Most unhinged automotive advice you got that you had to convince yourself not to follow?

Got to thinkin about a coworkers at Eglin, about 15 years back.

Was working on a clutch job for a project car of his.  He wanted to drain the 90wt, fill it with "diesel or kerosene and let it idle in gear with the car in the air." Idea was it would still provide enough lubricity to handle the light load, while also washing everything and clearing anything between the gears and syncros.

As i remember, the only thing that stopped him was me saying  didn't know if the seals would stand up, so he agreed to hold off till he could look into it.

Third gen F-body

I've heard claims of adding sawdust to the rear diff to quiet it down. Then there is also the use of string wrapped around the ball joint or tie rod shaft to take up play long enough to pass inspection. 
 

My own questionable actions have been:

- using used oil to top off an engine that was burning oil at a rate of 1 qt per 1-2 tanks of gas 

- using vice grips to take up slack in the parking brake cable for inspection

- using the plastic tube from a ball point pen to in place of a fuel filter on the side of the road to get an old Accord running and home. 

20W-50 in everything. Because its race oil. I'm glad I never followed that, even 30 years ago. The FR-S would be very, very unhappy.

Sooo....

85-140 in a crankcase to bring zero oil pressure up and quiet a rod knock. It worked until it didn't. 

There are so many

Dumping Bon Ami cleaner down carb to "help" seat the rings.

Using the gearbox to slow the car to save the brakes (my idiot Brother told me this) 

Drain the oil from the dashpots on the Hitachi CV carbs on my Datsun "cuz the slides will raise faster". I actually tried this in the garage and it caused a massive bog on rapid throttle openings.

Your exhaust system needs back pressure.

Do all your braking in a straight line.

Lean is mean (jetting two strokes).

"You should buy a McLaren"

Oh wait...you said unhinged advice that I didn't follow...

The original plan is probably not going to fix anything, but it would do no harm.

Rattling lifters in an old Chevrolet engine?  Add 2 liters of atf to the sump and drive it gently for a week.  

It works.

Replace the thermostat in your racecar with a washer. I get where he was coming from and I thought about it and... glad I didn't.

Appleseed said:

20W-50 in everything. Because its race oil. I'm glad I never followed that, even 30 years ago. The FR-S would be very, very unhappy.

If it was a dedicated race FR-S or maybe even only operated in hot environments, that would work fine. The factory-recommended 0W20 is the absolute thinnest oil that engine can survive on, if they weren't trying to wring the very last MPG out of it I think the factory recommendation would've been 5W30.

One time I was accompanying a friend who was kicking tires at an exotic car dealer.  It was a slow day so there was a salesman chatting with us, and he tried to convince me that a brand new Gallardo would be cheaper to own than my S4.  I didn't fall for it. :)

Tom1200 said:

Using the gearbox to slow the car to save the brakes (my idiot Brother told me this) 

 

When I bought my Fiat Dino coupe decades ago, the seller and I went for a ride in his Ferrari 275GTB. He let me drive it a bit. And I was instantly chastised for doing the above.

"Brake pads are cheaper than Ferrari transmission parts."

Streetwiseguy said:

The original plan is probably not going to fix anything, but it would do no harm.

Rattling lifters in an old Chevrolet engine?  Add 2 liters of atf to the sump and drive it gently for a week.  

It works.

My S40 was setting exhaust phaser codes when I acquired it.  (1.9l four, it watches for an off-on exhaust timing switch X seconds after startup)  I drained the oil and ran a complete oil fill of Gulf Dexron VI.  I changed the oil filter every 100mi as it plugged up with gunk that fast.  After 500mi or so I drained the ATF and... refilled with ATF.  After 1000mi it stopped setting the cam code and I refilled with 5W20 synthetic.

At no time was I gentle with it, I just drove it as normal.

buzzboy said:

Replace the thermostat in your racecar with a washer. I get where he was coming from and I thought about it and... glad I didn't.

Why's that?

You need to restriction to create pressure in the block so the cooling system can work, generally you want to shoot for 50-70psi.

But some thermostats can actually be forced shut by the water pressure, so they present a very real liability.  I had a BBF that was generating well over 250psi in the block.  With the radiator cap off, it was amusing to see coolant flowing through the radiator at idle, and then you could raise the RPM to 1500-2000 and the water flow would stop.  And the water pressure in the engine would skyrocket.  The water pump was closing the thermostat.

Ended up using a special gate style thermostat, with holes drilled in it, and added another thermostat bypass to the system, to keep pressures below 100psi.  It had been blowing core plugs out and exploding hoses before I engineered a solution.

