Hello everyone, i dont mean to start a new useless thread but I start threads ONLY when theres nothing related to what i am looking for. Either in the forum, or on google.
So heres my issue, I bought my first car as soon as i turned 18 a few months ago. 85 corvette l98 with 130 thousand miles on it. I decided to take on that project. But after a lot of research and work i still cant find some answers to the following questions
1. At what voltage do you keep your corvettes battery? whats a healthy voltage?, (OR at what voltage should my battery be?) Mine dies a lot and wont start at around 11 volts until i use cables to start it. I think i need a new battery but i dont know at what voltage is too high (if theres such thing) is "duralast gold" good for my car?
2. What is a good oil pressure? What is too low or too high?
3. what is a good rpm? my car idles sometimes low and sometimes high. the previous owner told me that it needs a new throtle position sensor, but that it cannot be bought new, that i should get a used one, why is this?
4. when jacking the car up, where exactly do you place the jack and the jackstands? i heard that i can twist the frame if im not careful.
5. and what is a good temperature? i feel like my car operates too hot and i dont think its normal, or maybe it is, but then again, im just a rookie..
THANKS TO ALL THAT HELP, I APPRECIATE IT VERY MUCH,

 

The battery should be a little over 12 volts. You might have a drain on the battery with a short some where. You should be charging somewhere between 13 - 14 volts when running.

Oil pressure will be about 10 pounds per 1000 RPM. An older engine with high miles might be a little less. So when you are traveling down the freeway at 55-70 the pressure should be about 30 psi or above.

you can buy a NEW TPS without a problem. First check the voltage with the key on and the car NOT running. It should be .54 volts just sitting. If you then open the TB by having someone in the car push the gas peddle all the way to the floor you should be around 4.3 volts. You problem may NOT be the TPS, I would check the Idle Air Control Valve located under the TB on the passenger side. There is a four prong plug that plugs into this. The best thing is to take off the TB and then remove it from the casting. Then remove the casting from under the TB. The passages often get clogged up with carbon. This valve controls the air that gets into the TB at idle. You could also have a vacuum leak somewhere that is contribution to this problem.

Jacking the car will depend on what you are trying to do. If it is the front end, I drive it up a couple of 2x4's to get the front end up. Then place the floor jack on the cross member and jack the whole front end up......DON"T forget to block the rear wheels. I then place jack stands on the frame. If it is the rear end, I jack it up from the side.

These cars run hotter than you are used to. Normal is about 220. If you are worried about this kind of temp, then do three things. First pull the plastic cover off the top of the radiator and clean all the leaves and junk that is between the radiator and the condenser. Next change out the thermostat to a 160 degree unit. I always drill a 1/16" hole in the metal that holds the stat. in place. I also position this hole to the front of the car when installing. This helps bleed off air in the system. You can also flush the system. I recommend that you remove the knock sensor on the passenger side and the plug on the driver's side of the block to fully drain the block. This is in addition to draining the radiator itself.

Good luck on your project......PM sent.

-John

 

You should not have to "keep" the battery at a given voltage. This is the function of the alternator, voltage regulator, and battery itself. In other words, if all systems are normal, it is completely self regulating. I suggest that you have your battery tested at an Advance Auto or Auto zone-type store to see what you have. Sounds like your battery might be marginal. Maybe test your alternator too. Dave

 

Variation in idle speed is sometimes caused by a vacuum leak. Another possibility is the EGR.

 

Hey Thanks John, Great advise!!! I appreciate it a lot.

 

Thanks Everyone, To Clear some things out, i put in a good alternator, theres no vaccum leaks, and i just did a major tune up, if it helps.

 

OH!!! I ALMOST FORGOT, This is also a rookie question, My glass top was cracked when i bough the car, i had planned to buy a new top but later on, over this period of time I've had the car, some S.O.B's have been messing in the parking lot, i have no garage, my garage has no door, it could be anyone, My brother's friends or the neighbors fatass cat. ANYWAYS, Nobody is gonna take the blame for breaking my top. So I'm gonna have to buy a new top sooner than i planned. Those things are expensive!!! so i decided on buying a used one for now. because my car needs to be safe and secure from the rain and thieves.
So my question is, DOES THE TOP FROM ANY C4 CORVETTE YEAR FIT MY 85 OR ANY OTHER c4? Because ive seen some for sale and it says "for sale 86-90 corvette top"
- Thanks for your help guys.

 

Hi

the years are 84-86 86-88 and 89-96
You can see by the front roof mounts, you can fit later roofs on an early c4. By getting the correct windshield header brackets from the particular year the roof is from. You will also need to drill new holes in the windshield header plastic trim, for the tool to fit the roof.

 

Ok so if the years are 84-86 AND THEN AGAIN 86-88 and so on. (I'm only focused on my year) Why does the picture say ''86E''? Theres two 86's

 

'86E was the "early" '86 with the cast iron heads. They had problems with the aluminum castings and delayed the introduction of the aluminum heads until April (or near then) when the convertibles were introduced. Apparently they also changed the top mount for the convertibles as well.

There are triangular-shaped marks on the side moldings that show you where to jack. If you jack in the wrong place you can break your side moldings.

Here's a picture of my passenger side molding in the front. I was getting teched for an autocross and I hear this CRUNCH and looked up to see this guy with a floor jack and a sheepish look. He told me he was a C3 owner and never jacked a C4 before. As you can see through the broken out part, the frame curves inward here. You're supposed to put the jack between the marks. There is also a pair of marks just in front of the rear wheel. (Wow. My oil pan leak is worse than I thought. I just researched the gasket part number this morning...)(My 6 month old Magnaflow front Y pipe is taking on a lovely patina, too.)

 

You might try Vette2Vette for a good used top for your car. I've dealt with them several times this year and am very satisfied with price and quality.

 

There are always a few guys here selling tops. just go to the for sale section and post that you want one. Sometimes you can even find them in your color.
If you unscrew the knock sensor, just understand it may have been in that engine for 25 years. go gentle with it. New ones are about $45-$50.
And on anythig you buy on this forum, if you can't resolve it with the person you bought it from, talk to a moderator, don't drag a person through the mud here.

First hot rod a C4? wow. my first car had a flathead, and the trickiest part of owning it was changing the distributor. That was a slot that got lined up with a blade with the rotor pointed in the right place.
The C4 is a pretty complicated car to learn on.
Good luck with your project.