Moparts
Another magnum motor question
Posted By: rattler
Another magnum motor question - 02/19/12 05:16 PM
I picked up a 5.9 magnum motor for the wife's Dart project. I know that i will have to change pans and pickups, but i was also wanting to put the original stle(72) pulleys and acceceries on. Can i just use the older sylye timing cover and water pump? The old drive brackets? And what do i do about the harmaonic balancer? Can you use the LA stlyle balancer and pulley off of a 360?
Posted By: Andrewh
Re: Another magnum motor question - 02/19/12 05:35 PM
the whole front end does bolt up, pulley's and all, BUT the harmonic is different.
I don't think you can reuse the LA stlye.
you will have 1 bolt that doesn't line up on the crank pulley.
Posted By: rattler
Re: Another magnum motor question - 02/19/12 07:41 PM
The serpentine pulley appears to be part of the harmanic balancer, that is why i thought that i might be able to use a regular LA style harmonic ballancer-pulley setup.
Posted By: BulletBob
Re: Another magnum motor question - 02/19/12 08:45 PM
To use your stock stuff you need a cam snout extension from Hughes. as far as the crank pulley Get you a balancer from a earlier MAG 5.9 & put it on & bolt your pulleys up 1 hole can be burred out to fit the sixth bolt. To use your stock Alt brackets you will need to grind a boss on the head down or move the tab on the bracket
Posted By: BulletBob
Re: Another magnum motor question - 02/19/12 08:47 PM
Which intake are you using?
Posted By: dfsmopars
Re: Another magnum motor question - 02/19/12 08:53 PM
I stuck the entire LA front end on the 5.9 I built for my Charger. I used the 318 timing chain cover, LA water pump, damper and all the accessories. I eliminated the mechanical fuel pump and am going with an electric one.
I have not started it yet but so far everything looks good to go. I hope to fire it up in the next two weeks.
Posted By: rattler
Re: Another magnum motor question - 02/19/12 09:44 PM
I haven't decided which intake carb combo to run yet. This will be a mild set-up for the wife. But, back to one of my questions, can i use an early LA 360 balancer?
Posted By: DaytonaTurbo
Re: Another magnum motor question - 02/20/12 12:30 AM
Maybe someone else can confirm, but I think the magnum and LA 360's are balanced differently, which is why you can't use an LA balancer.
Posted By: BulletBob
Re: Another magnum motor question - 02/20/12 12:51 AM
They do balance different that's why I posted about using A earlier 5.9 Mag balancer
Posted By: BulletBob
Re: Another magnum motor question - 02/20/12 12:56 AM
If you go back with the V belt drive that came with the car You will need the Crosswinds intake or the Dual plane from MP for a Mag. This way you can use factory off the shelf bypass hose & such.
I've done this swap a few times
Posted By: rattler
Re: Another magnum motor question - 02/20/12 01:09 AM
What year balancer would i need Bob?
Posted By: BulletBob
Re: Another magnum motor question - 02/20/12 01:17 AM
94-mid 99 I had to change the balancer on my 2000 R/T Dak to use a true underdrive pulley kit.. if there's any problems or questions I can help you. I've done the LA to Mag swap in different cars & trucks about 8 times or so in the last 5 years. 518 swaps too.
Posted By: Andrewh
Re: Another magnum motor question - 02/20/12 01:57 AM
97 I thought was the cut off year. they change in 98, but could be just electrical.
Posted By: BulletBob
Re: Another magnum motor question - 02/20/12 02:21 AM
The electrical changed every time the 518 had changes it looks like to me. Some trans shops will put a 2 pin or 3 pin valvebody in a 46RE.
Posted By: rattler
Re: Another magnum motor question - 02/20/12 02:24 AM
I was looking at online parts sources and it listed 94 thru 03 as one part, and 93 back to 79 as being another balancer. I am just trying to round up the right parts before i need them.
Posted By: GO_Fish
Re: Another magnum motor question - 02/20/12 02:40 AM
That's correct 93 and back LA 360's used a different balancer (IIRC) than 94+ 5.9 Magnums. That is because the Magnum used a different crank, with lighter rods and pistons than the old 360 LA did. I'd be concerned that bad things will happen if you try and mix/match them.
Are you sure the serpentine pulley won't come off of the Magnum balancer? I'm having a hard time visualizing that the pulley and balancer are one part... (balancer is iron and the pulley, stamped steel)?
Posted By: BulletBob
Re: Another magnum motor question - 02/20/12 02:48 AM
If I remember correct the reason that I changed the balancer on my Dak because the pulley & balancer was two piece pressed together. I know I changed the WP to a bolt on pulley style (92-96) so the pulleys would work
Find the balancer & put it on & ride.
