Thread: new noise after V8 cam install

The front cam journal has a groove which feeds the oil through the keyway to feed the cam chain.
This would replce the groove in a bearing shell.
Regards Philip A

howdy - am wondering if there is a connection between the vertical scrape marks on the walls of this cylinder and an extremely worn lobe on the cam for that cylinder. i'm not near the car at the moment so can't work out if it is an inlet or exhaust valve lobe gone on this cylinder.

this cylinder was not firing at idle ie take off spark plug lead and no difference, but once some revs were up it would kick in.

some more eye candy of cam lobes which have seen better days.

will be taking old cam back to have measured against specs, initial comparison showed 10 thou diff between one of normal looking lobes on old camshaft being smaller than the new camshaft. this was from the base/round of the cam to the top of the lobe so approx 5 thou diff if talking 'radius'. i expect this diff to be even less once the guys at the camshaft shop can tell me how much the old camshaft had worn.

I don't think so as mine is worse on No6 and my compression on that cylinder is high at 170Lbs per sq in. See photos.
Looks like a piston picking up. Could be quite old.
Regards Philip A

[QUOTE=pibby;1544680]howdy - am wondering if there is a connection between the vertical scrape marks on the walls of this cylinder and an extremely worn lobe on the cam for that cylinder. i'm not near the car at the moment so can't work out if it is an inlet or exhaust valve lobe gone on this cylinder.

G`day ,

i don`t think the 2 related but as said i`d suggest you remove it and have a look at the rings .

Your pic is pretty clear and shows the how far the marks are around the cylinder and i`d suggest greater than what a piston could grab .

Your pic also appear to shows marks at the very top of the liner where neither the piston or rings run .

well the finish line hasn't quite been reached.....car still in workshop (geez - would have to be 3 or 4 months by now???)....went and bought a td5 defender to keep mobile.

motor is all back together but guess what...there is a new noise. i haven't heard it as i'm back home but the mechanic was saying it was not a lifter noise, more like a noise up at the rocker arm end and across all cylinders. so new camshaft and lifters etc gone back in with reco heads and tin gasket (mechanic said he couldn't get a composite). I know he has been careful and diligent and careful putting things back together and checked things on the way. oil pump is fine, says oil light goes off straight away on start up.

reading rimmers parts catalogue the tin gasket is approx 0.5mm and composite approx 1.2mm so thinner by approx 273 thou thinner.

assume the heads have been shaved 30 thou.

Lifter preload should be between 20-50 thou.

So adding up thinner gasket and shaved head it’s 57 thou thinner.

Asked him to check lifter preload but he hasn’t.

So is the lifter preload now potentially past the 20-50 thou (even working backwards with the 1.6 rocker ratio at the lifter end if I’m guessing right) and without personally understanding how the hydraulic lifters work, things are now out of spec and causing this new noise? And what the heck could the noise be and most importantly is this doing any damage?? Is it just a matter of shimming the rockers up and we’re done?????


Thanks,

Brett.

Is it just a matter of shimming the rockers up and we’re done?????

Maybe. When I checked mine with a new cam, lifters,etc they were way over , and I cannot figure out why , and I have all standard and matching head, gaskets etc.
There is a maximum preload that the lifters will take and they may bottom out. The standard is 30 thou to 60 thou. I would make the mechanic check them or DIY. You make up a tool by bending the ends of a bit of coathanger ( the bent bit being about 3MM long) then filing down to the the required thickness checking with a micrometer or vernier.

reading rimmers parts catalogue the tin gasket is approx 0.5mm and composite approx 1.2mm so thinner by approx 273 thou thinner.

That is 27.3 thou or around 30thou.


Regards Philip A

BTW, I just reviewed this whole post, and the cause of my knock was the poor quality cam and lifters I bought which destroyed themselves in 10KK. There is another thread on this

I now have a new OEM cam and lifters ( and Rollmaster chain) and it is as quiet as a mouse.
Regards Philip A

Originally Posted by PhilipA

There is a maximum preload that the lifters will take and they may bottom out. The standard is 30 thou to 60 thou.

thanks Philip. would you/anyone happen to know approx what preload this may start occuring at? this is my guess as to what is happening. I can't test as car is in a different state.

was hoping to have this confirmed so I can tell mechanic to check the bl**dy things and I can come and get my car back.

(I have read of people with 100 thou preload without problems)