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Exposed transmission - How do you seal at the firewall?

Discussion in 'The Hokey Ass Message Board' started by Flipper, Oct 31, 2011.

  1. Flipper
    Joined: May 10, 2003
    Posts: 3,312

    Flipper
    Member
    from Kentucky

    For the guys with the transmission sitting with you in the interior of the car....How are you sealing up around the bellhousing? I can't come up with a good solution that allows for engine movement (rubber motor mounts).

    Please post pics of how you did it.

    Thanks.
     
  2. burnin53
    Joined: Mar 22, 2009
    Posts: 596

    burnin53
    Member
    from cuba,n.y.

    Cover it with a floor.
     
  3. I suppose you could sandwich a big sheetmetal mid-plate between the engine and trans and rivet heavy leather strips between the edges of the plate and firewall...

    But, yeah, what he ^^^^^^^^^^^^^^^^ said...
     
  4. Now that is way too practical.

    I suppose I would take rubber like 1/8 thick and cut it to lay against the bell housing and screw it to the firewall, it wouldn't seal it but it would cover it up some.
     
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  5. burnin53
    Joined: Mar 22, 2009
    Posts: 596

    burnin53
    Member
    from cuba,n.y.

    Trannys put out quite a bit of heat,I know I wouldn't want it sittin' next to me.
    And if you ever had a clutch explode,you'll be hobbling around on two stumps where your feet used to be.:eek:
     
  6. brad chevy
    Joined: Nov 22, 2009
    Posts: 2,627

    brad chevy
    Member

    Post some pics of your setup,might help.
     
  7. Get a big long oil pan from a straight 6 or 8 and put the sump end toward the firewall and cut it to fit the floor - instant trans tunnel.... Or a chunk of floor out of the boneyard... or imagine something else that has that shape... :rolleyes::rolleyes::rolleyes: or close to it.... Skys the limit...
     
  8. Ned Ludd
    Joined: May 15, 2009
    Posts: 4,004

    Ned Ludd
    Member

    I've been wondering about something like that. If the gearbox is "divorced" one can have a sort of domed floor panel over the bellhousing with a hole with a rubber boot of some sort where the front driveshaft comes out. Of course one doesn't want an exposed drive shaft next to one's ankle, so that would run in a sleeve with another boot or something to the front of the gearbox. That would put the clutch in a less threatening position, and allow a bit less engine heat to be conducted via the bellhousing.
     
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  10. metalshapes
    Joined: Nov 18, 2002
    Posts: 10,740

    metalshapes
    Tech Editor

    I've got a big burn scar on my leg from a bellhousing.
    Not even the tranny itself...
    ( from one of my front engined race cars )


    The transaxle on an another racer would get hotter than the oilpan.
    ( found that out trying to fix something between races )
     
  11. American Metrics
    Joined: Oct 1, 2009
    Posts: 39

    American Metrics
    Member

    The transmission in my sedan is also exposed. I haven't figured a way to cover it and still fit my size 16 feet next to it. I've thought of using some kind of rubber mat but never actually tried it. I hope someone has a simple solution:D
     
  12. Flipper
    Joined: May 10, 2003
    Posts: 3,312

    Flipper
    Member
    from Kentucky

    Scratch built, jag powered boat tailed, open wheeled speedster
    [​IMG]

    trans is a 4 speed with an auxilary overdrive unit. The overdrive is one of the things that complicates things. If I make the tunnel so that I could slide the trans in from the front, the tunnel will have to be a wide mofo.
    [​IMG]

    The trans is pretty cool looking and would look all that bad out in the open. ...kind like this pic Kiwi Kev recently posted.

    [​IMG]
     
  13. metalshapes
    Joined: Nov 18, 2002
    Posts: 10,740

    metalshapes
    Tech Editor

    I'd make a tranny tunnel that unbolts and comes out through the interior.

    That way it can hug the odd shape of the tranny& OD, and you can take it out of the way when the tranny needs to slide foreward to get it out of the car.
     
  14. opu27
    Joined: Mar 1, 2011
    Posts: 150

    opu27
    Member
    from ONYX,CALIF

    IF you have a shift handle that comes through the floor. get a big sponge, get it wet and place it over the shift handle onto the trans then put the floorboard over it. sponge will dry and give you a perfect seal.
     