Posted By: dfsmopars
Re: Another magnum motor question - 02/20/12 03:12 AM
Quote:
To use your stock stuff you need a cam snout extension from Hughes. as far as the crank pulley Get you a balancer from a earlier MAG 5.9 & put it on & bolt your pulleys up 1 hole can be burred out to fit the sixth bolt. To use your stock Alt brackets you will need to grind a boss on the head down or move the tab on the bracket
Alright, let me get this straight. With a '94 block, stock crank, KB pistons and an externally balanced flex plate from a Magnum, the LA damper from a '72 318 will not be good? What will happen? Is there a catastrphic imbalance or an annoying vibration? Is it something I can break-in the engine with and change later if I recognize a problem? I have everything put together and you have my gotten my attention.
Posted By: HotRodDave
Re: Another magnum motor question - 02/20/12 05:20 AM
You are asking for trouble, that thing is gonna be way out of balance.
One...the KB pistons are lighter than stock.
Two the magnum and LA are balanced different on the front and back of the eninge.
When I was 19 I built a 360 once without balancing it and used the KB 107 piston, 360 rods, 360 crank and at first used 360 balancer and converter weight, vibrated real bad and ate HP. I got told to balance it, instead I looked up the weights and figured it would be closer to a 5.9 balance factor, put in a neutral converter a 5.9 plate and damper and it was better but still bad, finnally pulled it all, balanced it properly and no other changes it felt smooth as glass and felt like another 50 HP, so now any engine I build that is not all stock gets balanced, even stock rebuilds I try to swap pistons around so the heavy ones counteract heavy ones and light ones counteract light ones and same with rods.
Posted By: dfsmopars
Re: Another magnum motor question - 02/20/12 12:08 PM
Quote:
You are asking for trouble, that thing is gonna be way out of balance.
One...the KB pistons are lighter than stock.
Two the magnum and LA are balanced different on the front and back of the eninge.
When I was 19 I built a 360 once without balancing it and used the KB 107 piston, 360 rods, 360 crank and at first used 360 balancer and converter weight, vibrated real bad and ate HP. I got told to balance it, instead I looked up the weights and figured it would be closer to a 5.9 balance factor, put in a neutral converter a 5.9 plate and damper and it was better but still bad, finnally pulled it all, balanced it properly and no other changes it felt smooth as glass and felt like another 50 HP, so now any engine I build that is not all stock gets balanced, even stock rebuilds I try to swap pistons around so the heavy ones counteract heavy ones and light ones counteract light ones and same with rods.
Rattler, I did not mean to derail your post. I hope you got the answer you were looking for. Apparently you ask the right questions ahead of your project unlike me. I did personally balance my rod and piston assemblies but it looks like I need to go shopping for a balancer. Thanks Dave.
Posted By: 70Cuda383
Re: Another magnum motor question - 02/20/12 03:13 PM
Rattler,
sometime around 2000 or 2001, the 5.9s got a single piece harmonic balancer and crank pulley all cast as one unit. All the parts stores also changed their computer listings for this one piece unit, and will tell you with 100% confidence that it's the exact same set-up as what an earlier 5.9L magnum came with, because that's what the computer shows.
the dealer can still get the original balancer and separate pulley but it's about $120 MORE than at advance auto, and there's a 6 week wait (that's what they told me when I called for one for my 98 dakota)
That said, I have one that's used, and I believe it's in good shape. it's a stock original piece with unknown miles. you could take your V-pulley and oval out one of the holes so it bolts up.
if you're interested, I'll make you a killer deal on it.
Posted By: 70Cuda383
Re: Another magnum motor question - 02/20/12 03:17 PM
Quote:
Quote:
To use your stock stuff you need a cam snout extension from Hughes. as far as the crank pulley Get you a balancer from a earlier MAG 5.9 & put it on & bolt your pulleys up 1 hole can be burred out to fit the sixth bolt. To use your stock Alt brackets you will need to grind a boss on the head down or move the tab on the bracket
Alright, let me get this straight. With a '94 block, stock crank, KB pistons and an externally balanced flex plate from a Magnum, the LA damper from a '72 318 will not be good? What will happen? Is there a catastrphic imbalance or an annoying vibration? Is it something I can break-in the engine with and change later if I recognize a problem? I have everything put together and you have my gotten my attention.
I know it's not what you want to hear, but you really need to take that assembly down, have a machine shop balance it for you. those KB pistons are WAY lighter than stock, and the mistmatched dampner and flexplate will NOT do good things for you. take it all in and let them get all the parts matched together.
Posted By: rattler
Re: Another magnum motor question - 02/21/12 12:59 AM
I may take you up on that offer Tom, this motor came out of a 99 Durango and it has the one peice pulley-balancer.