SR20DET head gasket thickness?

Thread in 'Technical Questions' started by captain_chaos, Oct 19, 2019.

  1. captain_chaos

    captain_chaos Member

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    Hi people.

    So, my SR is getting a bit further with the rebuild. Head is all skimmed, valves reseated, BC springs and retainers, new BC guides.

    Black has been decked, put together with Manley rods and CP (8.5) pistons and bored out to 86.5mm with all new Duraglide shells and I also had my crank + damper + flywheel + clutch cover balanced.

    Once the head has been skimmed and the block has been decked, in total, 0.25mm has been taken off.

    When the engine was stripped, turned out the head has never been skimmed in its life and was on the original HG after we measured the head height.

    I'm about to hit 'buy' on a head gasket but in two minds what size to get. Strictly speaking a 1.5mm is the next logical choice but its a bit much and one or two people suggested going with a 1.2mm as the clearance should be fine.

    Could anyone else please help as there are still SR20 guru's on this forum.
     
  2. asmo666

    asmo666 New Member

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    Depends what cams You have.
     
  3. captain_chaos

    captain_chaos Member

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    Just had a bit more measuring done with a stock cheap head gasket.
    Gasket was 1.9mm uncompressed and nipped down to 1.8mm my the first torque stage.
    Done a squish test with a bit of soft Solder and it compressed down to 1.7mm
    Current cams will be stock then later Step 2 HKS cams so 12.0mm lift against stock 11.5mm
     
  4. asmo666

    asmo666 New Member

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    Only difference is how much boost and power You want.
    Thicker - more boost, less power on low boost, less knocking.
    Thinner - less boost, more power, careful mapping, better turbo response. Aggressive cams + VTC might give you a small hole in piston.

    You choose :)

    I've got 550whp, 28 psi boost on e85, cosworth headgasket 1.1mm and 272 Jun cams + VTC. valve sits 1.7 mm from mahle piston in full opening.
     
  5. captain_chaos

    captain_chaos Member

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    I have ended up going for a 1.2mm Tomei gasket. I wont be pushing mad numbers out of mine, will limit it to 400hp to the crank. Main thing I want is a responsive setup. Cams will be 264s so nothing massive or aggressive. Kind of overbuilding the engine so I can put up with abuse all day long
     

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