Hello to all

I need help from anyone who knows, my XJR will not start for several years,
It appears that from what I have read, that the cam timing is 90 degrees off, is this possible without distroying the engine, is the AJ16 motor an interfearence engine, and speacificly is the XJR with its lower compression an interfearence engine. Can I retime the cams and of coarse fix what ever caused the jump in the first place.
does anybody know, any help would be greatly appreciated.
Thanks

Darryl
360-582-0338

 

Hello to all

It appears that the cam to crank timing is, as it should. be #1 TDC and the #4 intake lobe pointed straight up, however when that is the case, the timing gear on the front pully 100- 140 degrees off, even though it appears to be firmly attached.
Some possible ideas, sheared crank key, even though I do not know how that could possibly happen,
Is the timing gear pressed on or vulcanized to the pully ?

anyboody had this happen

Darryl

 

Wish I could help.

Somebody will eventually come along who knows but, to be honest, these engines have so few internal problems or failures that most of us have never had to dig into one

I know much less about my XJR than I did my previous Jags

Cheers
DD

 

Thanks for the imput Doug

From all the posting that I have seen from you, on the XJR, it looks like you are the man when it come to the R.
I just was reading your post about your harmonic pully, failure, so when you had it off, how was the timing gear attached. and is this unrealated to the pully failure ( the timing gear rotating ), I have to pull it anyway as something is clealy not right. and did you use the dampner doctor ?

Also I saw your post on the XJ220 that you were working on thats pretty cool, ( Tonkin's) ? how many of those can there be in the NW

Anyway thanks for your help.
It would be great to finaly get this R back on the road, as I am wearing out my 96 VDP, 221,000, but thats small change compared to my 72 XJ6 475,000 and still going

Darryl

 

When I had the mighty 3.2 apart for chains etc a long while back, the huge bolt holding the pulley in place was NOT as tight as I would have expected, or have experienced on any other Jag. My suspicions that someone had been here before was thus confirmed.

The beast, the V12, is well documented for that key/s (as there are 2) to fail, usually preceded by a weird knocking from the front of the engine, and that is with all as tight as specified.

The key was a tad "bashed up", and if that fails the pulley can/will spin at will.

The tooth wheel is firmly bolted to the pulley pack, and that is not your issue.

The chances of a chain "jumping" is almost impossible in my opinion. There are too many dampers/guides/etc in place. If the top tensioner is removed, "maybe" it could, but it would not run with it removed, and the gush of oil would be enormous.

I would be removing that front pulley and I reckon you will find the key sheared, and the timing wheel is out as much as you have found.

 

+1 to Grant. Only one key on the 4.0L NA version, no experience with SC version. Timing gear bolted securely to the keyed part of the pully. Failing damper can't affect the timing, but a sheared key surely would.

 

I've been into my 97s timing chain several times working on the upper tensioner and I can't see any way the 4.0 would jump time. IIRC wouldn't that lobe be up "twice" during the crank rotation cycle?j

 

Nope.

The camshafts rotate at half engine speed.

 

Thanks to all for the good info thus far,
So I pulled the dampner, and shure enough, the key was just remnants, a little sliver in the crank slot and a little sliver in the dampner slot, well that would certanly explane why the dam thing would not start, and I must say that is a pretty wimpy key, espeacialy for a car with a supercharger, the XK engines key is 3 times that size without a supercharger.
I have been building and working on cars for 35 years, and this is the first time I have seen a sheared key. You learn something every day.
As a side note, I am not the first person here, the dampner had obveusly failed at some point and someone had welded the timing wheel to the outer portion of the dampner, thus negating the dampner, tying the inner and outer parts together. Thats a first also for me. So off to the rebuilder, and whats the deal with Dale mfg, he is cheaper than the dampner doctor by half, but he is closed every third month, ( what a way to run a buisness ) I wish I could do that.
Anyway after all this time, and money spent it is good to finnaly find a reason for the no start. ( lets hope it will start with a rebuilt dampnerand of course a key ) So does anyone want to buy a XJR ECU as I bought one trying different things to get it to run it for sale.

Darryl
D&B Enterprises
www.barchetta3500.com

 

Better contact either Dale or the Damper Doctor first and make sure they can rebuild it before you spend $$ shipping it. Not sure they'll be able to help if it's welded up.
That might help explain the sheared key, though....

 

hello to all

It finaly runs, I cannot beleive it, after 4 years of sitting in my yard mocking me, With a new woodruf key, so the timing gear is where it is supposed to be in relation to the crank and cams, that did the trick.
One thing thought the tach worked for a few minutes and then stopped, and does not appear to be working at all now. And yes the cps is new, so what could cause the tach to not work ? any ideas anyone

Darryl