(The root cause was fancy gee-whiz aftermarket parts - a showy billet serpentine drive that had a really bad water pump pulley ratio that overdrove the pump, and a fancy very expensive intake manifold that was too cool to have a press-in bypass hose nipple, so it had a threaded fitting which was sexier.... and also reduced the bypass area to about 35% of what Ford intended)

buzzboy said:

Replace the thermostat in your racecar with a washer. I get where he was coming from and I thought about it and... glad I didn't.

I'm guessing the person that said that was basing it on these without necessarily understanding the science behind it that Pete had in his post:

An Australian racer I knew had come to the US for Drag Week, and his car had been tied up in customs so he couldn't run it. He asked if he could borrow my Dodge Dart and enter it. 

The Dart wasn't running. 

I actually tried to go through and fix it to the point the car could drive, but gave up after a few setbacks. In hindsight, I probably could have gotten the Dart drive if I did an all night thrash to get everything together, and if I had, it wouldn't have ended well. I lost a rod bearing on the dyno not long after.

Tom1200 said:

Using the gearbox to slow the car to save the brakes (my idiot Brother told me this) 

My dad does this. A reminder to never buy a used car from him. 

LanEvo said:

Tom1200 said:

Using the gearbox to slow the car to save the brakes (my idiot Brother told me this) 

My dad does this. A reminder to never buy a used car from him. 

I was taught this way - my automotive mentors were all raised during the depression, and life long farm boys. 
In their defense, back then, a manual trans., - in US made cars (nobody could afford then furrin' things )  - were robust enough it was actually a good plan. 
Most folks today, have never driven a non synchronized trans., though. And a lot has changed since then. 

Downshifting to reduce brake wear isn't inherently bad.  It's only going to cause meaningful extra wear if it's done ham-fistedly (poor rev matching, etc.).  Heck, even some autos can be rev matched on a manual downshift with a little practice (some just get confused by the throttle blip though).  Do it right and you should hardly be able to feel it engage in the lower gear (auto or manual). 

Wasn't there something about bumping a starter to get your distributor to drop in?  (Kinda fuzzy as I get older)

In reply to rslifkin :

Because I'm odd enough to practice stuff like that, on most motorcycles I've owned, a few cars and several pick ups, I could shift them smoother without the clutch, than with!  Don't remember what car it was (but was a 5-speed) but my smoothest shifts were no clutch for 1-2, and 2-3, clutch for 3-4 and 4-5! 
But, it's almost a moot point, since the % of people today that know what that 3rd pedal is for is SO small!

Power tuning, except we kind of did this. I had and overcammed 350 with a tunnel ram in my C10 pickup when I was 16. It had a homemade porting job and an oversized Holly double Pumper and ran like a true bag of E36 M3. One day my friend also 16, but a self-proclaimed mechanic said he could get it running really well by power tuning it. So we took the hood off and I did 8th mile acceleration runs down his suburban street while he sat under the hood adjusting the timing. It was lots of fun and there might have been beer but I didn't run any better at the end of the night.

In reply to 03Panther :

I would routinely upshift my motorcycle without the clutch, but downshifting wasn't a good idea.  I've done it with a few cars, but just enough to see if I could (there was one time where the clutch slave cylinder failed and I had to make it home.)  It's trickier than with a bike, you have to find that sweet spot where you can do it without grinding gears.

In reply to stuart in mn :

As long as it's done at the correct rm and speed, downshifting (bike, car, semi - anything) is all the same - albeit each it completely different. I'm blessed with a good feel for it, and have put in the practice!

Done wrong, down can lock up the driven tires... an bike is WAY less forgiving. Would NOT recommend it!

But, we are way off topic 

Just like "setting a battery on concrete ruins them."    Was good advice when first said, but todays stuff is different!

I'll try to make this short but it takes a little prefacing. I owned (for 25 years) a Blazer with an engine I built, (carbureted, 'cuz I'm old). Lots of camshaft overlap caused this thing to be really dirty (emissions) at idle but got better at higher RPM. Really struggled to pass emission testing. My bi-yearly solution was to set the idle to 1475 RPM, get it nice and warm and cross my fingers it would squeak by yet another test as rising standards were constantly working against me. Mind you, the idle threshold at inspection stations was no more than 1500 RPM. 

So here I was in line for inspection, truck idling way too high and me acting like I don't know what's up. Sometimes it would take several trips to test station to get it to pass. 

Now, many of the guys running these stations were, or at least claimed to be, somewhat mechanical and I was just acting like, "huh, I don't know, it's just the way it is". One guy in particular seemed to take pity on my situation and gave me some advice. With me looking over his shoulder, he pointed at the two idle mixture screws and informed me that "one controls hydrocarbons, and the other nitrogen oxide emissions". 

Yeah, no. I'm glad you're running the test station and not working on cars for a living.

"Flip the air filter cover"

You gotta be on up there to remember that.