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Old 9th August 2008, 19:33   #1
sworks
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Default 1.8 K series info

Quite a lot of posts keep popping up about head gasket failure on 1.8 engines so here's some info that might be of interest

The K series engine is made up of 7 castings bolted together. There are 3 major castings (cylinder head, cylinder block and the bearing ladder) and 4 minor castings (camshaft carrier, camshaft cover, oil rail and sump).
Each of the 10 head bolts pass through the head, block and bearing ladder and screw into the oil rail. This puts the head, block and bearing ladder into compression with all the tensile loads being carried by the head bolts.

The head bolt condition is critical and they are designed to 'stretch' when the engine warms up. It is a common myth that the bolts must be replaced each time the head is removed but this is not the case.
With the head and head gasket removed, screw the bolt down into the oil rail until it's finger tight.
Measure the difference from the block face to the underside of the bolt head. If the distance is greater than 97mm the bolt MUST be replaced, 97mm or less and the bolts can be re-used.
There is another way of measuring the head bolt lengths but only if the oil rail has been removed.
(This info is for you to read and I accept no blame if you snap a head bolt)

There are 2 dowels fitted to the block which were originally nylon then later changed to steel. Make sure steel dowels are used and set to a height of 10 - 11mm above the block face.
The cylinder liner protrusion (the amount the liner sits above the block face) should be 0 - 0.10mm for 1.8 engines.

In some instances if the engine has over heated you can have problems with a groove appearing in the fire ring of the head, this is caused by the liner and most people just skim the head to get rid of this problem.
Rovers policy was that under no circumstances should the heads be skimmed, just replaced! This wasn't just a marketing ploy to get people to buy new heads as skimming can lead to other problems.

Another myth is that if the head is removed it must be skimmed, I would only skim a head if it was a last resort. How many people know that if a head is skimmed it is possible that 1 of the head bolts may have to be shortened to stop it from bottoming out on the sump - hence causing gasket failure again due to no clamping force at that point?
The arrival of the new head gasket, shim and oil rail (from X part) or just the gasket and shim from Land Rover helps this problem as the shim helps replace what has been skimmed (if it has) and can to some extent reduce the effect of the damaged fire ring. It must also be remembered that head gasket failure is usually caused by a coolant leak from elsewhere, so check the coolant level regularly.
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