Big End(s) gone?? BMC 1.5

[HappyBunny]

Not such a Happy bunny today

 

Having just spent some money getting my loom sorted, the sparky fired her up to check everything working and YES all was well (after some issues with a split charge relay struggling with my solar panel input ... but thats another story).

 

So we gave it one more go before he left, just to be sure .... fired up easily BUT now has a worrying metallic knocking/tapping sound ..... seems to be coming from the front/top of engine.... first thoughts of myself and sparky .... big end bearing gone somewhere .... or maybe timing chain slipped? or dropped a valve? .... something seriously amiss. She didn't appear to be smoking more than usual, but it was the sort of noise that you kill the engine pretty quick. Further attempts to start her failed

 

Turning her over by hand revealed that something was "catching" as the crank turned and definite feeling of lost compression...... now well out of my league, so have someone coming to take the head off and investigate further next week ....... and I appreciate diagnostics over tinternet are not possible BUT

 

What I would like some advice on as I cry into my coffee is .....

 

If it is a big end bearing problem .... what might have caused it? (is it just a costly coincidence that it happened after having new loom?)or do they just go

 

Can it be fixed? (presumably that will depend on whether any damage has been done elsewhere?)

 

Or am I looking at a replacement engine?

Is it better the BMC devil you know, or the fleabay "it was running when we took it out" job?

 

And what sort of price for a second hand engine? (I'm assuming new will be out of my league ... and I guess thats a bit of a "how long is a piece of string question)

 

What could I replace it with? I have just started to find my way round that engine. I have some major contingency money, but she is an old boat, though with a good survey .....

 

So really it is all hypothetical at the moment, until further investigations take place ... but any words of comfort or solace would be welcome .... and if anyone is in the vicinity (Bugsworth basin, Peak forest) and fancies a quick furtle (ooer )or listen I would be grateful

[RLWP]

Before writing the engine off, it is important to identify what has really happened. Front/top of the engine doesn't sound like bottom end bearings. Has you water pump bearing collapsed (for instance)

 

Also, you have had someone working on your boat. What did they do, have they make a cock-up and left something dragging on the fan belt (for instance)

 

Richard

Edited March 15, 2013 by RLWP

[BEngo]

Not such a Happy bunny today

 

Having just spent some money getting my loom sorted, the sparky fired her up to check everything working and YES all was well (after some issues with a split charge relay struggling with my solar panel input ... but thats another story).

 

So we gave it one more go before he left, just to be sure .... fired up easily BUT now has a worrying metallic knocking/tapping sound ..... seems to be coming from the front/top of engine.... first thoughts of myself and sparky .... big end bearing gone somewhere .... or maybe timing chain slipped? or dropped a valve? .... something seriously amiss. She didn't appear to be smoking more than usual, but it was the sort of noise that you kill the engine pretty quick. Further attempts to start her failed

 

Turning her over by hand revealed that something was "catching" as the crank turned and definite feeling of lost compression...... now well out of my league, so have someone coming to take the head off and investigate further next week ....... and I appreciate diagnostics over tinternet are not possible BUT

 

What I would like some advice on as I cry into my coffee is .....

 

If it is a big end bearing problem .... what might have caused it? (is it just a costly coincidence that it happened after having new loom?)or do they just go

 

Can it be fixed? (presumably that will depend on whether any damage has been done elsewhere?)

 

Or am I looking at a replacement engine?

Is it better the BMC devil you know, or the fleabay "it was running when we took it out" job?

 

And what sort of price for a second hand engine? (I'm assuming new will be out of my league ... and I guess thats a bit of a "how long is a piece of string question)

 

What could I replace it with? I have just started to find my way round that engine. I have some major contingency money, but she is an old boat, though with a good survey .....

 

So really it is all hypothetical at the moment, until further investigations take place ... but any words of comfort or solace would be welcome .... and if anyone is in the vicinity (Bugsworth basin, Peak forest) and fancies a quick furtle (ooer )or listen I would be grateful

 

Thoughts:

 

Front/ Top end clatter might well be tappets or a valve spring- have you checked the valve clearances and springs? A dropped/burnt valve will result in no compression on one cylinder and the engine would be hard to start and produce mucho white smoke.

 

Big ends should not produce a 'catching' feeling and will not affect compression either. Really bad tappets, or a broken valve spring could. Timing chain much more likely to break than slip IMHO and engine will stop if that happens.

 

It ran albeit making noises, so the DPA pump is clearly not seriously deranged.

 

Is the starter motor OK? not stuck into the ring gear? Not sure this would produce 'catching' though.

 

RLWP makesgood points, especially about something that has happened whilst the engiine is being worked near, but what might make a racket and then prevent it being re-started?

 

N

[RLWP]

If you have someone coming capable of taking the head off, trust them and put aside the engine problems until they have been. There is nothing more that can be done now except for fruitless, anxiety causing speculation

 

Been there, done that

 

Richard

[HappyBunny]

Hmm agreed about speculation BUT already there are some other possible causes in these replies that I can explore,

 

The Sparky is time served and well respected, and initially she ran sweet.

 

Thanks for your suggestions :-)

[RLWP]

Perhaps that sounded critical. Put it this way, when I have something go wrong, I usually suspect the last thing that I worked on as I know that I sometimes make mistakes. As a problem solving method, it serves me well

 

Richard

[Chalky]

Fully agree with Richard. Chances are it was something that had been disturbed whilst working on the electrics and that't the most likely cause. One manager I worked for on Range Rover electrical always assumed that the fault was caused by the last thing that had been disturbed. He was usually right!

 

Timing chains rattle - the one on my MG was completely past it but the engine still ran.

