AMX 360 need help!

I have been helping a friend work on his 74 AMX for 2 weeks now.

Heres what the issue is the car keeps grinding up distributor gears. This is the third one. The car will run for a bit few hundred miles then the gears will get chewed up until the gears are gone causeing it to jump timing. And the car dies. The cam gear looks like it is in nice shape. The distributor gear looks to be meshing a little off. What would cause this? what are the next trouble shooting steps?

Thanks for your help

jesse

here are pictures of the distibutor gear. half way down the page.
http://theamcforum.com/forum/no-spark-at-a-loss_topic23954_page7.html

 

What cam is in it?

I hear billet cams can eat distributor gears. Try a bronze gear

 

Its a factory spec cam. It's not a bronze gear. I feel its something not lineing up. I just don't know what it could be or where to look. I'm just at the end of my trouble shooting scope of practice. Thats why I'm reaching out for help.

To add to your question though. the distrubutor gear even without a bronze gear should last longer than a hundred miles. Thanks for the responce I will research using a bronze gear tonight.

 

Bent distributor shaft? Bad gear on cam? Oil pump dragging heavily (possibly from bits of chewed gear lodged in it?)

 

is the cam walking in and out? I forget if AMC used a retainer behind the cam gear to hold the cam or a button. it's been a while since I built an AMC, I'll have to think about it. Or maybe get a book

 

Bronze gears should not be used in street motors, they don't last very long ~ 2500-3000 miles is average. If it is a Steel Billet roller, use a melonized gear or one of our Billet Distributors with the proper gear. http://www.summitracing.com/search/Part-Type/Distributors/Brand/PerTronix/Make/AMERICAN-MOTORS/?Ns=Rank%7cAsc

 

Is it an aftermarket timing cover? it is also the oil pump on those AMC motors. When you need a new oil pump that is what you get. Some of the aftermarket housings are better than others.

 

I used a high volume high pressure pump on a Buick and had distributor problems, whats he using for a pump, is everything aligned?

 

Engine was just rebuilt. The issue was happening before the engine was rebuilt and again right now. brand new distributor this time. I will find out about the timing cover. The same cam is being used this time and I was told by my friend not touched during the rebuild. The last time it happened before this week an engine guy said the cam gear was on backwards, I didn't think this was possible but he said he switched it around and replaced the gear. This was a year ago when my friend said this last happened.(car sat since while the engine was rebuilt and other body work was being completed) that engine guy may have been smoking something. how do I check for walking? I have heard of this before.

I'm thinking that the oil pump gear off or cam gear off somehow. just my uneducated .02

 

It may not be aligned we are going to drain the oil tonight and pull the pan. How do I check for this alignment?

 

I had the same exact problem on an AMC 304 right after a rebuild. It did this twice, and it turned out it wasn't oiling up front. I set the engine aside, and replaced it with a 360. Later, I needed a front timing cover and removed the one on the 304, and lo and behold, it was dry as a bone in there. Something had plugged the oil galley. We turned the engine over untill the oil pressure came up, and nothing pumped out to the front cam gears and etc. Never DID figure out what mucked it up...

 

My brother, a friend and I all built 360's for our Jeeps and my friends had this same problem. After his chewed up several mallory gears I got him a cam button and spring meant for a 231 buick (I think,this was 25 years ago) He didn't have any more problems. If you look inside the timing cover there is a machined flat spot straight out from the end of the cam like it was meant to have one.

Scott

 

AMC had a problem with getting oil to the cam bearings, we used to drill into the oil passage and run an external line to the cam oil passage.

