I have a Long 460 45HP Tractor. It has a 3 cyl Uzina Diesel Engine. It has low compression, tons of blow by, hard to start. It takes a squirt or two of starting fluid in front of the filter to start everytime unless it has a very full battery and it is very warm outside. When it is cold outside(35 and below) it is almost impossible to start even with starting fluid straight in to the intake without going through the filter. Now to my question. Should I go with a heavier weight oil to try and keep more compression or go with a lighter weight oil so it will spin faster and start easier? If i do go with a lighter weight oil will it create worse compression issues?