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AMC 360 PISTONS

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LMM1996 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote LMM1996 Quote  Post ReplyReply Direct Link To This Post Posted: Feb/22/2019 at 8:57am
My block didn't need decked so we didn't do it. I always try to do as little of that as possible that way it leaves me something to work with later on. The heads were milled .015 I believe to get the chambers to 58cc. This is just a street engine going in a jeep so I wasn't going for max compression. Just wanted to get it around 10:1. All in all I don't think you can go wrong with the Wiseco pistons as they are a great value. You just have to do a little homework which isn't a bad thing.



Edited by LMM1996 - Feb/22/2019 at 8:59am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Feb/22/2019 at 9:49am
So sorry to offend anyone, but machining is not always required. You can scrape/stone a flat surface finish a block or head by hand.
We did steel to steel surfaces on turbines, pumps, compressors ... by hand with scrapers and stones. All to correct manufacturer specified finish and tolerance. No gaskets or compounds for sealing.
You need a couple of good quality machinists straight edges, machinist carbide scrapers, feeler gauges, flashlight, and dedicated stones of several grits. And cleaning supplies!

If you have ever scraped a lathe bed/ways or milling machine, you will be fine. 

Do not use a power tool. Fastest way to ensure you need a machine shop.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote wheelz Quote  Post ReplyReply Direct Link To This Post Posted: Feb/22/2019 at 10:12am
I dont see the point in running nice Wiseco forged pistons on stock cast 360 rods in any performance build. Spend another 400 bucks and get Molnars and eliminate the weak link. I have one 360 I bought used and refreshed recently with .060 Badger pistons and has stock rods with polished beams and ARP bolts. If Wiseco made a .060 piston I would have thrown out the pistons and rods but went with a cam with a 6000 rpm limit which is pretty much the limit for a cast piston 360 
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Post Options Post Options   Thanks (1) Thanks(1)   Quote SC397 Quote  Post ReplyReply Direct Link To This Post Posted: Feb/22/2019 at 10:29am
Originally posted by Trader Trader wrote:

OK, I do street builds only.
I have never seen a 360 or 401 that has needed the block milled.
Stone or float glass with paper and full contact (0.001" to 0.002") which any gasket and very tin coat of Hylomar takes care of. No leaks, ever!
Unless the engine has seen extreme use, who is milling and why??? ... Beyond custom performance modifications.
Never seen a cast head warped over 0.002", this does not need machining if you take off high spots (very little elbow grease, 10 to 15 minutes work).
A manufacturer of custom parts should be assuming stock. If not then they should be stating required modification.
My opinion.
  


90% of my builds are for street as well but most of the blocks I get look like they came out of Lake Erie.  Most cores have been torn down and sit for years as a bare block.  Regardless, I have them all decked to at least made square with the mains and to have a good gasket surface.  usually it is no more than .008" on the block and heads.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Feb/22/2019 at 11:06am
Have to agree, if the surfaces are bad, machine.
On the pistons question, calculations are 5500 RPM (rounding off) for top end of the factory components due to rod length. I know many, including myself have gotten away with more, and sometimes not.
From my experience it's the top cast piston ring lands that fail first. This would be a case for forged pistons as extra insurance for a spirited street driver.
Would like others to chime in on what they have seem as the most common failure point of hard driven 360's.

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Post Options Post Options   Thanks (1) Thanks(1)   Quote LMM1996 Quote  Post ReplyReply Direct Link To This Post Posted: Feb/22/2019 at 11:19am
Originally posted by wheelz wheelz wrote:

I dont see the point in running nice Wiseco forged pistons on stock cast 360 rods in any performance build. Spend another 400 bucks and get Molnars and eliminate the weak link. I have one 360 I bought used and refreshed recently with .060 Badger pistons and has stock rods with polished beams and ARP bolts. If Wiseco made a .060 piston I would have thrown out the pistons and rods but went with a cam with a 6000 rpm limit which is pretty much the limit for a cast piston 360 

  Its all a matter of opinion, but you don't really need aftermarket rods unless you are using a power adder or plan on turning some RPMs. I can't speak for everybody, but in my case I didn't need to spend 600.00 on aftermarket rods. The motor will most likely never be over 6000 rpm, and will never have a power adder on it. I doubt my engine will make 400hp so I didn't see any reason to upgrade those parts. The stock crank and rods should be good up to around 500hp so I just had ARP bolts put in and had the original rods resized and the rotating assembly balanced.  Again I can't speak for everybody, but in my case, I had to buy new pistons so an extra 50-100.00 for the Wisecos was a no brainer. Especially since they made it much easier to get the compression bumped up to a more ideal number. Getting the compression above 9.0:1 is one of the best things you can do to these, or any low comp motor for that matter.


