toobroketoretire

Every automotive forum has it's myths whether it be Mustang, Camaro, Chevelle, Corvette, or Mopar forums. These myths are started by ignorant people who believe these myths are true but with no evidence to back up their beliefs. Here's a list of the most common myths that you will often hear:

1. Chevrolet hydraulic lifters need to be adjusted "hot and running". That's not true. Chevrolet hydraulic lifters have approximately .150" of plunger travel and it takes 1-1/8 turns of the rocker arm's adjustment nut to center the plunger. The shop manual calls for 1 full turn down from ZERO lash to make the adjustment easy but anything from 3/4 to 1-1/2 turns is fine which makes adjusting them "hot and running" a silly and messy waste of time. Never turn the adjustment nut down only 1/2 turn because that really screws up the geometry of the valve train.

2. 1/2 turn down from ZERO lash prevents valve float and lifter "pump up". That's not true as valve float and lifter pump up is the result of too much rpm for the springs to close the valves. The only way to prevent lifter pump up is to give them several thousands of an inch of lash and the ONLY way to prevent valve float is by using stiffer springs.

3. Thermostats need holes drilled into them. That's not true. The only advantage holes give you is the ability to fill the cooling system a tiny bit faster. But in real cold weather those holes will prevent the engine from warming up quickly because coolant is being allowed to circulate thru the radiator prematurely.

4. Chevrolet engines have "air pockets". That's not true. On an initial fill there are tiny places where air gets trapped but they are insignificant. Once the coolant begins circulating the air gets purged.

5. Cooler thermostats allow cooler engine temperatures. That's not true as once the thermostat opens its up to the radiator and the air flow thru it to cool the engine.

6. High volume water pumps make the engine run cooler. That's not true as coolant must remain in the radiator core long enough to shed heat and speeding it up accomplishes nothing other than making you poorer and the manufacturer richer.

7. Robert Shaw thermostats fail in the "open" position. That's not true as they fail in the closed position just like any other thermostat because the spring forces them closed.

8. Big blocks run hot. That's not true. As big blocks are physically larger than a small block less air gets circulated around them so the engine compartment and interior of the car gets warmer.

9. Distributors need to be shimmed to limit timing fluctuations. That's not true. When the engine is running the distributor gear and shaft are forced upward against the gear's thrust washer because of the helical gears and the torque needed to drive the oil pump. Timing fluctuations are caused by slop in the timing chain and upper distributor bushing; not distributor shaft end play.

10. A dwell meter is needed to accurately set points. That's not true as any dwell angle between 28 and 32 degrees is sufficient to allow adequate coil saturation. On new points a .019" feeler gauge will give the preferred 30 degree dwell angle. As its not a critical adjustment any gap from .017" to .021" will do.

11. Chevrolet engines need 36 degrees of total timing in by 2000 rpm. This is true for drag racing when running 100+ octane gasoline but for street engines running 87 to 93 octane gasoline 30-32 degrees @ 4000 rpm is preferred to prevent pinging. If 36 degrees @ 2000 rpm was needed for street driven cars G.M. would have provided distributors that allowed that.

12. EGR valves cause a loss in horsepower at wide open throttle. That's not true because the vacuum-operated EGR valve fully closes under full power.

13. Indexing spark plugs increases horsepower. Yes, maybe 2-3 horsepower under maximum throttle openings but the gain is so minimal its not worth the effort for street driven cars.

14. Starters fail because they get "heat soaked". That's not true but the starter solenoid will lose magnetic strength when it's coil windings get severely heated and that is why the solenoids came with heat shields. Slow cranking is caused by either low battery voltage or a bad electrical connection; usually at the aluminum block-to-frame ground cable.

15. The steel push rod guide plates are for "assembly" purposes. That's not true. The steel guide plates are necessary for all of the 2.02" X 1.60" valve heads because they have a 1-7/8" center-to-center valve spacing; 1/8" wider than the smaller valve heads that use a 1-3/4" center-to-center valve spacing. As cast iron is relatively soft slots in the head would quickly wear out from the side thrust of the crooked push rods.

16. "Figure 8's" are needed after a rear end oil change. That's not true. The factory and dealerships never did figure 8's because the oil and friction modifier soaks into the clutch plates in a matter of minutes and even faster with a single right and left turn. And after an oil change the clutch packs are already soaked with the old oil and friction modifier so there is no gain whatsoever.

Brass Pass

Alwyn678

Good to know

OzBeast

I'm confused. Are you calling him a troll, or an Ultra Double Pumper?

COOLTED

Trying....to....resist....

