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View Full Version : Please Help, I need some advice (kinda long)


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MIDNIGHT
11-02-2004, 01:53 PM
:!: :!: :!: I think I'm gonna put a SBC in my jeep now!!!

Naw J/K. I rebuilt my '78 360 about 20,000 miles ago. I wasn't aware of all the oiling issues at the time and didn't have the internet handy to research and wouldn't have know where to look if I had. I rebuilt my engine with a a FSM and a JP issue that had an article that was doing the same. I have rebuilt numerous SBC engines, but the AMC was a first for me.

The JP article talked about priming the oil pump with vasoline, so I did and said nothing about making sure the castings around the slots and holes in the timing set were correct. IIRC all the parts of that nature were either melling or sealed power. I guess I got lucky b/c nothing has seized up yet and I havent chewd any dizzy gears. I did know to check the oil pump housing and the adaptor for wearing which had a few scapes but didn't look bad at all, but I didn't mic anything. (I did use a new oil pump kit though) I think it was sealed power.

My motor runs like a top and since the rebuild I have not had any problems. However, I have had a slow knocking sound at idle since the rebuild, but have never found any metal in the oil at changes (every 2500 miles) and has never gotten any louder or changed tune so thought it could be something as simple as the fuel pump pumping, etc. and haven't thought much about it.

The thing is, is that the engine runs as quiet as a mouse cold until the engine warms to running temp and thats when the knock starts getting noticeble. (BTW, its not a loud knock meaning I can't even hear it unless my head is very close to the engine.) Trying to diagnose the noise, I have even taken all of the belts loose and the fan, so no other noises would distract me and cranked the engine after it had been sitting all night (stone cold) and the motor did not make any sounds out of the ordinary, even with a mechanics stethoscope, not one sound until about 8-10 minutes later when it warmed up and the knock slowly became noticeable.

Also, another noise that has been brought to my attention (and louder only when engine has gotten to running temps). I noticed it when I had removed my transmission tunnel cover to change my transmission fluid and took a trip down the road. This noise is most noticeable at 2200 rpms. It starts up at around 2000-2100 and fades away around 2300 rpms. It sounds like noisy rocker arms or lifters. I don't run fram filters and I had decent oil pressure. IIRC aorund 45-55 cold and doesn't seem flutuate with rpms until it has warmed up and then I have 15-20 @ 750 rpms and around 50 driving down the road.

What got me reading into oil pumps is the fact that I have noticed sometimes that the oil pressure will increase when I let off the throttle and someone told me it was probably my relief spring and directed me to here for a high pressure spring (oil pump kit) Fuzz401 as a matter a fact. Don't get me wrong, these noises do not sound detrimental, but after reading all this info, its kinda got me worried. Honestly, I would have never had any concern until I read the info on this forum. Any advice on the noises would be great and I guess I will be buying the oil pump kit from here and seeing if that corrects any of the noises and my crazy oil pressure readings. BTW, I have a good mechanical oil gauge.

Don't know if its of any importance, but another thing is that ever since this engine has been completely rebuilt, if I crank it up when it is stone cold after sitting all night and the outside temperature is below 35 deg, the lifters clank for 2-3 seconds and quit.

I'm pretty sure none of of bearings are being chewed away or I would think I would find bearing peices in the oil when changing it. Any suggestions would be great, sorry for the long post.

jeepsr4ever
11-02-2004, 02:01 PM
CAUTION!

Check to make sure the flexplate bolts are all tight first.


Sounds like a pressure spring or oil filter bypass spring. Usually when the oil fluctuates with the elease of the throttle its the oil filter bypass opening and the knock may be caused by main bearings chewed away from the dirty oil let in from the bypass opening.

Lets hope its the flexplate....

MIDNIGHT
11-02-2004, 03:02 PM
Well what I really wanted to hear was worst case scenario! like DONT CRANK IT, ITS GONNA BLOW!!!!

Wish it was the flex plate, but just had it apart installing a clutch. Flywheel bolts and PP bolts were torqued to spec and red loctited. I guess I'll just keep hoping it is a noisy valvetrain or lifter @ that rpm.

I mean really, if it was a bearing going bad, would you not find peices of bearing in the oil. I've even dug into a few of the filters worried about the situation and found nothing. The oil is always metal free and still gold looking as far as that goes. Anyways every bearing I've ever heard go bad made hella noise at any RPM. Not just a certian spot in the RPM range.

Thanks for your time reading the post.

jeepsr4ever
11-02-2004, 03:22 PM
:-| Take a piece of metal put one end to your ear and the other to parts of the motor while its running this will pinpoint the knock

MIDNIGHT
11-02-2004, 03:49 PM
Trying to diagnose the noise, I have even taken all of the belts loose and the fan, so no other noises would distract me and cranked the engine after it had been sitting all night (stone cold) and the motor did not make any sounds out of the ordinary, even with a mechanics stethoscope,

I carried it one step further. Bought the $5 tool. Cant seem to pinpoint it anywhere, although the tool (that method) works really well.

