whats wrong with my engine?

[Brealbags]

About 1000 miles ago it was rebuilt to replace rings (oil scraper ring was very worn and coking up all the cylinders and head)

I also replaced big end bearings and main bearings plus all gaskets / seals

I never seperated the small end - piston / conrod assembly when they were out.

Ever since then its been tapping at sort of midrange revs and slight throttle. You cant hear it when under load or on tickover or on overrun. Its a sort of light tapping like the tappets but faster.

I have been told by a pro its the little end bearings which would make sense since i didnt replace them. But i have also been told they are not available so im not sure.

I know people here have done a lot of rebuilds so i was wondering what you think??????????

thanks

[MAXIBOY]

couple of questions..

did your rebore or hone the bores when the pistons were out..

[Brealbags]

no rebore but yes they were inspected, measured, checked for ovality and rehoned. The bores looked fine apart from slight glazing and lipped but it was sorted.

[MAXIBOY]

never heard of the little ends going on these

but maybe..where the tapping before in the previous engine.

[Brealbags]

no it was quiet before the rebuild. im just thinking that with me cleaning the piston/ conrod assembly then putting it back in the engine it may have dried up the bearing or something.

not sure if little end bearings are available i may have to get a complete conrod set if it is that. i assume the bearings are pressed in and heat shrunk into the small end.

[MAXIBOY]

they never dry up mate as there oil feed from the rod big end bearing..

you sure the big end shells were fitted correctly..

apart from that only other thing i ever seen like this is when the wrong head gasket has been fitted and it over hangs the bores and the piston catches the gasket..but i don;t think this can be done on a willy..

[Brealbags]

its not a willy its valver (F7P) i got the head gasket from an independant engine services place not officially renault. (Probably another stupid thing i did lol). Im pretty sure they have been fitted correctly i am not a pro just a trainee but i work in a main dealer garage and got the advise of 6 other pros one of them is ex renault. Plus its not a bottom end kind of noise.

Someone said it sounds like a little end knock so thats what i assumed it was. Anyway i had to take it fully off the road a few weeks ago because the noise suddenly worsened while on the motorway and its now very loud you can hear all the time!

[MAXIBOY]

sounds more like a big end really if it got very loud....

will need to strip and inspect..lets us know what you find mate

[Coops]

cannot replace little end bearings, they are machined directly into the piston and rod end itself, its not a removable bearing.

is it definatley coming from inside the engine, its not injectors? as they can create a ticking sound and if one sticks/is worn etc or blocked up it will get loud

[Brealbags]

weve had a good listen today and its definatly a top end knocking. i know its rare but its what weve said from the start.

its relative to crank speed not cam speed and its not big end or main bearings cos they would be a more of a rumble, its more of a lighter knock. and its too irregular to be tappets

its tearing my head off at the mo iv never heard the engine running sweet!

So looks like im going to have to source some con-rods from somewhere anybody got any ideas??

[Brealbags]

Im going to get the head and sump off on saturday to have a look round. I could whip a piston out then and see whats what.

[MAXIBOY]

its not detonation at all maybe..maybe a broken ring.... :?

[stan]

sounds like big ends.

for reference, the little ends of the rods can be re-bushed

[Coops]

can they :shock:

[stan]

yes :D

[Coops]

8)

[Brealbags]

im quite sure its not big ends if you heard it u would agree with me i think. all bottom end bearings and rings are new. im just going to have to take a piston out and look. Maybe gudgeon pin is knackered :?

[stan]

did you have the crank ground?

did you measure the bearing clearances?

sounds from your description like big ends. get a vid up?

[Brealbags]

ill try and get a video up then im not sure if it will come out ok tho.
Didnt have the crank ground just checked the journals with a gauge they seemed fine.

Big ends would be more of a deeper rumble. its a very light, fast tapping but only at certain revs and throttle. It would be play in the small end as the piston changes direction. Nothing to do with valve gear either because you can hear that separate. i know its wierd ill try and get a vid

[stan]

Big ends tend to knock (start quietly and get louder with time) at mid rpm and light load, i.e. as you come off the throttle, or trailing throttle.

Did you actually check the running clearance ont he bearings? I would start by doing this before changing other parts.

[Brealbags]

hi just want to start with an apology... got my engine out and stripped and big ends are shot to pieces. :( So i was wrong. Everyone that heard the car said little ends so i believed them.

So big end bearings and crank journals are scored. May get crank reground and oversize bearings in but im not sure what to do yet. :?

Do you think i might as well get a williams engine instead or repair the crank and stuff?