AMX 360 need help!

What I find really odd is that I don't think I've heard of Buick guys having this issue, despite a nearly identical setup (where do you think AMC got the idea?). Maybe they're lucky and still getting factory parts?

And to re-iterate, AMCs don't have a problem with cam-walk.

 

No more cam walk problem than anything else anyway. I've seen a few that cam walk caused a problem (cracked timing cover), but it IS rare. Usually a flaw in the casting or roller lifters, as far as I can tell. Not any more of a problem than the typical US V-8.

I have to agree -- Buick timing covers are obviously available, probably licensed someone to repro them. A LOT more Buicks (real Buick V-8s) out there than AMCs! As I mentioned, the AMC timing cover had to be reverse engineered and the first ones were slightly off, probably due to measurement conversions (English to metric -- produced in China). I've seen a few things with that problem over the years!

 

but thats a curiosity that can be solved by buying one or finding someone that has one.. (the amc vs buick)

 

I'm using an aftermarket cover on the V6 Buick in my Toyota with a high volume pump, HEI distributor, along with a PAW no name cam, and never had a problem. the aftermarket cover uses a rubber lip seal, while the original cover used a rope seal and I didn't notice any evidence of any ground off part numbers so I'm asuming it was a new part not from a reworked mold

 

I was just going to suggest the oiling issue. Mark Donohue and the Penske team ran into that same issue with their Trans Am Javelin engines in 1970. They originally developed the external oil kit. Apparently they told AMC about it, but the factory didn't see it as being a real problem. Possibly might have something to do with particular timing cover or block castings????

 

Or it could be that the T/A team had the problem only because they were revving the heck out of the engine all the time, and going up and down with revs quickly and often. that's something a typical street car or even a drag car will never see, not often or for the length of time those cars did anyway!

 

so, i looked up the 1970 buick v8, and although the distributor DOES come in at an angle on the front of the engine, the covers themselves are not the same style, nor are the water pumps. im guessing even if the outline was similar, the pump plumbing is not the same, so it would not work.


now, heres the million cheerio question.... would the stripped dist. gear tooth profile indicate anything about the position of the cam in the block? the gear is chewed evenly from top to bottom, as well as about 3/4 of the tooth deep, which is the 'recommended' depth for oiling between the gears. now, lets just say it says everything and the gear itself being even from top to bottom means its set in the proper spot, it would leave the gear tensile strength as the only question. right?

correct this hair-brained idea, but it just clicked, because, oh i dunno, ive been thinking about this non-stop for 3 weeks.

 

Oh, absolutely...!

 

So it looks something like this...I couldn't find any problem with alignment issues. The only thing I will say is sometimes aftermarket dizzys may bind with the oil pump and need a little taken off. Does your dizzy slide in without much effort when the gears mesh? Then alignment is probalby not the issue.

 

right, it slides in ok, just the normal PITA with the twist to find tdc and line up the dist. and the difference between my gears and what you show is every gear has pretty much been eaten from top to bottom. i see your drive gear is missing the top of some teeth, but mine seemed to be top to bottom. i suspect this is true, and its just a case of needing matched sets.

 

poppajules, that theory might work with the bronze gear, but less likely with the steel gears. With the bronze gear load in the oil pump can be a problem. Make sure the oil pump clearances are good. There's an AMC TSM on-line at http://www.tocmp.com/manuals/AMC/1973/Service/ that describes how to check the oil pump clearances. And make sure the pressure relief valve isn't sticking.

I suppose it's still possible that the gear wasn't properly hardened even if it's steel, but a plain steel gear with plenty oil and a light load shouldn't wear down that quick if the gears are meshing properly. We never had this problem with US sourced AMC factory gears and timing covers, it's obviously an aftermarket problem, and hardness could be part of it.

I knew the Buick cover wouldn't work on the AMC, was just saying that the systems are similar.

