Bulltear cam gear help

melton83

A tape measure........

fifesjeep

:shock: Yeah man, I guess that'll get you close but if you're off even 1/64" (.015") that would matter and make a world of difference... If the gears don't mesh at the correct pitch circle then the gears will chew one another etc... Chances are that's the problem...
check this out.... this shows where the gears should mesh (This is for spur gears) but it's almost the same as helical.
http://shopswarf.orcon.net.nz/gear2.gif
Here is a better site, scroll down and look at the disadvantages of Helical gears...
http://www.agroengineers.com/gears/Helical-Gears.shtml

melton83

Thanks for the info fifesjeep. I know there are much more accurate ways to measure things when it comes to mechanics, but the tape measure was all I had at the house. I'm fairly new to this kind of work. Does anyone know the dimensions of an AMC 304 distributor, as far as how long the shaft is supposed to be, so to speak. I no longer have my old distributor. Just wanted to say thanks again to everyone here with all this great knowledge on AMCs, helping us amateurs keep'em alive.

ironman_gq

use gear marking compound

jeepsr4ever

melton83 wrote
OK, i just got a call from the machine shop, and they asked if I had my original distributor from before the rebuild. the one in it now is a ProForm HEI. They want to try switching them and seeing how if that fixes the problem. Before installing I measured the distributor shaft lengths and they were both the same, also I had the matched bulltear gears installed. So do you guys think just switching the distributors would really fix the problem. Oh, they also deteremined that there was no oiling issue, the gears were getting plenty.

If you ruined a set of our Chromoly gears their is no other gear out there that will work. We need to find the root of the problem. I am guessing its either a oiling issue or an alingment issue.

ironman_gq

post a picture of the gears if you can. sometimes you can tell what caused them to fail by the wear pattern

fifesjeep

jeepsr4ever wrote
melton83 wrote
OK, i just got a call from the machine shop, and they asked if I had my original distributor from before the rebuild. the one in it now is a ProForm HEI. They want to try switching them and seeing how if that fixes the problem. Before installing I measured the distributor shaft lengths and they were both the same, also I had the matched bulltear gears installed. So do you guys think just switching the distributors would really fix the problem. Oh, they also deteremined that there was no oiling issue, the gears were getting plenty.

If you ruined a set of our Chromoly gears their is no other gear out there that will work. We need to find the root of the problem. I am guessing its either a oiling issue or an alingment issue.

Gear mesh... I'm 99% sure that this is the problem... If you don't have the gears meshing properly then they are eventually going to build heat which will cause expansion (Even if it's minimal) which in-turn will cause more friction... The garage said that you are getting oil to the gears and that's not the issue... You can have plenty of oil getting to those gears... but if they're not meshing correctly one or the other gear will get chewed (I'm beating a dead horse I know). But without the oil that gear would've been toast a long time ago... You need to have that garage find the correct depth in-order to have the proper gear mesh. This will be a trial and error process with that distributor... It's also a good idea to check the gears tooth thickness/circular pitch/addendum/dedendum,whole depth and the list goes on and on etc. It's a good practice to know how to use a gear tooth vernier... In-order to check some of the above. A good engine shop/garage should be able to figure this stuff. I've made plenty of Spur Gears, Helical gears, worm and worm wheels etc... Try making a set of worm gears and a worm wheel and not having the proper height or tooth dimensions #-o and then do a test run with minimal lube... :idea: the gears will basically fuse together (Sort of)

rustyfloors

I'm with MC & fifesjeep! If you chewed up a set of chromoly gears it has to be a mesh issue or your oil pump gears are tight! What was you oil pressure when it ran good? I know this is a different animal but, I had the same problem with a strait 6 ford! It would chew up dizzy gear or shear the roll pin every 50 miles or so! The root of the problem was the oil pump! Just my .2

Paul Nance

I also lost a set of gears with pro comp dist . diz shaft was under size made and replaced bushings &shimeout all but.020 thosands end play replaced gear with one from ebay for after market dizs .had it replace oil & gear drive roll pin with a smaler pin . one that would fit in oil pump drive slot . so far about 3,000 miles every thing still works .migh go ---- tomorrow hope not. good luck building a 360 it will have a new diz with mached gears .i now have 304 ,.060 over &other mis. parts .

melton83

I Well I was forced to have the machine shop fix the problem because I'm just not to that level yet to be able to troubleshoot this kind of thing. ( Plus my wife was getting fed up with only having one car). They did a dye test and found that the cam gear was riding to high and had to be lowered down. Well there are two different holes on the end of my HEI dizzy shaft for mounting the dizzy gear, so they droped it down to the lowest hole, and found it was meshing up where it should be so that fixed that. They put on a MSD gear set. They also were aware of the known AMC oiling problems and drilled a hole that would allow more oil to squirt onto the gears. So far so good. I reaaalllly hope this doesn't happen again!!

fifesjeep

melton83 wrote
I Well I was forced to have the machine shop fix the problem because I'm just not to that level yet to be able to troubleshoot this kind of thing. ( Plus my wife was getting fed up with only having one car). They did a dye test and found that the cam gear was riding to high and had to be lowered down. Well there are two different holes on the end of my HEI dizzy shaft for mounting the dizzy gear, so they droped it down to the lowest hole, and found it was meshing up where it should be so that fixed that. They put on a MSD gear set. They also were aware of the known AMC oiling problems and drilled a hole that would allow more oil to squirt onto the gears. So far so good. I reaaalllly hope this doesn't happen again!!

