The V8 Owners Forum -

Recently pulled the heads off (2000 Thor 4.6) due to low compression on the passenger side bulkhead cylinder and second cylinder from the front drivers side. Block and heads measured flat with a straight edge. Cleaned it all up and put it back together. Should the heads have been skimmed regardless or was the fault in the gasket although not visible?
Musings required.

Would have gone through he routine- taken the heads to get he valve seating pressure tested a very light skim which would show any slight warping, and wet testing the pressures to check the rings, although a pressure drop in adjacent cylinders (is that the case??) can mean gasket I believe. Or just change the gasket warm the engine up and re-test?

DaviesDJ wrote:Would have gone through he routine- taken the heads to get he valve seating pressure tested a very light skim which would show any slight warping, and wet testing the pressures to check the rings, although a pressure drop in adjacent cylinders (is that the case??) can mean gasket I believe. Or just change the gasket warm the engine up and re-test?

I think he means low comp on 7 and 2. So not gasket related regarding leaks between the two cylinders.

mgme wrote:Recently pulled the heads off (2000 Thor 4.6) due to low compression on the passenger side bulkhead cylinder and second cylinder from the front drivers side. Block and heads measured flat with a straight edge. Cleaned it all up and put it back together. Should the heads have been skimmed regardless or was the fault in the gasket although not visible?
Musings required.

You have rebuilt using new head gaskets yes?
Do you still have low comp on these two pots?

If you had the heads off you should have at least re seated / re ground the valves on these two cylinders to rule these out.

Is it still the same??