 

7th post down
http://theamcforum.com/forum/amc-360-cam-distgear-problem_topic3695_page2.html

 

Talked to an AMC guy ~ coupe of things to look for. The front covers are known to wear where the shaft goes, anything over .020" clearance will wipe out dist gears due to loss of volume supplying the gear. Also the newer Mopar supplied dist gears were found to be of suspect quality a few years ago and there are tons of those still out sold as new. They strongly recommend these to cure the problem it f the front cover is good and there is oil getting to the front cover area (in other words no blocked passages) http://www.bulltear.com/catalog/product_info.php?cPath=21_35&products_id=169

 

Just talked to my friend the timing cover and oil pump drive gear are new and still the same issue as the last time.

found this http://www.jeepforum.com/forum/f8/another-bad-hei-dist-gear-supplier-556951/


Talks about wrong gear profile and the inferior gears going around (its a jeep site but I believe same engine) and the pics look like a spitting image of my friends issue. Just found this on a random search but looks promising. just like hotroddon said.

whats a way to check oil preasure at the gear?

 

It's not so much that the gear needs pressure as it needs a steady bath.

 

How can I check this? My buddy is joining the forum tonight to get in on this!

 

yep, im the buddy.

so, the first thread posted by guns is my thread on amcforum. it seems like more heckling than helping to a certain extent, but there are three procedures i am planning on looking into. possibly four and ill mention that towards the end.

first, since the timing cover is where the dist. goes in at an angle, i can pull it off and slide the dist. in to check clearances, and the oil pump is also bolted to the cover retaining all of the gears, filter and drive shaft for the pump. i will slide the dist. in and check the clearance and if theres any pressure against the oil pump shaft when held down firmly with the hold down bracket. next, while the cover is off, pull the big nut out of the oil pump housing and verify the spring for the bypass valve comes out easily with a magnet, if not simply falling out. (apparently if this funks up, this can seize the gears as well) last, run some gear paint on the splines of a new dist. gear, install it, and turn the engine over a few times, repull it, and inspect the mesh with the drive gear on the cam.

ok, five things... other is check any endplay of the cam, as the tolerance should be .000 movement.. ok six things, put a straight edge on cam and crank sprockets and verify they are in line with one another. (this will also verify the cam is not walking, in theory since the crank wont walk without breaking alot of things)

and finally, what was mentioned here, the galleys out of the pump housing into the block.

the drive gear on the cam looked to be coated in oil when i pulled the dist., but that doesnt necessarily mean its enough, or that its more than a splash while under load.

i also have the original timing cover, which i can check tolerances with compared to the new cover, only issue is theres a ding on the front of the old cover which kinda chewed up the furthest out edge of the oil pump gears, probably starting this whole mess.

hope that helps, and thanks for starting the thread, jesse.

 

In addition to all this you need to make sure the oil supply from the front cam bearing is making it through a series of holes, passages and slots to the distributor drive gear and timing set. Aftermarket parts may lack passages/slots and/or have alignment issues (blocking passages) ....not to mention the parts could have been assembled incorrectly thus blocking passages, etc.... The driven and drive gears should be replaced as a set on these motors. (the drive gear comes off the cam). Here are a couple of threads to check out.

http://www.msorc.com/archive/index.php?t-732.html

http://www.jeepsunlimited.com/forums/showthread.php?t=163934

-Bigchief.

 

is it yellow?

 

Jim its brown.

 

I chased this gremlin for 4 years in the Rebel Reaper. This last winter what ever I did, fixed the problem? I did all the things you have either tried or are contemplating. I cut a cover for inspection purpose. I blued everything. I lapped in new gears. I opened the slot in the back of the cam timing gear. I opened the slots in the fuel pump cam and cam gear. I drilled more holes in the cam gear. I tried bronze cam gear. I tried a bronze dizzy gear. I blamed the msd for quite a while. I switched timing covers. I used matched oe gears. New Msd gears. What ever gears I could find. It really sucked. I even went to 10W30 oil to lower the drag on the gears. I was running a comp cams solid cam and had a custom button. I drilled the oil galley plug with a small hole to spray oil directly on the gears, nada! My next step was to cut the whole oil pump assembly off and run a belt drive!

