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300 tdi head gasket


Mo Murphy
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The Landy has suddenly started overheating and the rocker compartment does seem to be pressurized, chuffing out oil vapour. I can't see any oil in the water or vice-versa. Will I be doing a head gasket change this week-end ? What is there to look out for. What parts would I need ? Could it be something else ?

Downhearted of Letchworth

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Thanks chaps, what is the best way to check the head for warping and if warped how much should be skimmed ? If the head is skimmed should I go to the next thickest gasket ? And lastly to prevent me getting stitched up through ignorence, what is the going rate to have the head skimmed ?

Ta

Mo

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You can check gasket face distortion with an engineers or printers rule Mo. Edge on between cyliders and length wise - use a torch to check for light leakage under the edge of the ruler, then feeler guage as there's a permissable amount of distortion that will be negated through the tightening sequence. Gasket thickness goes up in tenths of a mil. I would suggest you use thickest available. I pay £20 for a 4-pot skim, and the shop will tell me how much was taken off if I ask in advance.

Most I ever paid for a 4-pot skim was £60, and the job was beautiful to be honest.

Les. :)

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Thanks chaps, what is the best way to check the head for warping and if warped how much should be skimmed ? If the head is skimmed should I go to the next thickest gasket ? And lastly to prevent me getting stitched up through ignorence, what is the going rate to have the head skimmed ?

Ta

Mo

Use the same gasket that you take off. Same thickness that is. The thickness of the gasket relates to the protrusion of the piston crowns above the block - skimming the head does not change that! If you were to skim the block or make any changes in the bottom end then you should measure and adjust the gasket as appropriate.

Good luck with it Mo. As said, it is quite a straight forward job.

Chris

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Use the same gasket that you take off. Same thickness that is. The thickness of the gasket relates to the protrusion of the piston crowns above the block - skimming the head does not change that! If you were to skim the block or make any changes in the bottom end then you should measure and adjust the gasket as appropriate.

Chris

Oops, I was wrong :rolleyes: your right :i-m_so_happy:

Just looked in RAVE Defender manual & it states if the head is warped --- do not reface,

if warping exceeds the maximum figure of 0.08mm Replace the head -- :wacko:

Edited by western
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Use the same gasket that you take off. Same thickness that is. The thickness of the gasket relates to the protrusion of the piston crowns above the block - skimming the head does not change that! If you were to skim the block or make any changes in the bottom end then you should measure and adjust the gasket as appropriate.

From an engineering point of view I take issue with that. You're reducing the volume above the piston at TDC whichever side you skim. How can it tell whether the gasket join is 0.2mm higher or lower?

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From an engineering point of view I take issue with that. You're reducing the volume above the piston at TDC whichever side you skim. How can it tell whether the gasket join is 0.2mm higher or lower?

Reducing the volume by how much? I take it that you have seen what the underside of a 300Tdi head is like.

The combustion chamber is in the piston crown.

The space between the piston crown and the flat face of the head has in important function to squish the gas in a designed manner, in conjuction with the shape of the bowl in the piston to create turbulence for efficient combustion.

The designers go to a lot of trouble to get the shape of the bowl and the squish clearance optimal for best combustion efficiency and emmissions. So much so that they have gaskets is such small increments of thickness and document the procedure for determining the correct thickness.

And lay people want to change the design on want basis? :rolleyes: Some percieved notion based on compression ratio - I don't think so!

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So is that a yes, same thickness gasket John or a no ?

Mo

IMHO, it is best to determine the height that the pistons protrude above the deck (can be done using a good, straight bar and feeler gauges), then look-up the recommended gasket. This is a precaution incase the correct gasket was not used last time.

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