TOPIC:

Hi all,

Once again I've got doubt in my mind
In short, should I replace the liner seals, someone has already suggested no need to, but can't help but think the seals might have been there for 35 years.

And if I did decide to replace, is this a job that could be done at home, or best left to a machine shop.
I've been quoted £150 Labour to push the liners out.

Thanks Pete.

That's a tough question to answer. The cooling system operates at around 8 psi if I remember right so there's a differential pressure between the coolant and the oil pan and if you had a leak on the lower seal you would find antifreeze in the oil. I would think that the upper seal if it leaked might be covered off by the head gasket sealing the possible leak between the liner and the cylinder due to the squish between the cylinder and the head.

If you had the new seals and wanted to do the job that's fine but a word of caution. I can't remember who had a crack at that job on this site, but they tried to drive the liners out with a hammer if I remember right using a block of wood and they cracked 2 of the liners. The liners are in with a light press fit somewhere around .001" - .0015" interference fit. If you had an oven to heat up the cylinder to 300-350 Deg F. the liners would probably just press out by hand since the coefficient of linear expansion (basically the number used in a calculation of determining the relationship of growth of different metals at the same temperature rise) would have the aluminum cylinder growing larger than the cylinder liner growth.

There have been reports of guys leaving their spare cylinders sitting on the bench for storage and coming back later on and finding the cylinder liners pushed out of the cylinder casting by gravity.

The other thought to consider would be how much corrosion has happened in the sealing area. If antifreeze was used and properly changed at regular intervals you might be alright. If some turkey used water for whatever reason there may be consequences.
In the world of tractor trailers in this day and age, Oil analysis is paramount. One of the critical tests they do is antifreeze content in the oil. Today's tractors are now going up to 1,000,000 miles before changing the oil. Mind you they are using centrifugal oil purification to keep the oil clean and then just adding a wear additive package when needed.

I know it's not a definitive answer but maybe it will help you decide.

cheers
KB

Long story short- Do you have coolant in your oil?

If not, you're fine. Thing is, I've almost never heard of these seals leaking. If you DO go through with it, you'll pretty much need a machine shop to do everything- pulling the sleeve, putting in another one (properly fitted to the piston), then milling the surface of the bores flush. It's not a "pull out old sleeve, replace with new" job.

If you've got all the parts, it's tore down far enough to do so, and a machine shop is willing to do it correctly while you're willing to eat the cost, by all means go for it. I personally don't think it's worth the hassle.

(And as for the guy cracking the sleeves trying to get them out- yeah, that was me.)

Lucien-Harpress wrote: Long story short- Do you have coolant in your oil?

If not, you're fine. Thing is, I've almost never heard of these seals leaking. If you DO go through with it, you'll pretty much need a machine shop to do everything- pulling the sleeve, putting in another one (properly fitted to the piston), then milling the surface of the bores flush. It's not a "pull out old sleeve, replace with new" job.

If you've got all the parts, it's tore down far enough to do so, and a machine shop is willing to do it correctly while you're willing to eat the cost, by all means go for it. I personally don't think it's worth the hassle.

(And as for the guy cracking the sleeves trying to get them out- yeah, that was me.)

+1 on everything said here! I was kinda surprised to hear that anyone was going to even try to do a seal job. I've had these sixes as far back as 1983 on my first Voyager, and have never heard of one leaking anything into anything. Personally, I feel that if something is leaking past the liner seals, there's a lot more wrong than I care to trust to just new seals. It kinda indicates neglect.

And, Lucien, thanks for your service in sharing your bad experience with us! Even failures are good learning experiences!

The only reasons I would have for pulling the sleeves out is coolant in the oil and if you can see evidence of erosion due to cavitation. I would not expect to see it on a Z13 barrel but it should always be checked. It starts off with pitting and slowly gets worse. I recently saw a Mitsubishi truck diesel where the liner had 7mm deep erosion and had formed two pin size holes in the bore.

Thanks for your replies,
One of the reasons I will be removing the head and barrels is because the oil level window is steaming up after the engine has warmed up. The oil still looks ok but it happens every time so can't just be condensation.
I will be using a second set of cylinders which look ok to me without any heavy corrosion and suspect the present ones maybe be corroded between water ways and oil ways at the head gasket level.
Anyway due to everyone's comments I think I will leave things along.
Cheers Pete.