Leaking Valves after Valve Job (1998 2.5L SOHC-4)

[Still Bill]

So, I just finished completely rubuilding a 1998 SOHC 2.5L. While installing the timing belt, before I had put manifolds on, I noticed some breathing of the valves on while they were closed as motor was turned with breaker bar. On ALL cylinders, both exhaust and intake side. The valves all sucked a little bit on power stroke, and exhaled a little bit on compression stroke. This happened even with cam removed.

We had ground the valves, but not lapped them. The engine builder swore that there was no problem, but said to bring the head back in if I was nervous. We took valves out and lapped them. All looked great; however, the "problem" still persisted. I went ahead and put motor back in and it runs great. Powerful and quiet, no backfires at all.

SO, the question is - is that normal behavior for these motors? Maybe because of the small springs?

By the way, I tested by holding my palm over the ports. I felt suction or pressure on the closed strokes, but not FULL pressure. Maybe about 10%, I'd guess. You wouldn't be able to tell after the manifolds are on.

Anyone have one of these motors on a stand that they can test for this?

 

[BRUTUS_T_HOG]

doesn't sound normal. valves should be able to seal tightly.

only thing i can think of is if you ground the valves and seats you might need to grind the valve stems to compensate... but with hydraulic lifters it doesn't sound likely.

i say if the engine is running good it shouldn't be a problem. might want to get a cylinder leakdown tester and measure the % of air lost from each cylinder