Possible Cylinder Head Leak AAN Engine (please help)

[UrS4boy]

I think your problem was two fold:

1. The cam cover gasket and half-moons were either not new ones or they weren't seated properly. Suggest you get a new set (item 17 below)

2. Somebody mixed up the cam cover bolts, there are two longer ones at the front (items 15 in the diagram below), the rest (item 16) are shorter. If you do change the cam cover gasket, remember that the two posts, item 19, have to be removed from the middle of the cam cover before it can be separated from the head.

[URquattroGus]

Thanks for the pointers URS4Boy;

The Gasket and half moons appear to be seated properly, I do also have two longer bolts holding the front of the cover down. I have used the two bolts that were origionally on the front to secure the two middle fixings near the spark plug. I have a 7A cam cover fitted.


I will have to wash it down yet again and check there is no oil blowing back, but I'm pretty confident its not that.

So do I need a special tool to check the torque of my arp nuts/studs?

[UrS4boy]

Thanks for the pointers URS4Boy; The Gasket and half moons appear to be seated properly, I do also have two longer bolts holding the front of the cover down. I have used the two bolts that were origionally on the front to secure the two middle fixings near the spark plug. I have a 7A cam cover fitted.
I will have to wash it down yet again and check there is no oil blowing back, but I'm pretty confident its not that. So do I need a special tool to check the torque of my arp nuts/studs?

You might have told us earlier that you had a 7A cam cover (all bolt length bets are off). As for checking the ARP nuts torque, you will need a torque wrench:

[newsh]

I think he's asking if he needs a special socket as the ARP nuts are 12 point?

[URquattroGus]

Thank you for stating the obvious and providing a picture. You know how to try and insult someone's intelligence.

Yes I have a couple of torque wrenches.

I meant that the nuts looked more like torx without close inspection.

Checked the torques of the head studs today, all checked out ok save for one that moved just very slightly.

Replaced the cam cover with even more care than usual.

Also dropped the oil and changed the filter today as I've just passed the 500 mile mark.

Leak still there, it's a mystery to me, its going back to the engine builder for him to have a look.

Shame, I would like to get to the bottom of it myself, particularly as its a few miles to get the car there.

[UrS4boy]

Thank you for stating the obvious and providing a picture. You know how to try and insult someone's intelligence. Yes I have a couple of torque wrenches. I meant that the nuts looked more like torx without close inspection.

Sorry. From one of your earlier comments, it wasn't clear that you were fully equipped, torque wrench-wise. Didn't mean to insult you.

[DJones]

Thank you for stating the obvious and providing a picture. You know how to try and insult someone's intelligence.

Yes I have a couple of torque wrenches.

I meant that the nuts looked more like torx without close inspection.

Checked the torques of the head studs today, all checked out ok save for one that moved just very slightly.

Replaced the cam cover with even more care than usual.

Also dropped the oil and changed the filter today as I've just passed the 500 mile mark.

Leak still there, it's a mystery to me, its going back to the engine builder for him to have a look.

Shame, I would like to get to the bottom of it myself, particularly as its a few miles to get the car there.

Angus what torque did you do check the bolts at?

[Audiboys4]

I had / have this same problem... Changed head gasket twice as i was affraid it was something wrong with the gaskets or the way I torqued the bolts... Gave up an delivered the engine to my engine builder and made him tear it apart and machine head and botom end again. He did not find anything , he has put the engine together again and I will soon mount it, to find out if the leak is still there... exactly same spot as you, and my exhaust did smell like it was burning some oil. Hope you find your problem...

[twenty valve]

ARP studs you need to get the torque setting that came with the bolt set mine were 65ft/lbs.

Torque up using the lube supplied, run engine up to full temp and leave to cool down over night. Re torque to peak torque setting only using correct sequence.

Then run it 150-200miles. Check it again by re torquing to peak torque.

Lastly check once more after 500 miles.

Due to the extraordinary length of the bolts they are very prone to excessive settling compared to other ARP bolts and have seen many a failed headgasket.

100% right! I found that out the hard way!

[URquattroGus]

UrS4boy; No offence taken, looking back I probably wasnt all that clear, I wasnt sure if you were teasing me

I used the factory sequence and was cautious so checked in several stages.

