Liner Seals

[Parzival]

So we got my heads of last week, and I haven't had time to go back out to the car until today. When we pulled the heads we were carful not to pull up the piston liners or turn over the engine. Some coolant was left in the cylinder banks and over the week it looks like some of it leaked down into the oil pan. (you've got to be kidding me!)
The liners look full seated, but this is alarming. The heads are waiting to surfaced, but now I need to make sure the liner seals are in good shape. I know what it means if they are not...

The real question"
1) Is it normal for some very slow leaking to occur when the heads are off due to the liners not have the clamping force on them from the heads?
2) Is there a way to verify the liner seals are ok, or not ok?

I guess I'm just waiting to hear how screwed I am,
On the plus side the metal in my block all looks nice and not corroded (No rot)

[David T]

If the coolant was not leaking into the oil before you took the heads off AND you did NOT move the pistons with the heads off you are probably OK.

[Parzival]

If the coolant was not leaking into the oil before you took the heads off AND you did NOT move the pistons with the heads off you are probably OK.

I like your optimism!
so just leaking slow because of the lack of clamping force perhaps?
It was left for a whole week.

[David T]

The coolant could have just leaked past the rings. When cold the gaps open up.

[Parzival]

The coolant could have just leaked past the rings. When cold the gaps open up.

Well there wasn't coolant in the pistons. It was in the water jacket, and over a week it sat there, and when I went back a week later it leaked into the pan, the only way it could have leaked was past the liner seals. Thats what I'm worried about.

[David T]

Did the oil level rise? Is there any coolant in the oil? I misunderstood, I thought you had said there was some coolant on top of the pistons. I guess you could pressurize the cooling system if you can block off the tops of the liners with a plate. Otherwise the safest course of action is to replace the liner seals if you doubt their integrity.

[Giamanut]

If you use an ordinary paper or metal shim you should use some kind of sealer. The type of shim the manual says to use would not need any additional sealer. Not sure what the availability is of those shims anymore. Important to use a sealer meant for this application if you do use a sealer. Lotus had a big problem with liner seal sealer in their early V-8's and it resulted in a recall. The sealer must remain somewhat flexible. If it hardens it cracks. Even though the liner is locked in place by the step in the block and the clamping pressure of the heads, it still moves slightly. The sealer must be flexible to accommodate that movement and the thermal variations along with the different expansion and contraction rates of the steel liners and the aluminum block. Some sealer require a primer. Some have very specific times that it can be assembled in before it dries out. Important details. In all cases all of the sealing surfaces must be scrupulously clean.

So Dave that is a great description thermal expansion alone would mandate somewhat flexible seals, and if anyone has seen real slow motion video of an old school engine block while running the deformation of the block is awe inspiring.
I do wonder if it would be possible to pull a liner out and with the right ring compressor install it back over the Piston. Not a suggestion just a thought, from what I have seen it might be theoretically possible to change seals without dropping the Oil pan.

[Parzival]

So Dave that is a great description thermal expansion alone would mandate somewhat flexible seals, and if anyone has seen real slow motion video of an old school engine block while running the deformation of the block is awe inspiring.
I do wonder if it would be possible to pull a liner out and with the right ring compressor install it back over the Piston. Not a suggestion just a thought, from what I have seen it might be theoretically possible to change seals without dropping the Oil pan.

THAT would be hard! I think it would be easier to drop that pan, its not hard to do, and most of these cars need new engine mounts anyway.

[Giamanut]

THAT would be hard! I think it would be easier to drop that pan, its not hard to do, and most of these cars need new engine mounts anyway.

Yes it would be easier to drop the pan, no real reason to do it any other way, just wonder if its possible. But then again i am a little off the wall.

[Giamanut]

THAT would be hard! I think it would be easier to drop that pan, its not hard to do, and most of these cars need new engine mounts anyway.

As a side note aircraft engine cylinders are installed over the piston they also have cylinder base seals so yeah it would not be unprecedented, at all really. In fact aviation ring compressor tools are designed for tight spaces. Again not a suggestion just a thought!