Excessive top end noise, mk2 16v

[Andy Mc]

I've just swapped the head (which is the old one I had on before I put a ported head on) and put in 2nd hand standard kr cams (off e-bay) and when I started the engine tonight there was an incredable rattling/banging (like metal against metal) noise coming from the head.

The timing is correct.

She idles without mis-firing.

The head has been built up my mate who is a qualified mechanic which includes new lifters, oil stem seals.

The only thing I can't guarentee is the quality of the cams, as they are 2nd hand.

Does anybody know why I'm getting this noise, are the cams to blame...? Is it normal for old cams against new followers to rattle and bang...? I only ran the engine for less then 60 seconds for fear of damaging it.

Any answers, as always will be greatly appreciated, cheers.

[animaniac]

the noise will be caused by movement between the cam lobes and the tappets!

the tappets will be hydrolic and would quieten down after starting....

even if they arnt hydrolic if the tappets are new there shouldnt be really any noise!!

but you will get noise if the cams and tappets were dry when you started the engine!!??

if this the cause?? after a long drive oil still coats the top end of the engine for some time after shut down
this is one of the reasons why regular car drivng is important so that the top end of the engine doesnt ever become dry!!

i remember reading an artical in revs mag in 1998 they did there worxs! they put a performance cam into a
xr2i and i remember them saying that you had to coat the cam in cam lube which came with it!!

they also said that once started they have to hold to the engine revs at 2 - 3000 rpm! so they didnt naff the cam!

i think the only reason they do this is to get oil from the bottom of the sump around the cam straight away!

the golfs dont have what they call oil rail above the cam...
so top end and camshaft lubrication requires oil from the sump.... which only rises when the engine revs are 3000 or more!!

this is why most cars engines rattle... lack of lubrication to the camshaft! = wear and then noise!
how many people drive with their revs over 3000k...!! this is why town driving naffs cars up!! whre as motorway driven cars are still in good nick despite having high milage... because at high rpms the engine is well lubricated!!

i hope this helps!!

[Veedubgt18v]

after fitting new tappets/or dimantling old heads, you should leave them rest for a bit so they can settle is waht you probably heard was a combination of tappets getting themselves sorted out and low oil pressure in the head, will take a couple of mins for the oil to circulate and get in the tappets

[Andy Mc]

Cheers for the responses guys, not sure what to do, might give the engine a longer run tonight sat on the driveway and rev her a bit to see if the noise disappears......if not, I've been offered another 16v unit, how difficult is it to replace like for like...? I will start a new topic on this....

[Veedubgt18v]

not hard at all engine out engine in cos all the wiring etc will be the same

let us know

[Andy Mc]

Will adding some cam lube help..?

Do you know of anywhere that stocks cam lube...GSF and Euro Car Parts don't list it online....

[Veedubgt18v]

just fill them with a syringe or something and lettly oil them, they jsut need half an hour to settle thats all

[Bam Bam]

...I would do the same, start her up and leave her on idle until you reach normal running temp. and the oil becomes more viscous, when its hot it will flow better and it should start to quieten the top end down after half an hour or so.

Jim.

[Veedubgt18v]

i meant leave it standing ffor half an hour to settle then tappets with the engine not running! but ts had long enough by now

the other thing i thought was are the cam retaining bolts done up correctly?

[mcrisp]

Its a Ford manual, but get hold of Burton Powers parts catalogue wchich contains an engine building guide telling you lots about this sort of thing.

The first few minutes of running with new cams and followers (new in the sense that they haven't been used together before, regardless of whether they are actually new) are absolutely crucial - this is when initial scuffing defines the wearing surfaces (ie the cam and follower wear to 'fit' together), and will make a huge difference on wear rate in the future.

Maximum oil pressure for at least a few minutes at first start up is vital - this ensures plenty of lubrication coming to the wearing surfaces, and makes sure the lifters pressurise up and get rid of any clearances as quickly as possible.  Most manuals specify 2-3 mins @ 2-3k revs is VITAL on startup.

Zinc based, thick cam lube is normally supplied with new cams, but try Kent or Piper for a bottle, and should be used to coat the cam lobes and bearings before installation.  Its ok for this stuff to be in your system even though its thick and smells like an alsation thats been drinking gearbox oil.  You'll be doing an oil change after a couple of hundred miles anyway...

I started a vauxhall 8v engine with dry lifters after full rebuild and the noise was horrendous, another 8 valves and I should think that accounts for the noise being loud.

Have you got this started and sorted now?  I've gotta do a top end rebuild on my new golf, so would be interesting to know how it went in the end.