Hi Grant, a couple more questions if you don't mind!


In addition to the crank oil seal I note there is an Intermediate Shaft Seal (EAC5721) but it seems to sit behind a cover plate so I don't understand what the seal actually does. Should this seal be replaced as well or can it be reused?


When you say to be sure the lower tensioner has 'fired'...how do you fire the lower tensioner? When I previously fired to upper tensioner I just cranked the motor with the fuel pump disconnected and let the oil pressure do its job. But with the lower tensioner I assume I need to be sure it's fired before putting the timing cover back on. Is there another trick for this one?


Thanks very much for your assistance.

 

Marke,

That seal is not fitted to our cars, mine has no seal in there, UNLESS you got the self levelling suspension, and a hydraulic pump fitted on that hole. I have NEVER seen an AJ16 with a pump there, only XJ40's.

Firing the lower tensioner is easy. A BIG screwdriver, a small amount of imagination, and lever the piston "back into the housing" and release, and the piston "should" follow the screwdriver. I lever on the chain AT the piston contact area. It really is not hard to figure out.

If not, do it again, until the lower chain has tension on it. I cannot stress the importance of firing this thing off, as it simply will NOT fire the same as the upper one does. Dont panic, it will "fire", just take your time.

 

Well I made a start last weekend but didn't have much time available.

So far I have removed cam cover, harmonic balancer (will be replaced), water pump and all hoses (will be replaced), upper tensioner and removed all the bolts from the timing cover. So next step is pull the timing cover and see what awaits me. I have the cam timing tool and its at TDC.

I must admit I am a bit nervous about replacing the timing chains. The engine has 205,000km on it. I could probably get away with just replacing the guides/dampers. But if I've gone this far maybe I should do the whole lot?

Grant (or any other expert) did you replace your oil pump chain as well? Is it possible to do with the sump on? I don't actually have an oil chain or damper as it didn't come in the timing chain kit. I usually get my parts from the UK but do you have a recommended supplier in Aust that could supply the oil pump chain and damper?

 

Marke,

NO did not do the oil pump chain, as it was tooooooo likely to drop into sump, as the access is TIGHT, and arthritis is rife. My oil pump damper was positioned in the far OUT position, so no contact whatsoever with the chain, so I reset it, and moved on. It is only a single row chain, and although some wear was evident, the reset appeared OK to me, and it is still SILENT.

Before you "pop" the timing cover, make sure you have removed that "centre bolt", which is the one just level with the harmonic pulley, at the 12 o'clock position. The AJ6 engine does not have that extra bolt, and I have seen some AJ16 covers broken coz the mechanic did not know/look for, that extra bolt.

The replacement of the chains is purely choice. I did mine, coz I had them, but the old chains were NOT worn to any measurable degree, trust me. In hind-sight, I would NOT do them, as it is a lot of extra work, and the tongue gets knotted lining things up. There will be wear signs, OK, but they are double row chains and are strong. The upper chain would be the one I would worry more about, as it gets a fair hammering from the cam lobe vibrations.

 

Thanks again Grant. Got the timing cover off this evening with a minimum of fuss. Can't say replacing the chains looks much fun, particularly with the head on. So they will most likely stay!
I did notice a lot of slack in the oil pump chain, my damper was still touching the chain but wasn't doing much in the way of providing tension. Got a new damper in in the post.
Hoping to make a lot of progress this weekend...

 

Hi Grant, you should really be charging me for all this advice! Anyway, another question if you don't mind...


What holds the distance piece/crankshaft spacer in place? I mean you can push it on the crank fairly easily, but does the harmonic balancer pull in far enough to stop it floating around on the crank? And it looks like it retains the bottom sprocket in place so you wouldn't want it floating around...

 

Marke,

That distance piece is sandwiched between the harmonic and the sprocket. It all basically becomes ONE unit when that bolt is tightened TIGHT.

Getting the spacer off can be time consuming due to roughness around the key slots, so a CAREFUL dressing with a fine file sorts that easily, and I use a "magnet on a stick" to pull that thing off the crank snout.

NO CHARGE MATE, EVER.

When I start forgetting you can all remind me of what I know.

 

Cheers Grant.
My spacer came off pretty easy when I was expecting it to be difficult, hence I started to worry if I'd missed something. I have a new one to put on even though the old one looks like it could have been reused.

 

Job complete (hopefully).

Retained the old chains, but have replaced all tensioner blades and chain rubbing blocks along with new water pump, thermostat, coolant hoses, harmonic balancer and spark plugs.

With the exception of the upper tensioner blade, all the other rubbing blocks were almost like new and certainly did not look like they had been there for 205,000km. It was all very clean inside. The upper tensioner blade however had deep uneven cuts in it although not down to the metal thankfully. Looks like the chain had done a lot of jumping around on that blade. Probably under the previous owner who had failed to replace the upper tensioner despite lots of warnings on start up.

The upper tensioner piston was in good nick although I only replaced it 2 years ago. The lower tensioner was very clean, the piston was unmarked so after a wash down it went straight back in.

The oil pump chain rubbing block was not providing much tension on the chain. I made sure the new block removed the slack when I put it on.
Biggest problem was getting the timing cover on....It kept wanting to catch the head gasket. Anyway I got it back on and yes it leaked between the head and timing cover on the lower side of the motors (side when the upper tensioner is). So I thought bugger head will have to come off. But as a last resort I cleaned all the residue off the outside of the motor and covered the problem area with huge amount of RTV Max Oil Resistant Silicone. I didn't hold how much hope but after a few days of driving there is no oil so far. Fingers crossed....

