Quote:
Originally Posted by rcair3d  Does anyone know how much blow by an m44 motor should have? |
Yes new motor fully broken in 2%-3%. Good motor but has mileage 5%. good core high mileage 8%-10%.
This is done with a leak down tester. I set my blow in pressure gauge at 100psi and and look for 97psi to 98psi on the leak gauge.
If you have a cylinder that has high blow-by you can check it further by squirting some oil in the spark plug hole and re-testing that cylinder. If the leak-down improves it is most likely cylinder, piston ring issues. If it does not improve it is most likely valve issues.
There is no acceptable amount of blow-by to measure with the car running but a leak-down is a great way to teat blow-by