2000 7.4 MPI Valve ticking after leak down test

[Mischief Managed]

I did a leak down test for fun (engine was running fine, I was just curious). There were times when I didn't quite have the piston in a cylinder under test at TDC and the pressure form the tester pushed the motor over backwards a few degrees. I didn't think anything of it.

When I was done, I fired it up and the engine rattled for a couple of seconds as though the lifters had bled down. It has never done that before. Also, I hear a light ticking now that I don't recall hearing before. It sounds like excessive valve lash on one valve. Could I have damaged anything by letting the motor turn backwards a little? It's a Generation VI, so it has roller lifters.

 

[tpenfield]

Re: 2000 7.4 MPI Valve ticking after leak down test

Sorry to hear about the valve issue after doing the leak test . . .How did my OTC Tester work out? I usually ran mine at 60 PSI line pressure, 'cuz my compressor could not hold it consistent enough above that level.

I would not think that a few degrees of backward rotation would do anything, particularly around TDC.

Did you run the engine for a while prior to doing the leak test? I would run the engine for a while longer just to see if the lifter pumps up some more.

What did you get for results?

 

[Scott Danforth]

Re: 2000 7.4 MPI Valve ticking after leak down test

doubt if you wrecked a lifter. however I would determine which bank the tick is coming from, and pull the valve cover to inspect. you may have a tweeked pushrod. if the pushrod is straight, I would then re-install and re-adjust the lash setting.

 

[Mischief Managed]

Re: 2000 7.4 MPI Valve ticking after leak down test

Sorry to hear about the valve issue after doing the leak test . . .How did my OTC Tester work out? I usually ran mine at 60 PSI line pressure, 'cuz my compressor could not hold it consistent enough above that level.

I would not think that a few degrees of backward rotation would do anything, particularly around TDC.

Did you run the engine for a while prior to doing the leak test? I would run the engine for a while longer just to see if the lifter pumps up some more.

What did you get for results?

I ran the engine until it was at normal temperature prior to the test. There was no issue with valves ticking or empty lifters prior to the test.

The OTC tester worked great. I ran it at 100 PSI in and 90 PSI on the internal regulator.

I got 5-8 percent on 6 of the cylinders. Cylinder #4 was 12% and #7 was 1%. Turned the motor over a few times and re-ran #4. No change. Not planning to do anything about it for now, it ran fine last year.

 

[Mischief Managed]

Re: 2000 7.4 MPI Valve ticking after leak down test

doubt if you wrecked a lifter. however I would determine which bank the tick is coming from, and pull the valve cover to inspect. you may have a tweeked pushrod. if the pushrod is straight, I would then re-install and re-adjust the lash setting.

There's no lash adjustment on my engine.

 

[tpenfield]

Re: 2000 7.4 MPI Valve ticking after leak down test

Those tests are OK, I would not worry. I'd like to know what that #7 cylinder had for breakfast . . .

You might want to pull the valve covers and tweak the valve adjustment on the 'ticker', it could have been close to needing an adjustment regardless of the test.

As long as it sounds better than Coopin's engine that was posted a couple weeks back, you're probably in good shape.


P.S. (I didn't see your email until about noon time)

 

[tpenfield]

Re: 2000 7.4 MPI Valve ticking after leak down test

There's no lash adjustment on my engine.

Were you able to fix the valve adjustment? I finally used the leak tester on my engine, the results were pretty good; everything was under 10% . . . a few were about 1-2%