Noise from engine under labour.

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boffer.9
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Noise from engine under labour.

Postby boffer.9 » Tue Sep 08, 2020 3:33 pm

I'm really hoping someone can help me out here! When accelerating up hill, I'm getting this clattering noise coming from the engine. It happens in the same circumstances as pinking would. As soon as I let my foot up off the pedal, the noise stops. It's not a pinking sound though, it's more of a tappet sound. It's driving me nuts! I can't fault the performance of the car though, it is very lively and responsive.These are all the parts I've replaced trying to cure the problem ( it didn't! ) 1) New rocker assembly. 2) New camshaft end float plate. 3) New cam followers. 4) New push rods. 5) New valve springs and 6) Re-con distributor. I've also re-built the carb and set it up. It has +40 oversize pistons with no significant wear in the bores. I'm stumped!

simmitc
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Re: Noise from engine under labour.

Postby simmitc » Tue Sep 08, 2020 3:56 pm

Check compression, exhaust for leaks, and that the silencer tube is correctly attached to the air filter.

Nickol
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Re: Noise from engine under labour.

Postby Nickol » Tue Sep 08, 2020 8:43 pm

I have a similar problem...no, it is an identical problem albeit not on a Minor. I had replaced all the main bearings and the big end bearings to no avail. The pistons are oversize as yours are indicating to me that at some stage the Engine has been rebored. All this can be done without removing it from the car. i.e. the costs of someone being paid for doing it are minimal.
I measured the Crank bearings both before and after removing the engine from the car as an experienced mechanic heard the sound and convinced me that the crank was worn. He was right . The measurements showed up excessive ovalness.
I am still awaiting to get the crank back from being reground so cannot say if this will cure the "tappet like" noise on acceleration or not.
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boffer.9
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Re: Noise from engine under labour.

Postby boffer.9 » Tue Sep 08, 2020 9:17 pm

simmitc wrote:
Tue Sep 08, 2020 3:56 pm
Check compression, exhaust for leaks, and that the silencer tube is correctly attached to the air filter.
Yeah thanks. Compression is excellent, air filter all good, too.

boffer.9
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Re: Noise from engine under labour.

Postby boffer.9 » Tue Sep 08, 2020 9:21 pm

Nickol wrote:
Tue Sep 08, 2020 8:43 pm
I have a similar problem...no, it is an identical problem albeit not on a Minor. I had replaced all the main bearings and the big end bearings to no avail. The pistons are oversize as yours are indicating to me that at some stage the Engine has been rebored. All this can be done without removing it from the car. i.e. the costs of someone being paid for doing it are minimal.
I measured the Crank bearings both before and after removing the engine from the car as an experienced mechanic heard the sound and convinced me that the crank was worn. He was right . The measurements showed up excessive ovalness.
I am still awaiting to get the crank back from being reground so cannot say if this will cure the "tappet like" noise on acceleration or not.
'd be very interested to hear the outcome, though The bottom end is actually very smooth on mine, one of the best I've had and I've had about 8 Minors in my time. not a sign of rumble or knock at all. Was your engine smooth otherwise?

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Re: Noise from engine under labour.

Postby Nickol » Wed Sep 09, 2020 9:15 am

Yes , the engine runs quite smoothly now and does not overheat anymore. It has plenty of power and accelerates well. My noise however only appears when the engine is warmed up. I installed an oil pressure gauge which indicated, especially when the engine was warm, low pressure. So I replaced all the bearing shells and big end ones. They were standard size and not particulary worn so I assume they had been replaced before - why I thought to myself had the cylinders been rebored and new pistons fitted but no work done to the crank?
I then put in a new oil pump which resulted in normal oil pressure. It even recorded pressure when the starter motor turned before the engine fired up. By the way, on cold starts, the engine "clonked" for a few seconds which I am told is also a classic crankshaft problem.

Like you I have had the head off and replaced the worn springs, the valves but the other items are as they were. In my case there was water ingress into cylinder nr 4 even though the head gasket was not broken. I replaced it anyway of course. I concluded it was because the head was not bolted down tight enough as some of the head holding down nuts were, not exactly loose, but very easy to undo. They were probably not retorqued after the head was removed before.

It will be a while before I have it back together again but I will return to this thread when it is done.
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boffer.9
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Re: Noise from engine under labour.

Postby boffer.9 » Wed Sep 09, 2020 7:22 pm

Many thanks for update.

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Re: Noise from engine under labour.