 

I wasn't suggesting that the Buick parts would work on an AMC. Just that Buick has the same setup, yet they don't seem to be plagued with this problem. A problem that was never seen before aftermarket parts came onto the scene.
Heck, even the motor in my Nissan pickup has the same setup.

 

Look carefully at the timing gear in the last post. Notice how the oil transfer slot is blocked.
Lots of good info in that whole series of pics.
http://realamcperformance.aimoo.com/Engines/Winter-Engine-Builds-3-1898227.html

 

yeah. im not a big fan of this right now...... i REALLY dont wanna pull the cam. i saw someone saying something about the edelbrock set, and thats what i believe is on there. maybe this is one thing that may be good to go back to stock off an old motor...

 

That's what most AMCers are doing when they can. A few have even snagged timing covers and dizzy gears from salvage yards just to have spares. Not a bad idea if there is a pull-a-part in the area! Just go on-line and check when they have an AMC or Jeep Grand Wagoneer come in.

 

You can use the Edelcock timing set, just study the pics in the link I posted so you know what it takes to make one work properly.

 

that was fun, we took the timing cover off, and didn't find much oil anywhere. The gears were dry, the end of the cam was dry, the little hole in it didn't have any oil dripping out. I had to go, but I think the next step might be to pull the intake/valvetrain and get the lifters and cam out, and see what's up with the front bearing. The gears look like they're meshing ok? it ate almost all of each tooth of the dist gear. The cam gear looks like it's still all there, but I suppose installing a new matched set would be wise.

 

well i will post pictures later, but two things that are an issue right now.. dist shaft sits about 1/16 in higher than 'seated' when pressed into the pump shaft. i tapped with a rubber mallet twice real good on the cam and it bumped back into the block about 1/32 in. the oil pump gears are scored a little bit from something being in the housing. bleh. im pretty frustrated right now, but either way... back on topic.

would these issues chew gears? the cam gear sits flush to the block, and the oil supply slot lines up with the hole from the cam... it has six notches on the front of the cam sprocket, and both drive gears (previously removed one and recently intalled one) have four oiling holes around the inside of the gear.

old cam drive gear had wear on both sides of teeth, ill post pictures of that as well... im pulling for straws on info.. inside of timing cover was pretty dry of oil, but it has been sitting for a few weeks without running, so i would say thats a mute point...

theres no visual wear on the inside of the timing cover that has the excess material in case the cam rides forward...

cam drive gear lined up square with the pump shaft...

 

Are you using an aftermarket distributor? Sometimes those won't go down into the oil pump as far as the AMC dizzy. Of you've been tightening the dizzy hold-down clamp down and forcing it in that's the problem. You're binding the oil pump gears and putting too much load on the dizzy gear. The fix is to use a washer/spacer under the dizzy or grind the end (may have to deepen the slot). This is more often a problem with the six using the Chevy six HEI dizzy (it fits!) or a Melling high volume oil pump (drive isn't as deep as factory oil pump and even a stock AMC dizzy might bind the pump). But I've seen it on the V-8 with aftermarket dizzys also -- or way different year dizzys. Could be from aftermarket oil pump gears too.

 

The thing that puzzles me the most on this is the WIDTH of the wear pattern. If it was a simple oil starvation issue then I'd think you'd see a typical concentrated wear pattern. The fact that the dizzy gear is wiped (up/down) it makes me think you have multiple issues here - oil starvation combined with distributor shaft movement. Which then makes me wonder if there is a correlation between distributor shaft movement and oil supply. I can't rememeber how this all fits, but that's what I would look to first. I assume we're talking a points or electronic dizzy so the load on the gear is virtually nothing (not like a magneto) so the problem should reveal itself IF we can look in the right place... well eventually ;-0
I've heard the "matched gear" argument - and while it makes sense - why does that not matter on any other engine??? Makes me think it's more of a clearance or material hardness issue. Along those lines I would take a file and run it across a good stock gear and an aftermarket one - while not the best test in the world - it will at least let you know if the hardness is in the same ball park. With this accelerated wear I would assume if the hardness is the issue - it'll be noticeable with a file test.

