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Colin Wood
Colin Wood Associate Editor
3/29/23 4:02 p.m.

A project car can be a fantastic learning experience, but they can also be quite humbling when something goes wrong–especially when it comes to your wallet.

What is the most expensive mistake you’ve made so far working on a project car? (And before you say it, “buying a project car” doesn’t count.)

Read the rest of the story

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
3/29/23 4:04 p.m.

Ever time a Ford V8 off of #5 cylinder because you had just worked on a bunch of Chevys?


The supercharged engine did not like that very much.

Paul_VR6 (Forum Supporter)
Paul_VR6 (Forum Supporter) UltraDork
3/29/23 4:11 p.m.

^ It almost always has to do with firing order and things like "does it sound like it's misfiring?" laugh

GameboyRMH GRM+ Memberand MegaDork
3/29/23 4:32 p.m.

Still not sure if it was not enough fuel, too much ignition advance, or an assembly error, but I had a freshly rebuilt 4AGE lunch itself one time, and not back when they were common, but into the era of 4AGE parts being hoarded collectibles.

Another time I accidentally put brake rotors onto hubs with a center bore flange diameter that I didn't realize was 1mm larger than it should've been. Felt a little snug going on but nothing major. It cracked the rotor hats wide open. They weren't super fancy racing rotors, but they were ordinary rotors sent to the Caribbean with hugely expensive shipping and massive import duties, which was almost as bad.


Ian F (Forum Supporter)
Ian F (Forum Supporter) MegaDork
3/29/23 4:33 p.m.

Ripping a CV boot because I'd forgotten one step during a LCA bushing job on a friend's car - popping the lower ball joint.  It's one reason why I prefer the owner of the car not "help".  They are often a distraction. 

Having to have my ex's Volvo wagon towed to a shop when I simply could not figure out how to get the timing belt off the lower pulley of a Volvo T5.

matthewmcl Dork
3/29/23 4:56 p.m.

Does "buying a bunch of parts that you never actually use because you change your mind by the time you get there," count? Man I have a lot of those...

amg_rx7 (Forum Supporter)
amg_rx7 (Forum Supporter) SuperDork
3/29/23 5:50 p.m.

Biggest mistake was buying it... Sigh...

3/29/23 5:54 p.m.

God God...still waiting for it to end!


Bad AOD led to two cam shaft changes due to low vacuum that led to three gearbox changes and three fuel mixer-system changes  and three manifolds before I figured out that it was the distributor and not the fuel mixers that were the issue.


Other than the fact that I am now past all that, I think Ford V8 swaps are the most horrible things in the world.That said, I would not have learned a lot had I not gone through the maze.



wae PowerDork
3/29/23 5:59 p.m.

I was having problems with the car cutting out at a rallycross one day so I whipped out the laptop and got Tunerstudio fired up.  I decided that the problem was that the overboost protection was kicking in for some reason.  So I went ahead and turned that off.  Problem solved!  It didn't cut out anymore.

Except, of course, that the overboost protection was kicking in because the car was, you know...  Overboosting.  The boost control had failed in some way that was keeping the wastegate closed.  The car ran absolutely amazingly until it cut out one last time due to an extra hole being placed in the block during an escape attempt by one of the rods.

I now have a strict "no laptop at the race" policy because I can't be trusted.

Scotty Con Queso
Scotty Con Queso SuperDork
3/29/23 6:04 p.m.

Destroyed the pump on a DSM 1g AWD auto trans trying to get the converter in place. The trans was specific to 91 only. I bought a 92-93 trans and the electronics were different. I wasn't smart enough and the info wasn't online at the time for me to fix it. Begged for help on DSMTuners with zero responses. Sold the whole mess for a massive waste of time and money. 

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
3/29/23 6:04 p.m.

