (that he never answered)

Not sure what happened, because Blueprint has a stellar reputation for good builds, but they hosed me hardcore.

In reply to DirtyBird222 :

We actually didn't discover the issue.I called someone who was an engineer for Yamaha's superbike effort. He knew instantly what was wrong.

 

And like others have said. I plan out a build. Buy a lot of parts. Then decide to go another direction. 

This.  I've got a garage full of assorted new parts that one day I'll find the time to put on ebay.

In reply to Curtis73 (Forum Supporter) :

Call your credit card company and raise hell. 

That's what those fees are for.

I had a triumph spitfire engine that I spent a bunch of time and money building only to have it immediately destroy itself because the machine shop didn't catch a massive crack in one of the water passages in the head. They covered the machine work on the replacement rebuild, but I was young and dumb and didn't make them pay for the whole darn thing. The replacement was still the best part of the car after 75K of being driven hard, before I put the car in storage because I was tired of working on it every time I drove it.

That was over 20 years ago, and there have been many projects since then... One of these days I'll pull it back out of storage and get it going again...

Thankfully, I could tell the CL seller was sketchy as hell from the jump. I paid scrap value for the entire miata despite him assuring me "the motor is in great shape!". Spoiler: the motor was not in great shape. 

It was German. 

The most expensive would be blowing up my turbo Honda K24 at a trackday event - though I did catch up to that Porsche GT2 :)...

Now, how much of that explosion was my fault is debatable, having bought the engine from a pro shop, putting thousands of miles on it previous to the failure, running a dry sump, and still having it pop at about 7000 rpm, way below redline. Posted many pics of the destroyed parts, asking for "expert" opinions on the failure cause. Result: 12 experts replied with 12 different opinions. My complete guess was that a rod bolt broke, but who knows. The failure sucked much of the joy out of owning the car because I could never push it has hard after that. And yes, that's a shattered piston pin... don't see that often!