It's running!!!!!

[MBF]

This is better than I thought you'd have from previous posts. Have you done a leakdown test to see why the low cylinders (valves or rings)? I'd recheck the valve lash with the engine hot (a loose valve won't burn, but one set too tight (not enough clearance) may. If these readings reflect your valves being properly adjusted, I'd be tempted to put it in and run it for awhile and see what it does. I'd also add the zinc additive (NAPA sells it under the LUCAS brand but there are others). That will keep the cam lobes and lifter's from galling. Running it in the truck up to temp under the load of propelling the truck may actually improve your readings. Do you have any idea why it was taken apart? Was it for a stuck valve? It sure sounded good sitting on the stand. Mike

Edited December 12, 2009 by MBFowler

[pflaming]

Here I go with another 'terms' question. What is a leakdown test? Is it similiar to a prostrate test? I am currently retesting the compression as the engine cools. I want to see what kind of compression I have when it is back to 'room temp'. Is this a leak down test?

How does one determine if the loss of compression is valve or ring related. I would guess the two work together.

[MBF]

A leakdown test is where you apply a regulated supply of compressed air (30-40 lbs) through the spark plug using a fitting similar to a compression tester w/o the check valve, and attached to a regulated air sourse. You watch, listen and see where the air it leaks from and how fast. You do this with all valve adjustments backed off so that all valves are closed and seated. If you have a leaking intake valve-you'll hear hissing in the carb, a burnt exhaust valve will be heard through the exhaust or tailpipe, leaking rings will be heard in the crankcase (on flatheads either through the road draft tube or the oil filler). A leaking head gasket may be heard through by bubbling in the cooling system.

You can also tell the condition of your rings by putting some oil in each cylinder through the spark plug hole, and then do your compression test again to see if it changes any of the reading significantly. That would indicate worn rings/cylinder. Mike

[Don Coatney]

[greg g]

once you get it running again, I would put a vacuum gauge on it, the vacuum gauge can give you a lot of engine condition information. Secondchange garage website has a very good and comprehensive chart on inturpreting vacuum gauge readings. The article features animated gauges representing the different readings and reactions and causes thereof. A vacuum gauge is an inexpensive aid to troubleshooting. Typically you would attach it to the fitting that powers your vacuum wiper motor. Just slip off the wiper tube and slip on the vacuum gauge tube.

As mentioned, the valves do not ride onthe cam, they ride on an intermediary part called a lifter or tappet. The clearence is set on the lifter by means of a threaded fitting you adjust and then lock with wrenches, with the cam rotated fully away from the lifter. Another member posted about some tappets wearing bowl shaped due to contact over the years with the valve. This indentation will leave a high ridge where the feeler gauge will ride, but in operation the valve will actually not be lifted till it reaches th bottom of the indentation. Probably not a big deal for most situations but something for, where excess valve train noise is a question.

These engines don't make a lot of valve noise, but a heavier metalic clicking might point to this type of wear. You can isolate the source of the noise by using a dowel or piece of broomstick, or similar. by placing the wood against a suspected noise producing area, the holding you ear against the other end the wood will isolate and trasmit the noise. By moving the piece around you can locate the noise. Just be careful of the fan.....

Another thought is that what you are hearing might be an exhaust leak between the manifold and block, which can sound like a metalic ticking, and mimic a noisey lifter by being located near the exhaust valve, and its lifter.