Unfortunate noise from top-end

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put the piston a tdc and rock crank to see it it has more delay before it moves compared with the others ,without hearing the noise its difficult to say ,any gasket or exhaust manifold blow would have evidence ,soot etc are you sure it was just one cylinder
 
Hey Dominic sorry to hear about the problems after your run up to the good town of Kirkintilloch for the 3" brake kit (and a visit to the outlaws).Hope it all gets sorted quickly and for minimal cost.Must say I was impressed with how smooth the engine idled and sounded on acceleration when I met you.Put me in half a mind to consider the ACR head and cam you had for my own project so am interested in the outcome
 
Thanks Nathan, was good to see your project and someone doing a proper job!

I really can't fault the ACR stuff, I'm sure these problems are all of my own making. Even with the noise it was flying a long on the way home and managed a bit over 22mpg on the motorway at 70ish all the way with a slight detour through Annan - it does feel like there's more downhill going South!...
 
Had a bit more of a play today...spent a couple of hours removing the rad and some more cleaning up.

I tried James's advice and rocked each cylinder and felt for any play at TDC there's the normal very slight back / forth/left/right on the rings but nothing untoward. I can't feel any play in the cranking action though they all feel smooth and no real delay at the top of the stroke.

Also, there is no noise cranking the engine with the head off...

Just looked an exhaust valves look to be cheap - the ones in the ACR heads seem to be the ones used in later defenders....is there any mileage in getting ones from a turbo engine as I'd guess they'd be stronger?
 

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Hi James,

Seats as pictured when valves freshly taken out and after very slight cleaning. Valve seats show no signs of pitting or marking but were pretty mucky

I've checked the valve clearances a few times over the past year and they are as per recommended by ACR (0.006" intake, 0.008" exhaust for their hi-torque cam)

I also (quickly) checked the camshaft timing and that is all within a degree of accuracy. Will check properly when I find my timing protractor
 

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pics not very clear but carbon on the seat would show its not sealing ,bottom half looks like it was sealing top doesnt but probably just the pic angle etc
 
One more question before I start to put it all back together. What's a normal amount of play for the valves in the guides. These are later defender type valves and guides by the looks of things. I get about 1mm play. Normal?

There's a video of me wiggling one here

I wasn't getting any blue smoke just checking before I put it all back...
 
Well I asked Roland at ACR and he reckoned guides were ok. So I put it all back together. Which has taken me a couple of hours each afternoon this week, most of Sunday and this evening.

Set it all up cold (tappets to 0.006 and 0.008 as per instructions for cam) and it ran lovely until it got warm then it started its ****ing tapping! Checked #3 tappet and it was at 0.012! nipped back up to 0.006 and sounded lovely. Went for a drive and its tapping again.

I'm beginning to think the rocker is bending or something weird like that...will try swapping it....
 
its hard to tell without actually testing valves/guides yourself but for new id expect very little movement ,i used to get a fit with barely any ,but even so not your tapping ,rocker bush ok
 
Roland said that these guides are silicon bronze and need a bit of extra room cold. Anway I don't thing a bit of play in the guides would account for the difference in valve clearance between hot/cold. All the other valves don't change hot to cold by more than one finger size on the feeler guage...

I pulled the spring back on the suspect rocker and slid the rocker up and down the shaft and tried it for wiggle and it was all feeling good, spring and washer seemed ok too. Shaft didn't look to be scored or worn.

The rocker assembly is all fairly new (3000 miles) as the old rocker ends were worn. I swapped all rockers and springs - can't remember if I swapped the shaft but I think I did. I'm tempted to just transplant the old ones back and see if it goes away....

Anyway it still drives perfectly fine...thanks for the responses...
 
dominicbeesley said:
Roland said that these guides are silicon bronze and need a bit of extra room cold. Anway I don't thing a bit of play in the guides would account for the difference in valve clearance between hot/cold. All the other valves don't change hot to cold by more than one finger size on the feeler guage...

I pulled the spring back on the suspect rocker and slid the rocker up and down the shaft and tried it for wiggle and it was all feeling good, spring and washer seemed ok too. Shaft didn't look to be scored or worn.

The rocker assembly is all fairly new (3000 miles) as the old rocker ends were worn. I swapped all rockers and springs - can't remember if I swapped the shaft but I think I did. I'm tempted to just transplant the old ones back and see if it goes away....

Anyway it still drives perfectly fine...thanks for the responses...
Click to expand...
yes like those k liners i linked too id fit them better than that myself but worn ones run ok,shaft wears on underside as does bush ,new parts can often be poor
 
I had another go at it this afternoon. I decided to try the old rocker that I'd replaced...still the same. There's a video here of it running with the rocker cover off. The sound isn't great but you can hear the ticking. It sounds worse at a slower tickover but I had to up the idle speed when all the pipes were off the carb.

So it doesn't seem to be the rocker as the old one is making the same annoying noise!:mad:

One thing I did try but couldn't video due to a lack of extra hands. When running, if I put pressure on the valve stem end in a side-to-side or back-to-front manner the noise stays the same but if I push down onto the end-cap with a screw driver it goes away. I'm thinking that might suggest that there's something up either with the spring or collets or end cap. If it were the guides then I'd expect the side-on pressure would affect it?

When I had them off I checked the springs against each other with a straight edge and the all looked to be the same height.

Bloody annoying this is....not helped by the fact that I bust one of the adjuster screw ends while I was fiddling so the whole lot will need to come off again:doh:

Still running really nice otherwise:confused:

If it is the spring is it possible to swap these without taking the head off. i.e. the piston at TDC or will I just end up buggering the vale/piston up?
 
only if you stuff the combustion chamber with a suitable rope etc,would seem more likely a tight spot in valve or follower catching
 
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