Ok, bit of history first..

 

After a 60k maint, the car had a nice oil leak - actually it kinda had it before it, but it seemed to get worse after the 60k was done. It mostly came out around the join between the two upper cam covers - but everywhere else was pretty plastered in oil too, and it only seemed to come out under pressure, not when the engine was off.

 

So, I've started stripping everything down (only 18 months after I stopped using the car, ahem).. and it's not quite what I expected.

 

The outer (non ribbed) side of the cam belt is dry - where I expected it to be oily, the inner side is a little oily, but most of the oil seems to be pooled on the inside 'rim' of the intake pulleys.. Which is odd.

 

(Click pics for a huuuge version)

You can just see a little oil pooled in the bottom of the drivers side pulley.

 

Much more pooled on the passenger side.

 

Not much oil elsewhere really - the back plates had a light smearing, everywhere down from the cams, and then everywhere under the engine etc is smeared with 'runoff'.

 

What was odd, is that from what I can see 'through' the hole in the back plates, the block looks clean.. I expected that to be the worst, and for it to be tracking down the cams and getting thrown out - not for it to be inside the cam pulleys like that.

 

So, any pointers where it might be coming from?

 

Tomorrow I'll pull the lower cover and belt off, cam pulleys and then the back plates, to see if there is oil visible on the block anywhere..

 

:headvswal

thats cam sprocket seals matey remove the 4x 7mm screws and replace the o-ring behind each plate check idler spring and replace if needed 10min job bud :)

thats cam sprocket seals matey remove the 4x 7mm screws and replace the o-ring behind each plate check idler spring and replace if needed 10min job bud :)

 

I was hoping someone was going to say that ;) I'll whip the end plates off tomorrow and inspect the o-rings - hopefully one of them got pinched or wasn't seated properly.

 

Might still pull all the rest off and clean the block down with Gunk and warm water, so I can see a bit better where the oil is coming from..

 

Oo, might even have it running again soon ;)

 

Got no money to tax or insure it, mind.. D'oh!

 

Cheers Greg :)

Right.. well, took the cam end plates off today and yep, there does seem to be a nice film of oil all round outside the O-ring..

 

I can't quite figure out how or why it was escaping, though.. The O-rings were nicely in their grooves, seated properly, weren't pinched anywhere, and are still slightly proud of the end plates so they hadn't been squashed totally flat or anything like that..

 

Greg - still reckon it's there that was leaking? I'm in two minds now as to whether to replace the O-rings and reassemble it all, or whether I should carry on stripping it down and have to shell out on a new cam belt, tensioner etc.. Bear in mind that the whole thing was only done maybe 2000 miles ago.

 

Hmm, some pics, though they don't really show the oil, they do show the mating faces etc (click for huge ones, as always):

 

Driver's side end plate

 

Passenger's side end plate

 

Driver's side cam

 

Passenger's side cam (the oil at the bottom is what ran out when I removed the end cap, obviously)

 

Tried to have a look through the cams again, there doesn't seem to be any leakage from the exhaust cam seals, but the inlet cam seals are hidden by the sprocket.. There was a little oil sat in the heads of the back plate retaining bolts, just behind the inlet cam sprocket, though.

 

Hmm..

Can't imagine how it could get into the front of the sprockets from anywhere else? Those little screws break very easily if they are screwed in too hard, were they all ok?

Can't imagine how it could get into the front of the sprockets from anywhere else? Those little screws break very easily if they are screwed in too hard, were they all ok?

 

Aye they're all fine - I've always made sure to not screw them up too tight, just nip them up basically.. And the o-rings weren't squashed totally flat (were still slightly proud of the plates by 1mm or so) so should have been making a good seal. Most odd.

sorry aaron look in pic this is your culprit 100% order new cam sprocket seals as you can see in pic iv marked with red dots they simply pry out then press new one in a little clear gasket sealent helps just rub a bit around the outside of the seal to give it a nice seal

 

to make it easier after removal of cam seal use old one to knock in new one it helps keep it go in straight and not kink,so you wont need to remove that cambelt or tensioner either :)

Ahh you meant those seals.. :) Not the o-rings.. Darn.. :D

Wait.. is that the cam seal that is normally replaced as part of the 60k, or a seal inside the cam sprocket itself?