The buzz sound I was getting at 1500-2000rpm under load is now gone. Also the motor is much quitter on idle. Previously you could basically hear the chain going around on idle. Now silence.

Thanks for your help Grant. I had no problems firing the tensioners. It was easy to understand once they were out. I pre-fired the upper one as well since the cam cover was off. So no ugly rattle on start up.

Now, fingers crossed my silicone holds!

 

Just to clarify, the TSB for the new upper tensioner was issued in 1996 so seems to "technically" only cover 95-96MY, but I would assume it also covers the 97?

http://www.jagrepair.com/images/TSB/...er%20Start.pdf

I think my 1997 XJR may have the same issue versus what I thought was the starter bendix failing to retract (still verifying) but wanted to double check that the part number for the new tensioner remains correct for the 1997 S/C AJ16.

Also, it appears that the tensioners I've seen listed come with the new o-ring installed, or does one need to order the 0-ring separately?


From the TSB above:


PARTS INFORMATION:

DESCRIPTION PART NUMBER QTY

Upper (secondary) tensioner assembly NBC 2031AA 1

O-ring EAC 4540 1

Housing gasket EAC 4557 1

Bolt FS 108251/J 1

 

The new tensioner fits the 97 and the one I ordered came with an "o"ring but no gasket.

 

Thanks, another quick question: Is there risk of damage to the engine as this issue continues? Or is it really just an annoying noise?

In other words, if I continue to drive mine for a few weeks before I get to replacing the part, am I at risk of jumping a cam tooth or other damage?

.

 

i had the noise since i bought the car, almost happened at every startup, but i believe its safe to drive tho, as u start the car the oil will push the tensioner out. i changed my out a few weeks back, 9/10 on startup without grind

 

Thanks

Well, some good news, I went out and verified that mine has the new tensioner (with the arrow) that a previous owner must have installed at some point.

Bad news, it is rattling pretty reliably at startup. So I assume my new one is defective.

So, what I thought would be an easy repair to swap out the old tensioner for the new model might not be true if one can't remove the new model upper tensioner without removing the front timing cover.

Can someone confirm if there is a way to remove the new model top tensioner successfully like the old one by just pulling it out so I can fit another new one?

I have no way to verify how long my new one has been fitted for certain, but I suspect it is less than two-three years old based on what I know of the previous owner.

.

 

When I replaced my upper chain tensioner on my XJ6 sometime last year, I didn't have to remove the timing cover.

What you do have to remove though is the camshaft position sensor. It is the trickiest part of the process but not hard at all. There is a little window on it with a circle that when lined up with the dimple inside the window, you're at TDC. Either try to rotate that engine so it's at TDC center before removal or remove the top cover (two torx head screws) and make a mark where the middle of the circle would be so you can line up the window again during installation.

After removing the camshaft position sensor, Installing the new upper chain tensioner is a less than 5 minute job. Just make sure the piston on the tensioner isn't pushed out or else you'll have a tougher time pushing the tensioner into place.

 

Mines been making noise at startup for three years even after I replaced the new tensioner with another new tensioner. Trust me, that engine IMHO is incapable of jumping a tooth. I'm not a fan of the tensioner design at all, Old or new version.

 

As said, and what I found/did.

When removing the tensioner, take care when drawing it out of the cylinder head hole, TAKE YOUR TIME, as the piston assembly is "free floating" in the cast iron bit. It can, without care, fall out, and drop inside the engine.

That is why the TSB states to remove the Camcover, and usng a large flat bladed screwdriver "push" the old unit out from inside.

The reason most of us have removed the timing cover, is to rectify the damage that has occured to the blades/dampers inside from this inefficient assembly. Add to that the use of "El-Cheapo" oil, and the engine components have little to no chance of survival.

The second reason for having the Camcover off, is to "pre-fire" the spring on the new unit. This will fire without doing this, but the Un-Holy rattle as it does so will scare the hell out of you, trust me.

 

Any chance/thoughts of heavier weight oil keeping the tensioner from leaking down?


I've also seen a previous owner fit a pre-start oil pressure pump/primer. I wonder if that might be a good idea.


.

 

Many, many thoughts out there.

My findings, as un-scientific as they get, is that prior to us "pedantic" owners getting these cars, they were "just a car".

Maintenece as such, was minimal.

Good quality oil was saved for the "new" car.

The score marks evident, even on the new one after short usage, indicate a fairly lousing design/materials used/whatever. Howver, in the big scheme of things they are just fine.

Mine runs Synthetic 15W40, and changed every 4 months regardless of distance travelled. The engine is still silent, and no "chinge/etc" ever. It has now done over 100K kms since sorting by me, and the car had 143K kms prior to that sorting, WITH an updated tensioner already in the engine.

When you take the time to get it out, and dissmantle it, just for giggles, that spring is SERIOUS in its tension.

I rekon the "angle of the dangle" of the piston pushing the blade against the chain is not ideal, and that is the main issue.

The blades etc on mine were a MESS. Worn beyond the expections I had, based on the mileage travelled, and that gets back to oil used, and lousy service intervals.

 

Here's an excellent read on the X300 timing chain, tensioners.

http://jimbutterworth.co.uk/8timingchains.htm