| Praylewd powr |
Another opinion/tech thread for you engine builders. I am in a bind......my headgasket (cometic 87.5mm bore) finally came in but the wrong one was ordered....shit (shop mistake). I am in need of the headgasket for my engine build and was told by Cometic and a few others that an 88mm bore HG would work fine on an 87.5mm bore block. The reason I am asking this is Cometic has 87, 88, and 89 mm bore sizes in stock...whereas the 87.5 would need to be custom made.
I am running up to 18 psi on my boosted H22 and do not want to run into sealing problems around the bores. Has anyone else had experience with using off-size headgaskets. I personally know one builder who is using an 88mm HG on an 87mm bore---boosted. I have also seen a few manufacturers that go up to 0.040" overbore on their gaskets (ie: allow a 3.84 inch bore gasket to be used on a 3.80 inch bore application).....the 88mm gasket would only be 20 thou larger than the bores.
Cometic says no problem.....just wanted to see what you guys thought. I will decide by tuesday.
Thanks.
D |
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| ae1969 |
I would use it.
Can't say for your specific application but...
On my car which has an open deck design and sealing is not as efficient as your closed deck design we use stock gaskets with 102 mm on a 100 mm bore and one over....and it holds.
As long as you have true/flat surfaces and you install the cometic gasket properly you should be fine.
The thing you really want to avoid is being one size smaller. I have seen this used in a number of applications that did not have standard sized bores. As you can imagine in boosted applications this was plagued with problems (hot spots etc.etc.)
You are lucky that your engine is a popular option for cometic and they provide you with 87,88 and 89 mm! ........... all we get is 1 size. hehehehe unless I want to really bore the bugger and go 104,106 |
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| Praylewd powr |
Thanks for the input....all the info I have found in the last 2 days tells me it should be fine.
D |
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