Need some help/ideas diagnosing engine noise

[Ozdunc]

It's a 1969 2a 2.25 petrol. Mileage unknown: odo reads 22700 but the speedo didn't work when I picked it up. Oil is clean, and coolant is green and the level for both is constant.

I've got two noises.
At idle its rattly in the top end, which I think is tappets. The noise doesn't go away with revs. I've got to replace the rocker gasket, so I'll adjust them when I do that.

Then the second noise is a knocking under load, but only really in 1,2 and 3 gear. Its frequency increases with engine speed, but dies away under light throttle.
My immediate conclusion was to to think bearings, either crankshaft to piston (big end?) or crankshaft to engine casing (main?). But having thought about it I'm not so sure because even at higher revs the knock is only 2-3 times a second.
If the crank is rotating at 2000rpm thats 33 times a second - wouldn't a bearing knock appear more like a deep buzziing, or constant roar at higher revs?
So my next thought is it might be the oil pump? Can these be cleaned/refurbed or should they be replaced? Is it as simple as dropping the sump to get at the pump?

I'd appreciate any suggestions.

Cheers
Duncan

[Ozdunc]

No-one? [bigsad]

Havn't had time to do anything this weekend, but I'm wondering whether the knock might be pre-ignition.
I'd always thought 'pinking' with a high pitched noise, but reading this
title_3.gif (http://www.landroverclub.net/Club/HTML/Noise_spark_knock.htm)
it sounds as if it could be more of a knocking noise.

I'll check the timing tomorrow and report back.

[JDNSW]

Your identification of tappets is probably right.

The other noise id difficult to identify from your description, but it could be timing chain, or is could simply be something loose on or near the engine, possibly loose geenerator mounts or something similar, or the exhaust system loose or touching the chassis somewhere. (or something similar)

John

[Ozdunc]

Thanks John, very helpful I wasnt even thinking it might be external.
It could be worn engine mounts allowing something to hit on accel but stop when not under load.
I had a look at the timing chain and set up when I changed the front seal and the chain and tensioner looked fine but I must confess to not actually checking anything. Doh!
I suppose all I can really do is methodically go through everything and check it over

[geodon]

Pinging (pre-ignition) sounds like the noise made by some nails in a tin can being shaken. It's an erratic rattle rather than a regular knock.

The power plant may be lurching backwards under load (soft mounts?) causing something to hit someting?

[isuzutoo-eh]

Couldn't be something simple like an exhaust leak could it? If on the manifold/head join it'll only sound on one cylinder's exhaust stroke. My County sounded like it needed a tappet adjustment when the exhaust manifold gasket first was breached, my Series has a similar leak but sounds very different again.

[Ozdunc]

Well I started him up this morning and had a look around.
Rattles a bit under acceleration in neutral but not the knock I get in gear. It doesn't feel as if the engine is rocking on its mounts, but I probably need to get an assistant to confirm.
The exhaust is within 3-5mm of the chassis where it goes under the x-member. I'll fab up an additional exhaust bracket to give a bit more gap there.

Also I stuck a timing light on the #1 lead and it showed the timing to be super retarded ~about 10deg. However the engine was cold, it had been running less than 5mins, and hadn't been started for a week or so.
I'm only used to adjusting timing by twisting the distributor, using the light to show the advance on the crankshaft, on a running engine with electronic ignition.
When you adjust the timing on a non-electronic distributor, what are you actually adjusting? The amount of vacuum acting on the distributor, or the position of when the points contact relative to the crank position? I'm presuming the former else how does the advance get auto adjusted. Anyone got a link to 'Distributors for Dummies':)?

Should I do the timing with the engine warm?
Is it possible to adjust the timing using a timing light?
Is it possible to tune without having to either remove a plug to find TDC on #1, or remove the rocker cover?
I read this thread http://www.aulro.com/afvb/series-ii-iia/149636-timing-2-25-2a.html but I'm still a bit confused about whether using a timing light is possible, and I'm a bit unsure about John's tuning by ear method as I'm not sure I know what 'good' sounds like on this engine.

Sorry for all the questions, but I like to know the 'why' as well as the 'how'
Cheers
Duncan

[Ozdunc]

Oops, forgot to reply to Mark.
New exhaust from manifold back, but I'll check for leaks on the engine/manifold join.
Cheers

[Ozdunc]

Anyone got a link to 'Distributors for Dummies':)?


Found one! Demystifying Land Rover distributors (http://www.expeditionlandrover.info/Distributer.htm)

From what I gather I rotate the dizzy as usual to retard or advance the timing running warm at idle.
And the electronic dizzy has just done away with the points and dwell adjustment.

So to set the points I just rotate the dizzy til the point arm is sitting at the peak on the cam lobe, the gap should be 15thou (whatever that is in metric).
Once thats set I can use the timing light to adjust to 6 BTDC, then adjust by ear from there?
What about dwell? Is that just governed by the points gap?

This is probably really painful for you but I'd hate to go in guns a blazin' and then bust something.

[Ozdunc]

Set the timing to 6deg BTDC this morning on a warm engine.
I'd say the revs dropped a little at idle, and I can now hear an erratic 'soft' miss, but no more than I can hear with my 80 series 4.5 1FZ-FE.
Bill drove very nicely ( maybe feeling a little down in torque at low revs), the knocking is still there, but I think quieter, that or the tappets got louder:D.
But again its very hard to tell, it 'seems' to be emanating from just infront of the firewall.

But the test drive was great, drove ~20km up and down the coast on a glorious winters morning with only a windscreen and beanie as protection. What's not to love about this little truck.

I think what I'll do next is the tappet adjustment and a compression test.

