New rebuild help needed
Thread Starter
Drifting
Joined: Aug 2012
Posts: 1,650
Likes: 2
From: Tulsa Oklahoma
New rebuild help needed
For those who may have followed, Know I just rebuilt my engine and where I am with it. I think I have the glowing header issue under control but had an observation tonight I need help with. I noticed the valve cover on the passenger side is twice as hot as the driver side. This is also the same side I had the glowing header problem on. Can anyone explain what is going on or at least put my mind at ease that this is ok? My timing is at 8* adv 650 rpm.
Melting Slicks
Joined: Jul 2010
Posts: 2,503
Likes: 33
From: McGrady NC
St. Jude Donor '15-'16
Which side is it? Is the PVC valve on that side? Is the exhaust crossover in the intake manifold open? Are all the vacuum fittings ok and no leaks? Lean cylinders on one side for any reason can make one head hotter. Does the engine run smoothly? I would look for intake gasket or vacuum line leaks causing lean cylinders on one side. Check the plugs on the hot side after the engine cools. If they're bleached white with blued tips you have a lean problem. If they are tan to brown they are ok. It's a little hard to troubleshoot from a distance but that is where I would start.
Melting Slicks
Joined: Feb 2006
Posts: 3,428
Likes: 5
From: Japan
Which side is it? Is the PVC valve on that side? Is the exhaust crossover in the intake manifold open? Are all the vacuum fittings ok and no leaks? Lean cylinders on one side for any reason can make one head hotter. Does the engine run smoothly? I would look for intake gasket or vacuum line leaks causing lean cylinders on one side. Check the plugs on the hot side after the engine cools. If they're bleached white with blued tips you have a lean problem. If they are tan to brown they are ok. It's a little hard to troubleshoot from a distance but that is where I would start.
Thread Starter
Drifting
Joined: Aug 2012
Posts: 1,650
Likes: 2
From: Tulsa Oklahoma
Which side is it? Is the PVC valve on that side? Is the exhaust crossover in the intake manifold open? Are all the vacuum fittings ok and no leaks? Lean cylinders on one side for any reason can make one head hotter. Does the engine run smoothly? I would look for intake gasket or vacuum line leaks causing lean cylinders on one side. Check the plugs on the hot side after the engine cools. If they're bleached white with blued tips you have a lean problem. If they are tan to brown they are ok. It's a little hard to troubleshoot from a distance but that is where I would start.
Thread Starter
Drifting
Joined: Aug 2012
Posts: 1,650
Likes: 2
From: Tulsa Oklahoma
Thread Starter
Drifting
Joined: Aug 2012
Posts: 1,650
Likes: 2
From: Tulsa Oklahoma
Fatcat, this is all good advice. There are a limited number of issues that could cause this. It can't be timing, because that affects all eight cylinders equally. As Casey mentioned, checking the plugs side-to-side will reveal a carburetion issue if it's there, but that would be unusual. You COULD try turning the left-side idle mixture screw out a turn or so to see if that cools it off, bit I'd be surprised if that does the trick. My biggest suspicion is a blocked coolant passage either in the right-side head gasket or inside the head itself. Of course it would require removal of the head to properly diagnose this, so you want to eliminate all the other possibilities beforehand. Hopefully it's carburetion...
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Race Director
Joined: Jul 2004
Posts: 12,684
Likes: 329
From: Scottsdale Arizona
There is a great pic of a closed heat riser valve in the for sale section:
http://forums.corvetteforum.com/c3-p...aust-part.html
This part goes between your passenger side exhaust manifold and the exhaust pipe. When cold (closed position) it diverts hot exhaust through the central passage of the passenger cylinder head, through the middle passage of the intake manifold and out the driver's side passage in the cylinder head into the driver's side exhaust manifold.
