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    1. #1
      Join Date
      Jun 2006
      Location
      Halden, Norway, Europe
      Posts
      213

      Set/move engine down and/or back.

      Hi,

      I'm trying to set my engine back and down as much as possible.

      What is the recommended minimum distance between the oil pan and k-member? Poly motor mounts

      Min. space between transmission and trans tunnel? Poly trans mount also.

      Anything else I need to consider? Any recommendations and/or best practises?

      Don't want to regret doing this in the future

      Thanks in advance for any help and useful info!



    2. #2
      Join Date
      Mar 2008
      Posts
      952
      you don't need much room for theo il pan- 1/4" shouldbe fine. just don't plan on taking the oil pan off in the car.
      at the firewall, ideally you'd want enough room to get the bellhousing bolts out, but depending on how easy you like things to be, you could jsut take the motor/trans out as a unit instead of just dropping the trans, or cut access holes in the firewall with a hole saw to bet to each bellhousing bolt and make some sort of covers for each hole. there is also distributor clearance to think about- but the firewall could be pounded out of the way or a notch welded in for clearance.
      once you've got the motor down and back, then you need to think about header fitment and collectors scraping on the ground, as well as driveline angles unless you also drop the trans crossmember the same amount as the engine.

    3. #3
      Join Date
      Dec 2007
      Location
      Carlsbad, Ca
      Posts
      1,213
      Country Flag: United States
      some people still cant wrap their heads around it, but i moved mine up and back. i didnt have crap for header or bell housing clearance and it was keeping the car from being dropped even further. with a lot of work, i was able to drop the car another 1.5". the motor still sits the same height off the ground, but the entire car is dropped around it.

      so, before doing so, make sure you have custom headers and a bellhousing that doesnt sit like my mcleod.

      Tim
      Tim

      The WidowMaker: Garage Built 70 Chevelle

      Special Thanks To: Rushforth Wheels, MuscleRodz, Kore3 & SC&C

      Build Thread Link

    4. #4
      Join Date
      Apr 2001
      Location
      Central CA USA
      Posts
      6,108
      Country Flag: United States
      If you do some calculations, you will find moving an engine a couple of inches isn't worth the effort if reducing front wheel weight is your goal. If you move it 8 to 10 inches, then it might be of benefit.
      It's far better to move something heavy like a battery from up front to the trunk, it would be equal to moving the engine back 10"!
      Last edited by David Pozzi; 10-12-2009 at 06:14 PM.
      67 Camaro RS that will be faster than anything Mary owns.

    5. #5
      Join Date
      Dec 2007
      Location
      Carlsbad, Ca
      Posts
      1,213
      Country Flag: United States
      read this thread to understand where pozzi is coming from. it saved me a lot of work when i was going to build a new firewall and move the motor even further back.

      http://www.chevelles.com/forums/show...e+back+battery
      Tim

      The WidowMaker: Garage Built 70 Chevelle

      Special Thanks To: Rushforth Wheels, MuscleRodz, Kore3 & SC&C

      Build Thread Link

    6. #6
      Join Date
      Jun 2006
      Location
      Halden, Norway, Europe
      Posts
      213
      Hi all,

      a lot of interesting reading here. I will post pictures later today of my progress so far. You all have a lot of valid points to consider and have changed my mind a little about my priorities...

    7. #7
      Join Date
      Apr 2001
      Location
      Rockford Illinois
      Posts
      3,947
      Country Flag: United States
      Quote Originally Posted by David Pozzi View Post
      If you do some calculations, you will find moving an engine a couple of inches isn't worth the effort if reducing front wheel weight is your goal. If you move it 8 to 10 inches, then it might be of benefit.
      It's far better to move something heavy like a battery from up front to the trunk, it would be equal to moving the engine back 10"!
      When I moved my battery to the trunk, I got one that weighed 1/2 as much so I moved my engine back 6" to make up the loss/gain,LOL


      It is going to be interesting to feel the difference when I get my car on the road and compare it to what it used to be like. With so many other mods to the suspension it may be hard to tell. 6" and down 2" is hopefully do something of a benefit but I know that 21lb. battery is going to do just as much to help.


      The biggest deal with going back is the hood hinges. You will be wanting them out of your way everytime you are under the hood. I switched my hood to open the other way because of it.



      It's also a lot of work. Like starting over kind of work. Everything changes something else and the amount of things that change when the engine goes back are endless. I found it easier to go back than to try and change the mounting of the engine in the front frame section I used.

