Alright, I have a 1980 150 with a freshly rebuilt 302. My first thought would be an intake leak.. When screwing the adjuster screws all the way down on the carb the truck did not die like its supposed to. I did a compression test and was running about 6-7 lbs at idle Sure enough I had a major intake leak. I don't understand how since I just put the intake on. I had some thoughts about putting an aluminun intake on, and some guys told me that aluminum wouldn't work well with hot and cold temperature and would leak often. I replaced the gaskets, and used a different type of sealer. Changed the oil and fired it back up. This time the engine will die and I have alot more compression (15-19) but I still have milk on my dipstick. Could this be the heads?? I just had them resurfaced. The dipstick was places on the timing chain cover on the front of the block. Would like give me a different reading than if the dipstick was on the side of the pan toward the rear? Trying to make this as clear as possible. The engine runs smooth and fires right up. Plenty of responce. I just dont know how much of the white is normal. I hope its not the heads, if it is, is there anyway to know for sure without taking them down?

Sorry if i confused anyone!

Thanks,

William

 

Do you drive long distances all the time? If you do, I would replace the oil then see what happens. If it comes back, I would say you have a coolant leak or external moisture is getting in somehow.

The milky appearance happens when you keep driving short distances. The motor doesn't get hot enough for a long enough period to get the water out.

 

A couple things to note.
If you are trying to test compression cylinder pressures it is done with the throttle wide open when cranking and the coil wire off, all plugs out..
If your measuring intake vacuum with the engine running it should be close to 18 inches on the scale.
The oil you have may play a part in the milky coatings however the engine must be run long enough for the PCV to keep the moisture from collecting to that point but won't always gaurrentee it won't still happen at times.
On a hot idling engine, use your vacuum gauge and slowly adjust for the highest smooth idle the needles will give.
On a 80 engine I know there is more to the correct adjustment but this should get you pretty close.