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Mechanic's bad news

vetteKID

Well-known member
Joined
Jul 1, 2002
Messages
122
Location
ellicott city, MD
Corvette
74 L-48 coupe & 85 454 coupe
To begin, my car just came out of winter storage, I took it to the mechanic to tune the new Edelbrock 600 carb, and replace the two front brakes. And I was quite happy when I got it back, ran well but still not as strong as it was when I bought it, and I did get on it a little bit. So I park it for the night, next day go to take the girlfriend for a ride and it runs like crap. Sputters, pops, will hardly hold an idle and back fires when you drive it. I knew the car had some valve tap, and it actually did go away the day I got it back. So I make it back to the mechanic and he spent a day trying the timing, carb, ignition, firing order. He pulled the valve covers and said that valves were bad. I came over and looked at them. The valve springs were off center by an 1/16 to 1/8 of an inch on the 3rd 4th and 8th cylinders (I don’t know whether it was exh or int). He said that I need to rebuild the heads, Could this be true? if so, new heads? upgrade the compression and new cam? Any ideas?
 

fine69

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Joined
Dec 12, 2004
Messages
975
Location
Maryland / D.C.
Corvette
'69 Convertible Vette; '72 Z28 Camaro Rally Sport
Did you or he try to adjust the valves? Could be an easy fix.
 

vetteKID

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Joined
Jul 1, 2002
Messages
122
Location
ellicott city, MD
Corvette
74 L-48 coupe & 85 454 coupe
he said he tried, but i think i may just get new heads anyway, extra compression/extra hp.....paycheck week. :D
 

fine69

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Joined
Dec 12, 2004
Messages
975
Location
Maryland / D.C.
Corvette
'69 Convertible Vette; '72 Z28 Camaro Rally Sport
"...but i think i may just get new heads anyway, extra compression/extra hp..."

It's not quite that easy. Be careful when selecting the heads. Too much of anything, and your car will run like a dog on the street.

I made those kinds of mistakes... car did great as long as I was was running at high RPMs and going everywhere at 80 mph! Sounds great, but not very practical.

Thanks to the good folks here at CAC, I was able to modify my rebuild and achieve the optimum setup. She runs better, stronger, and faster than she ever did back in 69!

Be sure to ask lots of questions. Good luck!
:w
 

Wayne robson

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Joined
Feb 24, 2007
Messages
169
Location
australia
Corvette
sold my last corvette.
if it was mine

Hi Vette Kid, if you dont mind about the cost, ok, but if it was my car this is what i would do, specially if you have the time, a garage,and competent and think you could do the job yourself, if its not driveable, get it trucked home, pay your mechanic for what he has done so far thank him, then spend a couple of weeks doing some homework looking at it and then decide, like fine 69 said i would not overdo it, but this will give you more time to decide the correct option. regards wayne.
 

gmjunkie

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Joined
Nov 11, 2004
Messages
4,547
Location
Old Fort NC/Vero Beach FL
Corvette
03 Z-51,78 L82 Coupe
Sounds like you need a timing set to me, not heads.

:)
Yep.That was my thought!! The thing about a Loose timing Chain and Gears,they sometimes jump when you shut them down!!:D :D
 

Vette79

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Joined
Jan 23, 2007
Messages
1,392
Location
Millersville, MD
Corvette
1979 L-48 Black Coupe
I just spoke to my mechanic about this very topic last weekend on a 80 he was working on. Same symptoms. Timing chain was loose.
 

Tom Bryant

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Administrator
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Nov 9, 2000
Messages
7,322
Location
Edgerton, Ohio, United States
Corvette
1959 black 270hp (9/2/69) 1981 Beige L81(10/20/80)
I agree. Given the year of your car you could have a timing gear that looks like this. Believe it or not this engine ran.

ecb42185.jpg
 

vetteKID

Well-known member
Joined
Jul 1, 2002
Messages
122
Location
ellicott city, MD
Corvette
74 L-48 coupe & 85 454 coupe
Thanks for the help guys, I think I’m going to go with some new non radical heads (just posted on tech/perf forum) and I just brought up a timing gear to the shop, the mechanic confirmed the timing chain problem.


Wayne, I would love to do it myself, however I do not have a garage (neighbors complained about my 73 roadrunner when I tried to rebuild the top end, which didn’t end well). I try to do most things myself, and I have gotten over my head and learned allot. Time is also an issue, I would love to get this car to Cruising ocean city md (hot rod weekend) next thurs.

I just want to say thanks again, you guys have been a big help.:beer
 

IH2LOSE

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Joined
May 24, 2001
Messages
3,908
Location
We Will All Meet Again
Corvette
1966,and a 1962 thats almost complete
he said he tried, but i think i may just get new heads anyway, extra compression/extra hp.....paycheck week. :D

Dont know if your getting the heads to correct your problem ?

But it may not be in your valves.

Heads alone will not improve your HP.

When looking to improve the performance of your motor you have to realize you starting with a motor rated at 190 hp ,depending on the present condition of the bottom end ,and where you want to end up and how much you want to spend you may want to look into a performance crate motor

Under 4000.00 you can get the zz4 motor 355 hp

almost double your hp and its a week end project

Just a thought
 

gmjunkie

Well-known member
Joined
Nov 11, 2004
Messages
4,547
Location
Old Fort NC/Vero Beach FL
Corvette
03 Z-51,78 L82 Coupe

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