TheAMCForum.com Homepage
Forum Home Forum Home > The Garage > AMC 6 Cylinder Engine Repair and Modifications
  New Posts New Posts RSS Feed - Concord won't idle suddenly
  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.

Concord won't idle suddenly

 Post Reply Post Reply Page  <1 234
Author
Message
farna View Drop Down
Supporter of TheAMCForum
Supporter of TheAMCForum
Avatar
Moderator Lost Dealership Project

Joined: Jul/08/2007
Location: South Carolina
Status: Offline
Points: 19610
Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Nov/15/2018 at 8:45am
Could have been low on oil, or lifters stuck due to sitting but pumped back up AFTER the pushrods came out. I'd try an engine oil flush just to clean it up, but it MIGHT be okay. I've had to "unstick" valves from bad gas (could be gunk in the tank dissolving from years past). Freed up, run a while, then stick again. When I finally thought I had it cleaned up (after third time of one or more sticking), it ran for 500 miles or so before another one stuck! rebuilding or at least totally disassembling and cleaning the head (remove valves and flush guide with solvent, or better yet hot tank the head) is about the only way to fix sticking valves. Hopefully that's not the issue with yours, just a collapsed lifter that has "come back". 
Frank Swygert
Back to Top
Fahques View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: Jan/06/2016
Location: philadelphia
Status: Offline
Points: 49
Post Options Post Options   Thanks (0) Thanks(0)   Quote Fahques Quote  Post ReplyReply Direct Link To This Post Posted: Nov/15/2018 at 10:13am
I was just making a list of things I should do to try to keep my engine running the way it is now. Plugs, wires, oils and filter changes. Engine flush was one of the things I was thinking. Any particular one recommended?

The distributor assembly is only a year old.

I always keep up with the oils and changing them every 3000 or so miles. The gas tank NOW is only 2 years old. When I got the car the tank leaked when full at the sender. So again, bad gas is a very possible culprit to some motor issues.

I'm hoping to get closer to the 100,000 mile mark before I have to rebuild anything engine related but if need be, I guess I will.
Hanky Panky
Back to Top
tomj View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jan/27/2010
Location: earth
Status: Offline
Points: 7522
Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Nov/16/2018 at 12:56am
frank's got a point. and a flush additive and a couple early oil changes is cheap enough.

78,000 miles isn't that low by then-standards. for most cars of that era, built as they were and sadly, maintained as the often were, 100K was a loooot of miles. (today that's nothing, but that's an extra half-century of gains in metalurgy, chemistry, control systems).

78,000 of frequent oil changes and top-notch maintenance, no problemo. but 78K of the ole concord ans teenager's handmedown, etc and that's a lot of deferred maintenance.

also it's 40 YEARS! of time and time eats cars, literally, just sitting there.

i seem to sound alarmist lately. i apologize for that. you CAN make it all go, i only mean to warn against undue optimism. a 78 Concord today is as old and as alien to most people today the way a Model T was when "we" (sic) were all younger.

what i argue is a reasonable approach for cars more or less like yours is, immediately ditch all fluids you dont personally know the history of: same with all rubber parts. hoses, belts, etc. the water pump, un-spun, will probably leak soon. do a heavy flush, then add water and water pump lube (and antifreeze if you're in a cold place), as little as possible "for now" so you can dump it/flush it as necessary without worrying about it. for a week or two still in mos tplaces you can run without antifreeze; get it to go on plain water. it's a better coolant than antifreeze any (except the ice part :-)

ditto oil. you probably did alread y-- change oil immediately. cheap oil OK (to me, that's Penzoil and that mass market crap), your flush treatments etc, then in 500, 1000 miles, change it again. then the next "real" change after that (1000, 2000, ...) something quality, with high-zinc/ZDDP.

just buy new hoses. they're cheap, it'll get you familiar with under-hood, and it's easy. one at a time and you won't get lost.

starters stick, batteries cake over/plates swell, auto transmissions need oil changes (no matter what anyone says, seriously, when has old/bad fluid improved a transmission, or anything).

brake system probably rusted inside. as a minimum get a quart or TWO of brake fluid, bleed it all. if it's rusty, expect to replace that stuff soon.

free lunches are getting expensive!

