Timing Chain Adjustment
 

Series 3, 4.2, XJ6,
Question,... I've got a rattle near the front of the engine that sounds like a few small rocks in a shaken beer can. Can't pin-point the location with a stethoscope so I tried to adjust the timing chain. After removing the breather housing and screen and loosening the locknut, I was not able to turn the tensioner CCW(facing the motor) at all. I tried turning it CW and it would only move easily about 3/16" circumference rotation. I then returned to a solid stop (and no more) CCW. Does this sound right for tensioner movement?
I still have the rattling.

Appreciate all the help, Jim

Did you use the special tool ?

This is made so it pushes in the spring-loaded locking pin, then the sprocket can be rotated using the tool. Of course the clamping nut has to be undone as well.

Camshaft Chain Tensioning Tool - 1949-1971 - Terrys Jaguar Parts - JD2BR

Right, without the special tool you'll have to press the locking pin with you finger and then turn the adjuster...most commonly using needle nose pliers.....until the excess slack is removed. And no tighter than that.

If the locking pin won't depress, which is sometimes the case, it can be wriggled out with a pair of pliers. For gods sake don't let it or the tiny spring fall into the engine. Clean the pin and the hole with solvent, reassemble with a drop of oil.

Pack the openings of the timing cover with rags to prevent 'stuff' from dropping inside. Remember to remove all the rags :). I accidentally left one in once. Gawd, what a mess. Spent hours picking shards of cloth out of the timing chain.

Cheers
DD

Timing chain adjust
 

Hi Guys,
Well this is getting interesting. The reason I had trouble understanding the adjustment routine is the locking pin device is stuck in the depressed position.
After stuffing a catch rag in the gap, I remover the locknut, washer and knurled disk. Note,... The disk center hole flat was deformed as if somebody had used extreme force CCW. This allowed for the small amount of rocking with the spanner.
After spraying carb cleaner, WD-40, and tapping the pin with a brass drift, I trying to extract it with pliers. NO WAY. This thing is stuck solid.
Please give me some ideas that doesn't involve major dis-assembly.

As always, Thankful for the help.:icon_sad:

Jim

I'd get a replacement serrated disc to replace the mangled one.

The stuck pin thing isn't really that big of a deal. I've come across a couple engines (including my own) where the pin was stuck in the depressed position and had been that way for god-knows-how-long. Apparently a well-tightened nut is sufficient to hold the adjustment.

The pin is probably being gripped by baked-on gunk. Try softening the gunk with propane torch.

Cheers
DD

One thing that concerns me is the fact that I can't rotate the tensioner in either direction coupled with the stuck down pin.
Thoughts?

A *fully* depressed pin should be clear of the serrated wheel, and allow the serrated wheel to turn.

I guessing your pin is not fully depressed and is still engaging the serrated wheel. Do I have that right?

OR....

Are you saying that the pin IS clear of the serrated wheel but you STILL can't turn the adjuster?


If the latter I'd say that the adjuster (which rotates/operates like a cam) is well and fully stuck by varnished/carbonized oil.

At this point my ability to visualize the situation is compromised by foggy memory. I think disassembly to clean-and-unstick the adjuster would be a bit intensive.

*Maybe* you could saturate the area with solvent (Aerosol brake wash, for example) in hopes that some of it will find its way into the gunked-up adjuster.

Hopefully someone with a better memory will come along and bail us out. Meanwhile, I'll mull

Cheers
DD

Yeah, the pin is fully depressed and "gunk glued" firmly in place,.... As I'm guessing, is the tensioner. I'm assuming that is how the serrated disk bore flat got deformed. Someone tried to force the tensioner and it didn't want to turn.
Is removing the cam covers allow for any access?
Thanks, Jim

You need to heat it up a bit then apply penetrating oil. a few gentle taps with a small hammer may also help. The adjuster eccentric seizes up quite often, especially if the engine has been standing a long time. Be careful nothing drops down into the timing case ! I had my engine apart, so loosening off this sprocket was easy as it was on the bench. You need another adjuster plate too, from the sound of it.

Fighting the good fight,...
First, hosed the area down with penetrating oil. Took a stand-off type two inch long 3/8" nut and drilled/tapped 7/16-20 half way through it. Screwed it onto the tensioner. Screwed a 3/8"x1 1/2" allen bolt in until it bottomed onto the tensioner shaft end. Jammed the two as tight as I could. Still got no detectable rotational movement on the tensioner.
Taking a beer break for the rest of the day.

A bit of heat and some tapping with a hammer, (but not tooo hard !). If it-still won't free-off, you might have to take the timing cover off. This a major job with the head still on, and difficult enough with it removed as the cover has studs on it to secure it to the head and the sump.

Hey Guys, Got up this AM with a whole new attitude. Went to the garage with my Golf Club Shaft Removal Heat Gun in hand and put some temperature on the tensioner. After about five minutes, some choice four letter words, the locking pin started to move. After getting that out, I put my jam-nut setup on the tensioner and it started to move. Aw,.... the sweet smell of success (and burning oil/gunk).
The engine does not rattle any more.
Adding one note,... The rags stuffed to block hardware loss should be removed prior to the heat application. I substituted aluminum foil.
I still have the rough and high idle RPM issues but it's nice to win once in a while.

Without you guys, I couldn't own this car. Thank you, again.
Jim

Glad to be of assistance ! Do I detect something burning here: -