In reply to wae :

I found out that Evan had the overboost protection somewhere around 20-24psi when I went to borrow it one time, stopped for fuel on the way home, and on the onramp in 2nd gear, maybe half throttle, I saw the boost gauge bend its peg as the engine cut out.  Not a good thing to feel in not-your-car, at night, 20 miles from anywhere.

the fishtank boost controller had rusted shut.

Engine was fine, but yeesh, dat boost cut was the scariest thing.





Olemiss540 HalfDork
3/29/23 7:21 p.m.
matthewmcl said:

Does "buying a bunch of parts that you never actually use because you change your mind by the time you get there," count? Man I have a lot of those...

Worse. Buying a boatload of parts to fix and issue and them not doing a damn thing post install. Done that for atleast 5 figures.

Next most expensive mistake on a project car was taking it to a shop.

AngryCorvair (Forum Supporter)
AngryCorvair (Forum Supporter) GRM+ Memberand MegaDork
3/29/23 7:23 p.m.

In reply to Scotty Con Queso :

Came here to confess the same mistake, on the Turbo350 in my 72 Monte Carlo.

alfadriver MegaDork
3/29/23 7:38 p.m.

Easily the biggest mistake was not believing the car could be made.  

Our second "challenge" car was to be both an autocrosser and a vintage racer.  And I was gifted with a couple of free chassis, and I literally mean free.  First one was too far gone to realistically do, but my freind felt sorry that his friend gave me that, so gave me his unused bare chassis.

It needed everything, but most important was the cage.  There was some other repair that I would need to do, but this was at the same time I got a welder, and I didn't know I could do it.  So when I got the chance to get a IT car that was basically the same thing, I jumped at the chance thinking it would be the easy button.  

In the end, it needed about the same kind of rust repair.  So the lack of a cage in my original chassis cost me like $15k.  Ok, maybe $8k when you factor in building a powertrain- but I had all of the parts to do that- just needed the high end parts.

Still, it took so long and burned me out that I only autocrossed that car once and sold it.  

Had I used my GRM challenge momentum and was bold enough to weld, I think I would have had a really cool challenge car that would have been a blast on the track and local parking lots.  Given past history and how the 05-08 challenges went, I think I could have at least gotten another vintage trophy from GRM.  Oh, well.

AnthonyGS (Forum Supporter)
AnthonyGS (Forum Supporter) GRM+ Memberand UberDork
3/29/23 8:33 p.m.
amg_rx7 (Forum Supporter) said:

Biggest mistake was buying it... Sigh...

Beat me to it.  This always x1000!

Stampie GRM+ Memberand MegaDork
3/29/23 8:43 p.m.

I bought a 70 Cadillac for $600.  Drove it for a bit and a friend told me he wanted an old classic to drive.  Sold it to him and later on he said he wanted to build a V8 sports car.  I found a 260z on eBay for $250ish dollars.  We spent several months trying to stuff that 472 into the 260z when my friend had to move across the country.  He ended up trading it all to me for $100 and a pool stick.  I didn't have time or room for a project much less two of them.  I sold the 472 and trans for $500.  Scrapped the 260z.  Wish I had it all back right now.

Kendall Frederick
Kendall Frederick GRM+ Memberand New Reader
3/29/23 9:10 p.m.

I fired up a freshly rebuilt engine in my GN, and went to break the cam in.  About 5 minutes in, it started to make noise.  I ask my buddy, "do you think that's a lifter?  We can't stop now, the cam will be trash..let's see if it pumps itself up."

I had forgotten to torque one of the rods.  It dropped the cap off and exited stage left (or right, I can't remember).  Broke the bottom of that bore off when it went.  I had a local jobber machine shop (H&M, for Jax locals) sleeve that hole, bought one piston, and had it running the next weekend.  With properly torqued rods.

I kept the broken rod on my bench for a long time as a conversation starter. 

codrus (Forum Supporter)
codrus (Forum Supporter) GRM+ Memberand PowerDork
3/29/23 9:16 p.m.

Does pushing the ABS into ice mode too close to the tire wall in turn 11 at Sears Point count?  That involved a fair bit of bodywork. :)


buzzboy SuperDork
3/29/23 9:40 p.m.