Postby boffer.9 » Thu Sep 10, 2020 10:02 pm

Nickol wrote:
Wed Sep 09, 2020 9:15 am
Yes , the engine runs quite smoothly now and does not overheat anymore. It has plenty of power and accelerates well. My noise however only appears when the engine is warmed up. I installed an oil pressure gauge which indicated, especially when the engine was warm, low pressure. So I replaced all the bearing shells and big end ones. They were standard size and not particulary worn so I assume they had been replaced before - why I thought to myself had the cylinders been rebored and new pistons fitted but no work done to the crank?
I then put in a new oil pump which resulted in normal oil pressure. It even recorded pressure when the starter motor turned before the engine fired up. By the way, on cold starts, the engine "clonked" for a few seconds which I am told is also a classic crankshaft problem.

Like you I have had the head off and replaced the worn springs, the valves but the other items are as they were. In my case there was water ingress into cylinder nr 4 even though the head gasket was not broken. I replaced it anyway of course. I concluded it was because the head was not bolted down tight enough as some of the head holding down nuts were, not exactly loose, but very easy to undo. They were probably not retorqued after the head was removed before.

It will be a while before I have it back together again but I will return to this thread when it is done.
Many thanks for your reply. I'm starting to think my problem might be piston slap or gudgeon pin Knock? What do you think?

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Re: Noise from engine under labour.

Postby Nickol » Fri Sep 11, 2020 4:52 pm

I had also considered these options and if the crankshaft regrinding does not cure the noise then that is one of the last possibilities. However in my case because enlarged pistons have been already fitted, i wish to assume they are ok. :(

They can also be done with the engine back in the car and I wish to avoid having the head off again at this stage.
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boffer.9
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Re: Noise from engine under labour.

Postby boffer.9 » Wed Sep 16, 2020 2:45 pm

Nickol wrote:
Fri Sep 11, 2020 4:52 pm
I had also considered these options and if the crankshaft regrinding does not cure the noise then that is one of the last possibilities. However in my case because enlarged pistons have been already fitted, i wish to assume they are ok. :(

They can also be done with the engine back in the car and I wish to avoid having the head off again at this stage.
A few days on and a bit more research, I'm convinced my problem is piston slap. The noise I described in my original post plus a hollow rattling noise on tick-over has convinced me. Oh well, off with the head and sump it is then!!

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Re: Noise from engine under labour.

Postby MorrisJohn » Mon Sep 28, 2020 8:08 am

I’m keen to hear the final outcome. I have what sounds like the same noise you describe under labour. It also stops immediately when taking my foot off the accelerator. Idle sounds fine and revving at stand sounds fine.

Like you I seem to now have a reasonable amount of power (having replaced the dizzy, installed electronic ignition, reset valve clearances, had timing done, checked compression, head gasket etc and all appears healthy).

Please do keep us posted.
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Re: Noise from engine under labour.

Postby Nickol » Mon Sep 28, 2020 11:39 am

My reground crank has arrived but i am in italy until the weekend. Hopefully next week, now suitably motivated, I can install it before the first snow comes
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oliver90owner
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Re: Noise from engine under labour.

Postby oliver90owner » Mon Sep 28, 2020 11:41 am

I’m sitting here quietly. My initial thoughts after the first post was worn crank/bearings.

If all of those component parts (reported as replaced) showed such signs of heavy wear, I would not be surprised if the rest of any unchanged parts are also well-worn.

It would appear that the pistons had been replaced earlier - hopefully with the appropriate reboring having taken place.

Service limits on crank journals has to be determined by careful measurement with precision tools - the crank can ‘look’ alright and have not exhibited serious warning signs before the engine was ‘reconditioned’. That can soon change when a comprehensive replacement with other new/reconditioned parts takes place.

‘Within service limits’ can apply today but if only marginal (and they won’t get any less) can soon be outside those limits after which the wear will only increase...

I am quietly expecting a report of ‘crank needs regrinding’. Remote diagnosis is not easy. If it were me, in that position, I would hope I would engage some local expert opinion before jumping to any expensive conclusion or expensive replacement of (apparently) worn but serviceable items.

Oil pressure gauges do come in useful at times. I remember the ‘idiot light’ coming on in my first car (1969?). My first port of call was the local garage, who easily (and rightly) diagnosed a faulty pressure switch simply by the mechanic listening to the engine - panic over.

