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    Results 1 to 17 of 17
    1. #1
      Join Date
      Jan 2008
      Posts
      116

      Engine/Transmission Tilt

      What is the preferred/recommended/allowed tilt of the engine/trans? I set my pinion angle (up) to match my trans shaft angle (down) -2 degrees. The engine/trans tilt is 5.6 degrees down, the car is already built. If I need to raise the trans it would require major surgery ie; cutting out the trans tunnel, something I don't want to do.
      Mike
      86 GN, stage II, TH400
      86 Buick GN, Stage 2 V6, Twin EFR Turbos

    2. #2
      Join Date
      Jul 2006
      Location
      Pensacola, FL
      Posts
      1,263
      Country Flag: United States
      That is way too much downward angle in my experience. -3 degrees or less is much more acceptable. I had to raise the tunnel after the fact on one of my very first builds. I wouldn't say it was major, but it was a needed inconvenience.

    3. #3
      Join Date
      Apr 2004
      Location
      OKC, OK
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      3,739
      Country Flag: United States
      Should be around 3* down engine/trans, roughly 2-3* down pinion for leafs, 0* down for 4 link will put you in the ball park.
      Mike Redpath
      Musclerodz & Customz
      405-288-0189
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    4. #4
      Join Date
      Aug 2008
      Location
      jacksonville,fl
      Posts
      970
      Country Flag: United States
      Sticking larger trans in tunnel than will fit & pointing trans down to compensate is a common mistake that leads to driveshaft vibration issues.

    5. #5
      Join Date
      Mar 2008
      Location
      Chicago suburbs
      Posts
      667
      Country Flag: United States
      If possible, you could lower the engine mounts to decrease the driveline angle.

    6. #6
      Join Date
      Aug 2007
      Location
      Jonesboro, Arkansas
      Posts
      2,506
      Country Flag: United States
      Quote Originally Posted by MuscleRodz View Post
      Should be around 3* down engine/trans, roughly 2-3* down pinion for leafs, 0* down for 4 link will put you in the ball park.
      OK here goes one of those dreaded ignorant questions. When measuring the degree of descent be it 3* or what ever, from where do you measure? I mean what do you attache a inclinometer to? On the rear end it's the machined area the cover bolts to (chevrolet) I think.

      Carl Wilson
      1968 Camaro - T-56 6 speed - 383 Stroker, 2014 Mustang GT seats. FiTech EFI, Tanks Inc. Tank with Deutschwerks fuel pump.

    7. #7
      Join Date
      Jul 2006
      Location
      Pensacola, FL
      Posts
      1,263
      Country Flag: United States
      Face of the harmonic balancer, oil pan rail, or trans output shaft (yoke removed)

    8. #8
      Join Date
      Aug 2007
      Location
      Jonesboro, Arkansas
      Posts
      2,506
      Country Flag: United States
      Quote Originally Posted by Z06vet View Post
      Face of the harmonic balancer, oil pan rail, or trans output shaft (yoke removed)
      Well that makes sense. Thanks for the answer!

      Carl Wilson
      1968 Camaro - T-56 6 speed - 383 Stroker, 2014 Mustang GT seats. FiTech EFI, Tanks Inc. Tank with Deutschwerks fuel pump.

    9. #9
      Join Date
      Sep 2005
      Posts
      49,371
      Country Flag: United States
      also check your angle finder to see if it's measuring correctly. There are a number of Apps for phones instead of using a HF piece

    10. #10
      Join Date
      Sep 2008
      Location
      Jacksonville, Florida
      Posts
      629
      Country Flag: United States
      The operating angles of the driveshaft, relative to the reared and trans is what is important. Simply changing the angle of one part without the proper working angle will not fix an issue, and could actually make it worse. Here is an easy calculator to help: https://spicerparts.com/calculators/...gle-calculator

      Most U-joints should have 3* or less operation angle, 3* being max and not ideal.
      Craig Scholl
      CJD Automotive, LLC
      Jacksonville, Florida
      904-400-1802
      www.cjdautomotive.com

      "I own a Mopar, I already know it won't be in stock, won't ship tomorrow, and won't fit without modification."

    11. #11
      Join Date
      Aug 2007
      Location
      Jonesboro, Arkansas
      Posts
      2,506
      Country Flag: United States
      Quote Originally Posted by sccacuda View Post
      The operating angles of the driveshaft, relative to the reared and trans is what is important. Simply changing the angle of one part without the proper working angle will not fix an issue, and could actually make it worse. Here is an easy calculator to help: https://spicerparts.com/calculators/...gle-calculator

      Most U-joints should have 3* or less operation angle, 3* being max and not ideal.
      That's some pretty good information. Clears up a lot in my feeble brain.