 

If it's the 60k one - can't you only do that with the sprocket off?

 

If it's not the normal cam->head seal, don't suppose you have a part number, do you greg? ;)

 

(Or failing that, does anyone know where I put my FAST CD? :lol: )

Wait.. is that the cam seal that is normally replaced as part of the 60k, or a seal inside the cam sprocket itself?

 

If it's the 60k one - can't you only do that with the sprocket off?

 

If it's not the normal cam->head seal, don't suppose you have a part number, do you greg? ;)

 

(Or failing that, does anyone know where I put my FAST CD? :lol: )

 

Is spose to be part of 60k service not always changed though,If you have an air gun the sprocket is easily removed then remove camshaft backplates then seals can be pryed out

 

as for seals ryan[baggins]has a spare couple at work could always buzz him and he can send you them,there only a few quid each i think ;)

Is spose to be part of 60k service not always changed though,If you have an air gun the sprocket is easily removed

 

as for seals ryan[baggins]has a spare couple at work could always buzz him and he can send you them,there only a few quid each i think ;)

 

Hmm.. then I have this horrible feeling it may be the head (or the cam) that's the problem - as those seals have all been changed twice, and yet the oil leak persists..

 

Basically - it leaked a bit before it's first 60k maint (not long after I bought the car).. it leaked more after it's first 60k maint.. After about another 5-10k the engine was swapped into another shell and it had another 60k kit done.. and it leaks even more now than originally. I can't believe I'd be unlucky enough to end up with the seals put in wrong twice (well, three times, considering it was already leaking when I got it), especially considering it was done by two different people (myself the first time, and I have a feeling Andy (Duff) put those seals in when we were rebuilding the engine the second time).

 

So I have this feeling that changing the cam seals isn't going to stop it at all :( (I have a spare set of cam seals anyhow :)).. Plus - surely if I remove that cam, I'm going to need to put a new cambelt tensioner etc on..

 

Damn.

Hmm.. then I have this horrible feeling it may be the head (or the cam) that's the problem - as those seals have all been changed twice, and yet the oil leak persists..

 

Basically - it leaked a bit before it's first 60k maint (not long after I bought the car).. it leaked more after it's first 60k maint.. After about another 5-10k the engine was swapped into another shell and it had another 60k kit done.. and it leaks even more now than originally. I can't believe I'd be unlucky enough to end up with the seals put in wrong twice (well, three times, considering it was already leaking when I got it), especially considering it was done by two different people (myself the first time, and I have a feeling Andy (Duff) put those seals in when we were rebuilding the engine the second time).

 

So I have this feeling that changing the cam seals isn't going to stop it at all :( (I have a spare set of cam seals anyhow :)).. Plus - surely if I remove that cam, I'm going to need to put a new cambelt tensioner etc on..

 

Damn.

 

 

no you dont need to replace tensioner just insert 10mm bolt in to side of tensioner so it cant open up fully then leave a 4-6mm gap as before ;)

 

hmm TBH aaron im learning the z game as i work at z tech with ryan so its difficult to say without seeing,i know yourself you have a pretty good knowledge of the 300 :p

 

if it gets to it your always welcome to pop down this neck of the woods bud ,anyhow it just seemed the puddle of oil in the sprocket suggested the cam seals on yours! perhaps when the seals were fitted the mating surface to the camshaft has been damaged or the covers are leaking?

Cheers greg - the help is much appreciated :) It's as much about talking it over with someone as anything else. You know how it is, I'm sure - bounce ideas off someone :) Partly why working alone gets to me a bit sometimes!

 

if it gets to it your always welcome to pop down this neck of the woods bud ,anyhow it just seemed the puddle of oil in the sprocket suggested the cam seals on yours! perhaps when the seals were fitted the mating surface to the camshaft has been damaged or the covers are leaking?

