QuestionI own a 1969 Mustang Grande - all original serial numbers, in great condition. It needs a tune up, overheats when driven hard and it's sat all winter. I need to know what the spec. timing settings are. In case it matters, the car is in NORTHERN British Columbia, Canada - and sits from Nov to May each year. Thanks!!
AnswerThe point dwell should be set first, at 26-31 degrees. If you are putting in new points, also change the condenser, and set the point dwell at about 27 degrees (it tends to increase for the first few thousand miles as the wear block seats in).
Then set the timing to 6 degrees BTC. Always set the points first, because the dwell affects the timing, but not vice-versa.
Overheating when driven hard can be caused by any of a very long list of things. From the easiest to the hardest: Check the lower radiator hose to see if the anti-collapse spring has been discarded - many mechanics do not understand why it is there, and throw it in the trash when they replace the hose. The water pump actually pulls a vacuum on the hose at high engine speeds, and this starves the cooling system for water - the spring prevents the hose from collapsing.
If that's OK, the next thing to check is the radiator itself. Drain enough coolant so that you can see the tops of the fins inside the top tank- if there are particles of crud in there, the radiator needs to be pulled out, disassembled and rodded out, then flow checked.
Make sure you see good flow across the top of the radiator fins when the thermostat opens - since it doesn't overheat in slow driving, I think this is OK.
If all the above is OK, things get messy:
Jack the front end of the car up about 2 feet and support it on heavy duty jack stands - do NOT use cinder blocks!!!
The next step is the messy one - open the block drains to see if any water runs out. If you poke in the drain hole with a small implement and doing that makes water drain faster, you know the block is full of mud.
You will have to remove the freeze out (AKA core) plugs from the sides of the block and flush out the block with high pressure water, poking around in there with hacksaw blades etc. to dislodge the mud. You may have to remove the motor mounts to get at all the plugs on the 351. If so, support the engine with a jack under a thick sturdy board under the oil pan to do this.
The rear plugs are always the worst for mud, and you will have to remove the starter to get at the ones on that side of the block.
Wear old clothes - you will be a mess when you are done. Before you start on this, have new plugs ready to install.
It is a good idea to install a coolant filter in the upper radiator hose before you start the engine after doing this job - there is always some circulating crud that will contaminate the nice clean radiator if you don't. Gano is a good brand - Google that name for coolant filters and you'll see what I'm talking about.
If there is crud in the block, there is also some in the heads, but that is too grim to deal with, it requires dis-assembly of the engine - so do the block first, and see if the problem is resolved.
Good Luck - and enjoy the summer in your beautiful place (we have friends in Sooke and have been up your way).
Dick