      Carl Wilson
      1968 Camaro - T-56 6 speed - 383 Stroker, 2014 Mustang GT seats. FiTech EFI, Tanks Inc. Tank with Deutschwerks fuel pump.


    12. #12
      Join Date
      Apr 2005
      Location
      USA
      Posts
      4,462
      Country Flag: United States
      The engine/transmission centerline angle and the pinion shaft centerline angle should be parallel ( or as close as possible ). The driveshaft angle should be around 3 degrees different from the other two.
      https://www.driveshaftshop.com/angle-calibration
      Jeff Tate
      U.S.A.
      "The best thing about participating in these events is that you get to hang out with a group of intelligent like minded people who live to achieve things in their lives. You won't find a lazy, mean, or dumb bone in their bodies." Bret Voelkel, RideTech

    13. #13
      Join Date
      Jan 2008
      Posts
      116
      I may have enough room to put a spacer between the trans & mount to kick it up to 3 degrees, I think the exhaust will need adjustment afterwards. There are plenty of G-body cars running TH400 trans so I don't think tunnel surgery is needed. Thanks for the advise.

      Mike
      86 Buick GN, Stage 2 V6, Twin EFR Turbos

    14. #14
      Join Date
      Jan 2008
      Posts
      116
      After much measuring following the Spicer calculator I found that yes, trans tunnel has to be cut. I think because I strayed from the stock ride height (lowered coil over suspension) and the poly stage II motor mounts I have run into this situation, can't really fight it, just have to deal with it. The driveshaft is almost straight as it sits, so the u-joints will eat themselves in short order. Luckily Hurst sells a trans tunnel kit for installing a T56 trans. in a G-body, the fun part this weekend was pulling out the interior and then removing the Dynamat from the trans tunnel (dry ice), that is some real sticky stuff.
      Before:
      Engine/trans 4.75 degrees down
      Pinion 2 degrees up (this is adjustable)
      Driveshaft 0.56 degrees down
      After: we'll see
      86 Buick GN, Stage 2 V6, Twin EFR Turbos

    15. #15
      Join Date
      Apr 2001
      Location
      The City of Fountains
      Posts
      15,971
      Country Flag: United States
      Quote Originally Posted by Hemi8 View Post
      After much measuring following the Spicer calculator I found that yes, trans tunnel has to be cut. I think because I strayed from the stock ride height (lowered coil over suspension) and the poly stage II motor mounts I have run into this situation, can't really fight it, just have to deal with it. The driveshaft is almost straight as it sits, so the u-joints will eat themselves in short order. Luckily Hurst sells a trans tunnel kit for installing a T56 trans. in a G-body, the fun part this weekend was pulling out the interior and then removing the Dynamat from the trans tunnel (dry ice), that is some real sticky stuff.
      Before:
      Engine/trans 4.75 degrees down
      Pinion 2 degrees up (this is adjustable)
      Driveshaft 0.56 degrees down
      After: we'll see
      Another option is to use a driveshaft with CV joints. I have a single CV shaft in my GTO and a dual CV shaft in my Cougar. They are made by The Driveshaft Shop.

      Andrew
      1970 GTO Version 3.0
      1967 Cougar build
      GM High-Tech Performance feature
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      Dr. EFI
      I deliver what EFI promises.
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      "You were the gun, your voice was the trigger, your bravery was the barrel, your eyes were the bullets." ~ Her

    16. #16
      Join Date
      Jan 2008
      Posts
      116
      Cut tunnel, raised the trans by 1.1" using a pile of shims and now have 2.90 degrees downward tilt. This caused my 4" driveshaft to hit the tunnel so I went with a 3.5" MW chromemoly shaft. Now I need to weld-in the Hurst trans tunnel (2 piece) after I fill in the stick shift hole.
      Now I'm looking for a high quality shifter. I have the Kwik Shift shifter from Precision but do not like it. I have a manual forward VB and with the Kwik Shift I can push it straight into neutral from 2nd gear, not cool. I think the Kwik shift is only good with CO2 shifted drag car setups. I am eyeing the TCI Outlaw shifter, looks like it has hard stop gates 1-2 and 2-3 for foolproof shifting.
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      86 Buick GN, Stage 2 V6, Twin EFR Turbos

    17. #17
      Join Date
      Oct 2018
      Location
      San Jose, CA
      Posts
      523
      Tremec makes a nice app for the iphone for finding angles. I have a canton oil pan with a flat bottom - so took my measurements off that.
      I ended up about 2.5* without using any shims - motor mounts are lowered .75" and speedtech T56 crossmember for 2nd gen camaro.
      Headers and exhaust work perfectly at that angle too btw - off the shelf stuff there, not custom made.
      1971 Camaro - 406 / T56
      2016 Camaro SS convertible
      2018 Colorado 4x4





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