Horrible engine noise

[alan.barker]

My personal choice would be to remove the Head. Which only takes me an hour.
Alan

[ChriS7ven]

Ok, I think that in order to see more clearly I will remove the cylinder head as you advise me to do.

I have the manual workshop, but I don't know the "Twin cam" cylinder head at all, I know more about the rustic crossflow of my "Seven"
I'll let you know when I'll start disassembling. See you soon.... maybe

[Pjr]

Sorry to hear about your troubles. Best of luck with it and keep us all posted.

[alan.barker]

Bon chance
Alan

[2cams70]

Removal of the cylinder head only takes one hour - yes. But getting it back on and all sealed up and leak free with the cams properly set is something else if you are inexperienced. Refitting the Twin Cam head properly is not easy unlike an iron headed crossflow. I'd recommend to just do a compression test first. If the compression test works out fine there is no need to lift the head at this point.

[englishmaninwales]

Removal of the cylinder head only takes one hour - yes. But getting it back on and all sealed up and leak free with the cams properly set is something else if you are inexperienced. Refitting the Twin Cam head properly is not easy unlike an iron headed crossflow. I'd recommend to just do a compression test first. If the compression test works out fine there is no need to lift the head at this point.

How to do a compression test if the engine will barely turn over? Or am I missing something? (It’ll be possible to do a leak down, though).
Malcolm

[2cams70]

Engine is turning over apparently. i think I'll abstain from contributing further to this topic however. I think it's going to be yet another one where we won't hear of a conclusion or progress

[englishmaninwales]

...i think I'll abstain from contributing further to this topic however...

Please don’t do that, your views are alway welcome! My comment was genuine about the compression test
Malcolm

[ChriS7ven]

That's the news, finally I took the car to a garage.
And I did the right thing, because the verdict has come down...
A connecting rod has been sunk.

Do you think it would be the best solution for the car, but also for my wallet?
Rebuild the engine, ordering the parts. (QED, Burton??)
Find a second hand engine? (But surely to be opened and rebuilt...)
Contact a specialist and for an engine in standard replacement????

what bad luck with this car

[2cams70]

You can work that out by putting a wooden dowl down each spark plug hole in turn whist rotating the engine like I said before. It's easily determined without lifting the head. Despite the diagnosis I'd be doing it just to be sure the mechanic isn't telling porkies. Original "L" blocks sell for quite a good price used and worth much more than a standard replacement 1500 or tall block. It's unusual to break a connecting rod unless the engine has been abused or previously been taken apart and poorly assembled.

You can't make any assessment about the cost to rebuild if that's the failure mode until it's been completely disassembled. You can be sure it won't be cheap though.

[nmauduit]

That's the news, finally I took the car to a garage.
And I did the right thing, because the verdict has come down...
A connecting rod has been sunk.

Do you think it would be the best solution for the car, but also for my wallet?
Rebuild the engine, ordering the parts. (QED, Burton??)
Find a second hand engine? (But surely to be opened and rebuilt...)
Contact a specialist and for an engine in standard replacement????

what bad luck with this car

For non French native speakers, a "sunk" connecting rod describes a spun rod bearing : I'm sorry to read that, which would be 2 distinct serious problems on this engine (earlier was described a timing chain eating the case).

As usual, it is not easy to diagnose and budget a repair without all the informations and the engine at hand (even with that actually), so don't take the following without a grain of salt or two... all standard disclaimers apply.

If the engine has run some (more than a minute) while eating away the timing case, bits of alloy may have travelled in the oil and damaged the bearing. Then if the engine has kept being run with a damaged bearing the crank may need regrinding. The diagnose can to a certain extent be performed within a few hours of dismantling work once the engine is out (e.g. taking the crankcase out to check if a bearing has been spun and how likely it is that the crank need a regrind, if still regrindable...).

I personnally would first investigate having the engine repaired, BUT it is even more difficult in France to find someone that will do it right than in the UK (as for warning, being arrogant in front of an inexperienced customer is not as strong a proof of proficiency as solid track record backed by customers actually using their LTCs). For exemple the journals of the crank need to be properly radiused if a regrind is to be performed. Tolerances need to be right where it matters, too. It is certainly worth taking time to get a good independent recommendation (several actually) before handing out a LTC to a repair shop in France.

I would purchase the spares required for the rebuild from QED (no affiliations, just a very satisfied customer, every time).

A second hand engine may be considered if this one is not salvageable, but they are expensive (4000-8000 is a typical bracket for a standard engine, +/-2000, no warranty of actual condition and history mostof the time) and again it is hard to be 100% of what is inside short of taking it apart (then rebuilding it right).

[alan.barker]

Google auto translation for Technical are rubbish.
Sounds like the same problem as Rohan with the Big End Shell.
A good idea to look at Rohan's rebuild.
Alan

[2cams70]

A spun bearing can usually be diagnosed before dismantling by:
1) Measuring the oil pressure
2) With a screwdriver whilst the engine is running short out each spark plug in turn and note whether there is a change in knocking sound from cylinder to cylinder.

Road engines don't generally spin bearings unless the engine's been apart at some stage and poorly assembled or replacement bearings have been fitted not having the correct crush

[nmauduit]

A spun bearing can usually be diagnosed before dismantling by:
1) Measuring the oil pressure
2) With a screwdriver whilst the engine is running short out each spark plug in turn and note whether there is a change in knocking sound from cylinder to cylinder.

Road engines don't generally spin bearings unless the engine's been apart at some stage and poorly assembled or replacement bearings have been fitted not having the correct crush

I said spun to point at the bearing issue rather than con rod, but collapsed may be more of an accurate translation of what "sunk" would generally mean here ("couler une bielle" in French, that is the babbit has flown away from the shell, then sinking is a false friend for flowing) - agreed, it would not go all the way to spinning the shell unless the engine is kept running without oil pressure.

The worry I would have in this case is
1) the sequence of troubles, and time during which the engine has been kept running with said troubles, then
2) the competence level of whomever makes a diagnostic upon which a course of action has to be decided (lots of small garages would not generally repair engines, and would have only 2 diagnoses to offer to support a huge quote which is really meant to deter one from repairs and opt for a swap instead, "sunk rod" , or "shrinkage" for damaged piston, supposedly from overheating due to a lubrication issue)

[Billmack]

I think the chain stuff is a red herring. Your troubles are going to be crank/rods/bearings/oil pump. My experiences are that if the pump sucks in a bubble of air it takes much longer than most engines to re prime. You may need a new crank and one connecting rod