Compression ratio/Quench/Cometic

Discussion in '96-04 - 2V Specific' started by Millzenator, May 14, 2007.

  1. Millzenator

    Millzenator New Member

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    Ok guys.. Need some math help here. I have a Teksid block bored .020, decked .010, 99 Windsor heads, milled .010 and chambers polished. Swirl dams not removed, but smoothed. I am using JE 7cc dished pistons. Custom Comps, Duration 269/269, Duration @ .050 Int=234 Exh=234, Lift = .545/.545, 113 lobe sep

    After assembly, I took my block to a reputable machine shop (the same one that did the machine work to the heads and block) to degree the cams in. I simply don't have much time, and didn't want to buy the degree kit. After installation, I apparently had a head gasket seating issue on the driver's side. About 8 months ago, I pulled the motor (it's still out of the car), and noticed PTV for both intake and exhaust on piston #6 and PTV for exhaust on #4. The contact was only 1-2mm long, and you could barely catch your fingernail in it. Needless to say, I'm pissed knowing I paid to have the cams degreed and am having PTV.

    Obviously, degreeing the cams again (at a different shop, or myself) is in order, but with the mill work done to the deck, would this have caused the PTV even if the cams were degreed? I have two sets of headgaskets that could go back on.. Felpro stock MLS, and Cometic .074's. Since this is going to be a N/A setup, I wanted to maintain an 11'ish:1 ratio. With my calculations, I am coming up with 11.44:1 using felpro PermaTorque .036's, and about a 10.20:1 using the Cometics. Would someone double check this? Also, what about quench effect using the thicker gaskets? My thoughts were the .074 Comectics would still leave me in the upper ranges for effective quench, but not too tall off the deck, since the deck/heads has been milled. I am assuming I now have a deck clearance of .002" since the mill.

    Lastly, would a degree issue cause PTV with BOTH valves on the same cylinder? It's my understanding the retardation or advance will add or remove clearance for either intake or exhaust, but not both. So, making sure the cams are dialed in would not help if PTV exists on both valves on the same piston. Please advise!
     
  2. DropTopPony

    DropTopPony Administrator Staff Member Admin SN95 Supporter

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    Millzy,
    so now i see why you haven't been around in awhile...sorry to here about your pistons, are they salvagable? I know a guy running those Cometic gaskets and i asked him about quench and he was reassured by his builder that he would be ok. He has now been running that setup over a year with no issues and he is also N/A but running a flat top piston and race gas.
     
  3. Millzenator

    Millzenator New Member

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    Good to see you Bob... :drunk: Been a while since I've been on the boards... I opened a new business.. www.highlinesauto.com It's taken up ALOT of my time, and I haven't had a chance in months to work on the car.

    Something isn't right, timing wise. I'll have to tinker with it, and get it working. I am so tired of seeing my car waste away in the garage!