      Goodluck
      Last edited by Jim Nilsen; 10-14-2009 at 10:29 AM.

    8. #8
      Join Date
      Feb 2009
      Location
      So-Cal
      Posts
      149
      Country Flag: United States
      Quote Originally Posted by David Pozzi View Post
      If you do some calculations, you will find moving an engine a couple of inches isn't worth the effort if reducing front wheel weight is your goal. If you move it 8 to 10 inches, then it might be of benefit.
      It's far better to move something heavy like a battery from up front to the trunk, it would be equal to moving the engine back 10"!
      I agree with David. Mostly becuase I have worked on lots of drag cars with motors moved back a few inches and they were a complete pain in the ass to work on. One thing to mention, I have not seen this done too often to a car that uses the stock firewall, you can, but it may take a lot of work.

      I have moved a motor back in a 65 chevelle 8 inches and that was a lot easier than I thought it would be, but then again it was a full on racecar.

      James
      James Faria
      07 GT500 740rwhp

    9. #9
      Join Date
      Jul 2007
      Location
      Olathe, KS
      Posts
      1,158
      Country Flag: United States
      What about lowering the engine within the car vs raising the engine and lowering the car. I'm on the border with this decision.
      I don't necessarily want a crazy low ride height because of exhaust/engine clearance. I wouldn't mind a slightly lower ride height if I could keep the exhaust off the ground.

      Would I be correct in the assumption that as long as the engine stays the same relative to the ground, you're effectively lowering the CG? Obviously unsprung weight stays at the same height as the car is lowered so we're only talking about lowering the body shell/ interior.

    10. #10
      Join Date
      Nov 2002
      Location
      state of confusion
      Posts
      1,499
      Country Flag: United States
      Yes. If nothing moves up relative to the ground and anything at all moves down, the CG has to drop.

      Taller or shorter tires will affect the CG height.


      Norm
      '08 GT coupe, 5M, suspension unstockish (the occasional track toy)
      '19 WRX, Turbo-H4/6M (the family sedan . . . seriously)
      Gone but not forgotten dep't:
      '01 Maxima 20AE 5M, '10 LGT 6M, '95 626, V6/5M; '79 Malibu, V8/4M-5M; '87 Maxima, V6/5M; '72 Pinto, I4/4M; '64 Dodge V8/3A

    11. #11
      Join Date
      Sep 2004
      Posts
      135
      Us 1st Gen car guys can move our engines back against the firewall so tight using stock parts that our dizzies give us fits!

      Better yet is to put the battery in the trunk over the pass side tire.

      pdq67

    12. #12
      Join Date
      May 2001
      Location
      Mesa, Az.
      Posts
      1,433
      Country Flag: United States
      Quote Originally Posted by The WidowMaker View Post
      read this thread to understand where pozzi is coming from. it saved me a lot of work when i was going to build a new firewall and move the motor even further back.

      http://www.chevelles.com/forums/show...e+back+battery
      That was a lot of help... Thanks for the link.
      Phillip
      64 Studebaker Daytona Twin Turbo- http://bit.ly/1SgxQ0g
      65 Cutlass F-85 - http://bit.ly/1W4lJm4

    13. #13
      Join Date
      Jan 2010
      Location
      Elk River, MN
      Posts
      676
      Moving it downward will give more of a "feel" difference than moving it back 2-3 inches or whatever you have in mind. With our 69 Corvette SCCA car, the motor is as low and back as we could get it without hacking the firewall, and it's a major PITA to do anything on. Bellhousing bolts, front pulley, you name it, it sucks to work on. Stock location or a little bit lower won't lose you much in performance, but will save your knuckles lots of injury

      -matt

    14. #14
      Join Date
      Apr 2001
      Location
      Rockford Illinois
      Posts
      3,947
      Country Flag: United States
      It's not apples to apples but it is interesting to note that my car and Bad Penny weigh almost the same amount overall, I may be 75 to 100 lb less but that has to be seen on the same set of scales to be certain.. The F/R weight is 52/48 on both cars at this time. My engine weighs 125 lb more from what most say is the difference between an LS and standard SBC. My engine is back 6 in. and both cars have the battery in the rear. The front body weight of the cars should be close since Steve has the carbon fiber stuff and I have a lightweight fiberglass hood and other lighter pieces to help.