 

You're right - I suspected the same thing on finding the oil where I did.. I think I'll pull the back plates off and have a good poke about back there.

 

I'm wondering if the mating surfaces were damaged in Japan before it ever got to me - I know that when I first stripped the engine down (a few years ago now) there were a lot of things missing that would suggest the engine had already been out of the car - not to mention one of the little mountings that Nissan suggest bolting an engine crane to had been snapped off the inlet plenum and ally welded back on at some point..

 

Worst comes to worse, I'll get two new heads - I know the block is sound, at least.. And heads can be done (just about) in situ. Don't have the space to pull the engine, sadly..

 

Wish I had the money to do a full resto, really - strip every nut and bolt, acid dip and respray etc.. Oh to have limitless funds eh? :)

Well.. Pulled the drivers side cam sprockets off, checked for signs of oil on the drivers head - nil.. and the cam was dry where it should have been etc, so I don't think that one was leaking from the cam seal.

 

But.. I can't get the passenger side intake cam sprocket off! Doesn't matter what I try.. I've tried pulling, pushing, levering, tapping it in every direction you can imagine with a rubber mallet, even putting wire through some of the holes and pulling (so it would come off square), but it won't budge a millimeter.

 

Look out for an "unfinished project" coming to a for sale section near you soon.

Right greg - I think you may be right about the cam seals leaking.. at least that's what the evidence on the sprocket rear indicates..

 

Take a look at these pics:

 

You can clearly see the yellow patina of old oil that spreads a fair way down the 'neck' (well past where the seal would be). However, I think that is 'old' old oil, i.e. not this leak, as you can see where it has been worn away (presumably by the new seal) - but I could be wrong..

 

You can also see (in the second pic) the black, burnt, oil at the very tip - which would be 'inside' the seal (engine side), and you can also see the 'step' that is perhaps 2mm from the end of the cam and maybe 0.5mm deep.. I wonder if that step is meant to be there, or perhaps if my sprockets are worn and therefore leaking?

 

I'll try a post on TTnet as well, see if anyone over there has come accross it.

 

Aaron

Also look for (deep) scratches/damage on the leaking camshaft(s) itself.

I've seen this before and in my case it was because someone pryed out the old seals a bit too enthusiastic and damaged 2 camshafts in the process....result: car needed 2 new camshafts to stop the leaks.

Aaron, how yer getting with yer results mate ? am watching tis with bated breath :D mine has the excat same symtoms as yours, a bloody hard to find leak, rebuild last year and all seals done, cambelt and all seals done again a few months ago and still she leaks out oh and i had a seized cam pulley too.

keep us posted mate :)

cheers

smithy

Also look for (deep) scratches/damage on the leaking camshaft(s) itself.

 

Hi Eric - I knew you'd show up eventually :)

 

I don't think it's the cams themselves, in this case though - with it only being the intakes that are leaking (the exhaust seals seem to be dry & clean), as the intake seals actually seal onto the head and the (rotating) cam sprocket, rather than the cam..

 

(There's no damage around the sealing areas that I can see, though, as an aside)

 

Aaron, how yer getting with yer results mate ? am watching tis with bated breath :D mine has the excat same symtoms as yours, a bloody hard to find leak, rebuild last year and all seals done, cambelt and all seals done again a few months ago and still she leaks out oh and i had a seized cam pulley too.

 

Hey Smithy - long time no speak and all that..

 

The concensus on TTnet seems to be that it's quite likely my cam sprockets are toast.. Other people see similar wear patterns to me, but the one person who had a spare on the bench to measure didn't think the lip on theirs was as bad. I'm thinking perhaps the lip on mine is now so big that the oil seal isn't sealing properly..

 

When I have some money (i.e. if I actually manage to get a job soon, before I go bankrupt!) I think I'll pick up some replacement cam sprockets from a known good engine, replace the seals and the sprockets and see what happens..

 

Don't hold your breath though bud, it might be a while before I have the cash! Wouldn't want you keeling over and depriving us all of shiney goodies! ;)