Engine failure - thoughts?

[rik220]

Hi,

As some of you may know I bought my 182 needing an engine. Now that the car is on the road again we decided to lift the head off the original engine to see if we could find the cause of failure.

Failure is in cylinder 2.
The spark plug threads are not good from the plug being struck (gap was totally closed and visible marks on it)

Engine ran on 3 cylinders, no bottom end noises at all, infact I had it at 7200 rev limit to check if the gearbox was fine before pulling the whole lot out.

Anyway onto the pics,

What’s your thoughts? Valve seats are still there, none of the valves have dropped. Only two of the 4 valves are visibly bent. No scoring on the cylinder walls so I’m assuming it wasn’t a ring failure.

Will remove the rod and piston at some stage this week hopefully.

Cheers,
Rick



Sent from my iPhone using Tapatalk

 

[bob the builder]

I would say a bolt has got in and been bouncing around in there

 

[rik220]

I would say a bolt has got in and been bouncing around in there

Would expect holes in the piston if this was the case.

Could be on the right track in regard to a foreign object.


Sent from my iPhone using Tapatalk

 

[npt]

Be something like a washer, are all the plugs the same make

 

[rik220]

Be something like a washer, are all the plugs the same make

All plugs were Denso ones. The one in that cylinder wouldn’t tighten and you can see the threads in the head aren’t in good shape it’s been hit that hard.

The air filter seemed to be fairly new, I changed it for a new genuine one when I got the new engine in. Unless the person who changed that air filterdropped a the likes of a small washer or nut in there and it eventually got sucked in. Would need to be small to get in past the valve you’d think.

I used a bore scope when the engine was in the car and was able to see all valves in their seat. I’d kind of thought that since none of the valves had dropped that it would of been ring land failure but that would of led to scoring on the cylinder wall which there isn’t.


Sent from my iPhone using Tapatalk

 

[TheCAB]

Safe to say a "foreign" object of some description has found its way into the cylinder.

Did the failure appear out of nowhere or had you recently carried out any work on the engine?

 

[STEVE.M]

All plugs were Denso ones. The one in that cylinder wouldn’t tighten and you can see the threads in the head aren’t in good shape it’s been HIT THAT HARD./QUOTE]

By what?

Denso????

Got a picture of said plug?

 

[rik220]

Safe to say a "foreign" object of some description has found its way into the cylinder.

Did the failure appear out of nowhere or had you recently carried out any work on the engine?

I bought the car needing an engine so the failure had already occurred.


Sent from my iPhone using Tapatalk

 

[rik220]

The plug is in the bin. Sadly no photos.

Maybe should of worded that better. The plug electrode was visibility marked and the plug gap was closed and offset to the centre of the plug if that makes sense.

All plugs in the engine were the proper NGK plugs, not denso (the replacement engine’s plugs were denso and I changed them to NGK)

There was nothing missing from the plug to suggest anything fell off it and into the cylinder. The threads are goosed in the head for that cylinder. This may be unrelated though but was an observation before I pulled the engine out.


Sent from my iPhone using Tapatalk

 

[TheCAB]

Helicoil insert (or a bit of one) finding its way into cylinder maybe -just an observation which could tie into the plug threads being knackered.

 

[AdDaMan]

Theres no way the bore would be ok if a foreign object was in there imo. Looks like a dodgy injector to me causing major det, but im surprised it didnt do more damage.

 

[STEVE.M]

Theres no way the bore would be ok if a foreign object was in there imo. Looks like a dodgy injector to me causing major det, but im surprised it didnt do more damage.

Don`t think detonation would close the plug gap!

 

[Krarl]

I’d say the tip of the spark plug has broken off and gone pinging around for a while[emoji23]

 

[R3k1355]

Looks like a dodgy injector to me causing major det, but im surprised it didnt do more damage.

Thats even more damage than you'd normally see with Det, and it's not fucked up the rings or put a hole in the piston either.

I’d say the tip of the spark plug has broken off and gone pinging around for a while[emoji23]

Maybe should of worded that better. The plug electrode was visibility marked and the plug gap was closed and offset to the centre of the plug if that makes sense.

 

[Cookson]

Yeah, det would usually put a hole in the piston face. Certainly a foreign object, possibly the helicoil as said above.

 

[DaveL485]

Thats foreign object damage, something has found its way into the cylinder and been smashed around.

 

[rik220]

A helicoil failing and dropping into the cylinder sounds plausible for sure. Thinking about it, if the plug was hit hard enough to destroy threads, the piston would be holed and potentially a bent rod and by this stage a spun bearing as a result.