      It makes me wonder what it would be like if I had my engine in the stock location? Did moving my engine back 6 in. gain the same F/R weight as taking off 125 lb. ? If I went with an LS would it make it 50/50? It definately would take 125 lb. off of the car by changing the engine but does it change the F/R that much?

      I can say this. Compared to the way my other 67 handled , you can definately tell that the front end is way more responsive to shift changes left to right but that may be attributed to the Vette suspension.

      I can hardly wait for the Motorstate to get here so it can be compared with the same scales.
      May The Horsepower Be With You !!!

    15. #15
      Join Date
      Oct 2009
      Location
      Longview, TX
      Posts
      13
      Beyond just front/rear weight distribution, what about the benefits of reducing the yaw moment of inertia value by moving the engine back?

      As the P.A.T. goes, the crucial factor is how far the mass is from the center of rotation (I total = I + M*d^2). Looking at a first gen F-body with 52/48 front/rear weight distribution, moving a 500lb engine 5" back, from 40" to only 35" forward of the vehicle CG, is comparable to totally removing a 50lb battery from the the engine compartment or trunk (~65" from CG either direction). And, ironically, you could actually increase the moment of inertia value if you placed the battery too far back in the trunk.

      So, with the engine moved I know the car would theoretically be easier to turn but how much could you "feel" it on a 3500 lb vehicle? Other than engine placement and suspension components there aren't many big ways to reduce a cars moment of inertia as everything basically has a fixed location. This is where chevy engineers took out two birds with one stone when they rear-mounted the tranny and brought the engine back further...

      But the question still stands, would it be worth the headache to move the engine?

      -Dave
      - '67 Firebird 400 Conv't

    16. #16
      Join Date
      Oct 2004
      Posts
      2,544
      Country Flag: United States
      Here's how Steve finally managed a perfect 50/50 weight distribution on Bad Penny. (Hope it's been long enough that we can joke about it :-) )

      Red Forman: "The Mustang's front end is problematic; get yourself a Firebird."

    17. #17
      Join Date
      Aug 2004
      Location
      CHICAGO SUBURBS
      Posts
      761
      One thing I haven't seen discussed here is the lever type action an engine can have from being rather far forward. Example, an S10 V8 conversion might only gain 300 total pounds. When checking the weight before and after you might find a 400lb front gain and a 100lb rear loss. This is when leaving the trans in it's stock location as is normally done with these trucks.
      Frank B. 1968 Camaro 355 Procharged 6 speed. 1983 V8 S10. 1984 Monte Carlo Magnusen Charged iron 6.0. Plus a few other junkers!

    18. #18
      Join Date
      Oct 2009
      Location
      Longview, TX
      Posts
      13
      To lose 100lbs off the rear in that manner, say 100" wheelbase, you'd have to add 1000lbs @ 10" forward of the front wheel contact patch, 500lbs @ 20", or 333 @ 30"... that seems a little impractical for a v8 swap unless the front wheels start out under the tranny. Good point though as any weight placed beyond the wheelbase certainly pulls weight off the other end of the car.
      - '67 Firebird 400 Conv't

    19. #19
      Join Date
      May 2007
      Location
      Orlando, FL
      Posts
      215
      Here's a spreadsheet which allows you to see the effect on wheel loads when components are moved:

      http://www.racetec.cc/shope/tim.43.htm

    20. #20
      Join Date
      Jun 2006
      Location
      Halden, Norway, Europe
      Posts
      213
      Quote Originally Posted by BillyShope View Post
      Here's a spreadsheet which allows you to see the effect on wheel loads when components are moved:

      http://www.racetec.cc/shope/tim.43.htm
      Thanks, very interesting to play around with. This is approximate values of what I've added up so far from the baseline 58% front weight ratio:

      - Moving engine/tranny back (700lbs -> 3") (-0.7%).
      - Moving battery to trunk (-2%)
      - Light front bumper (-1%) adds tiny amount to CGH
      - Remove A/C compressor (-1%) adds tiny amount to CGH
      - Lee steering box, ATS spindles, SPC arms, new alu radiator, lighter wheels + tires front (about the same weight out back) (-1% estimate), also adds a bit to CGH, but not much ~0.05"

      Which adds up to an increase in CGH of ~0.2" and a front weight ratio of 52.3%. Still a way to go to reach 50/50. A carbon fiber hood would probably be one of the relatively simplest and best solutions.





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