Leaky exhaust valves

[gammaxy]

I'm no expert, but I think what you're seeing is actually caused by the lead in 100LL and does not indicate you are running too lean. Does your VW guy have experience looking inside engines that have run 100LL?

http://www.shell.com/business-customers ... 71600.html

Two of the exhaust valves look slightly green in the picture (might just be the picture). It would be interesting if those are the same valves that are leaking.

https://www.aopa.org/training-and-safet ... lve-safety

[rizzz]

I'm no expert, but I think what you're seeing is actually caused by the lead in 100LL and does not indicate you are running too lean. Does your VW guy have experience looking inside engines that have run 100LL?

http://www.shell.com/business-customers ... 71600.html

Two of the exhaust valves look slightly green in the picture (might just be the picture). It would be interesting if those are the same valves that are leaking.

https://www.aopa.org/training-and-safet ... lve-safety

I was thinking this was due to lead as well, I doubt I'm running too lean as I often have to lean out to make the engine run smoother.
I'm not sure if he has any experience with engines running 100LL, I guess not, but he did tell me to run normal 98 if I could.
I told him I have an AeroCarb and due to its sensitivity to air in the fuel system I have not tried this, even though I have my compression ratio set to allow for it (7.89)

[rizzz]

In any case, he's sending the heads off to be sand blasted, valves & seats fixed & checked and the surface contacting the cylinders cut to make sure there are no leaks there either.

[WaiexN143NM]

Hi all,
Been using the tcp , its been around for 40+ yrs. aircraft spruce sells for $42.50 qt, and yes get the reusable siringe $5 , makes extract out of the can and measuring simple. Faa cert. For lycoming, continental, franklin engines. NON turboed aircraft.
Decalin, a few have posted here with good results. Never tried myself. Non certified. About $35 qt.
We use the tcp on our jab 3300. Yes, 30ml per 10 gal.
Prevents lead oxide build up. Plugs and valve train. Lots of aerovee posts here on valve train problems.
This may help some of the problems. Good luck and safe flying.

WaiexN143NM
Michael

[mike.smith]

OK, just got back from the airport, despite trying the many suggestions, in the end the heads had to come off as nothing seemed to improve the situation.

Here's what they look like, not pretty.
Right:
The cylinders look good though but the piston faces have the same burnt look.

Took them to my VW guy, his reaction:
Holy $#&!!" these have seen some heat, how lean are you running this thing???!!!

My response to that was, what do you mean? I always thought I was running too rich?

I dunno. From what is visible they look pretty good to me. They aren't supposed to look shiny and new. Color pattern looks symmetrical. Tan color looks like normal lead bromide as pointed out in a previous post. I'm guessing to you your piston heads probably look like they are in bad shape with lots of pitting and rough areas. But it's probably just normal lead deposits and the pistons are fine, unless you see scoring on the cylinder walls. Last time I saw the same thing I found that "nasty" stuff came off with a dental pick. It was just deposits.

Pictures can be deceiving, but nothing on the valve faces was jumping out at me.

[rizzz]

I dunno. From what is visible they look pretty good to me. They aren't supposed to look shiny and new. Color pattern looks symmetrical. Tan color looks like normal lead bromide as pointed out in a previous post. I'm guessing to you your piston heads probably look like they are in bad shape with lots of pitting and rough areas. But it's probably just normal lead deposits and the pistons are fine, unless you see scoring on the cylinder walls. Last time I saw the same thing I found that "nasty" stuff came off with a dental pick. It was just deposits.

Pictures can be deceiving, but nothing on the valve faces was jumping out at me.

Here's what the pistons & cylinders look like, lots of lead deposits indeed and it does come off with some effort.
I read somewhere oven cleaner is the stuff to use to get these cleaned up as long as it's not left on there for too long. I'll do some more research before I start spraying that stuff on there though.

In the meantime, I'm waiting for the heads to get serviced so not much else I can do at this stage.

[vwglenn]

I wouldn't use oven cleaner on there. Honestly I wouldn't mess with them at all. All I would do would be to verify that the rings haven't synced up.

As far as being worried about leaded fuel...these things originally ran on leaded fuel. Many moons ago, I used to run my bug on left over 100LL we pulled from aircraft tanks for maintenance. Why? Because it was free and my car was the only one at the shop that could run leaded fuel. I regularly bounced between 87 unleaded and 100ll. Bug didn't care either way.

[mike.smith]

Here's what the pistons & cylinders look like, lots of lead deposits indeed and it does come off with some effort.
I read somewhere oven cleaner is the stuff to use to get these cleaned up as long as it's not left on there for too long. I'll do some more research before I start spraying that stuff on there though.

In the meantime, I'm waiting for the heads to get serviced so not much else I can do at this stage.

Those look to be in great shape. Better than mine looked :-) No need to go cleaning anything. It's all well and normal.

[rizzz]

Thanks for the info guys, I feel a bit better about this now.
I'll leave the pistons alone and just wait for the heads to get back.

[Klimek]

rizz,
From what I see the valves and head look good. The one area of concern is the dark area on the lower 1/3 of the #3 cylinder as compared to the #4.
This usually indicates a leak at the cylinder/head mating area. Maybe it's just the camera angle.
Most old beetle style engines did not have a head gasket (copper ring) and leaks like this were common.
As you know, always install a new copper gasket after head removal.
Frank
ONEX 090