dusterglenn
Well-Known Member
Can an LA360 crank be used as a replacement for a Magnum360? I know the balance is different between the two engines. But is the weight/balance difference the crank, rods, pistons, or all of the above?
LA vs Magnum crankshaft
- Thread starter dusterglenn
- Start date
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dusterglenn
Well-Known Member
Well, I've got a magnum that spun a rod bearing and took out the crank. Otherwise it looks good. Also have a 70's LA 360 crankshaft the looks like it just needs a quick polish.
So if I used the magnum pistons, rods, damper and flex plate with the LA crankshaft, will it run as is, or be out of balance?
So if I used the magnum pistons, rods, damper and flex plate with the LA crankshaft, will it run as is, or be out of balance?
Dragonbat13
Well-Known Member
Yes.
dusterglenn
Well-Known Member
"Yes" - good to go?
Or
"Yes" - out of balance?
Feel free to elaborate, they're not charging us by the word here....
Or
"Yes" - out of balance?
Feel free to elaborate, they're not charging us by the word here....
sbmmustang
Well-Known Member
OUT of balance.
dusterglenn
Well-Known Member
So, I decided to search the interwebs to see what's available for a replacement magnum crank. Every site I found showed two choices. Auto or manual trans. Machined for a pilot bearing or not. But, they all showed the same two part numbers for all years 71-02.
Dragonbat13
Well-Known Member
When you get a new crankshaft it will have to be balanced in most cases. Where are you finding these crankshafts?
When the connecting rods are lighter, as is the case in the magnum, it throws the bobweight off. The bobweight is what determines how much material is drilled or added to the crankshaft counterweights to balance the engine. Magnum rods and pistons are different from LA rods and pistons, therefore the bobweights are different. Now, you can put LA rods and pistons in a magnum, or you can put magnum rods and pistons on an LA crankshaft. But in either case, to do it right would require a rebalance.
The pilot bushing issue will be determined if you are running an automatic or manual transmission.
When the connecting rods are lighter, as is the case in the magnum, it throws the bobweight off. The bobweight is what determines how much material is drilled or added to the crankshaft counterweights to balance the engine. Magnum rods and pistons are different from LA rods and pistons, therefore the bobweights are different. Now, you can put LA rods and pistons in a magnum, or you can put magnum rods and pistons on an LA crankshaft. But in either case, to do it right would require a rebalance.
The pilot bushing issue will be determined if you are running an automatic or manual transmission.
dusterglenn
Well-Known Member
I haven't called or emailed to ask if the crankshafts need to be balanced for specific aplications. I kinda thought if there was a clear difference between 92-93, they'd list a different part number...
some of the sites I saw:
http://www.standardcrankshaft.com/crankshaftkitcatalog.html?sid=4744
http://crankshaftsupply.com/kits_chrysler.htm
http://www.crank-kit.com/index.php?page=products&make=CHRYSLER&makeId=2
http://www.apmengineparts.com/chrysler-jeep-5-9-360-v8-71-03-crankshaft-kit.html
some of the sites I saw:
http://www.standardcrankshaft.com/crankshaftkitcatalog.html?sid=4744
http://crankshaftsupply.com/kits_chrysler.htm
http://www.crank-kit.com/index.php?page=products&make=CHRYSLER&makeId=2
http://www.apmengineparts.com/chrysler-jeep-5-9-360-v8-71-03-crankshaft-kit.html
Make it easier, on yourself. Give the crankshaft company ,the casting number, off of yours. That tells them, what you need. If running a stock Magnum 360 rod/piston set,I wouldn't worry about balancing in a street/slight strip application.
The inspection & installation, make it live. Check the journals for rust & dimples,crank snout for good threads(then you pay for it!). Wash the crank off, hit those crank oiling holes with a bottle brush & solvent (WD-40 works).You will find cast iron grindings in there,it's necessary. Crank end play,Plastigage rods & mains as well.
Standard Crankshaft ,does nice work . Had one N.I.B,sold it to TX Dart here. Decent piece.
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