My XJR recently broke down due to the timing chain tensioners failing. Here is a basic rundown before I ask questions:

-Car was running 60 mph when engine failed.
-Tried to start vehicle after pulling over.
-Engine most likely seized
-Upon investigation of the front of engine, I found a giant crack in the timing chain cover.
-I also found a sprocket with a broken bolt (this fell out of the front of the engine)

The questions I have are:

1. Are my heads warped? Or just valve damage?

2. What sprocket will I need to replace, and where do I find the bolt?

3. When I delve in to this job (it's so cold outside now) where exactly is the CKP sensor located on this vehicle?

Thanks, and I'm excited to get started on the rebuild.

 

I like your enthusiasm.

Did the engine turn over at all when you tried to restart or it is really seized? I'd be starting with removing the heads to see the extent of damage first.

An engine manual on ebay could be a good investment too.

Maybe start a thread with pictures as you go for the best advise. Sad affair indeed.

 

Thank you for the reply!

Inititally the engine turned over, but sounded as if it locked up shortly after. I would assume, however, that the reason for the seize is due to the chain not being in place (At least I hope so).

When I get a warmer day I'm going to remove the heads and check for valve damage. I've been involved in engine-rebuild projects before, and I know if the block isn't destroyed, everything else can be repaired.

 

It can be repaired, but the used engine may be cheaper. If your engine ejected a cam sprocket, then the cam may be buggered, the valves are almost certainly bent, the chain case is broken and who knows what else! Normally, a chain upgrade is only tensioners and gaskets.

 

I expect a chain broke, not a tensioner. Considering the externally visible damage, it's time to look for a replacement engine and remove what parts are still useable for sale or spares.

 

+ on the engine replacement.

In your case I would recommend a GOOD-USED-ENGINE.
When sprockets "fall out the front of the engine" it's time to think about what is damaged INSIDE the engine as well.

bob gauff