Engine issue with my '68 :(
Thread Starter
Team Owner
Joined: Jul 2001
Posts: 182,997
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From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Engine issue with my '68 :(
Just took the Vette out for a spin.. On my way home, I heard a backfire from the drivers side exhaust and the car would die.. It would start back up but refuses to idle. Was able to drive the car home but it feels like it's running on 6 or 7 cylinders and will not idle.. There is no smoke from the exhaust and oil pressure is good and stable.. I was thinking that it may be a valve spring issue?? I hope that it's nothing on the bottom end..
Any suggestions where to start? I guess pulling off the valve covers and checking the springs may be a good start. Engine only has about 10k miles on it since rebuild by the previous owner.. 10 years ago but only 10k miles on the rebuild..
Any suggestions where to start? I guess pulling off the valve covers and checking the springs may be a good start. Engine only has about 10k miles on it since rebuild by the previous owner.. 10 years ago but only 10k miles on the rebuild..
Last edited by GrandSportC3; Nov 6, 2017 at 05:29 PM.
Race Director
Joined: Jul 2015
Posts: 13,082
Likes: 3,399
From: SW Florida.
does it crank at the same speed, or faster. if timing jumped a couple f teeth, it'll run but be weak. and with a lot less compression, you will hear it cranking faster on the starter. pull valve covers and watch valves while cranking for 1 or 2 not moving. then bump starter till #1 exh just closing and #1 intake just opening and timing mark should be right around TDC. quickie valve timing check.
Racer
Joined: Sep 2011
Posts: 414
Likes: 55
From: Humboldt county Ca
Sounds like the fire went out on one plug. I'm with Chapter 2--- check your ignition system and plug wires first. Maybe you shorted a plug wire on a manifold.
Last edited by stumpshot; Nov 6, 2017 at 06:05 PM.
Thread Starter
Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
does it crank at the same speed, or faster. if timing jumped a couple f teeth, it'll run but be weak. and with a lot less compression, you will hear it cranking faster on the starter. pull valve covers and watch valves while cranking for 1 or 2 not moving. then bump starter till #1 exh just closing and #1 intake just opening and timing mark should be right around TDC. quickie valve timing check.
Thread Starter
Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
will check the distributor after I check the valvetrain first.. I had a similar issue when I had my race car.. Turned out that I had a broken valve spring..
Thread Starter
Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Not sure when I will get to start looking at it.. Kinda busy right now..
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Thread Starter
Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
I just hope that it's nothing on the bottom end.. I don't think so but nothing is impossible.. Good thing is that the oil pressure is good.. indicating no issues with bearings..
Last edited by GrandSportC3; Nov 6, 2017 at 06:56 PM.
Pro
Joined: Dec 2014
Posts: 699
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From: Charlotte NC
What engine? If it is a bbc with Qjet I'd check the base gasket. Everybody leaves out the metal plate and eventually the paper burns through - making a huge lean condition below 1500. Above that it runs fine. I know - this happened to me
Thread Starter
Team Owner
Joined: Jul 2001
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From: Lakeland, FL
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St. Jude Donor '03, '06, '17
It's a 327/300 with a modified Holley 750 with vacuum secondaries.. I highly doubt that it's related to that.. The symptoms don't indicate a lean condition.. Lean usually means higher idle.. My car dies below 1500 rpm...
Last edited by GrandSportC3; Nov 6, 2017 at 09:01 PM.
Burning Brakes
Joined: Oct 2012
Posts: 1,152
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Diagnosing over the internet is impossible. It could be a dozen things. At best you could post a video but until you start pulling parts off to inspect its just a guess.
Last edited by Dynra Rockets; Nov 7, 2017 at 02:16 AM.
Thread Starter
Team Owner
Joined: Jul 2001
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From: Lakeland, FL
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St. Jude Donor '03, '06, '17
Thanks.. I will check for that. Unless it's the valve springs, I will have to take off the heads anyways which means that I have to replace the head gasket anyways..
Thread Starter
Team Owner
Joined: Jul 2001
Posts: 182,997
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From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Thread Starter
Team Owner
Joined: Jul 2001
Posts: 182,997
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From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Burning Brakes
Joined: Oct 2012
Posts: 1,152
Likes: 252
What is showing on a vacuum gauge?
What are the results of a compression test?
What are the results of a leak down test?
What happens when you spray carb cleaner around the carb and intake manifold gaskets?
What are the results of a compression test?
What are the results of a leak down test?
What happens when you spray carb cleaner around the carb and intake manifold gaskets?
Thread Starter
Team Owner
Joined: Jul 2001
Posts: 182,997
Likes: 88
From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
Haven't even started to look at the issue... Got little time.. Will work my way through all the potential causes..