The heat riser helps with cold weather drivability on first start up. Easy way to tell if it's working properly is if you have true duals. On cold start, only the driver's side exhaust will have vapour coming out. When it warms up, vapour will come out of both pipes.
http://forums.corvetteforum.com/c3-p...aust-part.html
This part goes between your passenger side exhaust manifold and the exhaust pipe. When cold (closed position) it diverts hot exhaust through the central passage of the passenger cylinder head, through the middle passage of the intake manifold and out the driver's side passage in the cylinder head into the driver's side exhaust manifold.
The heat riser helps with cold weather drivability on first start up. Easy way to tell if it's working properly is if you have true duals. On cold start, only the driver's side exhaust will have vapour coming out. When it warms up, vapour will come out of both pipes.
Thread Starter
Drifting
Joined: Aug 2012
Posts: 1,650
Likes: 2
From: Tulsa Oklahoma
There is a great pic of a closed heat riser valve in the for sale section:
http://forums.corvetteforum.com/c3-p...aust-part.html
This part goes between your passenger side exhaust manifold and the exhaust pipe. When cold (closed position) it diverts hot exhaust through the central passage of the passenger cylinder head, through the middle passage of the intake manifold and out the driver's side passage in the cylinder head into the driver's side exhaust manifold.
The heat riser helps with cold weather drivability on first start up. Easy way to tell if it's working properly is if you have true duals. On cold start, only the driver's side exhaust will have vapour coming out. When it warms up, vapour will come out of both pipes.
http://forums.corvetteforum.com/c3-p...aust-part.html
This part goes between your passenger side exhaust manifold and the exhaust pipe. When cold (closed position) it diverts hot exhaust through the central passage of the passenger cylinder head, through the middle passage of the intake manifold and out the driver's side passage in the cylinder head into the driver's side exhaust manifold.
The heat riser helps with cold weather drivability on first start up. Easy way to tell if it's working properly is if you have true duals. On cold start, only the driver's side exhaust will have vapour coming out. When it warms up, vapour will come out of both pipes.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
That is not your issue though. I think you either have an air pocket in your cooling system, an intake gasket leak or if you have a dual plane intake with a full center divider your carb is way lean on the pass side. Fix it before you drive it or you will burn an exhaust valve and trash your heads if not worse.
Thread Starter
Drifting
Joined: Aug 2012
Posts: 1,650
Likes: 2
From: Tulsa Oklahoma
That is not your issue though. I think you either have an air pocket in your cooling system, an intake gasket leak or if you have a dual plane intake with a full center divider your carb is way lean on the pass side. Fix it before you drive it or you will burn an exhaust valve and trash your heads if not worse.
Melting Slicks
Joined: Feb 2006
Posts: 3,428
Likes: 5
From: Japan
There had been some 'back-and-forth' regarding those heads...I can't help wondering if there's some kind of casting flaw in the right-side head or if the gasket is blocking a cooling passage...have you pulled the plugs yet? That would be the first thing to check.
Safety Car
Joined: Sep 2012
Posts: 4,688
Likes: 41
From: Palm Harbor, Florida
I do have a dual plane intake, I worked on it last night and think I got it. I drove to the exhaust shop today, about 20 miles and didn't seem to have a prob. Going by a buddies when I leave here to have him help with timing and carb. He will know how to help me identify of I have an intake leak also. I'll keep you all posted. Thanks!
Thread Starter
Drifting
Joined: Aug 2012
Posts: 1,650
Likes: 2
From: Tulsa Oklahoma
I didn't have a prob with the headers glowing but the car died a few times while driving and just didn't seem to be getting enough fuel if I hit the accel. I pulled a couple plugs on pass side and they were a medium brown. So I took a nap and woke up thinking maybe I need to check my fuel lines and found where I tied into the main line, the hose had pinched slightly. Is it possible since it obviously wasn't pinched closed ( because I could drive) that it is restricting the fuel flow enough to be causing it to just die at times? Also, the fuel comes in on the pass side of the carb ( Holley 670) and maybe just didn't have enough to keep up the drivers side of the carb which feeds the pass side of the engine causing it to run lean? I obviously need to fix it but just wanted some thoughts from the pros!