  15. budd
    Joined: Oct 31, 2006
    Posts: 3,478

    budd
    Member

    a trans can explode without warning, i have had a auto trans, turbo 350, snap off at the bellhousing, it came up and wacked the floor before droping down on the pavement, seen the results of flywheels come apart that looked like a bomb went off, but if you know the risks and are not worried?
     
  16. outlawsteel
    Joined: Feb 19, 2009
    Posts: 360

    outlawsteel
    Member

    You dont want to leave that uncovered IMO. Unless you dont mind have a few less body parts if it decides to come apart. The simple solution IMO would be to make a tunnel that will unbolt from the floor. I have some ideas floating around in my head for your setup if you want to pm me I'll throw them at ya.
     
  17. "T'RANTULA"
    Joined: Aug 6, 2011
    Posts: 658

    "T'RANTULA"
    Member
    from Ohio

    I had the same issue with my 55 chevy, they set the engine back and ran it with nothin covering the trans, I just built a fire wall around it. And Like everyone has said clutches can explode with no warning, I have a friend named Stubby cause he ran with out an explosion proof bell housing... CAN YOU GUESS WHY HE GOT THE NAME?
     
  18. budd
    Joined: Oct 31, 2006
    Posts: 3,478

    budd
    Member

    oh my god it cut his penius in two...


    [QUOTE="T'RANTULA";7098744]I had the same issue with my 55 chevy, they set the engine back and ran it with nothin covering the trans, I just built a fire wall around it. And Like everyone has said clutches can explode with no warning, I have a friend named Stubby cause he ran with out an explosion proof bell housing... CAN YOU GUESS WHY HE GOT THE NAME?[/QUOTE]
     
  19. brad chevy
    Joined: Nov 22, 2009
    Posts: 2,627

    brad chevy
    Member

    Metalshapes has the right idea. Build a bolt-in tunnel around it.You have plenty of leg room. With that bell housing,trannie and overdive unit the heat is going to get to you. Looks over saftey is not the way to go.
     
  20. 117harv
    Joined: Nov 12, 2009
    Posts: 6,590

    117harv
    Member

    The sky is falling....? Im sure it has happened but a thin piece of sheet metal wont make much differance. Now the drive shaft on the other hand, yes a cover and maybe a loop at the yoke.

    As far as extra heat, an automatic for sure but a manual i wouldn't think too much.
     
  21. metalshapes
    Joined: Nov 18, 2002
    Posts: 10,740

    metalshapes
    Tech Editor

    As far as all the explosion stories, I agree with you.

    This is a Jag 6cyl with the tranny it came with, and ( I'm guessing ) skinny bias rear tires.

    Not a super high power sticky slick situation.


    As far as the heat, I didnt think so either.
    But I was proven wrong.
    ( both of the ones I talked about are manuals )

    The transaxle is in my Fiat Abarth, and its right on the ragged edge of that it can handle torque wise.
    So I thought I was probably distorting the hell out of the case in race situations, making the transmission losses high.
    High drag = lots of heat...

    But then I burned my leg ( badly, because the concentration and adrenaline made me not feel it untill I got out of the car ) on the Bell of my Mallock.
    That tranny is not stressed to its limit.
     
    Last edited: Oct 31, 2011
  22. burnin53
    Joined: Mar 22, 2009
    Posts: 596

    burnin53
    Member
    from cuba,n.y.

    If you're just gonna just go around the block it won't get too hot.
    But,actually drive it for a couple hours or so and I say you almost can't set your hand on it and keep it there.
    In the heat of summer,I guarantee you'll hate it.

    And that thin sheet metal will at least slow the shrapnel if you do happen to blow a clutch.
     
  23. Hot Rods Ta Hell
    Joined: Apr 20, 2008
    Posts: 4,061

    Hot Rods Ta Hell
    Member

    I'm more concerned/interested in your chassis design. While you've started to plate the front portion of the frame, it looks to just be butt welded up to the firewall area of the "passenger box".
    Do you have plans to stiffen up this transition?
    I'm not a chassis engineer, but it just seems like it needs more to avoid caving at the firewall.
     

