Knocking/tapping noises from head

[aesc]

Hi,

Started my car up this morning and there was quite a loud knocking/tapping noise coming from the head and it continued for a few minutes too, not just for a second or so like it usually does.

Ive been hearing knocking/tapping noises from my engine when its cold lately (99% sure they are coming from the head), but they seem to disappear once it has warmed up. Its almost like a tappet or lifter type sound, although i dont have them of course. It still runs fine etc, doesnt spit any blue smoke out the back or anything when you start it up, but yeah seemed strange. Oil level was ok too.

1. So what could be making this noise? Do the shim clearances need to be readjusted (kind of like how tappets do on Hondas)?

I also thought I might have some sort of rattle in the head because the studs that hold my headers on were very loose and also I have previously had to tighten the bolt that hold the intercooler onto the rocker cover up a few times lately although that hasnt come loose in the last month or so. Seems odd that these would come loose.

2. What could be causing the rattle in the head?

Any help would be appreciated

Thanks

[CozmoNz]

Clogged / semi blocked oil gallery.

generally that ticking happens for 1-2 seconds on older cars (even longer on some), when there is no / very little oil around the cam/s

subaru's are bi0tches at doing it.

when did you last do an oil change?
how many km's on the engine?
been giving it shit lately then suddenly turning it off? (hot to cold etc).


Could try Proma, (only $23ish if i remember right).

but then again, it could be completely different .

[Mr Revhead]

cosmo, what you are describing is noisy hydrolic lifters, which the 4age dosnt have, so proma etc wont help at all.

[aesc]

Yeah it has done the clicking noise after startup for 1-2 seconds basically since I have owned it. Didnt think much of it. But this was louded and went for a lot longer than normal.

It had a decent run over the weekend, Nelson and back too

Last oil change, about 2000kms ago
109,000kms on engine
Na not problems with turning off or anything, no problems with driveability at all

[CozmoNz]

Hm, ive heard a few dohc cars do it though.

even my mates 180sx does it for the first 1-2 seconds...

low oil pressure? / lack of oil etc would usualy explain it.

go empty your oil out, then start the car, $50 says it makes that noise .

[fuel]

Hm, ive heard a few dohc cars do it though.

even my mates 180sx does it for the first 1-2 seconds...

low oil pressure? / lack of oil etc would usualy explain it.

go empty your oil out, then start the car, $50 says it makes that noise .

$50 also says he will ruin a bearing if he does that too. In fact you might as well give him $2000 to rebuild his engine. I hope you weren't serious with that advice.

[pc]

Check oil level, probably not enough.

maybe bung oil pump.
maybe blocked oil feeds in head/cams.

[aesc]

Yeah not that keen on running the engine with no oil in it.

So anyway back to the topic...

Do 4age's need the shim clearances readjusting every so often??

[Mr Revhead]

go see a mech, hard to diagnose with out seeing/hearing.
got an oil pressure gauge? whats it reading? does noise stop when pressure is up etc?

[aesc]

go see a mech, hard to diagnose with out seeing/hearing.
got an oil pressure gauge? whats it reading? does noise stop when pressure is up etc?

I think ill have to go see a mech.

Na dont have an oil pressure gauge unfortunately. Will see if it does it tonight as well.

[CozmoNz]

Ok, before anyone goes *YOU GIVE BAD ADVICE*.

NEVER RUN AN ENGINE WITHOUT OIL.

just so you know.... im not telling you to do it.. im just saying, the noise was created because lack of oil pressure / oil.

so basically... something either isnt doing its job, or theres a clog....

(and that was a wink, saying baha, ie - dont do it, its very stupid to do that).

point is, its oil related.

[aesc]

Yeah i know what you were saying Cozmo. Does seem oil related as it basically disappears once warmed up.

[fangsport]

my redto AE92 does exactly the same thing, i initally thought it was cam bearings ,until i was informed they don't have any. low oil was the cause.

[aesc]

True. Well when I started it up this morning I checked the oil after I turned it off (cos I was horrified by the sound) and it was halfway between full and empty. So it used a bit in the open road driving I had done over the weekend. Put some oil in it this morning then tonight after work started it up and there wasnt the bad knocking noise there was this morning..

But there was still the light tapping/knocking noise ive been experiencing for a few months. Only happens when cold but only seems to happen when there isnt any load ie when revs drop between gear changes, or when you re it in neutral and the revs drop

It has been suggested to me that it could be big ends but I had heard somewhere the big ends are mainly only noisy when warm? When the engine oil is warm its thicker and therefore cushions the bearings?

[ChaosAD]

I know a few cars with rumbly bottem ends that quieten down once warmed up. Maybe once the oil warms up and thins out it can get to the bearings easier and apply more pressure to them.

[Lloyd]

Hm, ive heard a few dohc cars do it though.

Ummm.... Subarus are dohc too. Hydraulic lifters make the noise since there isn't any oil pressure when you first start it up. SR20s and the like do that too. 4AGEs dont have hydraulic lifters so its not that.

When the engine oil is warm its thicker and therefore cushions the bearings?

Oil gets thinner as it heats up.

Shim clearances shouldn't really need adjusting. How long does it stay noisy for?

[aesc]

Well the first time it was real noisy was this morning and so far is a pretty isolated incident, but it lasted about 30 secs - 1 min or so. But this other lighter tapping noise will last for as long as it will take for the engine to heat up fully, up to 15 mins i suppose. But will do it less and less once the engine becomes warmer

[sergei]

maybe it has got something to do with forged pistons you got - too big clearance on cold?
and forged tend to be noisier on cold....
but by your description it sound more oil pressure related...

[dragg_racer666]

bro check your tappets and your shimm chearences. had the same peob and took it to the guarage and they done it for me. but a timly job.

[aesc]

Hmm well its going it early next week, they are gonna put an oil pressure gauge on it to see if thats ok.

Mech suggested to me that the exhaust man could be making the noise as it has come loose and couldve buggered the gasket, which makes a tapping noise when cold and gradually gets better once engine warms up. He said that to me even before i said to him that i had found the exhaust man studs loose so heres hoping its only that