If you know how take the rocker cover off and turn the engine over by hand (usually a big spanner (1 1/8" AF?) on the crank shaft nut). Don't crank it on the starter. The valves should go up and down and the crank should turn "freely". If it sticks then it's probably head off.

 

Also look for loose nuts and bolts round pumps and alternators. If one has rattled loose then this might be jamming things.

[luctor et emergo]

Work done on the loom? Electrics? May point towards starter problem.

 

What about the alternator belt pully? When that worked loose on my friend's (lister SR2) engine it made one hell of a racket.

[HappyBunny]

Feeling a bit more positive now, as there are several things that are well within my capabilities to investigate now.

 

Thanks so much for your time people. Your replies have helped me focus

 

Weather forecast bit better for tomorrow too :-) so will get in there tomorrow morning and start process of elimination

[RLWP]

 

Weather forecast bit better for tomorrow too :-)

 

 

Now, I don't care what the weather man says

When the weatherman says it's raining

You'll never hear me complaining...

 

Richard

[Grace and Favour]

Feeling a bit more positive now, as there are several things that are well within my capabilities to investigate now.

 

Thanks so much for your time people. Your replies have helped me focus

 

Weather forecast bit better for tomorrow too :-) so will get in there tomorrow morning and start process of elimination

 

Take a torch with you - and be prepared for the process of illumination

[David Mack]

If you know how take the rocker cover off and turn the engine over by hand (usually a big spanner (1 1/8" AF?) on the crank shaft nut).

 

And make sure the engine stop control is fully in the STOP position first. I know it is very unlikely to start if you turn it over with a spanner, but you don't want your hand on the spanner if it does!

[RLWP]

Take a torch with you - and be prepared for the process of illumination

 

Take your manuscript with you

 

 

Richard

[Arthur Brown]

Unless you can find a well refurbished BMC you will have to spend about £1K on refitting any other engine into that space, so it may be worth doing a real repair if it will come in at less than that.

[ditchcrawler]

I don't think your big ends have gone

[Monkey 1]

Our bmc had the same noise, Identical to that of a bottom end knock. Being a car mechanic by trade I would have put money on it being that too, even the guys at Stone boat yard thought so. I had the engine out & the bottom inspected, nothing wrong. The only problem we found was the drive plate was deteriorated & was knocking back & forth so it was replaced. Also the water pump was grumbling a bit so that was swapped. We ran the engine on a test bench & it was perfect again!

 

We are still unsure exactly what was causing the knock.

[HappyBunny]

Hmmm that manuscript is about as enlightening as the BMC manual I have .... and call me a fairweather mechanic but I can't stand rain trickling down my builders cleavage ....

 

Anyway, checked as many of the suggestions as I could .... and nothing untoward under rocker cover or anywhere else. .... and in fact she turned quite freely by hand yesterday .... so going to try and check water pump bearing tomorrow, as got my stall open today.

 

Glad to have solar panels and be stuck somewhere nice :-)

[nebulae]

Was the oil pressure light still on when the engine was running(or oil pressure register on the gauge)If the engine has oil pressure its probably not big ends.Agree with above points.Check last things worked on first.Check for obvious.Drive plate is a good place to start as it should be cheaper to split the engine and gearbox than start stripping the engine.Stick with B.M.C.and stick with your old engine if possible(unless it was a dog before your present problem)Hope the problem turns out to be a simple one.

[RLWP]

Hmmm that manuscript is about as enlightening as the BMC manual I have {snip}

 

I thought it was highly illuminating

 

Richard

Edited March 17, 2013 by RLWP

[HappyBunny]

Well the plot thickens ..... some good news and some bad/mysterious news .... and no, it appears big end bearings were not the culprit, but not sure what was exactly or how it got there.

 

The head came off today and revealed what appears to be the remains of one or possibly two small wood/self tapping screws embedded into the top of two of the pistons. Some damage to at least one valve, but it has gone to workshop to have the valves removed replaced and reground as necessary. Seems to be no scoring on the barrels and rings intact,so it seems that repair is possible and that the engine will not have to come out DEEP JOY

 

From what was left embedded on the piston tops it appears to be a small screw(s)that had somehow got in there ... how and when is another mystery, but the thread and screw head were clearly visible ... have a pic of one bit, but the other bit pinged off into the darkness. And how did bits get into two cylinders .... very strange

 

Anyway, she is going to have a well overdue de-coke and hopefully be sorted soon. Thanks again for all suggestions and let it be said that JIM fixed it for me (Jim Ling that is thoruoghly recommended if you are on the Macc or Peak Forest )

 

 

 

 

[cheshire~rose]

Ouch!

 

Are you missing any fasteners from your air filter housing? The most usual way for foreign objects to find their way in is through the inlet manifold when the air filter is off.

 

It is always a good plan to count all the bits you take off and count them back on again before starting the engine. If in dobt a flexi magnet thing down the air intake holes might find any metal bits before they get sucked in, But then again they might not

[jake_crew]

Had this on BMC A series once - a small ball bearing ball. The top of the piston looked like it had BAD acne.

 

How it got on there I will never know.

 

One of life's little mysteries.

[RLWP]

Had this on BMC A series once - a small ball bearing ball. The top of the piston looked like it had BAD acne.

 

How it got on there I will never know.

 

One of life's little mysteries.

 

Are you sure it wasn't a Ford Escort? They had an accelerator pump in the carburettor with a little ball as a check valve. If you took the top off to clean the carb, and turned the throttle, the little ball jumped out and dropped down the manifold

 

I have opened up a couple of Escort engines with lots of little dents in one of the pistons

 

Richard