Hey forum, I'm thinking about picking up an XJ8 on the cheap that had its secondary tensioners break and fixing it myself to get a nice running XJ on a bargain. The seller claims there is no valve damage (according to his mechanic), I'm wondering if there is any easy way to confirm this if I go check out this car. I could hand turn the crank until its on its timing mark and then check if the flat part of the cams is facing up. For the driver's side I could stick a camera down the oil filler but what about the pass side?
Anyone got any ideas on how to check this out?

 

The car maybe a good opportunity or a great drive way decoration!
First there is no timing mark to line up.
Second there is no way to look inside the cam covers that will give you any information.
Third ask him to provide the compression readings for the cylinders. If they are not available then NO one knows if valves are bent or not.
Under no circumstances rotate the engine by hand or starter if it is known a tensioner has failed. To do so would guaranty if a valve isn't yet bent it might just get bent.

All that said it is possible to have a tensioner failure without the timing being effected and damaging the engine. If you decide to buy it make sure you have the special tools to lock the crankshaft and align the the camshafts. then change the bad tensioner, do a compression test and see if you got a winner or more serious problems.

Don't get me wrong. I'm not raining on your parade. If it was me I would go for it. It wouldn't be the first time time a non savvy Jag mechanic got it wrong.

 

There is a timing mark, it is on the flywheel, it's used to line up the flywheel to install the crank locking tool. If the timing is correct when this mark is in position the front of the cams should have a flat section facing up this would be where the cam locking tools are installed.
You could look into driver's side cam through the oil cap with an endoscopic camera, but I don't know how one would check the passenger side.
I don't think a compression test was preformed he just said his mechanic told he the engine wasn't damaged, he didn't know how the mechanic came to that conclusion.

 

Anyone else?

 

If it's cheap enough and there aren't a laundry list of other things to address I'd be inclined to go for it.
My big question was how they did a compression test without turning the engine over with the starter.
Maybe as Vern stated the secondary tensioners are just allowing more cam mislocation than factory specs but not enough to cause valves to hit the pistons.
Of course the real trouble with these projects is the "creeping elegance", while I'm here I should change this.
That's usually how I make a bad deal out of my finds!
Good luck.

 

If you had a really, really high quality endoscope type camera, you could stick it down the spark plug holes to look at the valves. I've tried that with a $200 Milwauki brand camera from Home Depot and could partly view the valves but the focal length and resolution on that camera makes it pretty much garbage anyway. I can only imagine what I'd see if I had a high quality one like they use for laparoscopic surgery. But the valves are like $10 each on RockAuto (look up part # for Lincoln LS and then search by part #). It would probably be like all the exhaust valves on one bank, $80, plus figure about $400 per head at the machine shop, and $75 each for head gaskets. If its just one side, figure about $600, plus $60 for the tools, plus fluids, plus any other "while I've got it this far apart".

 

If you decide to do this, I have the cam tools and setting pin I can sell to you.

 

I've already got a set, but thanks

 

I have had about an 80% success rate with broken chains not damaging the valves on cars I have bought. The easiest way to check is to remove the cam cover and check to see if any of the valve buckets are "stuck" at a lower level than the rest. The second test is to *remove* the exhaust cam (likely the chain is broken, if not you can break apart with a chain tool) then with the fuel injector relay out do a compression test its gonna be about 0 if you have a bent valve. For extra precaution you could hand turn the engine a full revolution or two before cranking.

You may be able to see down the spark plug hole and find a valve that does not close, but the compression test is a sure fire way to know.

 

if its cheap and looks good I say go for it;they make great yard orniments, as I had my old non running 96 for a few years before selling it.it spruced up the driveway and looked good beside my 01 xj8.