1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5
http://www.ramblerLore.com

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

Joined: Jan/09/2011
Location: Flagstaff, AZ
Status: Offline
Points: 4741
Post Options Post Options   Thanks (0) Thanks(0)   Quote FSJunkie Quote  Post ReplyReply Direct Link To This Post Posted: Nov/16/2018 at 1:43am
78,000 miles is not a lot for a 258. The AMC six had an engineered design life of 100,000 miles. I've taken apart 258's at nearly 200,000 miles that had virtually zero wear inside. They badly needed a timing chain and many of them had bad sludge buildup and cooling system rust due to neglect, but otherwise there was very little wear inside. So little wear in fact, that the pistons and bearing clearances still checked out to OE spec and they had perfect compression. Look at 4.0L's. They are basically the same engine just higher stress and not a durable but they 200,000 miles or more routinely. 

The lifters are a pain to remove on these engines. You have to remove the cylinder head to get the lifters out. If you suspect the lifters are sticking you can pour some engine crankcase cleaning solvent down the pushrods and let it soak on the lifters for a while. Pour it all in there and let it soak for a few days then put the valve cover back on and run the engine with the solvent in there for a few hundred miles. I mean take it out on the highway and run it hard with the solvent in there. Any sticky lifters will be free after that.

Stuck valves can be found either by having a bent pushrod or by tapping each valve lightly with a hammer. Free valves will bounce the hammer back with a light "click" noise while stuck valves will won't bounce the hammer back and will made a dull "thud" like you were hammering on the engine block itself. 




1955 Packard
1966 Marlin
1972 Wagoneer
1973 Ambassador
1977 Hornet
1982 Concord D/L
1984 Eagle Limited
Back to Top
Fahques View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: Jan/06/2016
Location: philadelphia
Status: Offline
Points: 49
Post Options Post Options   Thanks (0) Thanks(0)   Quote Fahques Quote  Post ReplyReply Direct Link To This Post Posted: Nov/16/2018 at 5:32am
tomj--ok, 100,000 not low miles. That makes sense. Cars today are lucky to still be drivable after 5 years. I doubt in 15 years we'll see many early 2000s ford, chevy, Subaru, hondas on the road. I've had a 65 mustang, a 75 granada, an 86 GTI, a 80 delta 88 royale and the 'newest' car I've ever had was a 96 Cadillac. And, I just got rid of that car before I got the Concord 3 years ok. Old cars were made to keep and cars today in my opinion are built to break.

Yes, I believe the Concord was sitting for a while before I got it but I've put 14xxx miles on it and have changed the oils and filters 8 times, the plugs and wires 4 times and try to keep up with it. It's cosmetically in GREAT condition.  2 small holes in the driver seat, 1 cigarette burn on the floor and a saggy headliner...that's it. Everything else is good...oh, except a cracked right turn signal housing. Some lady in a 2008 ford compass jammed her brakes in front of me and I rear ended her. I cracked the housing. Her...the whole lower half of her compass fell off. Plastic VS. Steel...Steel wins.

But you called it on the brakes. I'm afraid of looking at those brakes. I took the wheels off just to get a peek at what I may be dealing with and all the crud on the outside....it can't be good on the inside. I'm scared of them.

Belts I've done when I replaced the water and fuel pumps last year and the vacuum hoses I was planning on doing when the valve cover was off but napa brought me the wrong size for all the main lines. The spool I got was the right size for the manifold size hose but not for all the main emission and distributor size stuff. I'll get to that hopefully next week.

What's that ? Free lunch?    Never heard of it...

FSJunkie--I'm hoping my engine is going to hold up to what you're saying. I'm not too experienced with inside engine work but from what I saw it wasn't too bad in there wear wise. The rockers were a little caked with a solid crud in spots but not sludgy so to speak.

One thing that did bother me is when I pulled the cover I found a loose random gold colored washer sitting in the head. It didn't look like a valve lock or a shim type thing, it looked like a regular washer. I looked around and couldn't at all figure out what it was for. Unless someone was in there before and did shim something. It is an aftermaket VC that's on there. I'm not sure.

