6

I just bought a 2000 Civic 1.6L ( d16y8 ) with no compression in one cylinder. Four years ago, the engine overheated, and was completely rebuilt by the Honda dealership. One of the things on the invoice was "cylinder head resurfacing".

Assuming that there is some warping and the head requires resurfacing again, but that the resurfacing would take the head past it's minimum height limit, why couldn't a thicker head gasket be used to compensate?

I ask because both the WSM seems to imply there is a hard limit, and I asked the mechanic I'm working with and he said it's not a good idea, but didn't really have time to explain.

Improve this question

2 Answers 2

Reset to default
4

The pressure generated at Top Dead Center on the Power stroke is very high. A "taller" gasket will have a larger cross-sectional area exposed to this pressure, so high "pounds/sq inch" grows proportionately as the area increases.

Even the best Multi Layer Steel head gaskets are not designed to be part of the cylinder, just to seal the head to the block. It's a gasket, not a spacer. In addition, it will be impossible to achieve proper head-bolt torque with a tall "squishy" gasket.

With a pure copper gasket, you might be able to approach 100 thousandths of an inch total gasket thickness without failure, and proper head bolt torque. Such a gasket would likely be custom and cost more than a new set of heads.

Your mechanic was right to advise against it. (Although many have tried... even such folly as using TWO gaskets to double the height. This doesn't end well in any story where one admits the truth...

On edit: Also keep in mind that you can't just "resurface" the warp out of an Overhead Cam head. The entire head is warped, not just the surface that interfaces the block. A proper head restoration will need a cam line bore and bearings. I've had some luck with aluminum heads, carefully measured and shimmed between clamped steel jig plates, in my kitchen oven as high as it would go for five hours. Cam bore alignment was restored, and only a .010 cut was required. My wife (now ex), however, was NOT amused...

Improve this answer
3
  • 1
    The annealing temperature of some alloys of Aluminum is as low as 650°F, so I would be careful setting the oven as high as it goes, and do not rely on the oven to hold temp. Use an accurate thermometer, find out what alloy you are working with to make sure you don't exceed the annealing temperature.
    – MooseLucifer
    Jun 23, 2016 at 16:32
  • 1
    @moose ... yep, but around 550 F IIRC I felt I was safe enough. Plus, my overall theory was try and save the head (BMW M10 early 121), because it was scrap anyway if I couldn't get the cam bore straight. And the absolute stink of this process would prevent me from trying to repeat this indoors. The head, however, came out incredibly clean.
    – SteveRacer
    Jun 23, 2016 at 17:09
  • Good point, last ditch efforts are kinda fun like that.
    – MooseLucifer
    Jun 23, 2016 at 17:25
2

You can compensate for decking loss with a thicker gasket, and there are many on the market for Honda engines (esp the b Series). I can't say how well they hold up tho, but I know people who have successfully used them in Frankenstein builds (b18b bottom with bseries vtec head) with a fair amount of boost, and they seem to do fine, and they are also commonly used when a stock head is milled due to warpage.

Id say it's worth a shot if you want to try, knowing that its a 50/50 chance and that you may end up having to buy a new head regardless. But if you are going to have to replace the head anyway, and are willing to experiment, I say go for it if you can find one that's the thickness you would need.

Improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .