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Old 10-29-2003, 05:56 PM   #1
pod
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hot spots, what are they

what are they what are their problems
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Old 10-29-2003, 08:21 PM   #2
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Re: hot spots, what are they

With relation to what?

Hot spots with in a water jacket?
With in a cylinder head?
With in a combustion chamber?
With in an exhaust manifold?
With in an electrical circut?
With in a bearing?
On a piston face?
On a brake disc face? or inside of a drum?
On a brake pad?
With in a radiator?
On covers and body panels around an engine or exhaust?
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Old 10-30-2003, 09:41 AM   #3
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on all engine related stuff above
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Old 11-01-2003, 06:13 AM   #4
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Re: hot spots, what are they

Ok, but thats a lot of explaining, be patiant and it will happen.
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Old 11-01-2003, 11:57 PM   #5
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Re: Re: hot spots, what are they

Would be nice if others can check my work here, ivymike, carrrnut etc etc.



Hot spots with in a water jacket?
The water jacket surrounds the bore and combustion chamber in the head, and has water constantly pumped through it to help cool the engine. If there is a blockage anywhere, either in the jacket surounding the block, or in the narrom passages in the head then the water is unable to flow past, and so heats up since there is no where for the heat to be dissiapated to. This creates a hot spot, which can cause severe damage to the engine, anything from a blown head gasket, to a cracked block or even a holed piston.


With in a cylinder head?
See above for hot spots in the water passages.

With in a combustion chamber?
Being the place where air and fuel are ignited under pressure it can get very very hot in here. Any sharp edges, say from poorly machined surfaces in the head, an edge of a valve seat sticking up, bit of carbon stuck to the side, or even a wrong spart plug can easily retain a lot of heat through the exhaust stroke, and the intake stroke. This heat is often enough to then ignite the incoming air fuel mixture before the piston is it at the top of its stroke. The result is pre-ignition, a very deadly condition for any engine. The suddenly expanding flame front will try and puch the piston down, while the rod and crank are pushing it up.
If allowed to happen for any length of time severe damage will result.
Iv personaly seen cracked and holed pistons. Broken Con rods. Broken cranks, cracked blocks, broken bearing cradels, cracked heads, bent valves etc etc.
It can also cause the engine to run on when switched off, while not as damaging, it normaly occurs with preigintion as well, and will usualy require a small degree of desieling from to high a compression ratio. (see seperate thread).
The hot spot will work like a spark plug, and often ignite the fuel air mixture at the top of the pistons stroke, if it occurs on enough cylinders the engine will continue to run as long as fuel and air are supplyed, and enough heat is generated to keep the hot spot hot.


More to come later.
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Old 11-02-2003, 03:42 PM   #6
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thanks, i didnt know there was so many hot spots
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Old 11-02-2003, 03:56 PM   #7
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Hot Spots as I have seen and fixed

The usual is carbon.

The cure is a manufacture provided service procedure to flash the combustion chamber with steam to force the carbon to break free from the piston face and valve face.

With the engine at normal operating temperature and approximately 2000 RPM, allow the engine to ingest by a vacuum hose 12 oz soda can of water.

A puff of steam and the carbon is gone.

The ChevRON TechRON is to clean the back side or tulip of the valve
and all components on the fuel path, of varnish.

You can use as often as needed.

This is a must deal if you are near a pinging point and using forced induction.

Later,
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