Easy Mike

I don't see anything C3 specific on your list so I question the title.

toobroketoretire

I'm just attempting to educate C3 owners. These silly C3 myths get started by ignorant people then get passed on as "fact" when in fact there's not a bit of truth to them. Much like the blind leading the blind. If you don't agree with any of my claims please provide evidence that proves otherwise.............................

Elba Mike

How about "flexing" when jacking up a Corvette. One of the things I was told was to unlatch or remove glass t tops, unlatch the hood and doors when jacking up the car. Being a admitted mechanical dumb ***, I have no idea if true or not.

resdoggie

I sometimes jack mine up NASCAR style with a motorcycle lift. From another thread awhile back that states what you are asking, there was no difference when I opened/closed the door on the floor or on the jacks and no change in the widths of the door gaps front/rear. Hence, my frame is solid and any flex is at a bare minimum to non existent.

MelWff

Admittedly it wasn't a C3, it was a 1996 C4. Our club would raffle off a new Corvette and take it to various shows during the season. We went to a show I believe in Wooster, Ma. and parked the coupe on uneven terrain. Removed the top with no problems. End of day we try to put the top back on and it wouldnt close, at least a 1/4" too far to latch it. My wife picks up the owners manual and starts reading through it. Right there in the manual it states something to the effect if you have trouble closing the top make sure you are on even terrain. Start the car up and move to a level area and the top goes on with no problem.

keithinspace

Wow. That's quite the statement there, Captain Humble.

Story:

We had a party at our house. A family friend meet another family friend around the fire pit. We were talking about colleges and work stuff.

One asked the other, "So...where did you go to school?"

The response, "I went to school in Tennessee majoring in chemistry. I work for the FBI in their crime lab."

The conversation moved along and I just smiled.

The respondent told the truth: She got her PhD in Chemistry from a little place in Tennessee, Vanderbilt University. She HEADS the FBI Biometrics/DNA crime lab in Quantico and regularly reports to Capital Hill and the White House.

I have 1,000 times more respect for what ISN'T said than what is. So you know.

When I purchased my car 4 years ago, I couldn't tell the difference between a big block and small block engine by looking at them. Or between Chevy and Ford. I knew how a car worked (rebuilt my first car at 15 and drove that car through college), but nothing about THIS car.

I have a next-door neighbor that "knows" EVERYTHING there is to know about these engines and made me feel like it all the time. He could not STAND that I was so clueless and that I wouldn't let him work on my car. He was VERY offended when I did not park it in his driveway for him to "fix" all the stuff wrong with it. Won't talk to me now.

I purchased my Corvette for the JOURNEY. I love learning. Having someone available that knows everything can be helpful sometimes, but I adore NOT knowing and finding out for myself. That's what I enjoy. Not having someone else fix my junk.

My engine builder was building 350's when he was 8. He has forgotten more than I will ever know. Never ONCE has he not listened to my thoughts and input. And never ONCE has he made me feel inferior because of my lack of knowledge. THAT'S the type of person I choose to be around.

So...don't be 'disheartened' by the 'weekend warriors' that 'challenge [your] 40 years of "hands on" professional knowledge'. They're just a bunch of punks that enjoy learning for themselves.

Like me.

But don't worry...I can tell the difference between a small block and big block now...

lionelhutz

Much like this info you just posted contains many glossed over 1/2 truths and plain ignorance?

4. Filling a closed system doesn't just leave insignificant pockets.

5. Wrong! It will with a good cooling system.

6. Wrong! You just proved a complete ignorance of thermodynamics.

7. Got proof? The manufacturer claims they fail open.

8. How does less air around the engine have any significance in the coolant temperature.

11. Wrong! Your numbers are out to lunch, too late and too little.

14. Heat soak is parts absorbing heat, which is what you then claim happens right after you said it doesn't.

COOLTED

There's that and every single service bulletin I read about limited slips says to drive in circles and figure 8's. I said that last time, but he decided to make a point of it anyway for some reason.

tracdogg2

I understand now!
Water pumps, thermostats, electric fans, and coolant have nothing to do with engine cooling. All the cooling is done by the mechanical fan blowing air ONTO the engine. So the bigger the engine the bigger the fan. The more air blowing back onto the engine, the cooler the interior.
Quick, someone call Tom DeWitt and tell him he's doing it wrong.

chevymans 77

Straight from STANT's web site;

ABC's of THERMOSTATS

The thermostat has two important jobs:

Accelerate engine warm-up: By blocking the circulation of coolant between the engine and radiator until the engine has reached its predetermined temperature

Regulate the engine's operating temperature: By opening and closing in response to specific changes in coolant temperature to keep the engine's temperature within the desired operating range

Not sure what you are saying about the T-stat as the radiator dissipates heat but the T-stat will control the flow of coolant to control the temp of the water circulating within the engine. The T-stat will open and close as needed per the water temp and thus will control the temp of the water circulating within the engine. The T-stat is not just an open or closed device, it will regulate the flow of water per the water temp. The wax motor within the T-stat has around a 15 to 20 degree working range in response to water temp.

