TheAMCForum.com Homepage
Forum Home Forum Home > The Garage > AMC V8 Engine Repair and Modifications
  New Posts New Posts RSS Feed - 290 dead. 401 is...altered?
  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.

290 dead. 401 is...altered?

 Post Reply Post Reply Page  123 4>
Author
Message
Eugor View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: Nov/26/2013
Location: Vancouver, B.C.
Status: Offline
Points: 111
Post Options Post Options   Thanks (0) Thanks(0)   Quote Eugor Quote  Post ReplyReply Direct Link To This Post Topic: 290 dead. 401 is...altered?
    Posted: Jan/24/2016 at 12:36am
Tore the 290 for the Rogue down to re-gasket it and found some deep pitting in a couple of the cylinders. It would need reboring and pistons seem to be horrendously expensive for this application (and hey, it would still be a 290).
 
So.....
 
A while back I bought a 401 & 727 on a flyer 'cus it was supposedly recently or freshly rebuilt and came with some cool stuff like a new set of headers, a pair of Edelbrock valve covers, a Performer intake, polished Eddy carb and misc. stuff. I also knew it to have 291 heads on it, so I figured whoever built it (unknown at this time) had done some research and found some good hard to find bits for it. THIS ENGINE WAS NEVER INTENDED FOR THE ROGUE as:
 
a: the car was going back to Dad when it was done and he didn't need the power in his mid eighties.
b: for  some reason I cannot explain, I do not like the idea of a 401 in this car. (I originally bought it in 1985 because I already had a 401 in the garage, but couldn't bring myself to put it in at that time, which is kinda how Dad ended up with the car originally - he liked it as it was)
 
I could picture it with a 343, a 390 or even a 360 & M11. but for some reason, the 401 seems wrong to me. Must be mental illness. Or the Spirit sitting in the back  yard...it would look better in that.
 
Unfortunately a) Dad died last March and it's my problem now. and
 
                       b) I don't want to put the money into the 290, but I do want to get this car on the road. Everything has gone wrong with it.
 
Anyway, I digress and nobody really cares anyway. Get to the issue right?
 
Having few other options, and already having it anyway, I started to pull down the 401 for inspection. I guess it's going in after all. Valve covers off - nice clean, not run much if at all. Brand new rockers & balls with zero wear, just a mark where they contact the valves that you really have to look for.  I should mention, I have seen video of this engine running in a frame, unsure if the cam has been run in properly (or even what it is at this point). Zero miles on this one. Some mismatched head bolts. hmmm. 1 grade 8 oddball bolt, no washer.
 
Intake off - a valley line. Someone has done some research and decided it was needed. Right or wrong, it wasn't "just a stock rebuild". No bottom pan on the intake though.
 
RH head off. I should have checked the torque on those bolts. A couple of them seemed to be about 65-70 ft/lbs to undo. And this:
 
 
 
 
As the kids say WT* is going on here? Anybody? At this point I'm thinking SBF and AOD... probably cheaper than fixing this mess! Why would you do this to a piston? New endmill and wanted to play? Got a screaming deal on a 390 piston and wanted to see if you could make it work? Definitely not a match to the other 3 (haven't pulled the other side apart yet) has a seam the others don't. These are not 72 up 401 pistons, they may be 71 style, but the last one I built was in 1991 and I didn't take pictiures of them at the time. Aren't the notches in the piston supposed to face forward?
 
Looking for insight, ideas. Maybe some consolation.
 
Frustrated in Vancouver.
Back to Top
rockAMX View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Sep/16/2011
Location: Lethbridge
Status: Offline
Points: 828
Post Options Post Options   Thanks (0) Thanks(0)   Quote rockAMX Quote  Post ReplyReply Direct Link To This Post Posted: Jan/24/2016 at 1:59am
Yes the notch should face the front of the block. The pistons will have to come out and be reversed. That will give you a chance to check the rod bearings and main bearings. No pan on the bottom of the intake? This seems very suspicious. The piston in the last picture is toast. It almost seems like this engine was just slapped together to sell from odd components. You should disassemble to whole thing and evaluate. You might be choosing in the end to rebuild the 401 or the 290.
DWR
1968 AMX

Back to Top
Fluffy73 View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Nov/21/2007
Location: Castlegar, BC
Status: Offline
Points: 2466
Post Options Post Options   Thanks (0) Thanks(0)   Quote Fluffy73 Quote  Post ReplyReply Direct Link To This Post Posted: Jan/24/2016 at 2:14am
"Which one of these is not like the other one? Which one of these does not belong."

That piston looks weird. No idea what the heck is going on with the dish area but that for sure is a cast piston while the others look like forged. I doubt it was ever run like that, it would've had a pretty nasty shimmy going on. I agree with Rock. That engine should be torn down and everything verified.  Best case scenario, you'd be into it for a set of pistons, maybe a bearing set, a balance job and a re-hone/match job for the new pistons.

Could be worse.


I am genetically incapable of being Politically Correct.
Back to Top
maximus7001 View Drop Down
Supporter of TheAMCForum
Supporter of TheAMCForum
Avatar

Joined: Jun/27/2011
Location: Winnipeg,Canada
Status: Offline
Points: 854
Post Options Post Options   Thanks (0) Thanks(0)   Quote maximus7001 Quote  Post ReplyReply Direct Link To This Post Posted: Jan/24/2016 at 5:22am
And it is already 30 over or at least the one in picture 2 is. Wonder if they are all 30 over. I have seen some wierd mismatches over the years and some back alley "milling" to make weights even. But I can see detonation happening from the sharp spots if the piston even held on long enough.