  24. hahahahahahahahahahahaha!!!!!!!:d
     
  25. smitty city
    Joined: Jun 13, 2010
    Posts: 108

    smitty city
    Member

    ridin' in the rain in the roadster:
    wife: water is coming in and i'm gettin' wet
    mike: that's cause it's rainin'
    wife: why don't you put in some side windows?
    mike: roadster don't have side windows
    wife: well, i think you need em
    mike: it's part of the adventure
    wife: i don't want adventure, i want dry
    mike: when it comes to being cool, there are some trade-offs
    wife: horseshit

    even with a metal covering or a scattershield, on a hot summer day you'll pobably be wishing for rain. i agree with burnin', it might be cool to you, but it's a huge trade-off. (safety AND heat)
     
  26. Flipper
    Joined: May 10, 2003
    Posts: 3,312

    Flipper
    Member
    from Kentucky

    There will be lots more tubes and gussets added when all is said and done. I'm trying to figure out the placement of some key components before I finish the structure.
     
  27. Flipper
    Joined: May 10, 2003
    Posts: 3,312

    Flipper
    Member
    from Kentucky

    I think that might be the way to go.
     
  28. Rickabilly
    Joined: Jul 17, 2011
    Posts: 22

    Rickabilly
    Member

    Hello All,
    I hate to contradict, But, many sports and race cars of the thirties ran trannies in the passenger compartment, just look up MGs of the thirties, their trannies were works of art with polished octagonal facets all over them, Art deco at it's best.

    Providing you haven't got a lot of traction, it is pretty hard to break a standard tranny with a standard engine, In this case the car looks to be much lighter than the Jag that the trans came from, and I've never heard of a Jag trans breaking in any sort of catastrophic manner, Manual trannys don't get anywhere near as hot as Autos, as the oil in an Auto is engaged in actively transferring power and there are serious power losses in this process, those losses heat the oil and as a result the tranny case gets hot, this just doesn't happen in a manual, In short try it out, and if it gets too hot cover it later. just like is done in many triumphs from the thirties right up into the seventies, the main reason for the tranny cover in the Triumph is to keep the noise at bay, noise will be another issue to consider. Another point about heat and manual transmissions is the amount of time spent in the one to one ratio, as the one to one ratio has no gearing under load therefore little heat buildup, some of the trannies mentioned are transaxles that effectively have no one to one ratio as well as, in most of the cases mentioned, being used in racing situations, in racing situations everything gets hot, I once burned my arm on a steering knuckle in the engine bay of my racing car, but having said that, I wouldn't hesitate to put a steering knuckle inside the cockpit, as it would be well protected from the radiant heat that a racing engine produces.

    Some of the Thirties race cars sandwich the firewall between the engine and bell housing, the firewall vibrates with the engine. The cowl is not attached to the firewall at all, the sealing is done by a "Roll" of canvas (sometimes leather) rivetted or sometimes "Laced" to the firewall with twine or thong the roll is filled with some sort of fibre, modern materials like polyester fibre fill would work fine. The roll is often around an inch to an inch and a half in diameter, and will eventually rub the paint off the panels, which looks pretty good on a patina'd ally body, but just causes rust on a steel body, If you are sandwiching the panel it might be a good idea to insulate the joint from heat as well preventing as much engine heat from travelling into the cockpit as possible, every little bit helps.

    Beware the firewall will get really hot, as it will conduct a lot of heat from the engine, but it can be insulated fom the inside quite easily, Ally firewalls transfer more heat than steel as well as looking better.

    Another thing to remember is that you might want to vent the bellhousing through some ducting out through the floor, as the materials used in clutches are not very good for breathing, especially if you are using old stock parts that probably contain asbestos.

    Best Regards
    Rick,
    PS I am looking forward to the next update on the Roofus, regardless of what you do with the tranny.
     
    Last edited: Oct 31, 2011
  29. Damn, Rick, I was hoping Flipper would think I came up with the idea! :D

    I think that the 30s-50s sports racer is the "look" Flipper is after. However, I still don't think it's a "good" idea to expose the trans inside the car...
     

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