 

I don't know, it looks to me like it's just not getting any oil because of a problem with the front cam bearing or journal.

Lack of oil will eat up parts pretty quick.

 

I think Jim's right about the oil issue being as the timing cover was dry AND I think there is an alignment issue the teeth to me looked to be worn as if something was out of alignment but I'm no expert. Like Julian said we did later tap on the cam and it seated a 16th toa 32nd back into the block maybe normal I'm not or the oil pump drive gear which looked to be a different design than the old one.

Thanks for you help guys

Confused in AZ

 

hey guys, i took more pictures of parts and comparisons, as well as made a few strides, id say. with the hold down bracket on the dist, i slid the two oil pump drives i have into the cover, and the aftermarket one sits out of the bottom of the cover about 1/32, and thats after trying to persuade it in there a bit. VERY tight fit in the old cover. old gear fits great, seats well, moves freely after i ground it down a bit. check out the pictures i posted on the other site, i posted a lot, or i would do it here, too...

http://theamcforum.com/forum/topic23954_post227838.html#227838

 

what i noticed was that the key was deep, but the sides were too high, so if the pump is together, the dist. sits too high, or vice versa. check out those pics, though i didnt take pictures of the mesh, as i couldnt get definitive pictures, although you can see it by eye. if i were to use the new gear, i would file down the two teeth, but im just gonna go back to the old cover, old gears, etc. and im thinking about just getting my auto zone replacement and see what happens.....

now, from my understanding the cam lobes have a slight taper on them to hold the cam to the back of the block, correct? stock valvetrain was hydraulic... would the hydraulic ride appropriately to hold the cam back? i guess it makes sense, it just seems like the hydraulic has 'too much give' and wouldnt hold it in place. either way, we bumped it back into the block that 1/32 inch, would this be enough to make a night and day change in oiling? i doubt it, but im no engine guru.

 

alright. im bringing this one from the dead, but i figured id offer an update. squirrel guns and i pulled the front apart, and i put some things back together to check oil delivery. timing set, fuel pump eccentric and drive gear removed. 5 qts. of oil, official method of priming the pump, and i now have oil down the thrust plate out of the top oil hole from the block and the cam oil hole. i also found alot of details pointing to other people having aftermarket timing sets (that i also have) and the oil slot doesnt line up with the hole. at least with the oil hole showing its not spun, i narrowed it down to the stuff on the cam. i widened that channel to span the oil hole, and im planning on putting it back together and trying it out this coming weekend.

 

Check with the folks on the International Full Size Jeep Association website. This was discussed a few years ago.

I remember there was a problem with aftermarket timing gears that had an oil supply hole that was blocked off due to manufacturing defect. There was also a problem with differing tooth profiles. Mis-matching them chewed up gears but in that instance, there was no oil supply problem.

Great bunch of folks over there.

 

yeah.. i pulled the dist. and had it pretty much bone dry. it should at least be a slight film of oil on the gears, but it was dry dry on the dist. gear at the minimum. so given that i have oil from the hole down the thrust plate, im pretty excited that i didnt spin any bearings or anything, but thanks for the heads up. im getting a set of matched up gears and with this oil issue hopefully resolved, i might be moving forward.

 

I had this problem this before. It stems from the upper timing gear. Ecspecially aftermarket ones. Turn down the upper timing gear enough to put a shim in. Then drill an 1/8" hole in the allen screw on the PASSENGER side of the motor. Worked for me. I did this probably 10 years ago and its still running strong. I got the info to do this of an old amc motor guy out in cali

 

I thought I would update. My buddy got the car running with a new distibutor and match set of gears he bought from a hamber on the cheap. Thanks for your help guys. It's aways nice to get another car back on the road.