Edited by LMM1996 - Feb/22/2019 at 11:22am
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Post Options Post Options   Thanks (1) Thanks(1)   Quote 1982AMCConcord Quote  Post ReplyReply Direct Link To This Post Posted: Feb/22/2019 at 11:43am
Originally posted by LMM1996 LMM1996 wrote:

Originally posted by wheelz wheelz wrote:

I dont see the point in running nice Wiseco forged pistons on stock cast 360 rods in any performance build. Spend another 400 bucks and get Molnars and eliminate the weak link. I have one 360 I bought used and refreshed recently with .060 Badger pistons and has stock rods with polished beams and ARP bolts. If Wiseco made a .060 piston I would have thrown out the pistons and rods but went with a cam with a 6000 rpm limit which is pretty much the limit for a cast piston 360 

  Its all a matter of opinion, but you don't really need aftermarket rods unless you are using a power adder or plan on turning some RPMs. I can't speak for everybody, but in my case I didn't need to spend 600.00 on aftermarket rods. The motor will most likely never be over 6000 rpm, and will never have a power adder on it. I doubt my engine will make 400hp so I didn't see any reason to upgrade those parts. The stock crank and rods should be good up to around 500hp so I just had ARP bolts put in and had the original rods resized.  Again I can't speak for everybody, but in my case, I had to buy new pistons so an extra 50-100.00 for the Wisecos was a no brainer. Especially since they made it much easier to get the compression bumped up to a more ideal number. Getting the compression above 9.0:1 is one of the best things you can do to these, or any low comp motor for that matter.


I completely agree... I was going to say something similar but you already beat me to it.  I have spent a lot of time talking with the guys on here and Facebook about my future 360 engine build. The 360 rods are the same at the 290, 304 and 343. And none of those engines are known for breaking the stock rods. While there are some guys that have abused their 360 to the point of killing it... I don't remember a single one of them blaming broken rods. I have several local friends who have said the same thing.. that they have routinely abused a 360 to within an inch of it's life and the rods haven't been what caused it to fail... its always the stock cast pistons or spun bearings. Honestly.. from my readings.. these engines are actually very hard to totally kill. I personally would not hesitate to use the stock rod with the Wiseco's for a standard street or hot street/strip build. If someone is running the drag strip every weekend... then yes.... swap rods... K1, Molnar... even the Scat rods are pretty nice for the money.. but beware.. there are two versions of the Scat rods. One uses 8740 chromoly steel and the other uses ARP2000 alloy... and that means a $125 price difference.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 69 ambassador 390 Quote  Post ReplyReply Direct Link To This Post Posted: Feb/22/2019 at 6:58pm
Originally posted by Trader Trader wrote:

So sorry to offend anyone, but machining is not always required. You can scrape/stone a flat surface finish a block or head by hand.
We did steel to steel surfaces on turbines, pumps, compressors ... by hand with scrapers and stones. All to correct manufacturer specified finish and tolerance. No gaskets or compounds for sealing.
You need a couple of good quality machinists straight edges, machinist carbide scrapers, feeler gauges, flashlight, and dedicated stones of several grits. And cleaning supplies!

If you have ever scraped a lathe bed/ways or milling machine, you will be fine. 

Do not use a power tool. Fastest way to ensure you need a machine shop.
 
You are right, If you have the correct tools.  Most people will just use a harbor Freight stone to do it.  I will stone and scrape a block myself if it's in good shape.  Most people will make it too smooth.
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Post Options Post Options   Thanks (1) Thanks(1)   Quote BassBoat Quote  Post ReplyReply Direct Link To This Post Posted: Feb/22/2019 at 7:26pm
I recently tore down a 360 that had been run hard for a long time.  Bracket raced for maybe 25 years.  I knew the 5 other owners of the car over the years.  The car got a performance valve job about about half way through its life, and a replacement crank and fresh valve springs just before I bought it.  I ran it to 6000-6300 for the three years I had it.  I got the engine from the guy I sold the car to when he had issues and put his 401 in.  I was always skeptical about those skinny bolts and cast rods in a 360.  But this car had 1973 amc cast pistons and rods and had the snot run out of it.  So I don't have concerns with stock rods and bolts any more.  Honestly, there was no obvious visible issue with the pistons or rods.  I suspect the rods are at the end of their life and will not re-use them.  But pistons?  only takes one bad tank of gas or one time with the timing off and you can bust the ring lands.  So I can see putting forged pistons on stock rods....
  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 1982AMCConcord Quote  Post ReplyReply Direct Link To This Post Posted: Feb/23/2019 at 9:50am
I have seen a few guys use these too...


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