The first large engine I rebuilt (in the 1980s) I needed to take into account the crank ovality, when adjusting the big end bearings for clearance.... there being no facilities to remove an engine (likely weighing over half a tonne) to gain access to a crank for which there were likely no new bearings on this side of the Atlantic anyway.

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Re: Noise from engine under labour.

Postby Nickol » Mon Sep 28, 2020 2:52 pm

The report was that the Mains were not too bad but the big ends needed doing. - whether that was really the cause of the noise.......?
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Re: Noise from engine under labour.

Postby kevin s » Mon Sep 28, 2020 3:31 pm

Piston slap is usually worse when the engine is cold, ignition timing can effect it as well

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Re: Noise from engine under labour.

Postby MorrisJohn » Wed Oct 07, 2020 9:46 pm

boffer.9 wrote:
Tue Sep 08, 2020 3:33 pm
I'm really hoping someone can help me out here! When accelerating up hill, I'm getting this clattering noise coming from the engine. It happens in the same circumstances as pinking would. As soon as I let my foot up off the pedal, the noise stops. It's not a pinking sound though, it's more of a tappet sound. It's driving me nuts! I can't fault the performance of the car though, it is very lively and responsive.These are all the parts I've replaced trying to cure the problem ( it didn't! ) 1) New rocker assembly. 2) New camshaft end float plate. 3) New cam followers. 4) New push rods. 5) New valve springs and 6) Re-con distributor. I've also re-built the carb and set it up. It has +40 oversize pistons with no significant wear in the bores. I'm stumped!
I have the same kind of noise you describe. I took a classic mini garage owner out in the Moggy today and he thought it sounded like the timing chain knocking to the side of its casing under labour. I don’t know yet if that’s definitely my problem, but just a suggestion for you. I’m considering fitting a duplex kit.
The Morris Minor, it’s one of the family.

oliver90owner
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Re: Noise from engine under labour.

Postby oliver90owner » Thu Oct 08, 2020 10:40 am

One of the problems is understanding the real signs observed by the driver and relayed, to us, as symptoms.

Unfortunately, most are unconfirmed symptoms. ‘Accelerating’, to me, means a change in velocity, often (but not always) an increase - whilst ‘under labour’ can mean no acceleration or even a negative value.

At constant speed under load, the cam drive is loaded by the oil pump, and valve lifting duty mainly (plus the distributor in a minor way) and is not much different than revving the engine while stationary - the cam is not more heavily loaded just because one might be increasing the load on the engine - it is probably just at constant speed.

‘Uphill’ is yet another specific description. I would test whether the same phenomenon occurred while driving downhill, to determine if the upwards slope was making the difference.

Before actually blaming the ‘clattering’ as emanating from the internals of the engine, I would be carefully considering and checking all possible external origins - mountings, steadies, loose exhausts, fans, belts etc. I have to assume this was done in both cases?

We are then left with checking the true timing, mixture control and changing the fuel supplier, before delving into the engine for internal noises. Boffer , it seems, has changed or checked most sources, leaving the crank as the likely suspect, IMO (I have to assume he has a serviceable timing chain and tensioner as he has changed items in that area). Your noise may not have been apparent earlier, but a single timing chain with good tensioner should not ‘clatter’. They just don’t last as long as the improved duplex modification.

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Re: Noise from engine under labour.

Postby philthehill » Thu Oct 08, 2020 10:53 am

You only get slack on the power side of the timing chain on overrun.
To get the enough slack in the chain so as it to hit the timing chain cover on either the power or return side of the chain the chain/tensioner rubbers have to be badly worn.
The return side of the timing chain is the part of the chain between the crank gear and the camshaft gear.
The power side of the timing chain is the part of the chain between camshaft gear and crankshaft gear.


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Re: Noise from engine under labour.

Postby geoberni » Thu Oct 08, 2020 2:03 pm

I don't understand why the mechanic says it's the timing chain 'when under labour'.
A few years back, I had a Vauxhall Corsa, I think it was a 1ltr (something small), and it had a timing chain.
They were renown for the timing chains becoming loose and slapping around due to a poor tensioner. If not changed, in extreme cases the chain would actually cut through the cover.
You could hear the thing rattling against the cover while idling.
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myoldjalopy
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Re: Noise from engine under labour.

Postby myoldjalopy » Thu Oct 08, 2020 7:09 pm

I don't understand why the mechanic says it's the timing chain 'when under labour'.
Nor do I. I can't see why it would make any difference under labour or no as to rattling - was hoping someone with expert knowledge could clarify this, please.


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