Have you two Steve's just made my day ?

The timing seemed pretty much ok before i started. I don't remember any significant misalignment.

Looking through Bluexkragtops thread, apparently with the valves stuck down they hit the piston.

I guess if you're going to have a valve stuck . . . up is better than down.

I'm wondering if this may have something to do with the water that went down the inlet bores when i cleaned the centre of the block.
I did get a bit of fine water spray out of the rearmost (and possibly the next one forward) spark plug holes when i cranked the engine to pump the water out.
But i'm talking about less than a desert spoon full.

Possibly some rust around the valve seat, stopping it seating properly?

Does having a valve stuck up mean the valves may be adjustable downwards, so that they seat properly?

The JTIS states the use of a special tool clamped to the cylinder head to adjust the valves, so i'm wondering if there may be a way to adjust them without removing the camshaft, and even without the special tool, since there's often more than one way of getting something done.

The tolerances on the rear most inlet cam stand out as being the most likely culprit, as steveasy has said.

If the valves are stuck up a bit, does this mean less chance of damage for the 100 (not 70) mile drive to XKRacer's?

 

When the cams rotate the valves HAVE to open, or the camshafts would break, or the caps be ripped up. More likely the engine would not turn over. So the valves can not be stuck in the closed position.

 

I think it would be a good idea to do a compression test now.
If the tight clearance is due to valve damage it should show.
https://www.jaguarforums.com/forum/x...earance-74476/
Different engine and a different outcome in this thread but it might shine some light.

 

Dear Roadhogg,
All assumptions but Im not convinced your valve is not hitting the piston, and that is your noise, and the pressure or vibs is reduceing the clearences to a min each time.
so a compression test is next. id not start the car again, at the moment you might just have a bent valve, or not seated properly. 70 miles and you could have a ruined engine.
I think you may have to remove head eventually. but an expert will be able to decide if an easier option is possible.

id arrange a trailor to move the car,

Steveeasy

 

Can anyone recommend a good car transport/recovery service in England then?

I've had a quote of London to Norwich for £220 so far.

Looks like it's going to XKRacer's as is.

Sorry Tony

 

£220 is not a bad price but it might be better if you use the money to join the AA... drive 2 mile down the road and give them a call and then let them bring to me

 

Done

 

Gents,

PLEASE keep us updated on this one...many of us are very curious about your findings.



.

 

+1 on that.

 

I don't suppose it could possibly be an improperly seated injector, or a leak at the inlet manifold?

I know i torqued down the inlet manifold bolts properly, but i re-used the gaskets on the advice of the guy that sold me the timing chain kit.
He said he didn't have any inlet gaskets in stock, but if they look ok they're normally quite re-usable.
I cleaned them up and they looked fine, no nicks, tears, wear or distortion.
Then a thin smear of grease on them.

I think all i can do now is get a torch and a mirror to look at the caps where the lobes make contact, and pull the spark plugs to see if any are discoloured.

If i can't find anything wrong i'll just have to put it back together and take XKRacer's advice.

But to me something doesn't seem right with the valve issue, unless it's water/rust related.

I can't see why the engine should suddenly develop a stuck/bent valve when it was ok before the work was started, and was only turned over by hand during the work.

Although the clearance is less than it should be, the cam lobe is compressing the valve caps/springs normally and they are springing back up.

So i'm thinking possibly rust round the valve seat from the water, and the cylinders may burn off the rust from the seats as the engine is run.

Just my clueless twopence worth.

 

content is a little over my head, but I enjoyed the read nonetheless. I'd like to follow this as well, to further my education on these engines. Roadhogg, you're in good hands there. (just try to resist the urge to buy a snazzy conversion kit)

 

Roadhogg,

No, it wouldn't be an improperly seated injector. The engine would run roughly and you would be creating a lot of exhaust smoke from all of the petrol leaking past the injector's o-ring. So rule that out.

