Glow from exhaust manifolds
Discussion
Hi,
just poking around the engine bay of my 94 Griffith 500 (when it was getting dark)and noticed the exhaust manifolds had a dull red glow to them where they exit the heads (pre cats were not glowing). The drivers sides were slightly duller than the passanger side and the front two cylinders pipes on both sides were glowing more than the corresponding back cylinders pipes.
The rear most cylinder pipe on the drivers side did not glow at all that I could see.
Can anyone tell me if this is normal for a small amount of glow off the exhaust manifold tubes or does this indicate a problem and would no glow of one cylinder indicate a worn cam lobe?
thanks,
Ozstyle
just poking around the engine bay of my 94 Griffith 500 (when it was getting dark)and noticed the exhaust manifolds had a dull red glow to them where they exit the heads (pre cats were not glowing). The drivers sides were slightly duller than the passanger side and the front two cylinders pipes on both sides were glowing more than the corresponding back cylinders pipes.
The rear most cylinder pipe on the drivers side did not glow at all that I could see.
Can anyone tell me if this is normal for a small amount of glow off the exhaust manifold tubes or does this indicate a problem and would no glow of one cylinder indicate a worn cam lobe?
thanks,
Ozstyle
I can't give you a definitive answer, but I can say that I observed a dull red glow on my 94 griff 500 on one of the manifolds when I had an ignition problem. This glow was close to the pre-cat region and I put it down to the assumption that unburnt fuel was entering the exhaust and igniting in the manifold. I can't be 100% sure that the manifolds don't glow when the engine is working normally. Do you have any other faults?
Hi,
I don't think there are any other faults that I am aware off. The only thing that I considered was the timing may be over retarded as I can't get the engine to pink at all. I think I read on a thread this may cause late burning of fuel and thus glowing manifolds. The glow is very dull and really just on the first inch or two of the tubes exiting the heads.
Comments?
Ozstyle
I don't think there are any other faults that I am aware off. The only thing that I considered was the timing may be over retarded as I can't get the engine to pink at all. I think I read on a thread this may cause late burning of fuel and thus glowing manifolds. The glow is very dull and really just on the first inch or two of the tubes exiting the heads.
Comments?
Ozstyle
The fact that you can't get your engine to Pink is not a worry (as long as you're using high Octane fuel) and doesn't necessarily mean that it's retarded - get a strobe if you want to check it! You didn't mention whether the glowing was directly after thrashing the engine, or whether it was doing it on low duty/tickover?
Hi all,
the dull glow was just while at idle/mild revs - all the powder coating still on chassis, engine mounts good, no burning of engine bay insulation. I've done a bit more searching on the net and from what I can gather the most common reasons for this are down to iether ignition problem or fueling problem (running lean), also faulty lambda sensors put forward as a cause. I don't think its a blocked cat as these are not glowingand the engine revs freely all the way to 6000 rpm . Its got 47000 on the clock and there is a slight top end tap so I think the cam is due to be changed - could this be a cause? Interested to find out the diagnosis on your car David.
Ozstyle
the dull glow was just while at idle/mild revs - all the powder coating still on chassis, engine mounts good, no burning of engine bay insulation. I've done a bit more searching on the net and from what I can gather the most common reasons for this are down to iether ignition problem or fueling problem (running lean), also faulty lambda sensors put forward as a cause. I don't think its a blocked cat as these are not glowingand the engine revs freely all the way to 6000 rpm . Its got 47000 on the clock and there is a slight top end tap so I think the cam is due to be changed - could this be a cause? Interested to find out the diagnosis on your car David.
Ozstyle
NicBowman said:
Don't want to be harbinger of doom, but if exhaust valves are leaking hot gas gets out where it should not. Compression test will reveal all. Headers will glow red if you are really gassing it, but should be even.
Nic
Yup, but possibly more than dull red for a couple of inches. When mine bent a valve just that one header lit up - and I mean lit up. Within ten seconds of starting the manifold was bright yellow for about 8 inches from the head. It looked fit to melt to be honest.Nic
Hi,
thanks for all the replies. I think I've fixed it. I let it run up to temperature as before, with the manifolds giving of a dull red glow I turned the distributor(approx 2 mm movement at the base) to advance the timing. The glow faded to the point were there is no more glow from the manifold tubes at idle. All I have to do is check the timing with a strobe, take it for a run to check for any pinking.
Ozstyle
thanks for all the replies. I think I've fixed it. I let it run up to temperature as before, with the manifolds giving of a dull red glow I turned the distributor(approx 2 mm movement at the base) to advance the timing. The glow faded to the point were there is no more glow from the manifold tubes at idle. All I have to do is check the timing with a strobe, take it for a run to check for any pinking.
Ozstyle
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