408 Question

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Summit has 30 different dampners for mopars and almost all of them are for External balanced 360's there are some internals if you go with ati or major brands, didn't you say it was a dorman?? cause those are all external except for the 318-340 ones, and those shouldn't fit due to different cranks?? give me a part number, now I am really curious....

here is the summit number that i ordered... RNB-594-132
 
IMG01140-20111129-2225.jpg


it is close to this on the front side.... but mine is not all the way around... it is just like that one bout half.
 
well that does come up as internal balanced 360 so you should be good, provided that's what they sent you, hmmmm I am stumped hopefully someone else can figure it out, what are you using for a fan?? maybe it is out of balance??
 
well that does come up as internal balanced 360 so you should be good, provided that's what they sent you, hmmmm I am stumped hopefully someone else can figure it out, what are you using for a fan?? maybe it is out of balance??

electric fan mounted to rad.
 
just got done talking to summit. the picture matches the part i have. It has three small holes in the motor side of the damper. that matches there picture and it is for a internally balance motor. However, the pulley side of the damper has a machined groove about 2/3 around it that is machined out to about 1/4" deep. that tells me it is for external... am i wrong? the only problem is that my part was shipped straight from the manufacturer, so they could have sent me the wrong one.

1. All 360's from the factory were externally balanced
2. The OEM damper you have needs returned, the listing is simply incorrect. it's for an OEM 360 yes. but not one that has been set up as internal balance. i'm assuming it's this one being it's the cheapest dorman damper that comes up on their site. Dorman is probably 99% OEM replacement parts. not aftermarket. Again the web listing on this damper calling it internal...is WRONG.
3. they also sell neutral balance flexplates. I would not use an OEM flexplate with an aftermarket internal balanced engine. if yours was from a 318, then yes thats an internal balance engine..but i still wouldn't use it.
 
If you look up that part number it shows it only fits the 360 and does not fit the 318 or 340. I thought all the la 360's were externally balanced?
 
so with the given info i have said, it correct that it more than likely the wrong damper? Guess i will need to order a new one.
 
so with the given info i have said, it correct that it more than likely the wrong damper? Guess i will need to order a new one.

I'd call Summit and tell them it is listed incorrectly and have them take it back on thier dime. And just have them to trade it for a 318/340 ballancer.

They have a pretty good return policy.
 
I'd call Summit and tell them it is listed incorrectly and have them take it back on thier dime. And just have them to trade it for a 318/340 ballancer.

They have a pretty good return policy.
I thought the ends of the crankshaft between the 318/340 and the 360 were different so you can't interchange them??
 
IIRC, I thought they were the same snout.
man now I am confused the one I have from Mancini says 272-360 so I am not sure now.....but the guys at Mancini know mopars since that's all they sell parts for so when and if you buy one tell them you have an internal balanced 360 and you should be good to go.
 
First off, if been watching this thread and having a few :drinkers: so bare with me....lol.

IIRC, I thought they were the same snout.

Yes, they all fit the crank.....

Hard to find a front pic......check out this thread and see if it looks like yours?

http://www.aspenandvolare.com/showt...-594-021-Harmonic-Balancer...Internal-balance

Dorman 594-021

I tried to drop a hint on my earlier above post but no one picked up on it.


I'm not familiar with the balancer he bought, but if it indeed is a neutral balance, then it's probably not his issue. A out of balance engine is not gonna vibrate in just a few hundred rpm range. Not to mention, I've never had a engine balanced without the damper being in the machinist hands, internal or external.
 
Ok... so with that being said... the other thought it could be is that there is a vac leak. Would that be a source of such problems?
 
Since the consensus here seems to believe that it sounds like a balance issue, I think that needs to be resolved first, one way or the other. Hopefully some others with more experience then me, will continue to comment on your situation with the damper, etc.
 
Likely an external balance damper on an internally balanced rotating assembly... not good.

Maybe verify that it's for an external balance assembly by calling the company and go from there. The dorman site says it's 360 and will not work on a 318 (internally balanced) so you have the wrong part.

If it looks like this on the front side it's an external balance unit.

large_2.JPG
 
Who balanced the engine ? Wounder why they did not notice the balancer being wrong--if it is wrong.

I got a Summit brand balancer and it has a place where you bolt a weight on/in it, if its for an external balance engine.
 
Check your engine bay clearances, too, make sure it's not hitting a header or something.
 
You don't balance an internal balance set up with the balancer attached.

You can spin the assembly once done with balancer attached to verify that it is in spec.

The listing at summit is wrong, approach them from that angle. Have a replacement balancer sent out.

Stop buying rotating assembly parts that are listed as 360 because you DON'T have a 360 anymore.
 
Yes that is what mine looked like. I pulled the one off the 318 and put it on it to check. Yes that was the problem, it does not have a vibration anymore. My brother works for napa, and he sells the dorman brand too. He checked into it and it is for and externally balanced motor. The summit listing is wrong.

Long story short... It is fixed! Thanks for all the help.
 
Just talked with summit and they are going correct the listing.
 
Ought to take back the balancer too.

You bought something that was listed incorrectly and it needed replacing.
 
Ought to take back the balancer too.

You bought something that was listed incorrectly and it needed replacing.

I asked about that... since I bought it in May of 2011 they said they could not take it back... but they was going to give me 20% off a replacement.
 
So glad to see the problem is resolved. Sorry I was of no help, just couldn't believe a out of balance situation would be in such a narrow range.......I learned something here, thanks. Now you can enjoy that big torque it was built for :).
 
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