Valvetrain problem??
Thread Starter
On The Tree
Joined: Mar 2004
Posts: 164
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From: WI
Valvetrain problem?? Two days ago a friend was driving my 99ZM6. I was in another car and I told my buddy in my car to get on it. He went first second then first on accident at about 75 MPH. After that car had SES light flashing and I scanned it it said Cyc #3 misfire. The car has 55,000 miles and original plugs and wires. So I replaced them with NGK's and thundervolt wires. I thought it would fix it but I hear ticking from exhuast and car runs like **** from 1500-2800 RPM. After 2800 car runs fine. I think he bent a pushrod. What do you guys think???
Thanx, Luke
Thanx, Luke
TECH Fanatic
Joined: Nov 2001
Posts: 1,248
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From: Kansas City, MO
He either bent a pushrod, collapsed a lifter, or broke a valvespring. Consistent misfires on a cylinder is usually indicative of a broken valvespring. If you bent a pushrod, the ticking would remain.
75mph in first gear is over 7500rpm. You could have done a lot of damage.
75mph in first gear is over 7500rpm. You could have done a lot of damage.
TECH Veteran
Joined: Aug 2003
Posts: 4,954
Likes: 1
From: Kent WA
probably a bent pushrod, at least that's the best you can hope for... time to pull the valve covers and find out.
Oh and make sure you get an aftermarket shifter... they go a long way to preventing mishaps like that. Also don't let that friend drive the car again!
Oh and make sure you get an aftermarket shifter... they go a long way to preventing mishaps like that. Also don't let that friend drive the car again!
I did the same thing at the track. 1-2-3-2... My car has a constant tick now that hasn't gone away. Stupid me. Went to the track again, but the car ran the best times I'd seen.
So apparently I have a bent pushrod and not a collapsed lifter.
So constant ticking is more than likely a bent pushrod, but you may have something else because my bent rod doesn't seem to have caused the performance loss or rough driving that you're seeing.
Crack that baby open.
So apparently I have a bent pushrod and not a collapsed lifter.
So constant ticking is more than likely a bent pushrod, but you may have something else because my bent rod doesn't seem to have caused the performance loss or rough driving that you're seeing.
Crack that baby open.
Thread Starter
On The Tree
Joined: Mar 2004
Posts: 164
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From: WI
Before I realized the problem I raced a corbra that is about dead even with my car. After the problem occured it was still even. When at WOT car run pretty good.
Originally Posted by Z28Venom
I did the same thing at the track. 1-2-3-2... My car has a constant tick now that hasn't gone away. Stupid me. Went to the track again, but the car ran the best times I'd seen.
So apparently I have a bent pushrod and not a collapsed lifter.
So constant ticking is more than likely a bent pushrod, but you may have something else because my bent rod doesn't seem to have caused the performance loss or rough driving that you're seeing.
Crack that baby open.
So apparently I have a bent pushrod and not a collapsed lifter.
So constant ticking is more than likely a bent pushrod, but you may have something else because my bent rod doesn't seem to have caused the performance loss or rough driving that you're seeing.
Crack that baby open.
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Thread Starter
On The Tree
Joined: Mar 2004
Posts: 164
Likes: 0
From: WI
UPDATE:
Pulled the valve cover, springs, rocker arms, and pushrods are fine. What else do you guys think?? But on the bright side I found out the car has 7.4 MTI hardened pushrods. That was a suprise.
Pulled the valve cover, springs, rocker arms, and pushrods are fine. What else do you guys think?? But on the bright side I found out the car has 7.4 MTI hardened pushrods. That was a suprise.
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