TheAMCForum.com Homepage
Forum Home Forum Home > The Garage > AMC V8 Engine Repair and Modifications
  New Posts New Posts RSS Feed - NX on 360
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Click for TheAMCForum Rules / Click for PDF version of Forum Rules
Your donations help keep this valuable resource free and growing. Thank you.

NX on 360

 Post Reply Post Reply Page  <12
Author
Message
PROSTOCKTOM View Drop Down
Supporter of TheAMCForum
Supporter of TheAMCForum
Avatar

Joined: Jun/20/2010
Location: Indiana
Status: Offline
Points: 2244
Post Options Post Options   Thanks (0) Thanks(0)   Quote PROSTOCKTOM Quote  Post ReplyReply Direct Link To This Post Posted: Jan/25/2023 at 2:35am
Kids were using Nitrous 40-years ago on new street cars and blowing the engines up right and left. Your 40-year old engine like others have already stated will most likely have some stress cracks already in the pistons. If you have long term plans for that engine the N2O is more than likely going to make it a short term possession.

"Animal Jim" Feurer an early Pro Mod racer talked extensively about what running Nitrous does to an engine block and pistons. One weekend of racing the bores would be so out of round that it needed all new sleeves installed just so the rings would seal again. 

Good luck with whatever you choose to do with it.

Tom
Molnar Technologies Full Service Dealer - Crankshafts & Connecting Rods

1969 AMC Rambler Rouge Race Car
1974 AMC Hornet Hatchback, Wally Booth Outlaw Nostalgic Pro Stock Race Car Project
Back to Top
jpnjim View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Nov/25/2007
Location: New England
Status: Offline
Points: 2781
Post Options Post Options   Thanks (0) Thanks(0)   Quote jpnjim Quote  Post ReplyReply Direct Link To This Post Posted: Jan/25/2023 at 4:09am
360's can take a decent amount of abuse,
those two weak spots (stock pistons & stock rod bolts) are the two glaring limitations in an otherwise very durable package.

A 360 Gremlin is also a fantastic machine, with tons of potential,
I'd just hate to see it ruined by one weak link.

I'd spray a 360 Gremlin if I had a spare/good 360, and a plan to use it, if things went sideways.

Otherwise I'd hate to see a nice 50 year old car with a 40+ year old engine taken off the street because of one night of fun.

Now that Wiseco makes very nice forged 360 pistons, and there's a couple of excellent options for rods,
it's easy to eliminate the 360's two biggest problems with off the shelf parts.

What intake and carb are you running?
Gears?
(2-piece axleshafts?)

Since the engine has a cam and headers, are you sure it doesn't have pistons and rod bolts already done?



71 P-code 4spd Javelin/AMX
some Jeeps and some Fords
Back to Top
BassBoat View Drop Down
AMC Addicted
AMC Addicted


Joined: Aug/29/2008
Status: Offline
Points: 1560
Post Options Post Options   Thanks (1) Thanks(1)   Quote BassBoat Quote  Post ReplyReply Direct Link To This Post Posted: Jan/25/2023 at 1:42pm
There was a guy on here years ago, Grant I think?  I know he ran 150 shot on a stock 360, in a Javelin I think?  For years.  I am in 100% agreement with the things said above, the stock parts on a 360 probably should be upgraded.  But I would risk a 100 shot.  
But someone else pointed out, you need to start working on the plan for your next engine.  If you are like me and have more motors than cars, and an inside track at a machine shop, might not be a catastrophe to damage your engine.  If you are like me and have more cars than sense and don't mind your hot rod sitting while you round up a fresh rotating assembly and get a block prepped, again, no big deal.  Bold prediction I would make, the thing that will go first will be the ring lands.  You will damage a few valve seats and scuff a few bores and see a lot of blue smoke out the exhaust.  In a year or two.

Back to Top
Buzzman72 View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Sep/15/2009
Location: Southern IN
Status: Offline
Points: 2449
Post Options Post Options   Thanks (0) Thanks(0)   Quote Buzzman72 Quote  Post ReplyReply Direct Link To This Post Posted: Jan/25/2023 at 3:38pm
Since it's unclear how much the OP knows about N2O, I'll start my post with a few facts.