Building my first "hot" ACVW engine(1641 with a mild cam) I didn't get one of the pushrod tube seals seated perfectly. After breaking it in I drove that engine 20 miles and the oil pressure light came on. I refilled the sump(2.5qts!), installed a replacement seal and drove the car another 200 miles. The engine seized the #3 main bearing on a sand road, outside cell service in the middle of the woods. At least the second rebuild was easier than the first.

z31maniac MegaDork
3/29/23 9:49 p.m.
amg_rx7 (Forum Supporter) said:

Biggest mistake was buying it... Sigh...

This right here.

Brotus7 Dork
3/29/23 9:58 p.m.

I bought a Europa.

ShinnyGroove (Forum Supporter)
ShinnyGroove (Forum Supporter) Dork
3/29/23 10:04 p.m.

Depowered a Miata steering rack and didnt put the steering input shaft back on the rack correctly. The subsequent trip into the gravel at Road Atlanta 10a is still being talked about. Thank god it didnt let loose coming down 12. 

Tom1200 UberDork
3/29/23 10:12 p.m.

The D-sports racer ran hot because we used the stock Yamaha 1000 radiator.

A friend gave us a monstor aluminum radiator.

Two engines later we discovered that it was over cooling the car. Yamaha 1000 engines are clearanced such that if you run them hard below 140F they will loose oil pressure to the rods.

This problem was so aggravating that I ended up selling the car. It turned me dream car into a nightmare.

ShawnG MegaDork
3/29/23 10:12 p.m.

I drilled a hole in the wrong place on a Ferrari 275 gtb.

I broke the incorrect windshield in a 65 AC Cobra.

I've accidentally kicked a freshly painted fender for a '34 Ford coupe across the shop.

Boss and I both had a hand in exploding the fuel tank for a 1934 Packard Twelve.

I'm sure there's more I can't think of right now.


Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
3/29/23 10:45 p.m.

I bought a GVOD unit (bloody expensive) for a TH400 without knowing that I had a pretty rare 13" long-tail version.  By the time I got around to the project I had missed the return window and GV wasn't sympathetic.  I had to order another tailshaft housing and coupler for big bucks.  I put the other parts on ebay and it took over a year of re-listing it before someone bit and they basically got it for half price.  In hindsight it would have been cheaper to buy a short-tail TH400, but the one I had was a fresh rebuild with some pretty serious money in it.

I also lost my shirt because [insert insurance company's name] denied a claim.  Many years ago, I bought a primo sweet W210 E300TD for the wife for $14k.  She got caught in a wicked hail storm and it turned every panel into a golf ball and broke the windshield, rear glass, and one side window.  Body shop said $10k to fix.  [insurance company name] denied the claim because I said the damage happened at 6:15pm and they said that NWS reported the hail didn't happen until 6:30.  I lawyered up, collected copies of all of my friends' claims that all said 6:15, and [insurance company] got a letter on Lawyer McLawyerson letterhead and their response was basically, "bring it."  Unfortunately [insurance company] was one of the ones that pays multiple actors in white aprons to make commercials that play during the superbowl, so Lawyer McLawyerson advised me to not pursue, citing [insurance company's] 80% success rate at beating litigation with their panel of about 100 big legal people.

During all of this, my project car was broken into.  They took the stereo and an ipod and left a broken window.  They denied the claim because I was at a friend's house and they couldn't reach the friend (who was now in rehab 6 states away) to corroborate the story.  Same deal.  Lawyered up, they said bring it, and it went nowhere.

Long story short, [insurance company] screwed me out of about $16k.  I had been with them for 6 years, insured up to 4 vehicles at a time, made two legit claims, and never got a cent.  I no longer insure my vehicles with companies that drown every commercial break with high-paid actors and mascots at the superbowl.  If they're that good at denying claims that they can afford that kind of marketing, they're not going to get my money.

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