Big end Knocking.

Hi I have a 2a 3 bearing 2.25 petrol engine and I think my big ends are knocking.
So my question is.
How could I tell for sure?
If it is the beg ends can they be replaced with the engine insitue?
Is it a difficult job ?
And about how much would it cost?

Thanks

what makes yer think thems knocking?

His doorbell dunt work

Good point
I don't know if she is knocking big ends but when she is warmed up and under load she's sounds like a diesel.
Also if I rev up out of gear I can hear quite a solid knocking.
Its not the tapets cause i did them and the are just fine.

stick yer hand brake on and try and pull away

Ok i'll try that tonight.
What am'i looking for?

loud thumps, bangs, and knocks from yer injun

Slippery said:

Ok i'll try that tonight.
What am'i looking for?

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If yer big ends are away they will knock like fook first thing until the oil gets to them, particularilly so until the oil light goes out. sharp jabs on the throttle at the same time and trust me if they are gone you will hear it.

Hi all
Well tried it last night and I got the following results.

Engine cold HB on 1st gear = no knock
Engine warm HB on 1st gear = no Knock Unless clutch sliped

Engine warm out of gear = Knock when throttle blipped
Engine warm driving any gear = Knock when lightly accelerating
Engine warm driving any gear = no knock when heavy accelerating.

Any idea's ?

Slippery said:

Hi all
Well tried it last night and I got the following results.

Engine cold HB on 1st gear = no knock
Engine warm HB on 1st gear = no Knock Unless clutch sliped

Engine warm out of gear = Knock when throttle blipped
Engine warm driving any gear = Knock when lightly accelerating
Engine warm driving any gear = no knock when heavy accelerating.

Any idea's ?

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So what was it like when you started up from cold then??

if they is fooked then even with oil on em they will knock with it in gear and the h/brake on , due to the load generated.
quite a few engines knock when cold but it dunt mean there is a problem, its just the way they are

slob said:

if they is fooked then even with oil on em they will knock with it in gear and the h/brake on , due to the load generated.
quite a few engines knock when cold but it dunt mean there is a problem, its just the way they are

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Yep but that engine wernt, it were normal, and yer right they can knock under load but I woz just trying to keep it simple.

Anyway wernt there a song "its just the way they are" I used to know a group that sung it "norfock and good", a duet so they were and they formed a trio a bit later, called "stille norfock and good."

It doesn’t sound like a big end, it would happen all the time when hot. There’s possibility of the oil warning light coming on also (hot)

If you find it is you can change the bearings quite easily, this is usually a quick fix due to wear on the crankshaft.

Hi all thanks for the advice.
So the everyone thinks its not the big ends but could be the cranck bearings?
Is it a engine out job to change the cranck bearings ? or is there a way i could check what is at fault?

Slippery said:

Hi all thanks for the advice.
So the everyone thinks its not the big ends but could be the cranck bearings?
Is it a engine out job to change the cranck bearings ? or is there a way i could check what is at fault?

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If it's the main bearings that you are talking about, then you can normally only get centre ones off, sometimes the front one, but I have never been able to get a rear one off without the gearbox out or engine out. I have cheated on occasions where you can slip the top bearings out past the crankshaft and left the rear one.

But take the sump off and take off the big ends first, the bearings should be grey sort of lead colour, if you see them worn through to the brass then they are gone, mark the caps with a centre dot or summit to make sure you fit them correctly in order, 1,2,3,4 and so on stick the marks all at one side, left side so all go same way. you will probably see some groves down to the brass where the oil feed hole is where at some time it's taken in ****, but that's not a problem, it is if a large surface area is worn through.

I doubt its the mains they give more of a rumble, but if you are in there take a couple of caps off.

And the last thing as you are in there, lever the crank forwards and backwards and check the float, if it's exessive then the thrust bearings are gone, but you should be able to get them out. Triumphs were bad for it and eventually it became difficult to get a gear since the clutch would not disenguage, so I guess with the engine running get somebody to press the clutch and see if the crank moves forward them back when released.

Check your oil pressure first just in case you have issues there, low oil pressure could still be present even though the light goes out and best to be safe