Now, I tried that method on the noise I hear at idle, but I haven't done that for the noise I hear at 2200 rpms. I'll try it.

Goose
11-02-2004, 03:54 PM
:shock: Dang MC My oil pressure is doing the same thing increasing when I let off the throttle!! (with 200 miles on a fresh engine..) whats the recommended fix for the bypass problem? I have the new pressure spring in that came with the stuff I ordered from you but I didnt do anything with the bypass.

jeepsr4ever
11-02-2004, 04:32 PM
either a new spring or new style oil filter adaptor...we need to come out with a new spring setup for that bypass

ol' school power
11-02-2004, 04:34 PM
If the lifters rattle a bit on a cold start, what are you using for an oil filter?
Also for some pressure woes, when you install the pickup into the block, are you checking the clearance between the screen/pickup and the bottom of the pan?

MIDNIGHT
11-02-2004, 07:18 PM
If the lifters rattle a bit on a cold start, what are you using for an oil filter?


I've used them all. Fram is what I started using, then tried purolator, a couple of K&N's and now I'm using Napa Golds.



Also for some pressure woes, when you install the pickup into the block, are you checking the clearance between the screen/pickup and the bottom of the pan?

Well pressure isn't my big problem. Its actually decent, it just does some weird things sometimes. (I have actually only seen it rise 5-10 lbs as I let off the gas a couple of times)

And back to the noise issue. When I returned home from work, I went strait out to the jeep and cranked it up. (with the tunnel cover still off) I still got no noise whatsoever until the engine warmed up to 180 and after diagnosing the sound in a little more detail it sounds more like clattering noise instead of a knock at 1500 and 2500. I crawled underneath the jeep and can't figure out where its coming from. Sounds like its in the top end. I laid my ear strait on the oil pan (before it got hot) and it sounded quiet like an electric motor running. Who knows???

Briteblock
11-02-2004, 09:31 PM
Electric motor :!:


Try some di-electric grease 8)

MIDNIGHT
11-03-2004, 07:11 AM
Electric motor

Yea, meaninig quiet. :roll:




Try some di-electric grease :t:

better yet just drop a chevy in and be done with it.

If I had ever known that AMC had ridiculous problems such as this, I would have never mess with one. I tried to go the cheap route by replacing my 258 with a 360. Plus I got the 360 for free in need of a rebuild so I can't complain too much. But, I should have known that free would equal some kind of bothersome worries. If I had just bought the $400 worth of adaptors for the chevy, I would never worry about my engine eating bearings b/c of poor oiling issues, especailly in an engine with 15-20,000 miles on it. How retarded.

FrankNB
11-03-2004, 09:48 AM
But an AMC engine adds to the coolness factor... a 350 is just another dime a dozen v8 engine.. :?

MIDNIGHT
11-03-2004, 10:17 AM
true.

and as much as I wanted a chevy at the time (mainly cause I had alot of chevy parts) I wanted to keep the Jeep all AMC for some reason. I just wish AMC would have worked the bugs out before production

Dusty
11-03-2004, 10:32 AM
Poor oiling issues.... not as much of an issue as building an engine based on POOR advice. Vasaline in the Oil pump gears will kill even a chevy engine. The vasaline takes so long to warm up and move out of the oil pump that it restricts the pump from doing anything for a fatal amount of time after inital fire up starving everything in the engine that needs oil imeadiately.


The Bugs arent that big of an issue as they are made out to be. the bypass spring issue can be avoided with a new one at assembly (which should be done) and the oiling issue could have been avoided by sticking a flathead screwdriver in and priming the system with oil before putting the distributor in and by not putting jelly in the oil pump housing. Other than that i say put it back together and run it.


I hate to say it but an engine is only as good as the way it is assembled and thus it lasts only that long. Have had and seen numerous AMC's go to 150-200k miles and have the block be in great condition for rebuild. Hell i bought a 401 in LA for $400 that the heads were done improperly and the timing cover had been stuffed with vasaline= long time without oil cause it takes so long to heat up and move the vasaline out. The engine's bottom end was roached.

Bought another one for $400 out of a beat J truck running with 235,000 miles on it, machinist said i could probably polish the bearing journals and run std bearings again and that the taper in the cylinders didnt merit boring it out at all. #-o

And the same holds true for GM motors i have had some go 50,000 miles before it blew it up and i have had some go 200k and work great all along. Its all about who built it how they build it.


Anyways you can rebuild that AMC for just as little as a 350. Compare the same rebuild kits... parts cast pistons ect you'll be within $100-200.

Its a shame that it happened to you, but it wasnt the oiling issues as much as they sound like constant headaches most guys with a little attention never experience these issues.






