I have the opportunity to buy a decent XJ8 for $1000. It has one little dent it it, which would be easily fixable, but the engine is toast. I'm 99% sure it's a broken timing chain. It's on a 2000 XJ8. If I can get it running again by just replacing the timing chain and tensioners, then I'm going to jump on this, but if it requires a major engine rebuild, or a new engine, I'm going to pass.

So is it possible to check to see if any of the valves have been broken without having to take off the heads? I was thinking that I could buy one of those fiber optic cameras and just check each cylinder from the spark plug hole. Is there an easier way?

 

How about a leakdown test? During the test, the piston has to be at top-dead center so that all valves are closed. If the valves are bent, the cylinder wouldn't be able to hold any air pressure during the test.

Just a thought...maybe not the optimal solution.

 

You could take the plugs out and turn the engine over by hand (ratchet on the crank 24mm) if you can turn it over easy at least you know then the valves are not hitting the pistons, there will be a little resistance as you approach TDC. A compression check would not go amiss then.

Otherwise it is a cam cover off.

 

The best and most accurate is to pull the cam cover over the offending head and unbolt the cams to relieve the valves. The do a leak down test. Or barring a leak down tester use compressed air and a rubber tipped air blower to seal the spark plug hole. Any bent valves with be readily apparant cause there little if any resistance to air and youll hear the exhuast or intake whistling dixie.....

 

I WOULD RECCOMMEND NOT DOING THIS, THE VALVES BEND REALLY REALLY EASY. IF THEY WERENT BENT BEFORE, THEY WILL BE WHEN THEY TOUCH A PISTON.......THIS IS SPEAKING FROM EXPERIANCE

 

Yes they do bend easy and trust me if the tensioner has gone and the cam has jumped they would of been bent a long time before you try to turn it over by hand, by the person who kept trying to make the car start straight after the tensioner broke!

This I know from experience

 

Never mind. It turns out that the guy has been flooded with people calling about the car. He upped the price. I actually went to look at it and it was all dinged up, the seat was worn, the tires were not brand new, as he claimed... It was a basket case. Oh well.

 

LOL THE ONLY REASON I SAID THAT IS BECAUSE OVER THE YRS I HAVE ACTUALLY HAD 2 CARS THAT SNAPPED CHAINS AND DIDNT BEND VALVES.....

 

Oh yeah stop shouting at me you will give me a complex