2262-9 288 motor distribution tube

Posted by aljcampo On 2010/9/11 15:34:14

Hi, This is my first post about an overheating problem I have on my 2262-9 288 motor. Here is some upfront info on what has been done so far. I had the engine rebuilt about 2000 miles ago. New pistons, rings, exhaust valves and guides, all seats and intake valves ground. Removed the freeze plugs and cleaned the block inside very well,it has a rebuilt water, new radiator and 160 thermostat and all hose are clean. The carb has been rebuilt, timing set to 6 deg BTDC and valves adjusted to spec after warmup.
If the outside temp is 70deg or higher, the motor temp will rise till the thermostat opens, then it will maintain normal temp for a minute or two then start to climb out of control and get hot. After driving it thru the winter and into the spring, I ended up with low compression in cyl #8. A leak down test said that the exhaust valve was bad. I have pulled the head, cleaned it much better than before inside and used a dremel tool to remove some casting deposits that were restricting some of the coolant openings especially about cyl #8 and 7. I then checked the mating openings in the block and removed some casting deposits in a few of them. I removed the distribution tube again and it is clean and looks OK. I also found the backing plate for the water pump outlet hole for water to go into the distribuion to not be a good fit for the tube. I will be replacing the plate for a better fit. I am also in the process of replacing the exhaust valve in#8. It is not out yet so I don't know the condition of the seat but hoping it is OK and only needs lappiing in with the new valve. I am planning to install a stainless steel exhaust valve in #8, is that a good idea or not? So, some questions; has anyone ever enlagred the holes in the rear of the distribution tube to put more water on the exhaust valve supports in the area of #8? If so by how much and what was the effect on the other cylinders? Also, does the distribution tube fit slightly inside of the water pump backing plate or just sit flush with it? One othe thing, I have an old spring compressor tool to remove the valve, have compressed the spring but can't get the keepers to release and free up the valve. Any hints on how to do that?
That's all for now. I would sure appreciate any helpful information. Thanks, Larry