Head skimming

[Guest]

Is there anyway to tell if a head has been skimmed before? Only reason being is i think there may have been a possibilty that my willy head has been skimmed before - can they be skimmed again??

 

[Guest]

can only skim it if the skimming will clear the valves when they are closed iirc

 

[Guest]

You can skim a head many times before it can't be done as in most cases not a lot needs to be taken off. My cylinder head needed 0.3mm of taking off and it was then flat.

 

[Guest]

Theres a half circle shaped cutout shape on the Face of the head between cylinders 2 and 3, As you skim the head the aluminum is removed the Cutout has a shallower depth, Measured from face of cylinder head to the base of cutout, when the Cutout disappears due to having a few head skims then you need to think about finding another head or Headsaver gasket

Heads can usually be skimmed a few times as rob said, only problem occurs is if the head has some pitting or indentations from when the headgasket has failed and the engineer needs to skim a little more off then usual to Remove the pitting

 

[Guest]

Atm there is about 1mm left on that cut out, is that a lot? Enough for a skim? Doesn't seem that pitted.
What is a headsaver gasket?

 

[Guest]

1mm is plenty i saw the cutout in your other post, its fine for a skim, doubt it'll be pitted bet there will be a little line between the 2 chambers where the gasket went,
Headsavers arent readily available, basically like a 2nd headgasket which saves the head from the scrap pile, for use when theve been skimmed a few times to many, Most Popular on the Rover K-Series range of engines

 

[Guest]

Ah right cool, only prob now is if i have the head skimmed i think the b/e could need a skim as well (still need to double check) - would doing both mean the valves will be too close to the pistons? Not sure what tolerances there is to play with.

 

[Guest]

0.3mm sounds huge for a head...

 

[Guest]

Was thinking about this the other day. I know my head has been skimmed at least twice.

Does the head need to be skimmed, everytime you remove it, even if its just to do other work and not HG fail?

 

[Guest]

It doesnt have to be skimmed it all depends. Most do get it skimmed to make sure that its flat and clean etc. 0.3mm is huge? I dont think so it was .3mm or .07mm cant remember which my dad said as he did it at his work.

 

[SEOSearch [Crawler]]

0.3 isnt huge really.
Would take about that to get a head flat.

You can whack loads off, so long as the piston/valve clearance allows, but the other thing is keeping cam timing consistent. The close the cams are to the crank, the more the tdc marks become out.

 

[Guest]

That's a good point really - thicker h/g to compensate I think skimming is done by checking to see if it IS flat first. I don't think something like new valves would mean skimming. Overheating would definitely need both pressure testing and skimming. I paid £60 CASH only to have some fucker nick the head .... (diesel head)

 

[Guest]

So i could get both the block and the head skimmed and be safe with the piston/valve clearance? How much would it take before the cam timing started to be affected noticably?

 

[Guest]

Tbh i dont think you need a Block skim, Time consuming and expensive, My headgasket on my old clio went in the same way your's did had a head skim and it were perfect after

Dave

 

[Guest]

as above, block is a lot tougher, its cast iron, where as the head is only alloy so more likely to be damaged. i have had 2 head gaskets go on 2 different engines in that exact spot also, only ever had the head skimmed and cleaned the block up myself, never had an issue and one of those lumps is my current f7p turbo, which has done 5k on current build and is strong as an ox :wink:

to check the block, carefully scrape and clean the gasket face, then run a straight edge across it, gently, with a light behind it, if you can see light between the gasket face and the straight edge then the block isnt flat and will need decking back true.

 

[Guest]

Ok excellent, thanks for all the advice, i'll be getting a nice new strait edge and checking it asap. Feel much better about the whole project now, just need to check the pistons then i can actually start spending some money on the engine.