Noisy engine & lack of power at speed

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MorrisJohn
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Re: Noisy engine & lack of power at speed

Post by MorrisJohn »

It was a relief. It was good to know I got almost everything correct (thanks to advice from others). I thought I had set the points using my feeler gauge. It took the RAC chap two goes to set them too. After the first time he set them they opened wide on their own accord after attempting to fire up. Strange. Second time was fine.

For someone with almost zero experience working on cars until now I’m happy with what I’ve learned.

I’m still going to switch her to electronic ignition using an accuspark conversion kit that fits nicely inside the new 25D dizzy. A nearby classic mini place is doing it for me and will set the timing properly using the gun. They do a lot of work on classics. RAC chap could only do it statically, which will suffice for now. Fingers crossed the new dizzy solves the lack of power under load.

I’ll keep the points and condenser in the boot though in case of sudden ignition failure, and it could be quickly switched back. I’d like to get the car into more regular use.

I’ll let you know at the end of the week if the problem is solved.
myoldjalopy wrote: Mon Aug 17, 2020 2:55 pm "it really has to be something relatively simple. Surely?"
You were right, John! What a relief........if you are sure you want to go electronic, then keep your new points dizzy in the boot in case the electric one fails. Of course, if the RAC man has got the car running sweet, there's an argument for leaving everything alone now. I'm sure you have learned a lot and can now set the points gap - as may be required ocassionally - in the future 8)
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MorrisJohn
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Re: Noisy engine & lack of power at speed

Post by MorrisJohn »

Returning to the original issue, lack of power and knocking noise when going uphill...

Having fitted the new dizzy I took the car a short drive this evening to see if it made any difference. It’s driving remarkably similarly to beforehand. Very little difference at all. The engine is not running on now when switched off, though the timing still cannot be 100% and is being done on Friday.

However, what is of concern is that the same power issue persists. As soon as I hit a hill there’s just no power and things get noisy. Incorrect timing won’t help that of course, but the fact there is still no power at the first sign of a hill makes me think it’s probably not been a problem with the advance weights/vacuum and that they can now be ruled out.

So...going back to earlier comments received. I’m now thinking possibly fuel supply or carb issues?

I will ask the garage on Friday to check the fuel supply pressure. Perhaps give the carb a clean? The fuel line from the pump to the carb is relatively new and in great condition.

Any other suggestions?
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Monty-4
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Re: Noisy engine & lack of power at speed

Post by Monty-4 »

The fuel pump will have a harder time on hills pulling fuel up from the tank as well as needing to meet the demand from your right foot, so it makes some sense.

I'd be worried about moving onto that until you're sure the timing is roughly correct though, or you may damage the engine and add to your problems.

It's an interesting case, I'm half tempted to drive the 400 miles to Glasgow with my timing gun to take a look myself to be honest - I used to live in Dundee and then Tayport!

Any mechanically minded club members nearby?
68' 4-door Saloon, another 'Monty'.
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Re: Noisy engine & lack of power at speed

Post by myoldjalopy »

To be honest, as I mentioned near the beginning of this thread, your lack of power problem could be caused by a number of different things - ignition, fuel, mechnical. If I were you, as you are taking it to the garage on Friday anyway to have the timing checked, I would ask them to sort it.
However, some simple things to check before then, if you feel like it, would be to check the plugs and their gaps (25 thou), remove the fuel line from the float chamber and see if the pump will easily pump a pint a minute into a container (taking all fire precautions). If it won't, remove the filter at the base of the pump and see if that is blocked with muck from the tank. Have a rag underneath as you do this as a splash of fuel will come out.
MorrisJohn
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Re: Noisy engine & lack of power at speed

Post by MorrisJohn »

Haha, thanks anyway. At times I rather wish I lived down south!

I think, as has been suggested by myoldjalopy, I’ll probably ask this mini garage to take a (hopefully relatively quick) look at it for me. At least they’ll know the engine well.

I’m reluctant to plough on myself in case I end up making things worse.
It's an interesting case, I'm half tempted to drive the 400 miles to Glasgow with my timing gun to take a look myself to be honest - I used to live in Dundee and then Tayport!
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Re: Noisy engine & lack of power at speed

Post by Chipper »

MorrisJohn wrote: Mon Aug 17, 2020 7:10 pm Returning to the original issue, lack of power and knocking noise when going uphill...

