Oil leak from Metal HG

campbellju

Moderators
Staff member
Since I've re-built the engine, the car has developed a reasonable oil leak from the HG. Its coming from the drivers side end where the timing chain and is weeping out once the engine gets warm.

My understanding this the area in the block/head is at atmospheric pressure so the oil is coming out by being splashed on the wall and running down but if it is as atmospheric pressure I'm amazed its leaking out.

The bolts holding the outside of the head down are only 6mm so its difficult to put any torque on them without ruining the block's thread. At the meet last night I was chatting to Andy Chan who has a similar problem (but to a much lesser) degeree and he said this problem is quite common.

I'm wondering if the Metal HG needs more compression than a standard HG and its not possible to torque up the bolts sufficiently to stop the weeping.

I did some more remedial work over the weekend and haven't yet had the chance to see if it was successful but my next step is to lift the engine on that side, remove the thread and use a nut and bolt.

Anyone else any similar experiences or solutions?

Cheers,
Jim.
 

antgtir

New Member
Alright mate, nice to have met you last night, sorry didnt really get to speak much, ill give you what i think: -

I know on past cars ive had if you take the oil cap off whilst the engine is running you can feel a bit of back pressure (this is normal) so i doubt that the internal pressure is exactly the same as atmosphere i.e. if there isn't a great seal then it will weep outwards.

Have you checked the head bolts to ensure they are still at the same torque setting?? The metal headgasket may have changed due to expansion and contraction therefore creating a gap between the two surfaces?? Ive never had any experience with metal head gaskets before so im only going off what i would see as being logical.

Id exhaust all other options before you take to drilling and re bolting mate. Hope this is of some use lol.

Goodluck, Ant.
 

campbellju

Moderators
Staff member
It was good to meet you, Amiee and all the other R owners too, next time I'll bring a big jacket so I can stay longer :roll: :wink: :wink:

Wished I'd come previously in hindsight but there never seemed to be a good time and the car was always off the road :oops:

antgtir said:
I know on past cars ive had if you take the oil cap off whilst the engine is running you can feel a bit of back pressure (this is normal) so i doubt that the internal pressure is exactly the same as atmosphere i.e. if there isn't a great seal then it will weep outwards.
That makes sense and explains why the oil is being pushed out of a hairline crack.

The head bolts were my first suspect, mentioned it to my mechanic mat e who helped me re-build it and he reminded me we tightened it up to the top of the Nissan Torque setting, He damaged an elbow and I broke the 1/2" extension bar. They are (were) tight. I don't know if being stretch belts whether they lose the Torque in the same was a normal bolt ??

Speaking of normal bolts, didn't put enough threadlock/torque on a bolt holding the thermostat in and when I parked up last night it had come loose just enough to start spraying water over the engine bay! :x Easy fixed but frustrating.

Glad I'm doing a 1000mile run in and not a 600 to get rid of all these gremilins.

Jim
 

antgtir

New Member
campbellju said:
The head bolts were my first suspect, mentioned it to my mechanic mat e who helped me re-build it and he reminded me we tightened it up to the top of the Nissan Torque setting, He damaged an elbow and I broke the 1/2" extension bar. They are (were) tight. I don't know if being stretch belts whether they lose the Torque in the same was a normal bolt ??
The Head bolts will stretch thats why they say change them everytime you take the head off. However you may have overtightened them and caused the gasket to crease?? Just a thought although if Nissan suggest the torque setting you used then hmm?? You did have the torque wrench set right didnt you lol?? :lol: :?

Where the two surfaces perfectly clean?? If there is any substantial muck on either of the two surfaces this will create in effect a gap in the gasket for oil to weep out of??

Like you say, this is the time where all the gremlins get ironed out, little feckers lol :roll: :lol:

Apart from this it could only really be a faulty gasket but i would have thought it may have been resonably easy to spot upon inspection.

Goodluck with the new water prob :roll: :p

Ant. :D
 

campbellju

Moderators
Staff member
At the time I was wondering if a metal HG needed extra Torque so I know there is sufficient but still within Nissan spec of 127Nm (Just checked)

The problem is you start to doubt everything and start wondering if the Torque wrench was accurate etc. The engine itself took us days to carefully build (shell bearings crank, pistons, cams, head bolts etc) by my matew who's buit a few performance engines in his time so I'm fairly confident with that. 3 of us (Another ex pro mechanic) then lashed the engine and everything else back together in a day and that's why all these Gremilins have come out :roll:

With the HG, its after chatting to Andy C about it and then Amiee (I think) she'd heard it was a common problem.

The water leak is just more threadlock and torque and a "Dunce" text message to whichever mate did the thermostat :lol:

Jim
 

nismoboy

New Member
i also have this problem and im left with a little patch of oil on the garage floor to remind me its there :( . As u say it just seems to seep out of the back of the engine drivers side, At first i thought it was the sump but its deffinatley the hg. I guess there are no quick fixes? Apart from changing the hg.
 
J

jiw

Guest
I take it you mean the timing chain casing, if so why not remove your oil pump bend that end of the HG down apply some liquid gasket to both sides and refit the oil pump, job done, i did this on mine when i fitted a new oil pump so it is possible, jeff :wink:
 

zia

Active Member
on the standard hg you have sealant imbeded into the hg. when you apply correct torque the hg will seal it self. with metal there is not sealant as such to creat a seal. and the solution would be to apply thin layer along the timing chain area.. there are three 8mm bolts on the head which really hold it in togeather and obviously you carn,t apply much pressure to these bolts.

zia
 

campbellju

Moderators
Staff member
Thanks gents.

I'd followed Steve's thread in the past but never saw the punchline. For the record, we looked at the time of re-building the engine but must have missed the sentence as the question came up at the time. :cry:

Jeff, I like your idea but changing the oil pump will be a hell of a job in situ?? I'd have a try but its a hell of a job, Is that what you did?

Cheers,
Jim
 
J

jiw

Guest
to do that repair would take a few hours, either that or you could go ahead and do the headgasket again :lol:

its a fairly easy job to do all you need is some good 1/4" and 3/8" drive ratchet gear :wink:
 
G

GartracS2

Guest
you only put sealant on the corners of the headgasket not all around or it pushes the headgasket up and f ucks it up royal.

Never thought to use head studs?
 

campbellju

Moderators
Staff member
GartracS2 said:
you only put sealant on the corners of the headgasket not all around or it pushes the headgasket up and f ucks it up royal.

Never thought to use head studs?
Decided against head studs as I only hoped to put the head on once before the next re-build :roll:

Jeff, I'm not mechanic of the year but am at home with a spanner (Got the knuckles/cuts to prove it) I'll take a look in the Nissan Manual and decide whther to do it or leave it?

I spent 2 hours tonight puting gasket sealer externally around the join and managed to get a long bolt through with a nut and get some proprer torque on the joint this time. Fingers crossed 8)

Jim
 

Thor

Member
At the time I was wondering if a metal HG needed extra Torque so I know there is sufficient but still within Nissan spec of 127Nm (Just checked)

Jim
Hi James!

now i have an oil leak at my cosworth 1.5mm HG too! We gave the headbolts 127NM as Nissan spec wrote and there was oil on the pistons and at the driversite (RHD) behind the engine outside. After we gave them extra Torque ~ 140NM it was sealed but is it correct or must i change the gasket against new one?

Regards
Sascha
 
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