This past winter I tore down the 401 for a fresh up. It looked like new, but I still changed the mains and rod bearings. New rings too. I also put a new crane roller cam in. With that I put on a new timing set with a torington roller bearing on the back side. For the gears I purchased a set of matched Bull Tear gears. So to sum this all up, I really don't know what fixed it, but it was either the cam, the timing set, or just really good gears? AMC v-8 are a damn good motor, but when this happens its their achillies heal.

 

ha, its not the one from the car show if thats what youre referencing. if the car wouldve been running, it wouldve been there, for sure.

you mention the bulltear gears, and ive heard conflicting stories about the quality. However, ive heard more good than bad with his equipment, and i continuously have it beat in my head from the other forum, that matched gears are the only way to go.

i am just not sure about how this necessarily matters, as anyone can go to any parts store and they offer one gear at a time. i understand that one gear can be harder than the other and tolerances for each can be slightly different, but my biggest hurdle at this point is the price tag for gears that might end up in my oil pan in shards. i dont wanna shell off 120 plus ship for something that is not necessarily the only issue. this is definitely frustrating, because when the oil pan was off last, i noticed bearings were new and almost perfect, bottom of pistons and skirts indicated they were new.. i dont want to give up on this car or engine, because im pretty sure this is parts and numbers matching, though i dont still have the engine code tag from the valve cover... another heartbreak.

 

when could I come over and take a look at it?

 

jim let me know when you go I'll be there.

 

eh, whenever, really. this weekend shouldnt be a problem, unless during the week would work better for you. im all ears and eyes for help with this issue.

 

ive been looking for how to install the cam, and i dont see anything out of the ordinary, ie the cam goes through the front of the block. correct me if im wrong, please. but ultimately i think the straight edge on the cam and crank sprockets will be the ultimate truth teller as to whether or not the cam has walked any. i read on another forum that someone had fabbed a button into the timing cover, but i think this is still covering up the real issue, and not solving what is really wrong.

 

Here is a long list of silly questions.

Is the correct cam bearing installed at the front of the engine and is the hole lined up facing the oil galley? It's the one with a groove all the way around.

Is there a hole in the cam going from the journal to the front of the cam? Is it clear?

Is there a slot leading to a chamfer on the back of cam timing gear? Does it line up with said hole?

Is the chamfer present on the back of the cam timing gear? It should lead oil both to the sprocket keyway and to a second slot on the opposite side of bore where the camshaft goes through.

Did you put the pump eccentric on backwards?

Are all of the holes in the gears clear?

Did you re-use the big, heavy duty flat washer that goes at the front of the cam? If so, good.

Are the two dowel pins present in the front of the block? They are critical.

Is the cam straight? Don't assume that it is just because it is new.

Do you have a factory cam to compare with the new one? Are the snouts the same length?

If you have the original cover, use it. The aftermarket ones are garbage.

If you can get a pair of original gears, use them. See above.

AMC V-8s don't need any kind of cam anti-walk device.

It probably wouldn't hurt to check the distributor shaft for straightness and side play.

I've seen high mile motors with a crapload of distributor end play, and the gears still looked as good as the day they left the factory. So I don't really think that's a factor.

When you prime the pump with a drill, look through the fuel pump window and see what kind of oil flow you have to the gears.

I've never used the Bulltear gearsets, but they might be the only option out there for a new matched set.

That's about everything I can think of. Hopefully you'll find something useful there.

There are two idiot free AMC sites out there where a guy can get good, non-retarded AMC engine advice.

http://amcdragracing.freeforums.org/index.php

http://realamcperformance.aimoo.com/

 

I have nothing but good things to say about Bull Tear. He stands behind his product. Curious on what cam and timing set you have in this motor. 69Rebel makes good points on his advise, similar to the posts you have seen on the amc pages. In my case, I tend to believe that the cam or timing set was the cluprit. The cam checked out fine with a dial indicator in the block. So? The timing set was a little loose. Was your block line bored when you re-built it? Stick with it, great running motor when you get this problem solved. I run harder than most and they all are putting motors in their cars and knock on wood, mine is still together. What valve cover tag do you need?