Good luck

MIDNIGHT
11-03-2004, 10:45 AM
[/quote]Poor oiling issues.... not as much of an issue as building an engine based on POOR advice. Vasaline in the Oil pump gears will kill even a chevy engine.
[quote]

I agree, but like I said before the internet wasn't available to me at the time for advice and all I knew was that the AMC oil pump was differnt and thats what the JP article said do. I doubt my bottom end is roached. I still primed it with an old dizzy and a drill as well as using a little vasoline.
The oil pressure was up before I cranked it.

But I never used vasline in a chevy motor rebuild.

pyagid
11-03-2004, 12:52 PM
----

Goose
11-03-2004, 02:45 PM
Just a thought, but after rereading this thread I have to mention a couple obvious things.. (please dont assume Im slamming you by pointing out the obvious) But have you pulled a vlve cover yet?? You know these goofy cast aluminum rocker bridges on amc motors do break and it wont "clatter like a SBC it kinda taps or clicks as the two pieces move against each other and this last is way obvious but since I have overlooked it myself (and since I am a Minor Diety when it comes to wrenching :roll: ) Does it still have the heat riser?? if so is Loose and flapping around like mine was?

Hope something helps.. I would seriously doubt that if you have no metal and it has oil pressure that anything is serious wrong.. but do listen closely to the rythm of the knocking sound If it sounds like "hoosier daddy hoosier daddy" Check the grille of the truck and see if it's grinning AMC's are well known for thier ability to breathe and jerk your chain at the same time..

Dusty
11-03-2004, 02:50 PM
........I would seriously doubt that if you have no metal and it has oil pressure that anything is serious wrong.. but do listen closely to the rythm of the knocking sound If it sounds like "hoosier daddy hoosier daddy" Check the grille of the truck and see if it's grinning AMC's are well known for thier ability to breathe and jerk your chain at the same time..



LOL.... seriously I hope i didnt come off as slamming you either, i did read all the previous info you posted. Got kinda wrapped up withthte vasaline issue but Goose makes a good point about no metal in the oil :shock:

ol' school power
11-03-2004, 05:52 PM
The AMC engines didn't last the first 30+ years and 100k+ miles cause they were flawed.
You just have to be careful with checking the aftermarket replacement parts since some of the suppliers aren't.
If the trouble is from a machine shop that doesn't know AMC, then they're idiots that have too much ego or not enough common sense to open a book. All the specs are published.

79cj7duner
01-21-2005, 03:59 PM
another ididot thing to check would be the exhaust. I know for a fact that my Jeep has a small exhaust leak at the manifold to pipe joint.
That being said, I just ordered all new rocker arms, bridges, and pivots to do my entire engine because I have now broken 2 bridges, and this time it bent a pushrod and threw a lifter out of it's bore. Just wonderful news on the amc front. Oh, I almost forgot, the valley pan is leaking water into the valve covers, so I ordered Mr. G. intake gaskets for that. I think I'm going to do the oiling mod while the intake is off.

tufcj
01-21-2005, 10:39 PM
DON'T do the oiling mod unless the engine is apart for rebuild. You won't believe the way that cast iron splinters when you drill and tap it. No matter how careful you are, there's NO WAY you could do it without getting metal frags into the oil passages, and that could kill your motor in short order.

The only time to do it is when you have a bare block on an engine stand, and can clean all the passages with brushes afterward. Doing it on an assembled engine will probably do more harm than good.

Bob
tufcj

Jeepin002
01-24-2005, 08:05 PM
I have a 360 in my CJ-7 could I get the Mr. G part number for the intake gasket? I just picked up a performer manifold and soon cam and timing gear. I ordered the valley pan gasket from Jeepdoc and I am not to impressed with stamped steel for an intake gasket.

Thanks

Bob
01-31-2005, 01:37 AM
What kind of lifters are you running? Rhoades variable duration lifters can make annoying noises at low RPM. Sounds like one or more rocker arms on a mechanical lifter valve train need adjustment but only sometimes and only at low RPM. They do not do well at AMC oil pressures.
Bob Fleming

Goose
01-31-2005, 01:57 AM
Thats good info on the Rhoades lifters.. I was thinking about trying them out.. (you know that ol something for nothing syndrome) more cam and still have torque/idle. but now that you mention it I'm surprised any lifters work at book spec 13-15 psi at idle..


Ahh Ya gotta love the gearhead way of life. :wink:

Jeepin002
02-01-2005, 10:06 AM
I have a 360 in my CJ-7 could I get the Mr. G part number for the intake gasket? I just picked up a performer manifold and soon cam and timing gear. I ordered the valley pan gasket from Jeepdoc and I am not to impressed with stamped steel for an intake gasket.

Thanks

nevermind

lthom49086
04-03-2005, 08:04 PM
my 79 amx with a 304 does same thing ,i took it to a guy that does nothing but amc;s and told me its cam walk ,even after replacing timing chain it did it.,went and bought a napa chain . NOISE IS GONE!!!!! explain that.

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