An Inconvenient Problem

[Mark Halligan]

Here’s an interesting one for the technically minded here.

I pulled the head off today due to an oil burning issue. I stripped it down completely and when I came to the exhaust valves I found something interesting.

Now this head has only been on the car for approx 2k miles, so I still remember the build up fairly well. At the time of this head build I already had ten VSOS’s ‘in stock’, these were from Audi.

This left me needing another ten, so while I was at ECP getting some gaskets I got another ten there. These were a different make from the ones I’d got from Audi, made by firm called FPM (at least that’s the brand mark on them).

I have used VSOS from ECP before with no probs....

I installed the seals from Audi onto the inlet valves and the seals from ECP onto the exhaust valves.

Anyway as you can see from the pics below some of the seals from ECP are looking a bit fooked. When I stripped the head, five of the ten exhaust seals appear to have melted!

The other five are fine, strange thing is that this is fairly random with at least one cylinder having one seal melted and the other unaffected. All of the seals were installed and seated correctly onto the guides.

I’ve tried Googling the FPM seals but I can’t really find out much about them i.e. what they are made of.

The motor still needs mapping so I have been taking it relatively easy, max EGT’s are recorded by a Greddy warning gauge and have never been above 730 C (probe immediately after the turbine). Burn patterns are identical across all five of the cylinders.

The biggest difference with this head build is the valves, with the usual sodium filled exhaust valves replaced with 034 Inconnel valves.

So what’s the cause?

Is it just that the FPM seals *****? (the ones I got from Audi are made in Brazil so I doubt they are anything too special either)

Do the Inconnel valves conduct too much heat from the valve head and up the stem to the seals? For sure there must be a difference here to the OEM sodium filled valves but I can’t believe that they conduct enough heat up the stems to melt valve seals!!

Got to laugh at these haven’t you…….

[Mark Halligan]

These poor little fellas look like they have been in there for a billion plus miles, not 2k!

[Mark Halligan]

One of the 'good' ones alongside one of the VSOS I got from Audi (the black one).

Any suggestions anyone?.............

[4WheelDrifter]

******. That's not good Mark.
If it's happened at random you'd think some of the seals are poorly made. If it was the valves causing the problem you'd think all of them would go the same. I was told that most of the heat from the valve is conducted through the seat anyway.

[Briggsy]

very strange. its a shame you didnt have any of the VSOS's on the exhaust side, that would have solved it straight away.
i dont think its an issue with the inconel valves, the temp at the stem will not be that much different from the sodium filled valves.
it must be to do with the quality of the FPM seals, although there must be a difference in material, why would they be different colour?
just my 2p.
jose.

[SteveH]

Mark,

I'd be suprised if those aftermarket seals were manufactured from the wrong material, but it could be a quality control issue during their manufacture. I'd personally be a little worried, as they do look like they have been cooked to cause that sort of damage. Do the 034 valves have minimal seating area? and do you have a 3 or 5 angle cut on the valve seats in the head? If you do, perhaps the valves are finding it difficult to transfer the heat to the head via the valve seat contact area. I know of one high power I5 that detonated recently due to the valve seat dropping out of the head, I believe it was using the same valves. Could be unrelated, but worth looking into...

[Corey]

Mark,
did you recut the seat to match the valve or just lap the valve in?
If you just lapped the valve in there is not enough contact between the seat and valve and the heat transfer will go up the stem and affect the seal.
The EGT temps are an average from all the cylinders, some will be running hotter.

[Mark Halligan]

Mark,

I'd be suprised if those aftermarket seals were manufactured from the wrong material, but it could be a quality control issue during their manufacture. I'd personally be a little worried, as they do look like they have been cooked to cause that sort of damage. Do the 034 valves have minimal seating area? and do you have a 3 or 5 angle cut on the valve seats in the head? If you do, perhaps the valves are finding it difficult to transfer the heat to the head via the valve seat contact area. I know of one high power I5 that detonated recently due to the valve seat dropping out of the head, I believe it was using the same valves. Could be unrelated, but worth looking into...

Hello Steve

You make some good points.

The valve cut was an expensive multi angle job, maybe this is the cause as the contact 'circle' and opportunity for heat transfer, may be smaller.

[Mark Halligan]

Yes Corey as I said above the valve seats were given an expensive recut (give me some credit please ), and this is why the more I think about it, the more concerned I am getting.

The EGT temps are an average from all the cylinders, some will be running hotter.

Yes of course any reading taken collectivelly from all of the runners, especially after the turbine, will be an average. However you can tell a lot from the burn pattern and none of the cylinders (or plugs for that matter) are showing any sign of overheating.

Besides if a cyl was overheating I would expect both Ex valves in that cyl to have the same problem and this was not the case.

I am hoping this is due to bad seal material.

Whilst I am getting good at pulling the head off of this block I don't really want to be doing it too often.

I am going to try to get hold of some Viton seals from Supertech whom I believe make the valves that 034 sell?

Hopefully these will be more robust and do the job.

[Corey]

Yes Corey as I said above the valve seats were given an expensive recut (give me some credit please ), and this is why the more I think about it, the more concerned I am getting.

you have fuill credit from me Mark,

Yes of course any reading taken collectivelly from all of the runners, especially after the turbine, will be an average. However you can tell a lot from the burn pattern and none of the cylinders (or plugs for that matter) are showing any sign of overheating.

Besides if a cyl was overheating I would expect both Ex valves in that cyl to have the same problem and this was not the case.

not always

I am hoping this is due to bad seal material.

Whilst I am getting good at pulling the head off of this block I don't really want to be doing it too often.

I am going to try to get hold of some Viton seals from Supertech whom I believe make the valves that 034 sell?

Hopefully these will be more robust and do the job.

I would be inclined to agree. I have a certain engine that the head is going on and off quite regularly also and feel the same as you with it.

I have used Viton in the past and have had very good results with their products, where other manufacturers have failed. I have an old contact there, I will dig out the little black book and have a looksee.

Supertech??? never heard of them :mischeif:

[Mark Halligan]

I have used Viton in the past and have had very good results with their products, where other manufacturers have failed. I have an old contact there, I will dig out the little black book and have a looksee.

Viton is a material, not a manufacturer....

[Corey]

I know, we had an old contact at a seal manufacturer (blue diamond). I should've made myself clearer.

[pixsaudisex2]

carnt you get the good valve seal and a bad one a do an experiment with an old valve and warm it up at the bottom and see what happens to a good seal and one of your bad ones to see if they have different temps that they melt at.. surely give you an idea if there sub standard parts..
just a thought.. o and hello mister mark..

[Mark Halligan]

carnt you get the good valve seal and a bad one a do an experiment with an old valve and warm it up at the bottom and see what happens to a good seal and one of your bad ones to see if they have different temps that they melt at.. surely give you an idea if there sub standard parts..
just a thought.. o and hello mister mark..

LOL Hello again, yep I might give that a try.

Either way though I will try to get hold of Supertech's Viton seals

[spink]

Were you planning on taking it to ADi this weekend?