Re: 3.9 Engine blocks ?

From: greg conner (dodgeboy93@hotmail.com)
Date: Tue Mar 30 2004 - 02:11:00 EST


Actually Tom, putting magnum heads on a premag block is quite a common
upgrade and the magnum v6 started in 1992. The only thing i wasnt sure
about was the motor mount boss simularities. I'm not sure how the castings
compare though ron, I doubt there is really much of a strength difference.
Just make sure if it is a pre92 block the right side has provisions to mount
the crank sensor. thats the only thing I could think of that may be
different. i dont know if the tbi premag v6's used a block mounted crank
trigger or not. I seem to rember they did, but I'm not sure if they mounted
the same way.

Greg Conner
1996 RC
3.9 hybrid

>From: Terrible Tom <SilverEightynine@aol.com>
>Reply-To: dakota-truck@dakota-truck.net
>To: dakota-truck-moderator@bent.twistedbits.net
>Subject: Re: DML: 3.9 Engine blocks ?
>Date: Tue, 30 Mar 2004 00:17:43 -0600
>
>
>ronald bruce taylor,jr wrote:
>>The block has been checked for cracks, I asked what it needed done to make
>>it useable and all it basically needed was the mains align bore honed,
>>punched .020-.030, and decked .010 to square it up.
>>
>>It has the mounting bosses cast in it that are similar to the ones on my
>>3.9, I'm just curious as to what makes the difference between the
>>Pre-Magnum and Magnum cylinder casing castings?
>>
>>I'm going back later this week to check it further and see if I can find
>>the casting Date on it..........
>>
>>Ron-
>>01'Dakota Sport 3.9 4WD
>>www.scsilverdak.1colony.com
>>
>>
>>
>>----- Original Message ----- From: "greg conner" <dodgeboy93@hotmail.com>
>>To: <dakota-truck@dakota-truck.net>
>>Sent: Monday, March 29, 2004 8:03 PM
>>Subject: RE: DML: 3.9 Engine blocks ?
>>
>>
>>
>>>Well all the 3.9's used a roller cam. Look on the side at the casting
>>>date.
>>> Your gonna want a mag block (92 and up) I dont beleive the older blocks
>>>have the bosses on them to use the motor mounts in your block.
>>>
>>>I'd check it over (maganflux) for cracks and such. Also check in and
>>>around
>>>the headbolt holes closely for cracks, thats a common spot on a high
>>>millage
>>>engine.
>>>
>>>
>>>
>>>Greg Conner
>>>1996 RC
>>>3.9 hybrid
>>>
>>>
>>>
>>>
>>>
>>>
>>>>From: "ronald bruce taylor,jr" <taylor9565@msn.com>
>>>>Reply-To: dakota-truck@dakota-truck.net
>>>>To: "Dakota Mailing List" <dakota-truck@dakota-truck.net>
>>>>Subject: DML: 3.9 Engine blocks ?
>>>>Date: Mon, 29 Mar 2004 19:13:50 -0500
>>>>
>>>>
>>>>I've run a across a Bare 3.9 engine block at a Pretty good price of
>>>>$40.00,
>>>>it needs to be fully machined and prepped for use.
>>>>
>>>>A local machine shop has it in the spare engine block core supply, and
>>>>they
>>>>offered it to me, since they don't do much in the way of V6
>>>>engines.
>>>>
>>>>I looked it over and it is a Roller Cam block, and at this price I find
>>>>it
>>>>cheap enough to buy for a possible candidate to build a Supercharger
>>>>specific shortblock.
>>>>
>>>>I just wonder if there are any differences over the 3.9 production run
>>>>in how these blocks were cast.
>>>>
>
>Magnum heads won't fit on premagnum motors and vise versa. I believe the
>differences are semi-subtle. Bolt patterns, water passages etc... stuff
>doesnt line up between the premags and magnums from what I understand.
>Thats why you never hear of anyone putting magnum production heads on a
>premag block. The heads also use different bolt patterns for the intake
>manifold. Premag intake manifolds bolts are at an angle and at different
>positions - magnums are horizontal and more uniformed in pattern.
>
>The blocks all should accept the same motor mounts between premag and
>magnum. That is pretty standard between 3.9, 5.2, and 5.9 engines. As
>long as you can determine if the 3.9 core you have is 92 or newer, you
>should be able to use it. I *think* 91 Daks had magnum 3.9's - I know they
>had premag 5.2s.
>
>--
>--------------------------------------------------------------
>"Why don't you ask me what it feels like to be a freak?"
>
>Terrible Tom -- AIM & Yahoo Name: SilverEightynine
>

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