High school autoshop slap together job?

Edited by maximus7001 - Jan/24/2016 at 5:31am
1968 Javelin SST

1997 GMC Safari AWD

2002 Chevy Malibu

1997 Ford Contour

Winnipeg, home of the Jets.
Back to Top
amcglass View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Dec/11/2011
Location: NW Ohio
Status: Offline
Points: 2133
Post Options Post Options   Thanks (0) Thanks(0)   Quote amcglass Quote  Post ReplyReply Direct Link To This Post Posted: Jan/24/2016 at 8:22am
have you checked the Bore to see if all cylinders are .30 over?

they also say Hindsight is 20/20 maybe you should still consider doing the 290 and save this 401 for a later date?
Javmanpres

2 donohue javelins 390s

74 Jav/AMX
71 Matador 2dr sedan delivery wagon     
Back to Top
sweatlock View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Apr/28/2014
Location: FL, USA
Status: Offline
Points: 1015
Post Options Post Options   Thanks (1) Thanks(1)   Quote sweatlock Quote  Post ReplyReply Direct Link To This Post Posted: Jan/24/2016 at 8:54am
As always, I'm a bit confused here - the thought of replacing the 290 with a 401 bothers you on some level, but replacing the 290 w/ a SBF & AOD doesn't? Interesting perspective.
Back to Top
Boris Badanov View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Dec/14/2013
Location: NH USA
Status: Offline
Points: 3109
Post Options Post Options   Thanks (0) Thanks(0)   Quote Boris Badanov Quote  Post ReplyReply Direct Link To This Post Posted: Jan/24/2016 at 10:36am
That 401 would be excellent in a Rogue, but it obviously needs a set of pistons at least.
IMO a 290 is a boat anchor. A 304 is sooooo much better why re-build a 290?
If you are on the cheap, sell the 401 and get a used 360.
I bet you can get a re-man 360 for less than the 401 carcass is worth.
Gremlin Dreams
Back to Top
Eugor View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: Nov/26/2013
Location: Vancouver, B.C.
Status: Offline
Points: 111
Post Options Post Options   Thanks (0) Thanks(0)   Quote Eugor Quote  Post ReplyReply Direct Link To This Post Posted: Jan/24/2016 at 12:11pm
Today's project - more teardown, more inspection.  Bore measurement. 

I don't think the 290 is a viable alternative for me, but hopefully I'll know better the state of the 401 after today. Of course, now I'm really starting to wonder what's been done to the trans. They were bolted together in the original car, but had no torque converter when they were separated.

And that adds expense and time - I'll have to build shift linkage, crossmember, cooling lines and driveshaft. And do something with the exhaust.  Anybody have a 4 speed setup for this thing??  That would make it worth doing.

I do have a line on a '70 304 that is still complete, so that might be a way to go. It would be cheaper to do than the 290 as long as the crank and block aren't trashed (although I seem to recall there were some problems with the 70 304 heads) and I could still use everything else (including the already rebuilt BW trans) and make it look stock to 99.9% of the people. Little healthier too.

Breakfast, coffee and out to the garage to investigate some more and consider alternatives.

Sweatlock, the SBF thing was absolutely tongue in cheek, I was expecting more derision on that actually. I'm the guy who seriously considered years ago building a nice 343 and stuffing it into a 68 Firebird,  just to be irksome.  I'd put a lot of time, money & effort on the 401 before I put anything but an AMC V8 into a factory V8 Rogue. I would convert it to 4 speed in a heartbeat though.







Edited by Eugor - Jan/24/2016 at 12:14pm
Back to Top
sweatlock View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Apr/28/2014
Location: FL, USA
Status: Offline
Points: 1015
Post Options Post Options   Thanks (0) Thanks(0)   Quote sweatlock Quote  Post ReplyReply Direct Link To This Post Posted: Jan/24/2016 at 12:41pm
Eugor, 401jim sent me a PM on a 290 shortblock he has that sounds like it's complete w/ new parts and ready to go - might be the cheaper AND easier option. If you're interested, send him a PM.

Understood about the SBF reference - actually, a 343 in a Pontiac sounds vey neat and combines two of my favorite Marques. I've owned a lot of Pontiacs in my day as well as AMC's and I'd have to say they are definitely my # 2 favorite.
Back to Top
ADAM12MATADOR View Drop Down
AMC Nut
AMC Nut
Avatar

Joined: Dec/03/2011
Location: New City, N.Y.
Status: Offline
Points: 305
Post Options Post Options   Thanks (0) Thanks(0)   Quote ADAM12MATADOR Quote  Post ReplyReply Direct Link To This Post Posted: Jan/24/2016 at 12:50pm
Make you a good deal. Will swap you a 1989 Ford Mustang H.O. 302 roller engine and a rebuilt AOD for your 401. What do you think? 
Back to Top
 Post Reply Post Reply Page  123 4>
  Share Topic   

Forum Jump Forum Permissions View Drop Down



This page was generated in 0.063 seconds.
All content of this site Copyright © 2012 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