compression is 480 psi on 3 holes and 440 psi in one, it has mech lifters - the low comp cylinder builds pressure a little slowbtw the motor has slight air huffing blowby, from the breather pipe
I only work on old high mileage VW mostly. Went to school at the University of Vortex Diesel, continuing education here at GTD Institute, and spent many years at the highly accredited School of Hard Knocks and Busted Knuckles. But have noticed at idle these things tend to huff some air pulses back out through the air intake hose. But only at idle/low speed.Was discovered by accident first time on a car with no known issues.Was just doing some minor incidentals for a friend.Checked my 89 NA Hydra and same thing.Both of those smooth out and symptom seems vanished by 1500 rpm or so.But they are not low mileage engines.
I think a T belt inspection and valve clearance adjustment is in order for that engine, I know that my then NA VW diesel blowed air from the air filter with slightly bad valve timing, but then when adjusted tried to suck the flesh off my hand - If I tried to plug the inlet with it.This toyota engine pushes my hand away when I block the inlet manifold and dies after 20 or 50 revs if I force it on.Its also returning a stupid 22mpg in a 1100 Kg car - Normally it gives out at least 35 - 38 mpg when new.