Noisy rocker

[Alex]

I have an ongoing issue......
Number 7 rocker will not go quiet....ok not strictly true,I did have it lovely and quiet but then it caused low compression as the valve obviously wasn't closing  :B. Not sure what's going on,I've adjusted to .10,.09,.07 I think 06 made it quiet ;D
The rocker face looks to be in nice condition no obvious marks etc.

What do I do?

[GT6 M]

most likely worn oot cam follower,or cam lobe, or both

is the push rod rotating, if not, then there summat rang wid,t follower

M

[Alex]

The cam was inspected before refitting as this issue was also apparent on the old bottom end(this is a rebuilt unit) the cam and followers haven't done that many miles as have only been fitted since just before last rbrr(only done 600 miles last year too).

[GT6 M]

Is the push rod rotating!!

other thing maybe worn rocker bore,or shaft wear, on that one.
its number 4 ex,correct, you got inserts in ex valve, loose!!!

you say it lost compression when set to 6, butt, whats the timing of the cam
lonnnng duration cams will suffer a loss of comp, as valves are open for so long
on overlap, so all comp gaa,s doon,t exhaust.
so was it low comp on all,or just the one set tight
best set others tight and see if they loose comp
all loose comp, its nowt to worry aboot

and besides, valve cant be open,  and loose comp,as there still a gap, correct mon ami

Are ye sure there is ne indent on rocker faces.

M

[Alex]

796 wrote:

Is the push rod rotating!!

other thing maybe worn rocker bore,or shaft wear, on that one.
its number 4 ex,correct, you got inserts in ex valve, loose!!!

you say it lost compression when set to 6, butt, whats the timing of the cam
lonnnng duration cams will suffer a loss of comp, as valves are open for so long
on overlap, so all comp gaa,s doon,t exhaust.
so was it low comp on all,or just the one set tight
best set others tight and see if they loose comp
all loose comp, its nowt to worry aboot

and besides, valve cant be open,  and loose comp,as there still a gap, correct mon ami

Are ye sure there is ne indent on rocker faces.

M

Um......
Sorry heavy night..... I had 170,170,165 and 100  compression.
I gapped no.7 and got that up to 170 so I'm guessing it wasn't closing?
Until I did this it wouldn't tickover when warm but actually performed really well.
It's a mk3 grind 1500 cam so nothing special.
Should the pushrods all rotate at tickover?

[Richard B]

Could the follower be sticking in the block?

[Alex]

Richard_B wrote:

Could the follower be sticking in the block?

I don't think so Richard as I spent a lot of time cleaning the block before building the engine up.

If I put a feeler gauge in the gap.....just small one it goes dead quiet if that makes a difference?

[Richard B]

Get a dial gauge and check that the gap is 10 thou?

It's got to be either; rocker. follower, cam lobe or follower bore.

[Alex]

How can I check the gap is 10 though with a dial gauge......am I being thick?

[GT6 M]

Alex says,  
If I put a feeler gauge in the gap.....just small one it goes dead quiet if that makes a difference?

well its altering the gap, which is mek,n it tighter, = less gap = less noise
so it goes back to  ,  is the rocker face really OK

OR, is the rocker v v slack on its shaft,or bearing surface.
nok could be the slack being took up.!!!

slacken adjuster reet off, and rocker should turn upside doon,
then get a hone and  dress the pad in an arc motion, till its all same shade of metal,
then re try it.

Yes all the push rods should rotate, as cam rotates follower, so it then rotates pushrod

check gaps by either a clock gauge, or a finger gauge,
take it ye got a clock gauge!!

M

[Rich_s]

Never knew they should rotate, mine has a rattle i cant trace but believe it is the cam followers, i was just going to pull the whole thing apart and check but can now do it without taking it apart, guess if they dont rotate then are worn too much.

thanks for that Marcus, can now hopefully trace my rattle.
rich

[Spider]

Had a similar issue with a 2.5 motor, twas down to a worn rocker shaft in my case, although you probably replaced yours when you rebuilt your motor.  :-/

[Richard B]

Alex wrote:

How can I check the gap is 10 though with a dial gauge......am I being thick?

;D


Or as Marcus says a clock gauge.


Without a feeler gauge  in the way. Put the tip of the dial gauge on the end of the rocker, push down on the rocker and set the gauge to zero. Then see if you have 10 thou movement on the gauge.

8)

[Nick Jones]

Try a different rocker?

Nick

[FGRob]

I had the same issue with one of my rockers, even though I had put a new shaft, cam and followers in, I got the bottom of it in the end, it was the actual rocker that had worn on the shaft so it was always going to knock, I did have a small issue with a groove on the tip as well.

I replaced the whole lot with roller rockers and put a new up-rated shaft is as well, runs like a Swiss watch now, plus I get the added bonus of extra lift on the valve.

The replacement rockers which are current sold come from India - need I say more, unless you can get original ones of course, that's the main reason I changed.

Not every ones cup of tea, but it solves a problem which had been bugging me for the past 5 years.

[Rich_s]

sorry to hijack smeones thread, having had my rocker off with engine running i can see one of my pushrods is not spinning much and another is not moving at all so guessing the 2 followers have stuck and worn which is causing the problem.

should be picking up new bits 2moro but wondered if the head def has to come off to change the cam followers?  think it does but for once engien running very well and dont want to pull it apart unless have to.

thanks
rich

[Velocita Rosso]

Worn rocker or shaft would be my guess
Remove all gear and swap the rockers around ...trial and error and see if the noise moves around