|
|
|
Your donations help keep this valuable resource free and growing. Thank you.
|
Looking for 401 pistons 30 over HELP |
Post Reply 
|
Page 123> |
| Author | |
bluetick 
AMC Apprentice 
Joined: Mar/12/2014 Location: colorado Status: Offline Points: 100 |
 Post Options
 Thanks(0)
 Quote Reply
 Topic: Looking for 401 pistons 30 over HELPPosted: Apr/13/2017 at 5:09pm |
|
I need cant find but need 30 over 10.5-1 pistons, stock rods 58cc head stock block height any help need drop in pistons . no playing with rods new wrist pin dia milling block heads other than clean up
 |
|
|
Still dreaming but the wife said no,Dam ask for forgiveness NOT PERMISSION just one more ,1972 AMX Z
|
|
 |
|
|
401harry
AMC Addicted 
Joined: Sep/27/2011 Location: Clearwater,Fl Status: Offline Points: 758 |
Post Options
Thanks(0)
Quote Reply
Posted: Apr/13/2017 at 5:24pm |
|
Wiseco PT .030 are at 10.3 Little over $ 400 for piston pins AND rings. I bought a set and added the Molnar rods for floating pins...worth the extra expense IMO. Your gonna have to re balance anyway with new pistons
|
|
|
|
|
farna
Supporter of TheAMCForum 
Moderator Lost Dealership Project Joined: Jul/08/2007 Location: South Carolina Status: Offline Points: 19672 |
Post Options
Thanks(0)
Quote Reply
Posted: Apr/13/2017 at 5:46pm |
|
The reason you can't find them easily is that AMC recommends a max overbore of 0.020" on the 401. There have been many that go to 0.030" though. I'd have the block sonic checked for thickness. An 0.030" overbore is generally safe, but with the thin walls you can have overheating issues. You might also want to consider a "short fill" in the water jackets for added strength (block fill up to the lower edge of the side plugs). For a drag/show car or weekend cruiser you should be fine, but if you plan on this being a long haul ride I'd reconsider. Have a shop check the block, and if you just have a couple cylinders that need more than 0.020" have them sleeved. Nothing wrong with sleeving, when done right it will add strength to the block. Costs a good bit to have all 8 sleeved, but it has been done to get a block back to factory bore.
|
|
|
Frank Swygert
|
|
|
|
|
SCRAGTOP
AMC Nut
Joined: Jul/03/2007 Location: Chesapeake, VA Status: Offline Points: 367 |
Post Options
Thanks(0)
Quote Reply
Posted: Apr/13/2017 at 9:17pm |
??? 20 thou max factory recommended overbore is going to stop the aftermarket piston companies from producing 30 over pistons for AMC 401s??? Who has been making the 20 thou over pistons for 401s over the last 35 years that I have been into AMCs??? Why haven't I got a few sets of those laying around? Why haven't I used a bunch of them before??? Oh yeah.... Now I remember... No piston companies make them as the next "standard" over bore size for 401s... duh!!!!! How did I not realize that!!! I guess thumbing thru every summit catalog or Jegs catalog, or PAW catalog (really showing my age there!) over the last 35 years and seeing the INDUSTRY STANDARD overbore of .030 on about every brand of engine I can recall seeing...One might be tempted to think that the major piston manufacturers changed the industry standard of .030 over to .020 over just for us... NOT!!!!!!! ??? How could you possibly make that statement ??? Also, I strongly disagree with your assertion that sleeving blocks will add strength to the block... The BEST reason (in my opinion of course) to bore an AMC block to .020 over on its first overbore is that it gives you an additional rebuild. First rebuild at .020, second rebuild at .030... If you jump to .030 first, you loose an opportunity for a build. Again, this is all my opinion. Keep in mind that a .030 overbore equates to .015 thickness of actual metal being removed off the cylinder wall. That's 1/64th of an inch (rounded)... That's not a lot of metal unless you are a machinist (I may do that once in a while too...) I would be very surprised if you had any overheating issues at .030... A .020 over rebuild isn't that big of a deal. Set of .060 over chevy sm block 400 pistons with a CH of 1.500 (or is it 1.550?) will get you there and bush your factory rods for the .927 chevy pin... I don't care too much for the thin wrist pin wall thickness on our factory rods... I think the aftermarket even makes AMC rods with the chevy .927 pin holes in them already... I think... Now, I am pulling all these specs out of the old 386 intel chip in my noggin...hope I got them right,
Edited by SCRAGTOP - Apr/13/2017 at 9:35pm |
|
|
|
|
SCRAGTOP
AMC Nut
Joined: Jul/03/2007 Location: Chesapeake, VA Status: Offline Points: 367 |
Post Options
Thanks(0)
Quote Reply
Posted: Apr/13/2017 at 9:58pm |
|
I think I quoted a CH for a chevy rod in my post above... Dang it sucks to get old...
I think I am rusted out and blowing oil by the rings...
|
|
|
|
|
farna
Supporter of TheAMCForum
Moderator Lost Dealership Project Joined: Jul/08/2007 Location: South Carolina Status: Offline Points: 19672 |
Post Options
Thanks(0)
Quote Reply
Posted: Apr/14/2017 at 5:53am |
|
I know 0.030" pistons are made for the 401, and at least used to be common. Probably not as much any more because their aren't that many being built (slow sellers). But nevertheless, the factory only recommends an 0.020" max overbore for the 401 (and the 390... same bore as 401). All the other sizes can be safely bored more.
I don't mind being disagreed with or corrected -- I don't know everything. But the attitude isn't necessary. As far as sleeved blocks, the sleeve material is usually stronger than the original block material, so at least theoretically the sidewalls should be stronger than the original casting. Does depend on how thick the casting is at the bottom of the bore and how much is taken out down there. A good press fit sleeve won't detract from block strength even if it doesn't add any. |
|
|
Frank Swygert
|
|
|
|
|
401jim
Supporter of TheAMCForum
Joined: Jan/07/2012 Location: Brunswick,Ohio Status: Offline Points: 793 |
Post Options
Thanks(0)
Quote Reply
Posted: Apr/14/2017 at 1:35pm |
|
Weisco sells oversize in .030 and .045 for the 401.
|
|
|
|
|
|
|
1948kaiser
AMC Addicted
Joined: Jan/25/2015 Location: south west flor Status: Offline Points: 833 |
Post Options
Thanks(0)
Quote Reply
Posted: Apr/14/2017 at 4:24pm |
|
i got dss pistons 30 over for a a 401 thur a amc supplier and had them made for 10 to 1 comp ratio. look at www.dssracing.com
|
|
|
|
|
jav70
AMC Nut
Joined: Apr/20/2008 Location: New Jersey Status: Offline Points: 257 |
Post Options
Thanks(0)
Quote Reply
Posted: Apr/16/2017 at 6:50am |
|
My 401 is bored 60 over, 10,000 miles and no issues. No overheating problems either.
|
|
|
AMC1970 javelin,1968 AMX 343, 1968 AMX 390
|
|
|
|
|
purple72Gremlin
AMC Addicted
Charter Member Joined: Jul/01/2007 Location: Illinois Status: Offline Points: 16610 |
Post Options
Thanks(0)
Quote Reply
Posted: Apr/16/2017 at 8:25am |
|
I have the one 401 that would have cleaned up at 0.20 over, but ended up going 30 over because couldnt find 20 over pistons and this was years ago
|
|
|
|
|
Post Reply
|
Page 123> |
Tweet
|
| Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |
Click for TheAMCForum Rules
Topic Options
farna wrote: