New Engine Questions

[Explorer]

Well, have about 300 miles on my engine now and starting to fine tune a bit. Runs fantastic, but have noticed a couple things. Vacuum seems low, 16". I expected more from this cam. Checked everything for vacuum leaks with no success. Antifreeze seems to be disapearing somewhere, slowly. I have overflow tank. 16lb cap, 190 degree thermostat and runs about 180 on the highway. It's not in the oil, no leaks, can't see any evidence of it on the plugs. Noticed a bit of oil vapor from the rear valve cover breather so installed a PCV system, took care of that part. Any suggestions or possible causes?
Edit: Engine is in sig line.

 

[rbohm]

Well, have about 300 miles on my engine now and starting to fine tune a bit. Runs fantastic, but have noticed a couple things. Vacuum seems low, 16". I expected more from this cam. Checked everything for vacuum leaks with no success. Antifreeze seems to be disapearing somewhere, slowly. I have overflow tank. 16lb cap, 190 degree thermostat and runs about 180 on the highway. It's not in the oil, no leaks, can't see any evidence of it on the plugs. Noticed a bit of oil vapor from the rear valve cover breather so installed a PCV system, took care of that part. Any suggestions or possible causes?
Edit: Engine is in sig line.

8) try adding a little timing to see if the vacuum reading comes up, though 16" isnt too far off.

as for the coolant disappearing, there are a number of things that can cause this;

a seeping hose connection somewhere
a heater core on its way out
a seeping head gasket
a pinhole leak in the radiator
the radiator cap not holding pressure
a seeping water pump or pump gasket
a cracked exhaust valve seat
a seeping freeze plug

the first thing you want to do is pressurize the cooling system and see if it holds pressure. this can be done at most any parts store. second check the cap to see if it is holding pressure, and check the vacuum break on the cap, i have had the little spring on those break and let coolant go out the system that way. if these things check out, add a dye to the coolant and look for evidence on leaking. also when you start the engine cold, look to see if you have any white smoke coming out the exhaust as that would indicate a possible cracked exhaust valve seat.

 

[Explorer]

Will do. Leak: Think I've got enough stuff to rig the pressure tester. Cap vents to recovery tank so think I can rule that part out. I'll pick up some dye and hope for the best. Really don't need the cracked valve seat. Timing: I need to rework the dizzy for more adjustment anyway. Thanks for places to start looking.

 

[rbohm]

Will do. Leak: Think I've got enough stuff to rig the pressure tester. Cap vents to recovery tank so think I can rule that part out. I'll pick up some dye and hope for the best. Really don't need the cracked valve seat. Timing: I need to rework the dizzy for more adjustment anyway. Thanks for places to start looking.

8) when you rig the pressure tester, remember that you only need a maximum pressure of 20psi. any more than that and you run the risk of causing a problem, not just locating one.

as for the cap, do not rule it out until you have actually tested it. it would be just your luck that you dont test the cap and that turns out to be your problem.

put the dye in before you pressure test the system for best results.