However, what is of concern is that the same power issue persists. As soon as I hit a hill there’s just no power and things get noisy.

Any other suggestions?
It sounds perhaps as if your engine is 'pinking' (pre-detonating) when under heavy load, which is usually down to over-advanced ignition. Re-check the timing, and also ensure the vacuum advance diaphragm on the side of the dizzy is working, when a vacuum is applied via the pipe leading to the side of the carb.

The dizzy should be turned via the (slackened) baseplate clamp to the point where it just doesn't pink when going up hills - that's the optimum ignition timing setting.

Also check you have the correct distributor for your engine - Lucas 25D4 dizzys come with all manner of advance curves to suit the huge range of engines they were fitted to.
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MorrisJohn
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Re: Noisy engine & lack of power at speed

Post by MorrisJohn »

Thanks for the further help 👍
It sounds perhaps as if your engine is 'pinking' (pre-detonating) when under heavy load, which is usually down to over-advanced ignition. Re-check the timing, and also ensure the vacuum advance diaphragm on the side of the dizzy is working, when a vacuum is applied via the pipe leading to the side of the carb.
I hope that’s the case. A proper timing set up and we’ll know for sure. The new dizzy came with the vacuum diaphragm too (see photo taken mid job). The rubber hose it connects to has been checked and doesn’t leak.
Also check you have the correct distributor for your engine - Lucas 25D4 dizzys come with all manner of advance curves to suit the huge range of engines they were fitted to.
The dizzy selected was the one for the Morris Minor 1000 (neg earth) from AccuSpark’s website. They’re all listed by vehicle then earth type.
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Chipper
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Re: Noisy engine & lack of power at speed

Post by Chipper »

All well and good, but it's worth checking that the vacuum advance diaphragm does actually turn the dizzy base-plate a few degrees when you suck on the end of the vacuum hose.
Maurice, E. Kent
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MorrisJohn
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Re: Noisy engine & lack of power at speed

Post by MorrisJohn »

Chipper wrote: Tue Aug 18, 2020 6:39 pm All well and good, but it's worth checking that the vacuum advance diaphragm does actually turn the dizzy base-plate a few degrees when you suck on the end of the vacuum hose.
Thank you, I’ll check that.
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Re: Noisy engine & lack of power at speed

Post by Dogsdad »

I would do a compression test ( or get a garage to do one) .
I have known a failing cylinder head gasket give rather similar symptoms and this will give a “noisy” engine.
This was on another car with an A series engine.
Hope you get it sorted as it can be dispiriting to have these problems.

R.M.
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Re: Noisy engine & lack of power at speed

Post by johngrigg »

I had a similar, but not exactly the same problem recently alright on the flat but wouldn’t pull uphill . Turned out to be binding brakes. You can check by stopping when the symptoms occur and feeling the wheels in the area of the brake drums . If one is hotter that will be the problem one, would also explain over heating .
.
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Re: Noisy engine & lack of power at speed

Post by myoldjalopy »

Well, I wondered about that, but it doesn't really explain why the engine gets 'clattery' under load......
Like 'Dogsdad', I also wondered about head gasket - when mine went between cylinders 3 and 4, the engine was very clattery under load, but in his first post the OP says a compression test gave good readings. Hopefully the garage will sort it later this week - its much easier diagnosing some things in situ rather than at a distance.
MorrisJohn
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Re: Noisy engine & lack of power at speed

Post by MorrisJohn »

I replaced two sticky brake cylinders and the brakes aren’t binding.

The compression test was very good, which was a relief. 190 PSI if I recall correctly and very consistent numbers across all four cylinders.

I’m hoping it’s just the carb needing cleaned out or something simple like that. I’ll let you know what the mini guys say on Friday afternoon. Fingers crossed.
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MorrisJohn
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Re: Noisy engine & lack of power at speed

Post by MorrisJohn »

Just got the car back from the mini specialist and here’s what they did/my observations:

This is what they did:

- Fitted electronic ignition
- Valve clearances adjusted (all to .012”). They look good.
- Timed
- Fuel mixture checked
- Carburettor checked = no issues
- Fuel pump checked = no issues
- New rocker cover gasket

She’s noticeably smoother to drive and particularly improved around town. She will now pick up speed much better under load. She managed to increase speed in 3rd/4th up all but the steepest of hills. That wouldn’t have happened before.

