10 replies to this topic

[Harrison541]

I've got a leak from the back of the head on the radiator side, right in the corner. I seem to have had constant oil leaks with this one, first it was the timing chain, so I re did that gasket, then some of the lower ones in the gearbox, then the clutch oil seal, thats had a new seal, and now its leaking out of the head. I was just thinking, what are the chances that the head gasket has been blown all along between a cylinder and an oil way, pressurising the oil and blowing it out of everywhere?

 

I've got none of the other head gasket failure symptoms, no sludge in oil, no coolant loss and the compression test was within 10% of each cylinder.

Edited by Harrison541, 03 February 2015 - 08:19 PM.

[sledgehammer]

wonder if it is the oil gallery closing rivet on the side of the head ?

 

will look for pic ...

 

found a post ...

 

http://www.theminifo...-wateroil-port/

Edited by sledgehammer, 03 February 2015 - 08:40 PM.

[Spider]

Good call

 

wonder if it is the oil gallery closing rivet on the side of the head ?

 

will look for pic ...

 

Here's one

 

 

While worth checking the plug, the Oil Pressure passage through the head gasket is also in the same location. They usually have a copper sealing ring in the gasket for sealing, but it doesn't take much to make them leak.

 

Either way, it's highly likely the head will need to come off, but give it all a really good clean forst and check exactl;y where the leak is coming from as once it's in bits, it's harder to work out.

[Harrison541]

So that's it in the centre of the photo? It's on the mating face pointing down.

That's the exact spot where it's leaking from, I'll have a look tomorrow. How would I go about replacing it I it was causing the leak?

[sonikk4]

A head gasket can leak oil without other signs of distress. The HG i originally used on my clubby last year leaked like a sieve but no over heating etc etc. i changed it to a Payen and this cured the problem.

 

There have been a few members on here suffering with issues from installing new copper HG's. 

[Spider]

So that's it in the centre of the photo? It's on the mating face pointing down.

That's the exact spot where it's leaking from, I'll have a look tomorrow. How would I go about replacing it I it was causing the leak?

 

 

The Red Line is pointing to the Plug, the Blue Line to the Pressure Oil Passage (which is sealed by the head gasket)

 

As they are very close to each other, it's very easy to think it's one when it's the other, hence why I suggest giving it a real super clean up and then check it right away (when running).

 

If it's the head gasket, then replace it. A few guys this why have had a few leak here with no other problems, so they ended up also putting a O ring inside the copper sealing ring of the gasket, problem solved.

 

if it's the Oil Plug, you'll need to pull it and re-fit a new one, however, I'd suggest going to a screwed plug as there maybe some distortion of one type of another that's causing the plug to leak. It's not unheard of but unusual for them to start leaking aftering being OK for so long. Usually if the plug is a problem, it will - but not always - leak from day one.

[sledgehammer]

just had a look at a 998 a+ head in my garage - the rivet is at the bottom of the head (yellow head - upside down)

 

some engines  had them at the top (I suspect to avoid voids in the head)

 

 (pics are the wrong way around - but you get what I mean)

 

http://www.theminifo...ttach_id=157739

Attached Files

•  headrivet.JPG   22.02K   17 downloads

Edited by sledgehammer, 03 February 2015 - 09:08 PM.

[westlin]

I have a similar leak. Just had the head skimed fitted a new bk450 gasket, but its spraying from that end of the head. One comment is to fit an oring. Is this on the red identified hole? As I need to take the head off to that do I need to replace gasket as it has done less than 100 miles.

thanks

[dl4112]

I have this same issue, oil leaking from on top of the head gasket but under the head. Not coming from the rivet, as have drilled it out and had it filled with aluminium at local engineering workshop. Is there an ultimate answer/solution to this problem? Its costing me a fortune in head gaskets every time I think I've solved the issue!

Cheers

[Spider]

I usually fit a Grub Screw with Loctite in to this Oilway drilling. Never had one leak.

 

With all the small bore heads, the horizontal drilling is very close to the deck of the block. If the drill had wandered (and that's not unusual) and the heads been skimmed, it can weep or indeed leak through the deck along this Oilway. I know you've had your Oilway plugged, however was it also pressure tested?

 

A friend had some trouble getting the gasket to seal on one of his, he ended up putting an O Ring in the Gasket, which I think he said worked. There should be a (usually) copper pressure ring around the Oilway passage through the gasket.

[tiger99]

If the head has been skimmed, there is what used to be an extremely well-known problem, now apparently forgotten, with the oil passage in the head, which can break through the surface after a heavy skim, outside the area of the reinforcing ring, maybe obviously but possibly just a pinhole or two. The fix used to be to open it right out and braze in a piece of copper tube. Fill it flush with braze, a very light skim to ensure that it is still flat, and all was well.

I often thought that plumber's solder would do as the temperature there hardly goes above 100°C. You would not then need a skim, just a scrape to ensure there were no protrusions, but if the repair passes through the area of the reinforcing ring you would need the harder braze. Nowadays MIG or TIG with a lot of preheat and slow cooling and a steel tube might be favoured by some welding experts.

Now why do we not hear of this any more? Maybe something has changed such as the depth of the oil passage in the casting? But older heads would still be at risk.

By the way you can most probably rule out a blow between cylinder and oil way pressurising the oil. It is invariably just an oil leak, freak cases excluded.