This engine would definitely run again with a new head and piston. I'm not going to scrap it for the time being anyway.

 

[Darren S]

And here's me thinking that the cylinders were numbered from left-to-right, in situ in the engine bay. I would have classed that as Cylinder 3. ?

 

[Robbie Corbett]

Has the car still got a cat? If so your object may be buried inside....

 

[bloke]

only takes a little bit of damage to the end of the thread on a plug and when you try and take it out it mullers the thread in the head itself.

 

[rik220]

Has the car still got a cat? If so your object may be buried inside....

Yes. Cat is still in the car. I actually looked in the cat briefly from the back yesterday when I had the mid pipe off. Didn’t see anything untoward.


Sent from my iPhone using Tapatalk

 

[rik220]

only takes a little bit of damage to the end of the thread on a plug and when you try and take it out it mullers the thread in the head itself.

Yes fair point.

What else can it be though, given that the valves and their seats are still in place? Ring land failure would leave the bore scored and would bits of piston even get past the rings?

I drained the oil and I don’t remember seeing metallic parts in it.


Sent from my iPhone using Tapatalk

 

[bloke]

if something has gone in and out then you won't have anything in the oil. from the damage to the head you can see in the last pic it's been a decent size whatever it was, worth looking in the front of the cat if you can be bothered but even then you'd be lucky to find anything anyway.

what's the seat of the spark plug hole look like?

 

[rik220]

if something has gone in and out then you won't have anything in the oil. from the damage to the head you can see in the last pic it's been a decent size whatever it was, worth looking in the front of the cat if you can be bothered but even then you'd be lucky to find anything anyway.

what's the seat of the spark plug hole look like?

Yes so that probably rules out piston failure as that would be evident in the oil.

What you mean seat of the plug hole? The top of the hole that you see peering down from the top the head?


Sent from my iPhone using Tapatalk

 

[bloke]

yup, looking down from the top.

windage tray is good at catching bits and stopping them dropping into the sump.
when i dropped the oil from this one pretty much nothing in it!!

 

[STEVE.M]

yup, looking down from the top.

windage tray is good at catching bits and stopping them dropping into the sump.
when i dropped the oil from this one pretty much nothing in it!!

View attachment 1390815

Someone stole my piston.

 

[STEVE.M]

Unless the previous owner can provide a sequence of events, it`s just guess work.

 

[rik220]

yup, looking down from the top.

windage tray is good at catching bits and stopping them dropping into the sump.
when i dropped the oil from this one pretty much nothing in it!!

View attachment 1390815

That’s nasty!!

Good point, that tray is pretty big too.

At this stage I probably won’t bother removing the rod and piston until I decide to rebuild it. If I do.

I notice previous owner information is no longer on the tax book. Fella I bought the car off bought the car in this state with the intention of fixing it but didn’t bother.


Sent from my iPhone using Tapatalk

 

[DaveL485]

And here's me thinking that the cylinders were numbered from left-to-right, in situ in the engine bay. I would have classed that as Cylinder 3. ?

Number 1 is always next to the flywheel, whatever the orientation.

 

[Darren S]

Number 1 is always next to the flywheel, whatever the orientation.

Never knew that - and makes perfect sense as to why!

 

[bozothenutter]

https://en.wikipedia.org/wiki/Firing_order

"When referring to engines, the front of the engine is the part where the pulleys for the accessories (such as the alternator and water pump) are, and the rear of the engine is where the flywheel is, through which the engine connects to the transmission. The front of the engine may point towards the front, side or rear of the car."
"In a straight engine the spark plugs (and cylinders) are numbered, starting with #1, usually from the front of the engine to the rear."

?

 

[STEVE.M]

https://en.wikipedia.org/wiki/Firing_order

"When referring to engines, the front of the engine is the part where the pulleys for the accessories (such as the alternator and water pump) are, and the rear of the engine is where the flywheel is, through which the engine connects to the transmission. The front of the engine may point towards the front, side or rear of the car."
"In a straight engine the spark plugs (and cylinders) are numbered, starting with #1, usually from the front of the engine to the rear."

?

I think the practise of numbering their cylinders 1234 from the gear box end must date back to the Renault R4, which was front wheel drive, but with the

gearbox mounted forward of the engine.

At the time, the cylinder closest to the front of the car was also closest to the gearbox.

 

[Coops Mk1]

Ai Renaults have always been numbered 'wrong'