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Engine Specific Info and Questions => IDI Engine => Topic started by: 85gti on August 17, 2008, 10:33:37 pm
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Hey guys I just found this site and I am in need of some diesel guru help. I need to know if my cylinder head can still be used with 1mm cracks between all the valves. I have been told it may be usable but I figured you were the guys to ask before I throw it back together to find that it doesn't work. Any help would be very appreciated. Thanks in advance!
-Dale
Oh and when I check the head surface for warpage what is the amount it can be warped using the feeler gauge?
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it really shouldn't be warped at all, but a little bit might be ok... the cracks should be ok but while you have it off, why not get it shaved & pressure tested to be sure?
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it really shouldn't be warped at all, but a little bit might be ok... the cracks should be ok but while you have it off, why not get it shaved & pressure tested to be sure?
okay that sounds good. i will need a special gasket too if i get it shaved correct?
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Mine has cracks between all of them. It's really not a big deal unless you start to lose coolant faster than you can add it and suddenly you have HUGE power from water injection and a rediculous amount of steam coming out the tail pipe.
I'd suggest a 1.9 metal head gasket. They are only 15$(CDN) more and last longer in my opinion just make sure you get the same number of notches. (holes)
I FREAKED when i saw my cracks and yeah sure they aren't harmless by any means but i wouldn't get a new head based on them alone unless you can afford it and are doing other extensive work as well.
oh and for head warpage i wouldn't worry about it too much unless you're taking it apart because it ran with no water/coolant in it for what ever reason and the head went Pooooooooooshhhhhh and oil went everywhere. someone on here will tell you the exact numbers though im sure.
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The gasket is determined by piston protrusion and not whether or not the head has been shaved.
Andrew
Okay thanks for the reply but can u explain a bit more?
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The gasket is determined by piston protrusion and not whether or not the head has been shaved.
Andrew
Okay thanks for the reply but can u explain a bit more?
The pistons protrude above the top of the block in the 1.6 engine. The amount of protrusion dictates the thickness of the head gasket.
The thickness of a head gasket is identified by the number of notches on the gasket. The notches are located about the center edge of the gasket. Looking from the front of the car, the notches can be seen on the gasket edge that sticks out from under the head next to the oil drain back (round part of block and head).
Check the Bentley manual, there is a good explanation of the gasket thickness and piston protrusion.
Like others have said, generally speaking, cracks between the valve seats is not a problem.
And, typically, if you can put a 4 thousandths feeler guage under a straight edge laying across the head, it is questionable whether or not a new head gasket will hold very long.
If you have the head off, check the clearnace, if its over the 0.004, then have it milled.
Side note: I have used fine steel wool and 600 sand paper with water to clean the surface of the diesel head.
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What he is trying to say is if your block gets decked you need a thicker headgasket, but because the head is flat and doesn't have a combustion chamber you don't need to worry about piston to head clearance. However depending on how much is shaved off you may have to worry about piston to valve clearance.