1. Registration trouble? Please use the "Contact Us" link at the bottom right corner of the page and your issue will be resolved.
    Dismiss Notice

Buick 3.8 In A CJ5

Discussion in 'Early CJ-5 and CJ-6 Tech' started by Pipedawg, Apr 13, 2018.

  1. Apr 13, 2018
    Pipedawg

    Pipedawg New Member

    South Jordan,...
    Joined:
    Aug 17, 2017
    Messages:
    12
    I have a rebuilt 3.8 I am going to put in my CJ5. I also have a BOP TH350 I can use. I am leaning more towards keeping my T90 transmission. My question is if I keep my T90 which Flywheel do I use on my 3.8. I found a bell housing that is advertised as bolting to a Dauntless and to a T90. I believe the bolt pattern is the same on my 3.8, but Novak says the Dauntless was never bolted to the T90. Any information will be appreciated.
     
  2. Apr 13, 2018
    Rich M.

    Rich M. Member

    Maryland
    Joined:
    Mar 23, 2008
    Messages:
    335
    BOP ( Buick/olds/Pontiac) pattern is the same as the 225 dauntless ( which was a gm design bought by Jeep, subsequently sold back) flywheel will depend on whether your 3.8 is odd or even fire. If odd the 225 flywheel can be used ( easy to source) if even they are available but pricey.
     
  3. Apr 13, 2018
    Pipedawg

    Pipedawg New Member

    South Jordan,...
    Joined:
    Aug 17, 2017
    Messages:
    12
    I have an even fire. I read that a 1995 Camaro flywheel would fit. Thank you for the information.
     
    Diverdc likes this.
  4. Apr 14, 2018
    timgr

    timgr Jeepin' Nerd Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    18,805
    Novak is correct that Jeep never paired the T-90 with the 225. They did, however, use the T-86 which is basically an updated T-90 (though the T-90 and T-86 are not compatible). Plenty of T-90s have been adapted to GM engines. Typically you use a plate adapter and a longer input shaft with the original GM (Buick) bellhousing. Read this article - Adapting the Chevrolet & GM Standard Shift Bellhousings to the Jeep T90 Transmission The C1 type adapter is the most common form and can often be found on the used market.

    There are neutral balanced engines (internal balance, without balance weights on the flywheel) and Detroit balanced engines like the odd-fire (external balance, with balance weights on the flywheel). If either the Chevy or the even-fire 231 are externally balanced, they won't be compatible with each other without rebalancing by a machine shop. If they are both neutral balance, they may be compatible. If you found a flywheel that bolted to your crank, worked with your starter and fit in the bellhousing, your machine shop could balance it to your engine.

    I would look at what replacement flywheels are offered for the even-fire engine. Check the online catalogs. TA Performance are the experts wrt Buick parts - you could call and ask them.
     
  5. Apr 19, 2018
    windyhill

    windyhill Sponsor Sponsor

    PA
    Joined:
    Nov 4, 2006
    Messages:
    1,370
    Do yourself a favor and upgrade the trans while your at it. T-18 4 speed out of a Ford is my best suggestion. I was in the same boat years ago and am super glad many times over I did the t18.
     
    Vanguard and fhoehle like this.
  6. Apr 19, 2018
    fhoehle

    fhoehle Sponsor Sponsor

    Eynon, PA
    Joined:
    Apr 11, 2012
    Messages:
    695
    I agree, if you are going through the trouble, do it all now. The T-18 is one of the nicest truck four speeds available.
     
  7. Apr 20, 2018
    Pipedawg

    Pipedawg New Member

    South Jordan,...
    Joined:
    Aug 17, 2017
    Messages:
    12
    Thank all of you for the information you have provided. I will take a look at the T18.
     
  8. May 12, 2018
    Dauntless1971

    Dauntless1971 Member

    Bend, OR
    Joined:
    Oct 22, 2004
    Messages:
    178

    My understanding is Center force is the only maker of new flywheels for 3.8 even fire. I have seen them for as little as $ 280 plus what 30 dollars shipping these days.
     
  9. Jun 5, 2018
    Bill Schmidt

    Bill Schmidt New Member

    CLOVERDALE CA
    Joined:
    Sep 3, 2016
    Messages:
    1
    I've got a 66 with the Dauntless and a T90 that needs rebuilding but I'm leaning towards the 4 speed swap. Will the Ford T18 drop right in with that bell housing?
     
  10. Jun 7, 2018
    chipdom

    chipdom Member

    Joined:
    Nov 3, 2013
    Messages:
    71
    I do not think so. check the Novak site for all the information you will need.
     
  11. Jun 14, 2018
    windyhill

    windyhill Sponsor Sponsor

    PA
    Joined:
    Nov 4, 2006
    Messages:
    1,370
    Stock buick v6 bell will work with the t-18 with a little modifying. You have to turn down the retainer on the T18 and open up the hole on the bell so they are a slip fit. It was easy and reasonable to have a machine shop do. I think you drill one hole and tap it out, (It's been years, but I did it and was not vary experienced at the time). you also have to grind the case on the t18 where the transfer case lever casting is. When it's done it's super compact and works great. Novak had info on how to do everything.
     
    Last edited: Jun 25, 2018
  12. Jun 21, 2018
    458soco

    458soco Member

    North Georgia
    Joined:
    Jan 29, 2014
    Messages:
    114
    Not to hijack this thread but could we please get more info on this???
     
