Clutch overheating while driving in parade

[Brenton M.]

My clutch is overheating very quick while driving my 65 396/425 in a parade. I'm beginning to wonder if it's adjusted correctly, it releases about 2.5 inc from floor. It gets so hot that it stalls the engine causing me to have to drop out of parade to let it cool down. I would love to be able to enjoy driving it in a parade. Is there a particular brand of clutch or pressure plate that's more suited for driving in heavy traffic. Any suggestions would be appreciated .

[Timothy B.]

Re: Clutch overheating while driving in parade

Brenton,

Do you have any information on the type of clutch used on the engine. Outside of that I would start with the linkage parts to make sure everything is correct for the 396 and installed correctly. That can be confusing and you are about to get a education.

[Jimmy P.]

Re: Clutch overheating while driving in parade

Brenton,
I don't know if there is a heavy duty clutch that can be installed for heavy traffic, it will be interesting to see from responses here if there is. I just wanted to let you know that I had a similar experience this summer while driving my 73 convertible in a very lengthy parade with frequent starting and stopping. I offered to drive a young lady contestant for a fellow local corvette club member who was unable to as a favor. It was in late August and the temperature was in the 90's. Luckily the parade route was on fairly level ground, so I was able to start putting the car in neutral and coasted as much as I could. Toward the end of the ( 2hr.) parade route I started to smell my clutch. Needless to say I don't think I'll volunteer for this parade again next year. I've driven in other parades but they were much shorter and I had no issues. I do remember reading/hearing some advice from others when searching for a four speed car, and that was "if you plan on driving the car in a lot of parades and heavy traffic buy an automatic".
Regards,
Jimmy

[Brenton M.]

Re: Clutch overheating while driving in parade

My linkage and clutch fork was ordered from corvette central . I can't remember where I bought the clutch, pressure plate and thb. From.

[Brenton M.]

Re: Clutch overheating while driving in parade

Thanks Jimmy. That sounds like the same type of issue that I experienced only my clutch had overheated after only 15 min into the parade. There were 100 cars and I was number 77.

[Duke W.]

Re: Clutch overheating while driving in parade

Submitting a manual transmission vintage Corvette, especially with a SHP engine, to "parade duty" is the WORST possible abuse.

If parades are an important part of your Corvette enjoyment, suggest you procure a base engine/automatic and make sure the all cooling system components are functioning at peak performance and the spark advance map is optimized for extensive idling and creeping in gear.

I've had a few "parade requests" for my vintage cars over the years, but always politely declined with an explanation why, if asked.

Proper clutch adjustment is indicated by 3/4-1" freeplay at the top, not where it engages. (See your service manual.)

Duke

[Mark E.]

Re: Clutch overheating while driving in parade

Assuming the clutch is in good condition, the most likely cause of a burning clutch is poor driving habits-

- Minimize slippage while engaging the clutch. One way to practice good clutch technique is to engage the clutch without using the accelerator. It takes practice to do this without killing the engine, but when mastered, slippage and heat (the two enemies of a clutch) are minimized. Obviously you can't always do this in normal driving, but practicing this will affect how you normally use the clutch. Most folks rev the engine then slip the clutch until about 10mph. That creates a lot of heat/wear, and is a tell-tale the driver is a novice who's afraid of killing the engine.

- Default position of left foot is on the floor and away from the pedal. When idling, don't depress the clutch more than 30 seconds; a better practice is to put the tranny in neutral, and let go of the clutch. I was taught to hold my breath whenever my foot is anywhere near the clutch pedal- this reminded me to let go of the clutch when I ran out of breath. This also prevents partial engagement (you may think you're fully disengaging the clutch, but sometimes the leg gets lazy and keeps the clutch partially engaged), and discourages the bad habit of slipping the clutch to continuously creep a few inches/feet. The bonus is that the throw out bearing lasts longer too.

Typical driving in traffic or a parade: Clutch is always depressed or being slipped with the engine reved to continuously creep forward a few inches. Default position of left foot is on the pedal. ===> Lots of heat and wear.

Low impact driving in traffic or a parade: Clutch is normally not engaged with foot off pedal. When you need to move forward, clutch is engaged and foot removed quickly and with minimal slippage while not using the accelerator. Cars creeps forward with clutch fully engaged and no foot on the pedal. To slow or stop, clutch is briefly engaged/disengaged to put tranny in neutral. Default position of left foot is on the floor away from the pedal. ===> Minimal heat and wear.

[Douglas L.]

Re: Clutch overheating while driving in parade

I think alot it has to do with the trans, M20 isnt so bad unless paired with 3.08 or higher gears but M21 is terrible in stop and go type situations with anything higher than 4.11s

[Mark E.]

Re: Clutch overheating while driving in parade

I think alot it has to do with the trans, M20 isnt so bad unless paired with 3.08 or higher gears but M21 is terrible in stop and go type situations with anything higher than 4.11s

The speed of a car sporting an M20 with 2.52 first, 3.08 axle and 27" diameter tires at 1,000 RPM-

1000/2.52/3.08 rev/min x 3.14 (pi) x 27 in/rev x 60 min/hr x 1ft/12inches x 1mile/5280ft = 10.3 miles/hr

Which is probably faster than most parades.

The same car but sporting an M21 with 2.20 first and 3.55 axle should chug at about the same speed.