1.8t liners sunk, which head gasket?
 

Hi all.
So I've just bought a 75 1.8t and the head gasket has gone after just 70 miles :(
l have pulled the head off and found the liners have sunk level with the block and an MLS headgasket had already been fitted. (I'm assuming whoever fitted it didnt check the liners or didn't have the money)
I am planning to fit liner shims but have read/heard conflicting facts on which head gasket to fit with them.
Should I fit an MLS or Elastomer (blue type) with the liner shims?:shrug:
Also, I'm going to get the head checked but is it completely necessary to have it skimmed?

I wait with baited breath as I cannot wait to get it back on the road!

Cheers

Ordinary gasket
 

Mls gasket no good in this case. If using the normal one without addressing the liners then buy a good quality one.
Seen this problem sorted by normal gasket
Best to get advice from one of the experts on here
Chris

Thanks, I am leaning towards the normal one even though some "experts" have informed me otherwise.

Sunk liners aren't really reliably fixed, elastomer is recommended for low liners but none are guaranteed to fix sunk liners because the reason they are sunk is because the block has gone soft and is normally scrap.

Head is also questionable if engine has got hot enough to undo the heat treatment on the block.

You can try elastomer gasket, but you may find yourself redoing the same job repeatedly.

More reliable fix would be to source another block or engine if head is also soft... May work out less hassle and cheaper in long run.

You must of had a serious overheat to soften the block.

From an amateur.

You will find that liner shims are actually .004" thick (not .003") and in theory this equates to a higher stick up than given in the specifications. Doesn't seem to give any issues though.

If you have at least .003" stick up go with MLS, but use the best available from Payen. If you can tolerate the gasket going again in say 50k miles then go with Payens elastomer gasket which has reinforced webbing and seems to come in blue nowadays. perhaps the elastomer material has changed to stop it reacting with the oil and shimmying out from the joint, possibly longer life with it :shrug:

It will be interesting to establish how the liners come out. If they have been hammered in to the block there will be a lip that forms on the edge of the block that makes them hard to remove without a decent drift/dolly. They will move about 2-3mm and then get tight as there is an undercut on the liner to allow it to be machined and to bottom out fully in the block and seal effectively. When they get to this stage the lip can shatter as you remove the liner rendering the block scrap, which it probably is anyway by that time, usually seen with liners when they get to lower than flush with block.

For the price I paid for the car I knew it was a bit of a gamble but the head gasket had obviously already gone and was quick fixed for the sale (I stopped as soon as the needle when too high!). For the price of the parts I'm willing to see if this fixes it.

When my VVC coupe had it's forged internals fitted in 2008 by DVA Power,they found that the liner heights were slightly low for an MLS gasket.They hand sanded the block face (checking with a square) until the liners were 4 thou proud.Five years later and with nearly 200 bhp going through it there have been no problems with the HG :)

Don't use shims, they aren't known to work, probably best to go with the elastomer gasket and take your chances.

With shims what tends to happen is because block is soft you raise the liners with shims and head just presses them down flush again so you end up flush again.

Liners aren't pressed or hammered in, they are just a hand tight fitting.

At te base there is a sealant, and that stops coolant leaking int the sump.

But a slight turn of crankshaft or slight twist or pull on the liners will contaminate the sealant seal, and then you need to remove the liners, clean them and apply fresh sealant.

They are very easily disturbed!

Slightly low is different to sunk, sunk is caused by soft block, low is production tolerances. Lots of engines came out the factory low, but it was accepted because its not such a problem with elastomer gasket which was being fitted. Reason they failed was because the elastomer separated rather than low liners. MLS was introduced as a more reliable fix towards end of production and liner heights were more critical

Why didnt they just do it by using a surfacing machine or killing machine... Would of produced better result and taken half the time probably.

I think you should measure before you decide. I don't think that has been done?.

If you can't do that, give it to someone who can.

After that, make up your mind as what to do.