Managed to get her cruising at 60/65mph without the speed falling off a cliff every time I hit an incline. Big improvement.

..the only thing is, when I take her to any speed over about 40mph under load she still doesn’t sound right. Like the noise you’d get if an engine was pinking...clatty. A noticeable rapid tappetty noise. As soon as I ease off the throttle it stops. I’ll maybe try recording it and putting it on YouTube for you to listen to. Not sure how well a recording would work, but can only try.

I really don’t know what else I can try, except maybe a rolling road set up? Everything seems to be good and all the checks say the engine is healthy.

But...at least now she can pick up speed, so it’s a big step forward.
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Re: Noisy engine & lack of power at speed

Post by simmitc »

Not sure of we've suggested this before, but check that the manifold nuts are tight on their studs and that the manifold gasket is OK. Also check that the exhaust is sealed to the manifold. It could just be exhaust noise. I know that you've double checked compressions, but from the description, it still sounds like the kind of noise you would get if the head gasket was starting to fail between a couple of the pots; but I would expect it to have failed completely by now, so look at the exhaust side.

Conversely, on the inlet side, is the silencer tube attached securely to the air filter housing? The joint can fracture, but that tends to produce more of a throaty roar rather than a pinkety tappety sound.
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Re: Noisy engine & lack of power at speed

Post by pgp001 »

Did your "Mini Specialist" do a road test ?
I would be interested to know what they thought of the "clatty" noise you mention.

Phil
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Re: Noisy engine & lack of power at speed

Post by MorrisJohn »

Thanks, I’ll check those out next 👍
simmitc wrote: Fri Aug 21, 2020 8:14 pm Not sure of we've suggested this before, but check that the manifold nuts are tight on their studs and that the manifold gasket is OK. Also check that the exhaust is sealed to the manifold. It could just be exhaust noise. I know that you've double checked compressions, but from the description, it still sounds like the kind of noise you would get if the head gasket was starting to fail between a couple of the pots; but I would expect it to have failed completely by now, so look at the exhaust side.

Conversely, on the inlet side, is the silencer tube attached securely to the air filter housing? The joint can fracture, but that tends to produce more of a throaty roar rather than a pinkety tappety sound.
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MorrisJohn
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Re: Noisy engine & lack of power at speed

Post by MorrisJohn »

Doesn’t seem so. Well, if they did it would have been on city roads as they’re in a very urban area...and it drives perfectly on those types of roads now.

They did say if it wasn’t fixed they’d look at it again for free (we’ll see!). They did have a few classic cars there, one of them being a Minor pick-up full rebuild, in addition to a lot of old minis. They should know what they’re doing :o I think I’ll give them a call later and get it back in to have further checks in relation to the points raised above.

It’s a shame, it’s otherwise an almost perfect car.
pgp001 wrote: Fri Aug 21, 2020 8:42 pm Did your "Mini Specialist" do a road test ?
I would be interested to know what they thought of the "clatty" noise you mention.

Phil
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Re: Noisy engine & lack of power at speed

Post by myoldjalopy »

If they will look at it again, take one of them for a ride in the car to where you know it will exhibit symptoms so they can hear the sound for themselves. Its quite hard guessing from just a verbal description of a noise - one man's 'rattle' can be another's 'clatter' :-?
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Re: Noisy engine & lack of power at speed

Post by MorrisJohn »

Yes, you’re quite right. Another pair of ears on it would be a good idea. I spoke to them about the exhaust manifold and they said they are fairly certain they’d have spotted that if there was any issue with it. Nevertheless I’ve ordered a new gasket, since they’re very inexpensive. It can be fitted and ruled out as an issue.

If that is the case it does leave more head scratching though. It’s a real puzzle.

myoldjalopy wrote: Sat Aug 22, 2020 10:45 am If they will look at it again, take one of them for a ride in the car to where you know it will exhibit symptoms so they can hear the sound for themselves. Its quite hard guessing from just a verbal description of a noise - one man's 'rattle' can be another's 'clatter' :-?
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