Doesn't sound like any kind of air leak to me, either. I also don't think the water issue would cause this noise. I still think there's some kind of issue with the camshaft, bucket, valve spring or valve. My guess is that you don't have any kind of real valve damage or timing issue, because other than the sound the engine seems to running rather smoothly. Which leads my suspicion to some kind of interference with a rotating cam or an issue in the bucket / valve spring area.

I think it's time to let Tony have a look and make his diagnosis. Otherwise we're all just tripping over ourselves trying to guess via video and 5,000 miles of ocean (for some of us).

Please post your findings! We'll be anxiously waiting.


.

 

Dear Roadhogg,

couple of random ideas. check cam lobes for damage, check cam journal torque settings.

knock sensors.
when you removed the inlet manifold, did this all go back ?.

VVT units
switches and plugs reconnected. could this upset the valve timming. I think you took these apart. I dont know anything about these units, but I believe they might advance and retard the timming.

Best of luck

Steveeasy

 

I've checked the cam lobes steve, can't see any sign of damage at all.

No wear, marks or scoring.

You mean the camshaft bolts?

I didn't touch them.

Knock sensors are grounded to the centre of the block, and the sensor plugs slot onto brackets either side of the thermostat housing.

They were connected.

VVT units have a solenoid that extends through the front of the cam cover, but they were re-connected properly.

I mentioned earlier that the cam lobes faced upward from the valves in fours.
IE: a pair of inlet lobes and a pair of exhaust lobes, for measurement of the gap between the bottom of the lobe and the shim, except in the case of the pair of inlets for 1 and 2 (from the rear cylinders forward).
You can see from the picture that the lobes for inlet 1 are facing up and exhaust 2 are facing down.
But if that wasn't correct and the timing/firing was that far out, then surely i would indeed have a serious misfire.
So those positions must be normal for those cylinders, i would guess.

In terms of wear on the lobes of inlet 1, ( with the smallest clearance of 0.1mm) you can see from the pic theres nothing wrong with them.

Valve buckets seem to be compressing and rising through the same range as the others.

I'm flummoxed.

Great thinking though steve, and thanks for the ideas fellas.

 

Hi Roadhogg,
I agree with you logically why would you suddenly get a problem with valves. but if you eliminate all other options, then going with caution, it points to valves.
I dont know how you can have a valve seat drop like the one in blue xkragtops engine, but it happened. and a posibility exists that if you got water in the bores, when the engine turned over damage could have been caused to the valve seat area.

To pin it down any further, you either have to do a leakdown or compression test, or at least pull the camshaft off and look in to the valves.

Best of luck with this.

steveeasy

 

Roadhogg,
out of interest, at the end of the inlet camshaft, nr the bulkhead, a part is fitted to the slot on the camshaft. what does it do?. does this have the potential to impact on anything whilst turning.

It seams to key in to the end of the camshaft, Almost shooting in the dark,

steveeasy

 

I don't know what that's for steve, it's been there all the time.

Perhaps some kind of balancing weight for the camshaft. I'm just guessing, someone probably knows.

And now for the bit where i get lynched by the mob.

The spark plugs on the left bank were only hand tight, and the rear most cylinder plug was less than that, hence the noise.

No choice but to fess up

I was so sure i'd done them, and i had, on the right bank, that i didn't re-check them, which should have been among the first things i did.

Guilty as charged, and no defense ur honour. Put me away.


Good news is she's running fine now, i think.

I'll find out tomorrow when i deliver her to Tony, hopefully under her own steam.

I'm so sorry, to everyone that has racked their brains to find a cure for that noise, because i didn't do one of the most basic things, and check the plugs.

 

Excellent glad you discovered your problem even if it was some what self inflicted...

That key in the end of the cam is what tells the sensor the position of the cam, which is bolted into the head, later AJ27 engine have 2 sensors 1 on each bank, hence it's name "cam positioning sensor"

 

Yes, completely self inflicted.

A lesson in methodical diagnosis.

Maybe that's why i'm not a mechanic, which is lucky for everyone else

 

I have done similar things in the past. It's great when a problem turns out to be so simple, and no damage done.