Neal

chevymans 77

1. Doesn't coolant need more time in the radiator to cool?

No. But a lot of people still think so. We have come up with some explanations for the Doubting Thomas.
Debunking the I Can Have It Both Ways Theory

The water has to have "time to cool" argument is most common one we hear. In a closed loop system if you keep the fluid in the heat exchanger you are simultaneously keeping it in the block longer. Unfortunately, the block is the part that is generating the heat. Sending hot coolant from your source (engine) through the heat exchanger (radiator) to the sink (air) will transfer heat as long as there is a temperature difference between the source and sink. The engine is still generating heat the whole time so why keep the coolant there any longer than you have to.

Debunking The Conscientious Electron Theory

We hear that the coolant has to stay in the system longer to cool but what is heat transfer really but conduction, convection and radiation of electrons. The fluid in your system transfers those electrons based principally on the source-sink differential and the exchange material's transfer rate. An electron moves at varying speeds - Bohr's model has it moving at 2 million meter/second and with a mere 11 million eV boost you can get an electron to 99.9% of the speed of light. Though they move at varying speeds physicists accept that electrons move fast - really really fast. Far faster than the flow rate of the water pump. Your engine coolant's electrons do not know (or care) how fast you send them through the system - they just knows that the source is hotter than the sink and off they go.

Debunking Grandpa's Flathead Theory

"But wait a minute, I know Grandpa used to put washers in his flathead to slow the flow and cool his engine." We know people did this too. They still do it but the cooling benefit is not from the slower flow but the increase in dynamic pressure in the block that builds from the restriction. Consider that Grandpa had two flathead water pumps sending twice the volume through the same size radiator core as the Model B 4 cylinder. Too much flow in this no pressure system results in fluid loss. Slowing flow rate helps prevent that. At some point Grandpa maxed out the throughput and began building pressure in his block. Increasing block pressure helps reduce the onset of hot spots on his cylinder walls and formation of steam pockets in his block. This is a real benefit and does help cooling but is only realized when throughput nears capacity or is at capacity. While these restrictions may make sense when your rpm is excessive or your flow rate exceeds your heat exchanger throughput, they do not make sense for most applications. If you doubt this thinking then try this simple Ask Dr. Science experiment; clamp off the lower hose while you watch your temp gauge. Hopefully, you will debunk Grandpa's theory yourself before you experience vapor lock and melt your engine.

Flow restriction is not all bad if it serves to prevent cavitation. Cavitation occurs when a pump turns so fast that you generate lower pressure and air bubbles or vapor forms. These bubbles eventually implode and damage the engine block wall and impeller. Rapidly spinning the impeller can literally rip the air from water but may not actually move the fluid, it's tantamount to turning an eggbeater in a paint bucket. Restricting the fluid flow to raise system pressure in the block may help prevent cavitation at higher RPM but is it necessary for most vehicles? Probably not.

Most vehicles do not need to restrict flow because they do not reach or sustain high RPM. Additionally, thin aluminum radiators already restrict by design e.g. fewer rows of thinner tubes. Restrict it further and you may as well hose clamp the lower radiator hose and we know how that works out. When you face Grandpa on the track you may want your washers, otherwise, keep them in the toolkit.

Simply put, you have a far better chance of keeping your cool with greater flow rate through your heat exchanger and exiting the system than holding it in your heat exchanger while generating heat in your engine block.

This is from the FLow Kooler web site, if I remember it correctly this was also a company of Howard Stewart that origanaly owned Stewart Components. He was considered the leader when it came to cooling for just about all racing bodies and the OEM.

Neal

Bad Bird

I recently built a liquid nitrogen cooling system for a scientific apparatus. I did a test where I varied the flow rate through the heat exchanger to see if more coolant flow was beneficial or detrimental. What I found was that higher flow rates were better, period. Unless you are stalling your pump/cavitating your coolant, that is.

TheSkunkWorks

Dear esteemed OP,

Thank you for submitting your latest application for King of the CF. Unfortunately, while your qualifications are unquestionably worthy of consideration, the authority to grant that honor is not mine, and therefore I am prohibited from officially addressing you as such. However, it is my distinct privilege to reinstate your membership in my ignore list. Welcome back! Stay as long as you like.

Brass Pass

OzBeast: Still confused?

74modified

Me too... Captain Humble has yet to explain how a C3 explodes, perhaps he will Expose some common myths to us dummies.