[dandlandyman]

Just be aware that the manual says to set the timing of a 7:1 CR engine at 6degrees BTDC, but an 8:1 engine is set at TDC. I have had some issues with timing on different fuels recently. You wouldn't believe how differently an engine tuned to run on premium will react to standard unleaded!

While you're fiddling with your valve clearances, keep an eye out for valves that are slow to close. A couple of years ago, I discovered i had a build-up of carbon around the valve stems and it was fouling inside the guides. Luckily, I recognised something was wrong before it seriously burned my valve seats. Later on, somewhere in my manuals, I found a mention that a decarbonising job is recommended on these engines around 60 to 70 thousand miles. I had about 85000 up on mine at that point. The cause is the cap-type stem seals go hard with age.

A throaty rattle can occur if you stab the throttle from idle in neutral. This, I've been told, is the pistons screwing slightly sideways in the bores, a sure sign of a worn engine. It will show up when you dismantle it as scuffed piston skirts. Loaded knocks are worn bearings, and worn main bearings will end up with a leaking rear crank seal. Pinking is a much more harsh rattle than bearing knocks.

Hope this helps.

Dan.
69 2A 88" pet4 (still frustratingly in disguise), 68 2B FC pet6 (for sale), 73 3 109" pet4 (next project, with a little luck), plus 12 other parts cars.

[Ozdunc]

Thanks for that Dan.
I presume a compression test should show up leaky valves as I'm not sure what I'm looking for with a slow to close valve.

Is there a fuel additive that will dissolve carbon? Or is it a head off job?
I've decided that since it's only going to be doing less than 2-3000kms a year I'll run him on 98

For the moment the rear main seems ok, it was leaking from the front timing cover but since I swapped that out it only seems to be leaking from the rocker gasket.

Is there any way of telling when a knock goes from - 'you need to do something about that sometime' to 'shut it down and do not drive til fixed'
or put another way are worn bearings catastrophic or merely annoying?

[chazza]

If it is a big-end bearing knock, it should be quiet, or relatively quiet when the engine is cold and the oil thicker. On initial start-up it should knock for a few seconds and then stop but return when the oil thins as it gets warm. It is easy to listen to when you stand near the engine and blip the throttle.

Check out these chaps; I have great success with their products Cost Effective Maintenance (http://www.costeffective.com.au/show_product.php?ItemId=25)

A compression test with sticking or burnt valves will show very low readings, which don't get better when oil is squirted into the cylinder. if the valve stays open it can be detected by squirting compressed air down the spark plug hole on TDC, whilst an assistant feels for airflow at the exhaust pipe.

As for nasty sounds, stop it if the noise is violent banging and investigate,

Cheers Charlie

[Ozdunc]

OK managed to do the tappets, they weren't too out of adjustment, and a compression test over the weekend.

Compression results are:
1: 145
2: 140
3: 145
4: 120 - adding oil went to 135.

So it looks like piston rings, but its not blowing any blue smoke under load, so I'm thinking of just driving it for a while over summer then starting a rebuild next autumn (Mar/Apr).
Plugs look good, light tan with no deposits.

Now I've adjusted the timing to run at 6BTDC, its idling low and not so smooth, so I'm thinking of doing a static adjustment, then tune by ear.
I'm not sure I've got the correct procedure.
Set the crank to 6BTDC using the pointer on the crank pulley.
With the top of the dizzy off and rotor removed, twist the dizzy til the points are at the max opening (might be there already?)
check and adjust the points gap - it should be 0.015.
Reconnect everything, and start it up, twist the dizzy to get the fastest idle whilst still sounding smooth. (Is this to compensate for any stretch in the timing chain?)
Go for drive, reduce advance if pinking occurs.

Its a Ducelier distributor.

[Timj]

Hi Ozdunc,

I think you have it a little wrong, you don't look for the maximum opening of the points while at 6dbtdc, you are looking for the moment the points spark as that is the trigger for the coil to actually fire the plug. The only reason to go to maximum opening is to set the gap of the points, you seem to be mixing up setting the gap and setting the timing, they are different operations.

So set the gap properly then set the mark on the crank to the desired position then turn the ignition on and when you turn the distributor you will see a spark on the points as they first open, stop right there and you should be ok. It is much easier to do it with a timing light as you can move it around with the engine running but either way works just fine. After initial setting you can take it for a run and see how it goes and see if you have any pinging, then you can advance it further until it does ping, then back off a little.

Cheers,

TimJ.

[Ozdunc]

Thanks Tim,

You are correct I was confused about points gap and timing. So I did a bit of reading (the internet is a wonderful thing). I'll set the points gap, then I'll set the timing.
I have a timing light, but when setting by ear do you disregard the timing light once its initially around 6BTDC and just go for the fastest idle speed?

[geodon]

I would NOT go for the fastest idling speed. That's a recipe for over advancement.

This is my Lucas Distributor technique as used over decades of BMC etc ownership. It's an IRL jobbie, ie done on the road.

1. Find a stretch of road with a slight incline.

2. Approach it in top gear at moderate speed & floor the "go" pedal.

3. If it doesn't ping, advance it a bit.

4. repeat till it pings then back off till it doesn't.

Early MG etc Lucas distributors had a vernier on the side to faciltate the really fine adjustments, but I'm not sure re LR's as mine has a Holden engine!

[Ozdunc]

Just to bring this to a close.

Adjusted the tappets - the top end is much quieter. Although the noise seems to come and go, esp at idle. Maybe I just need to clean my ears.

New dizzy cap and rotor, contacts looked in good condition so working on the if it aint bust don't fix it method, I left em alone.

I've adjusted the timing to ~8degBTDC, idles much nicer, and seems to have more power. I ran it in 4th up some hills at full throttle til it really started lugging under load and no pinking. I reckon I could add a bit more advance, but with the piston rings in the no4 pot and the knocking I don't want to put to much load through it, so I'll leave it at that for know.