First 20LBft, then 40lft and 65lft and then 75lbft (this is what the bolt instructions said and what the builder used on this and some other engines)

This is using the original audi washers not the crap ARP ones.

I feel more relaxed now that I know the head is not loose.

It's going back to its maker when I get a chance, and I'm sure he'll sort it.

My exhaust never burns any oil that I can make out. It's almost as if it is running from closer to the front of the block to that lower ledge at the rear corner. I'm not convinced it is coming out exactly on the rear corner.

Also, it seems the oil loss is slightly less than I thought, to a degree It seems to take a while for the oil to drain back to the sump i.e there is a higher indicated level when dipping from cold in the morning.

STill smiling though, had a great drive yesterday, the way my car handles now is really fun, and I can tell it's going to have the performance to match

[DJones]

UrS4boy; No offence taken, looking back I probably wasnt all that clear, I wasnt sure if you were teasing me

I used the factory sequence and was cautious so checked in several stages.

First 20LBft, then 40lft and 65lft and then 75lbft (this is what the bolt instructions said and what the builder used on this and some other engines)

This is using the original audi washers not the crap ARP ones.

I feel more relaxed now that I know the head is not loose.

It's going back to its maker when I get a chance, and I'm sure he'll sort it.

My exhaust never burns any oil that I can make out. It's almost as if it is running from closer to the front of the block to that lower ledge at the rear corner. I'm not convinced it is coming out exactly on the rear corner.

Also, it seems the oil loss is slightly less than I thought, to a degree It seems to take a while for the oil to drain back to the sump i.e there is a higher indicated level when dipping from cold in the morning.

STill smiling though, had a great drive yesterday, the way my car handles now is really fun, and I can tell it's going to have the performance to match

Angus,

In my honest opinion 75lbft might be your problem, I personally think that is far too much for ARP bolts.

60lbft is the maximum I would go to. You may have flattened the embossed part of the metal head gasket too much hence its not sealing correctly.

I have a friend that only goes to 50lbft on ARP’s regardless of the engine type for the reason stated above, half of this again is some considerable clamping force..

Hope it helps.

Darren

[URquattroGus]

DJones, yes, the thought had crossed my mind.

I hope its not the case. It's amazing really, a search on here bought up suggestions for anything from 60-80lbft and the same on motorgeek. Everyone seems to have a different view.

The thing is, as I understand it the oil ways on that side are drain backs not and pressureised?

The leak may be from near the front of the engine, its hard to see whats going on below the exhaust manifold. There may be a damp spot below the front engine mount on the front left of the engine biut its so hard to see.

My last stab in the dark is a leaking camshaft seal....

No sign of oil on the cam sprocket or behind the very top of the cover, maybe it could leak down and back along a crease in the block?

[DJones]

DJones, yes, the thought had crossed my mind.

I hope its not the case. It's amazing really, a search on here bought up suggestions for anything from 60-80lbft and the same on motorgeek. Everyone seems to have a different view.

The thing is, as I understand it the oil ways on that side are drain backs not and pressureised?

The leak may be from near the front of the engine, its hard to see whats going on below the exhaust manifold. There may be a damp spot below the front engine mount on the front left of the engine biut its so hard to see.

My last stab in the dark is a leaking camshaft seal....

No sign of oil on the cam sprocket or behind the very top of the cover, maybe it could leak down and back along a crease in the block?

Angus,

Its hard to find where it comes from, hot engine, vibration and the wind that blows through when you are on the move could result in it coming from anywhere.

It doesn't normally defy gravity though i.e go upwards.

Once you start turning the boost up you will chase leaks forever regardless of the breather system. 1.5 to 1.6 bar seems to be the limit for leaks after that they seem to spring strange leeks that have a habit of coming and going.

I have one that you would think comes from the rear oil seal but its not, Ive circum to giving it the occasional wipe down with some spirit to keep it clean..

Fun fun fun....

Darren.

[URquattroGus]

Update on this. I haven't seenn it with my own eyes yet, but apparntly it's an aluminum bung that is weeping on the front of the head. It is then getting drawn/blown along the block/can cover towards the back of the engine.

Thought people might like to know if they are searching for a similar problem.