Not that I know much but I DO suspect the lifters. Especially hearing what I've learned here. The rocker wasn't busted, the bridge wasn't busted, the pivots were good as were the bolts. The pushrod was just slipped. Seems to me the lifter is the problem. If I slip the same rod in a while..then yes, the lifter is shot I'd assume.

I'm not looking forward to pulling lifters but it'll teach me something if I have to do so. Just by doing the VC I've learned alot about what's going on under that crazy 258 hood and I've learned how to not slam other's tools on concrete floor.

When I replaced the pushrods and rockers, I hand cranked the engine and all SEEMED to be working correctly, Meaning the valves appeared the function but it could have just been me being hopeful. It's running good...for now....shhhh, don't say anything, the Concord might hear you.

I'll do the solvent thing, the oil thing and if I do throw a rod again I'll hammer test valves.

It did snow here yesterday for the first time this season so weather is now predicting when I'll get to that.

Thanks again for all the good info. It helps ALOT.




Edited by Fahques - Nov/16/2018 at 5:37am
Hanky Panky
Back to Top
tomj View Drop Down
AMC Addicted
AMC Addicted
Avatar

Joined: Jan/27/2010
Location: earth
Status: Offline
Points: 7522
Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Nov/17/2018 at 11:22pm
yeah, FSjunkie's advice seems best. for the record, the 64-up six is about as bulletproof an engine as ever made; the longevity problems that have occurred are well known by now (the early heads with top-oiling past a headbolt; plastic timing gear wear; later plastic valve covers; warping exhaust manifolds) and none are (1) serious or (2) what you have.

the rest is crap maintenance. my pessimism on the cause of the dropped pushrod may be needless.

the brakes: yeah the good news is, none of that stuff is all that expensive. i and others replace lines with stock lengths bent carefully by hand. my '61 american has only one line (to the rear) made of two lines and a coupler. the rest i was able to eat the extra length by generous radius bends. i bought about 6, 8? lengths from Summit, ruined a couple. they're cheap enough, and i end up using the bad ones (eg. for nicely fitting master cylinder bench-bleeder tubes).

and it is very satisfying to strip off all the cruddy, rusty crap brake parts off each backing plate, and leave it all clean and squeaky-clean. i usedta shop rockauto often, and would fine drums on clearance sale and buy them ahead of need -- at least four at $10 each (in pairs). still have a set.

1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5
http://www.ramblerLore.com

Back to Top
Fahques View Drop Down
AMC Apprentice
AMC Apprentice
Avatar

Joined: Jan/06/2016
Location: philadelphia
Status: Offline
Points: 49
Post Options Post Options   Thanks (0) Thanks(0)   Quote Fahques Quote  Post ReplyReply Direct Link To This Post Posted: Nov/18/2018 at 7:33am
Pessimism I understand completely. If it wasn't for pessimism I maybe 100% apathetic.

Before I saw the dropped rod I was too thinking along the lines of a broken piston situation, burnt valves...something serious that would require MAJOR work or ditching the car. I've grown to love this car and I'd HATE to get rid of it.

Funny you mention drums, I was looking on rockauto just last night to see what brake replacement might cost me and the finned drums are 35 a piece. The ones on the car MIGHT be able to be reused but they are rusty as all get out and I'm not sure it's a good idea to reuse questionable parts for brakes. I need those. Meanwhile I'll dream of squeaky clean brake parts and plates.

And tubing I'm going to need to do as well. Most likely ALL the tubing. Bending by hand....ninja style....nice!!!

Brakes and a muffler is what I'm trying to address before winter shows up for real. It's no fun laying under a car in PA in February. I promise.

I'll just keep peeling through posts on this beloved site, some on youtube and the mighty TSM.

I noticed yesterday that my fresh valve cover gasket started leaking a tad. Not looking forward to that today but....you know.


Hanky Panky
Back to Top
 Post Reply Post Reply Page  <1 234
  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 0.156 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