Atmospheric air is roughly 21% oxygen by volume. N2O is 36% oxygen by volume. Because higher oxygen level in the engine without extra fuel being added will likely melt the pistons [like a cutting torch], most N20 kits add a provision to add additional fuel to the cylinders with the N2O. With additional fuel, and the additional oxygen to burn this fuel, cylinder pressures increase. More N20 and fuel means more cylinder pressure whenever a spark plug fires. While this increases power, it also adds stress to the pistons, connecting rods, connecting rod bolts, and even the cylinder head bolts.

Once you understand this, it's easy to understand why most of the posts on this thread show a concern for pistons, rods, and rod bolts. In extreme cases, head bolts may stretch, and crankshafts may also be damaged.

For these reasons, the advice being given about using forged pistons, forged rods, and ARP rod bolts with N2O is completely valid. Which is why adding N2O to a tired engine is a bad idea.
Buzzman72...void where prohibited, your mileage may vary, objects in mirror may be closer than they appear, and alcohol may intensify any side effects.
Back to Top
70Xcode View Drop Down
AMC Fan
AMC Fan


Joined: Jan/25/2023
Location: NJ
Status: Offline
Points: 15
Post Options Post Options   Thanks (0) Thanks(0)   Quote 70Xcode Quote  Post ReplyReply Direct Link To This Post Posted: Jan/26/2023 at 8:59pm
You'll be fine with a 100 shot.... not much more 
Back to Top
sweatlock View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Apr/28/2014
Location: Largo, FL
Status: Offline
Points: 2654
Post Options Post Options   Thanks (0) Thanks(0)   Quote sweatlock Quote  Post ReplyReply Direct Link To This Post Posted: Jan/27/2023 at 7:28am
Everyone’s mentioning the pistons and con rods and going to forged, wouldn’t that make the weak link the con rod bearings with all that extra ‘push’? 

In my experience, when you beef up one area it just pushes the failure point somewhere else…
Back to Top
jpnjim View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Nov/25/2007
Location: New England
Status: Offline
Points: 2781
Post Options Post Options   Thanks (0) Thanks(0)   Quote jpnjim Quote  Post ReplyReply Direct Link To This Post Posted: Jan/27/2023 at 7:50am
Legitimate question,
 I think even kinda worn rod bearings would be up to a couple hundred more horsepower over a stock/mildly modified 200-300hp 360 for a few seconds at a time.

I'd worry more about maintaining oil pressure more than I would about the bearings themselves,
but I wouldn't lose sleep over that either.

The reason I worry about stock pistons is day to day life (detonation) breaks off those ring lands even in non-performance applications.

The stock rod bolts don't like RPM for too long.
My rule of thumb redline for a stock 360 is to keep it under 6000, but I've heard of others that don't trust them past 5500.

Nitros makes me worry about rod bolts after breaking the 5500-6000 rpm rule more than the extra 100-125hp does.
71 P-code 4spd Javelin/AMX
some Jeeps and some Fords
Back to Top
motorhead_1 View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Apr/16/2014
Location: AZ
Status: Offline
Points: 916
Post Options Post Options   Thanks (0) Thanks(0)   Quote motorhead_1 Quote  Post ReplyReply Direct Link To This Post Posted: Jan/27/2023 at 1:09pm
are you planning a wet or dry shot?
i have NOS on my 401 rambler. 100 shot wet. separate fuel system for the nitrous with fuel pressure cut off, window switch (3500-5500rpm), etc. i have yet to test it out. 
i have hyper-u-cracked them pistons. i'm curious to how they hold up on a wet shot

69 SC/Rambler tribute 401/th400, 68 Rebel SST LSA, 66 F100 460/c6, 88 Merkur Xr4Ti, 71 Jaguar XJ6 LS1
Back to Top
 Post Reply Post Reply Page  <12
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.03
Copyright ©2001-2019 Web Wiz Ltd.

This page was generated in 0.055 seconds.
All content of this site Copyright © 2018 TheAMCForum unless otherwise noted, all rights reserved.
PROBLEMS LOGGING IN or REGISTERING:
If you have problems logging in or registering, then please contact a Moderator or