Clacking Engine III

[Mark S]

Distributor removed and there is wear on the drive gear. But all the teeth are worn so it does this explain the tapping? The distributor spins freely and I've turned the pump by hand with a ratchet and it feels ok, no notchiness but I haven't tried at speed with a drill on the hex shaft yet. I'm assuming the drive gear on the jackshaft will also be worn, or is the distributor gear slightly softer and sacrificial? (hoping)

The oil pump is the County unit, fitted when I rebuilt the engine. It has always delivered pressure to spec but do these put too much load on the gear?

Paranoia got the better of me, and thinking I haven't found the definitive source of the tapping (and if the jackshaft has to come out) I'd look at the water pump. All ok, operation nice and smooth gears fine so I don't think the jackshaft front bearing is thrashing about. No signs of anything catching.

Now I'm in this position I have several options.

1) See if I can see or feel any damage on the jackshaft gear, if not, rob the distributor gear off a Sprint distributor that I have in the garage, fit the original oil pump, re-build the water pump with an RHP bearing now that it's out, put it all back together.

2) Buy an new distributor gear.

3) Now I've got this far, inspect the chains and sprockets, take out the jackshaft, inspect the gears.

4) Buy a new jackshaft (are these and the new distributor gears any good and properly hardened?) I don't believe a Sprint jackshaft will fit.

Is this wear excessive for 85k?

Any advice or recommendations or advice where I go from here?

Mark

[Peter707R]

I’d say that gear isn’t that bad - I had one wear such that the front and rear faces had worn to a point. Was there much backlash in the distributor before you took it out? It should just be possible to see the edge of the jack shaft by shining a torch down the hole left by removing the distributor. I phased “clacking” during warm up - I believe it’s down to the timing chains having wear but it settles down after a few minutes so I’m leaving alone.

[Mark S]

Thanks Peter,

Won't this distributor gear be through the hardening and wear will now accelerate? Do you think a new distributor gear with the old jackshaft would be a bad idea?

Still doesn't explain the clacking. Could the pump bearing feel smooth but do strange things when warmed up and running at speed?

[Peter]

Mark, Have just seen your post and gone back to the original post and videos, there clearly is something wrong. The gear wear doesn’t look bad to me and I’m puzzled as to the cause of the noise. Does sound like top end but you say you’ve checked all the valves and buckets... A couple of thoughts:
1. Have you done a compression test?
2. Have you looked at the oil? If something is wearing you might find some grey deposits in the oil filter

Peter

[Mark S]

Thanks Peter,

As you say, initial thoughts were tappet noise, worn bucket, broken spring but all looks good, gaps all still within tolerance and no real noise of concern from either head.

I've run with the LHS cam cover off, all quiet, A little noise from the chain area but nothing like I'm looking for.

I haven't done a compression test but have pulled all the leads individually and no difference.

Tapping is at cam speed, it doesn't sound like a bottom end knock (the reason I rebuilt the engine in the first place), neither does it sound like piston slap. I can't see it being chain related or jackshaft bearings as it runs at a different speed.

Once I'd bought a stethoscope, the noisiest bits are the distributor, and noisier still, the water pump. I can feel the tapping on the pump cover, the hoses connected to the pump cover but not a lot on the inlet manifold, again pointing to it not being head related. I assume the noise is transmitting along the jackshaft.

So the pump runs at engine speed, but who knows the speed of the cage in the pump bearing. It has been suggested that this could run at half engine speed.

I'm tempted to rebuild the pump as the bearing could be noisy at speed but it feels nice, smooth and pump free to turn. But it will probably feel different once the impeller is off and not dragging against the mechanical seal and maintaining a thrust on the bearing due to the spring in the seal.

Next step could be new jackshaft at �180 and distributor gear at �55 but is it worth it? I can't feel any play at either end so assume the bearings are good. I know there is wear but it is even wear on all teeth so even a chipped jackshaft gear tooth would tap at a different speed. Rimmers list a replacement jackshaft gear which suggests the jackshaft comes apart, but has anyone changed one?

If I just do the water pump and it's still tapping, I could try re-fitting the old oil pump but then I'm stumped.

Any more ideas of what I could check or where else the noise could be coming from.

Thanks to everyone for their thoughts so far, all are appreciated and any help gratefully received..

[Lingen]

Mark.
The jackshaft certainly doesn't come apart, as iIt is machined out of a solid billet. Perhaps they mean the chain sprocket.
Mike.

[Matt Cook]

I’m sure you are aware of the numerous threads on external water pumps..... both mechanical and electrical. You could fit a bung in place of the water pump put everything else back together and start her up, as the tapping noise starts very soon after start up, I’m sure you could run the engine quite safely for a couple of minutes without any water circulation, just full of water. This would of course eliminate the water pump from the equation. You would then have 3 choices, rebuild your pump, fit Stagdad’s mechanic external pump or fit an electric pump (EJ Ward).
It’s a bit of work but it could pin point the problem without doing anything more invasive.

[Mark S]

Mark.
The jackshaft certainly doesn't come apart, as iIt is machined out of a solid billet. Perhaps they mean the chain sprocket.
Mike.

I've checked again and the part I was looking at on Rimmer's site was for a Rover V8 distributor drive gear. Looks very similar to the Stag jackshaft gear.

Thanks for keeping me right Mike

[Mark S]

I’m sure you are aware of the numerous threads on external water pumps..... both mechanical and electrical. You could fit a bung in place of the water pump put everything else back together and start her up, as the tapping noise starts very soon after start up, I’m sure you could run the engine quite safely for a couple of minutes without any water circulation, just full of water. This would of course eliminate the water pump from the equation. You would then have 3 choices, rebuild your pump, fit Stagdad’s mechanic external pump or fit an electric pump (EJ Ward).
It’s a bit of work but it could pin point the problem without doing anything more invasive.

Thanks Matt,
I know what you are saying, drop the manifold back on loosely, fit the distributor and give it a whirl. It would prove once and for all if the noise was from the pump but I don't fancy starting the engine without water in it and risk hot spots in the heads.
The pump teeth aren't worn and there is no reason to expect a re-built pump would fail or be noisy. I may as well rebuild the pump I've got for �35 with a quality bearing. The bung is more expensive than rebuilding the pump and do I really want the hassle and cost of moving the alternator, fitting an external pump etc or �640 for an electric pump.
When I get to work to strip and rebuild the pump with the press I could still find the bearing totally shot.

[flying farmer]

Doesn't look much wrong with the teeth at either end.

You should be able to view the jackshaft teeth with a torch. I have seen many worn teeth at the distributor end, often I have seen a colour change in the wear spot even when the teeth were not worn to a point. I suspect it might have been a sign the surface hardening was wearing through so I have always changed the shaft if it looked like that, rather than risk a later failure.

Since you already have a pump suitable for rebuild I would use that, at least that will settle whether it is the current pump making a noise.

Neil

[Peter]

Mark,
1. Do a compression test it will confirm rings and valves are OK - certainly before stripping the engine
2. Can you detect the “clack” on the starter?
a. With the plugs in
b. With the plugs out
similarly you could spin it over without the water pump and without the distributor/ oil pump (don’t overdo this one) might help get you closer to the issue
Be wary of the “new” jack shafts I was warned off them by my engine machine shop some of the hardening isn’t as good as the originals. You could also run the engine with the front timing cover removed and watch the jack shaft gear - starter or actual running.
worried you could strip the whole engine and not find the cause....

Peter

[Mark S]

Doesn't look much wrong with the teeth at either end.

You should be able to view the jackshaft teeth with a torch. I have seen many worn teeth at the distributor end, often I have seen a colour change in the wear spot even when the teeth were not worn to a point. I suspect it might have been a sign the surface hardening was wearing through so I have always changed the shaft if it looked like that, rather than risk a later failure.

Since you already have a pump suitable for rebuild I would use that, at least that will settle whether it is the current pump making a noise.

Neil

Thanks Neil,
I think next step is to rebuild the pump and see what the bearing is like.
If you think the distributor teeth look ok, would you be happy to re-use it. I could buy a s/h jackshaft and it could be worse than the one I've got. I'll have a look down the hole tomorrow.
Current thinking is pump back in and rebuild.

[Mark S]

Mark,
1. Do a compression test it will confirm rings and valves are OK - certainly before stripping the engine
2. Can you detect the “clack” on the starter?
a. With the plugs in
b. With the plugs out
similarly you could spin it over without the water pump and without the distributor/ oil pump (don’t overdo this one) might help get you closer to the issue
Be wary of the “new” jack shafts I was warned off them by my engine machine shop some of the hardening isn’t as good as the originals. You could also run the engine with the front timing cover removed and watch the jack shaft gear - starter or actual running.
worried you could strip the whole engine and not find the cause....

Peter

Thanks Peter,
No clack with the engine stone cold when first started and I think the starter noise would drown it out anyway whilst cranking. Could fit the distributor and do a compression test but the last one I did a few years ago was spot on.
No sparklies in the oil and like you say, wary of remanufactured parts not lasting a long or fitting as well as originals.
Watching the jackshaft gear may show if it's pulsing but I could do without taking the rad out, crank pulley and cover off. I'd try fitting the old oil pump first. What else is there to create a tight spot and make a noise that could transmit along the jackshaft?

[Peter]

Mark, I understand the compressions were fine when you did a test some years ago but you didn’t have the noise then, doing another test now will reveal wether anything has changed - it’s worth doing whilst you still can.
The fact that the engine is quiet when cold I hadn’t understood from the previous posts and is significant. It’s not therefore likely to be a chipped or misaligned gear or any loose foreign body, but I’m not sure what it is but perhaps someone else would have an understanding.

Peter

[Mark S]

Mark, I understand the compressions were fine when you did a test some years ago but you didn’t have the noise then, doing another test now will reveal wether anything has changed - it’s worth doing whilst you still can.
The fact that the engine is quiet when cold I hadn’t understood from the previous posts and is significant. It’s not therefore likely to be a chipped or misaligned gear or any loose foreign body, but I’m not sure what it is but perhaps someone else would have an understanding.

Peter

Thanks Peter,
I'll do a compression test before rebuilding, but my hunch from where the loudest noises seem to be coming from with a stethoscope, even with lack of evidence so far, is that the cause is something connected with or driven by the jackshaft.