If the valves haven't been bent, I would replace the timing chains and tensioners and get the V8 going again. The third generation tensioners should last a long time. A chain/tensioner/gasket kit are about$1200. Think about it.

 

My experience is that more than half the time when the secondary chain breaks, the exhaust cam stops in a 'GOOD' place and the valves don't contact the pistons.

It seems to depend on the speed and timing of the chain failure. At idle or shut down the cam will probably stop at a 'valves closed' position and you just need to replace the secondary chain and BOTH tensioners. If the chain fails at high engine RPM, then the valves are probably BENT (inertia??)

I bought my 1999 XJ8L for $500.00 because the owner did not want to repair the broken timing chain and chance the bent valve possibility. It was at the dealer and they quoted a timing chain job at minimum and engine replacement at maximum.

The customer just wanted the car GONE. I just replaced ALL chains, guides and tensioners and the car has been flawless for several years now.

I really was not worried as I have three 4.0 V8 engines in my shop for parts. (it's great to be a 'pack rat')

bob gauff

 

The upper tensioners, which are the ones to replace, are less than $200, including tool rental if you DIY and it is not a major job. Getting the valve covers off and on is far more than half the job.