Loud knocking on idle

[gttjames]

Car has had, clutch, sump sealed, timing chain and tensioner, water pump, crankshaft main oil seal all replaced, been in and running for the last 300 miles, and its just started making a loud knocking on idle and still does from 750rpm - 1400rpm, any revs over this and its smooth as anything and is still running fine and driving fine even when driven hard.

Ideas anyone? Is it just tappets needing adjustment? Picture a old 1.1 fiesta on idle/ revving at 1100rpm and you can picture the sound lol

Now if it is it leaves me with a problem, as far as i new the engine was standard but the dyno showed peak power at 6500 rpm so its been cammed, anyone know what came its likely to be with peak power at 6500? And what settings to use?

cheers

[Matt Cole]

if its from the bottom then could be a bearing which is not good. From the top it may be a worn rocker. Wip the cover off and reset them all from cold and see if one is out. Unfortunately the tips can wear concave and will never be quiet unless re-ground.

[gttjames]

But when revved at 1500rpm onwards there is no knocking atall and is as smooth as anything - does this rule out bottom end damage atall?

And resest the tappets to haynes manual settings or different as the cam?

thanks

[Ashy]

you would know if the bottom end was knocking, you could always use a piece of pipe in your ear to identify if its top end or bottome end if you were unsure.

Try the easy things first like adjusting the tappets, I would just set them to the standard settings in the book and see how it sounds. Peak power at 6.5k doesnt necessarily mean its been cam'd it could be a bigger than std turbo.

[Rob@Backyardracing]

Seized Piston maybe... You would expect a tappet to tap all the time at all rpm, a big end would rattle more if you very lightly tap throttle on and off on idle and listen to the over run... What boost and set up do you run?

[dave j gtt]

Rob, with a seized piston would you see a compression loss?

[andyrg]

Rob, with a seized piston would you see a compression loss?


If the rings had damage then yes, If they rings had stuck in too the piston creating it to move int he bore,

[Rob@Backyardracing]

Rob, with a seized piston would you see a compression loss?

Thats not allways the case would you beleave, ive seen many cars (ok m96 engines etc) still make good compression with scored bores... Only until you get a camera down that you will find the problem..

[Markey Mark (BD)]

I know you have fitted a new tensioner for the timing chain but see if its coming from there, poss that this is faulty

[gttjames]

Ok il look into it furthur.

I dont know anything about the engine internalls other than the bits iv done to it, iv put a t25 on it, and the carbs been set up at around 16/17psi, spec is in my profile

[gttjames]

Was going to take it to work this morning, started, let it idle and no noise from it, pulled away, then about 30 seconds up the road at very low revs it just died. Cranking it over it just sounds like its not firring, no oil in header, mayo in oil cap.culdnt do much more for the timebeing as needed to get to work

worried

[gttjames]

Well with the filler cap off it, if you crank it over nothing you can see through the filler cap moves

[Ashy]

so when you crank it, it is actually turning over? you can hear it and see the bottom pulley moving? But with the filler cap off none of the rockers are moving?

[Ashy]

by the way if thats the case dont keep cranking it over...

You need someone who knows what they are doing to look at it asap, do you know any local members?

[BWilkie]

Tensioner?

I had the exact symtoms. Did you release the tensioner after putting it in?

I didnt and I thought the bottom end was falling out! lol

[Markey Mark (BD)]

Well with the filler cap off it, if you crank it over nothing you can see through the filler cap moves

Pull the timing cover off mate and have alook in there, if thre engines kicking over but the rockers aren't moving suspect broken chain or what i have seen twice the bolt for the cam pulley come loose and pulley come off.

[gttjames]

If the chain/tensioner has failed im taking it theres alot of internall work to be done? It wasnt at high revs when the engine stopped, about 1500rpm. And since then all iv done is crank it over as initially just thought it cut out.

Ok il whip the cover off tomorrow and see what the score is, can i get away with just taking the cover off without draining the oil?

[Kris M]

yes, the timig cover will come off without draining the oil, especially if you have the O/S jacked up anyway :)

[Danny4da]

i had a loud knocking coming from bottom end toward the gearbox end and that was the flywheel bolts had came loose have a look at that if you have had a clutch done recently but dont think that would cause it to die on ya!!

[gttjames]

Got timing cover off, chains still there and all looks alright. It feels really loose though, i can push it back and forth very easily - couldnt see much more as just finished and is dark

[Markey Mark (BD)]

Whats the tensioner look like mate? Sounds like thats not sprung out and its stuck in the compressed position.

Check the cam pullet bolt just to be sure.

[gttjames]

Well heres some pics, everything looks ok to me, but is the chain supposed to have this much movement
http://i15.photobucket.com/albums/a371/sr50james/r5problems003.jpg
http://i15.photobucket.com/albums/a371/sr50james/r5problems004.jpg
http://i15.photobucket.com/albums/a371/sr50james/r5problems005.jpg

[Ashy]

its ages since I've rebuilt a C1J but isn't that tensioner in the locked position? plus why can't I see the lower gear? don't remember it being so small :scratch:

[dangerous dave]

its spring loaded, as it wears it keeps pressure.. im sure theres some flex that looks extreme when photo'd like that.. but perhaps i've never really had a problem so never noticed how much movements in it..

if the chain was knocking or catching surely it would show some signs of being "f*cked" by now:)

you can see as your moving it the springs doing its job keeping the pressure on.. looks ok to me..

[gttjames]

Yer never felt it before so didnt know if there was supposed to be that much movement, but like sed it is sprung loaded.

So next step rocker cover off and try turning it over and see whats going on?

[dangerous dave]

im to lazy to read the whole thread so might repeat a few things..

exhaust tapping the steering rack? engine mount gone? anything else loose?

or stick another block in your car for now and see if the problems solved while your pull your engine apart..