  13. Jun 21, 2018
    timgr

    timgr Jeepin' Nerd Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    18,805
    Novak has quite a lot of discussion of adapting the Ford T-18 to GM bell on their site The Novak Guide to the Adapting Ford Style Transmissions to GM Engines Suggest you read everything on that site related to the T-18 and adapting it to GM engines. The truck 4-speed upgrade is very popular, and there has been plenty of discussion of this topic on the site. You can dig out answers to your questions with a little browsing and reading.
     
    Vanguard likes this.
  14. Jun 21, 2018
    timgr

    timgr Jeepin' Nerd Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    18,805
    Hi Bill - first post! Welcome to the site.

    There is no transmission that will just "drop in" to replace the T-90. Any transmission swap will require some modifications. For the truck 4-speeds, you need to adapt the transmission to the engine, and the transfer case to the transmission. This can be done with junkyard parts and some minor machining, or you can buy commercial adapter kits that will let you bolt them together. Typically the transmission has to come completely apart to replace the main shaft, as part of the adapter kit. You will need to move the cross member, and modify and adapt the mounting. You will have to change the lengths of your driveshafts. You will need to modify the floors to clear the new, larger transmission. You may need to modify the clutch linkage to work with the new transmission. Lots to change, but it's been done many times, typically with excellent results. It will also cost quite a lot more than refreshing or replacing your T-90, even if you can find all the junkyard parts to make it work.
     
    Sierra Bum likes this.
  15. Jun 21, 2018
    Bowbender

    Bowbender I'm workin' on it! Sponsor

    Northern Minn.
    Joined:
    Nov 14, 2014
    Messages:
    235
    Nice, concise summary Tim. I would add: Unless you are good at the junkyard thing and have the time, Novak's kit isn't out of line for what you get, and it's a one stop deal.
     
  16. Jun 21, 2018
    Sierra Bum

    Sierra Bum Member

    The High Sierra
    Joined:
    Oct 23, 2017
    Messages:
    66
    All the major granny gear truck 4 speeds are worth a look and each has it's quirks to make a swap successful. And they all have a proven great reputation. Again look at the Novak "research" link for lots of good, accurate info on the all the swap combinations. As noted the adapter kits form Novak or Advanced Adapters are well worth it.

    SM420 : shortest case, lowest first gear around (7:1), bolts right to a dauntless bell
    SM465 : Novak makes a 1" adapter to the M18 case. big, heavy, 6.5:1 first gear. Almost bolts right to dauntless bell
    NP435 : Popular in Ford trucks, a few different versions, adaptable to many applications
    T18 : popular for lots of good reasons, must be aware of the many different versions out there, bolt patterns etc., and some do not have a true "granny gear", which most of us want.
    T19 : a 4:1 first gear box, some dodge? versions have a 5ish:1 first gear (i think)
    T98 : Early version of the T18, came stock in some early CJ5's with the 4 banger. a bit antiquated and difficult to find parts for (or so I hear)
     
  17. Jun 22, 2018
    sterlclan

    sterlclan Member Sponsor

    exploring the...
    Joined:
    Feb 21, 2009
    Messages:
    2,462
    I used a Novak adaptor for the 435 to 20 in my 74 very nice parts.
     
  18. Jun 22, 2018
    458soco

    458soco Member

    North Georgia
    Joined:
    Jan 29, 2014
    Messages:
    114
    I have looked at all the adapters on Novak and AA's sites but I was unaware some of the 4 speeds would bolt up with little to no mods. Very nice to know. Ill be on the hunt for one now. Thank yall for the info!!
     
  19. Jun 25, 2018
    windyhill

    windyhill Sponsor Sponsor

    PA
    Joined:
    Nov 4, 2006
    Messages:
    1,370
    My experiences and 2 cents:
    SM420 huge bulge on passenger side, creates issues with the driveshaft etc. Case is short, but the adapter is long to make room for the bulge. Also no reverse light switch and getting hard to find parts.
    SM465 Big and heavy! 175 lbs. wide as well. pinches area for gas pedal. Shaft collars are a PITA to remove and replace when swapping tail shaft.
    T18, Stick with the ford version, Jeep made 14 diff. versions, (not all parts interchange or are compatible.) easy to rebuild and swap tail shaft, Parts are available, 1" adapter, shortest overall length with adapter. great granny gear. (note: there is a non granny gear version as well.)
    NP435 haven't swapped but look similar to t-18. T19 also similar to t18 I think without granny first? and as stated, T98 hard to get parts and has value to keep it stock for a 4 cyl.
     
  20. Jun 28, 2018
    Keys5a

    Keys5a Sponsor Sponsor

    Joined:
    Jan 23, 2014
    Messages:
    1,450
    I have an NP435 with an NP208 t/c from a Dodge Ramcharger. It has a compound (granny) first gear with a 6.68 ratio. The transfer case hase a 2.62 low range reduction. This combination yields a usable crawl ratio. The only peculiarities are a fairly long adapter used by Dodge between the two, and the transmission case front face (mates to bellhousing) has a 4 bolt pattern with the lowest holes level with the input shaft. It needs additional mounting holes tapped lower. That, and the transmission has pto covers on both sides. The whole combination is a bit long for use in a CJ, but it would be great in longer wheelbase vehicles like my old Willys wagon.
    -Donny
     

Share This Page

New Posts