08 Mitsubishi Eclipse 4 Cyl.Timing Belt

I have a 2008 Mitsubishi Eclipse 4 cyl. that the timing belt came loose (top camshaft not spinning) maybe from a loose tensioner. I know this type of engine is an interference engine. My question is if I can do a relative compression test and see if the valves got damaged? Since the crankshaft is spinning and camshaft is not. Is there a better way (maybe going in cylinder with a pressure transducer) to check if that valves got damaged? Any help would be greatly appreciated

IMO, without a belt on the engine, your options for testing are limited. Most every scope test I can think of would be invalid since the cam timing won't be correct.

You could CAREFULLY line up the crank and cam timing belt marks (like you would when installing a timing belt), then do a leak down test on #1. If it passes, carefully move the crank and cam to the #3 TDC position and retest. On and on, until you either find a cylinder that fails, or they all pass.

Did I mention you should do this carefully? :silly: There's lots of way to go wrong with the above procedure. For all that work, I think you're better off temporarily installing a timing belt and proceed with testing from there. If anything bent, you'll find out quickly. If it didn't, the engine should start.

Can you pull the spark plugs to look at the cylinder positions? If you can, slowly, turn the crank to a position that all pistons are NOT at TDC (0°, or 360°), but are positioned in the middle of the cylinder (90°, or 270°), then you should be able to, safely, turn the cam shaft. If you can pull the valve cover, that would be great. Look at the cam for a cylinder with both valves closed. Now you can do a leak-down test, with a leak-down tester. Or, I like to put a pulse sensor in the Tailpipe, Intake Manifold, and Dipstick tube. Blast some air into the cylinder. Watch the pulse sensor to see where the blast goes.

This is also a great method but I was trying to spend the least amount of time on this. I will definitely add these testing methods to my diagnostic techniques. Thank you for your input and your time:)