I figured as much... As for drilling a hole for extra oiling... I'm not 100% sure if you actually needed that... They did say that you were getting good oil supply already... and that wasn't the issue... :-| Did they disassemble the block before they drilled it? If not you're going to have fine metal shavings getting into everything... Bearing and journal surfaces,oil pump/filter, lifters, pushrods etc... Chances are it'll settle to the bottom but... Even that, I'd have them yank it, clean it and rebuild it for free...

Mudrat

WARNING ENGINEERING CONTENT!! :mrgreen: =D>

fifesjeep wrote
:shock: ... if you're off even 1/64" (.015") that would matter and make a world of difference... If the gears don't mesh at the correct pitch circle then the gears will chew one another etc... Chances are that's the problem...
check this out.... this shows where the gears should mesh (This is for spur gears) but it's almost the same as helical.
http://shopswarf.orcon.net.nz/gear2.gif
Here is a better site, scroll down and look at the disadvantages of Helical gears...
http://www.agroengineers.com/gears/Helical-Gears.shtml

You can use the same principle in electric motors too! By making the rotor and stator function like a helical gear, you increase power, the efficiency, and decrease what's called motor slot frequency (noise). Cool stuff though :t:

fifesjeep

Mudrat wrote
WARNING ENGINEERING CONTENT!! :mrgreen: =D>

fifesjeep wrote
:shock: ... if you're off even 1/64" (.015") that would matter and make a world of difference... If the gears don't mesh at the correct pitch circle then the gears will chew one another etc... Chances are that's the problem...
check this out.... this shows where the gears should mesh (This is for spur gears) but it's almost the same as helical.
http://shopswarf.orcon.net.nz/gear2.gif
Here is a better site, scroll down and look at the disadvantages of Helical gears...
http://www.agroengineers.com/gears/Helical-Gears.shtml

You can use the same principle in electric motors too! By making the rotor and stator function like a helical gear, you increase power, the efficiency, and decrease what's called motor slot frequency (noise). Cool stuff though :t:

By nature the Helical gear is a quieter design due to the gears running mesh... Although the gear efficiency (transfer of energy) isn't as good as the noisey spur gear but then again Helical Gears are stronger than a typical spur gear of the same tooth size... There's pro's and con's to each... Never really gave electric motors any sort of thought... :-| Makes sense though. I actually miss making gears... Well, sort of... The set-up for the most part sucks... It's been a short minute since I made any sort of gear.. about 8 months I think #-o Last gears I made were helical gears... I dislike setting up the gear-train too... You think somebody would make a quick select for a wide range... Bolt it up to the Horizontal Mill, select the needed gear train and go... Oh-well.. I can always wish. :roll:
I'm waiting until the CNC software becomes so easy to operate that a monkey can do it and then they'll start laying these over payed button pushers off 8) Then the pay focus will be back on to the manual machines where the real machinists are :mrgreen: Manual machining is a skilled Art, working a computer that has self check sequences is...????? A skilled button pusher??? :idea:

maccj5

ive had the same thing happen 304 in 73 cj5 new omix t cover omix cam gear msd dizz new rebuild 1,500 miles= cam gear junk----- put on new gear went with stock dizz 2,200 miles =cam gear junk, pulled motor havent checked it out yet found great running 401 to put in am building 2 other 401's have several 360's to build going to go with the bull tear gears for future builds and a lot checking on specs its a real pita to keep pulling engines because of these pesky little gears p.s both dizzy gears were ok :(:

fifesjeep

Honestly, the stock gears are fine just as long as everything else is correct... Gear mesh, minimal vertical play in the distributor shaft, tight tolerances with distributor and timing cover... alot of things come into play...

AMX69PHATTY

It's pretty cool that AMC motors stock from the factory were fine and never known to eat dizzy gears more or less. Stock AMC motors have ran over 100k miles all the time wth stock dizzy gears with no problems. The factory seemed to know what they were doing when it came to dizzy drives.

fifesjeep

AMX69PHATTY wrote
It's pretty cool that AMC motors stock from the factory were fine and never known to eat dizzy gears more or less. Stock AMC motors have ran over 100k miles all the time wth stock dizzy gears with no problems. The factory seemed to know what they were doing when it came to dizzy drives.

Yup that's what I was basically saying... By putting in the hardened gears all that's going to do is move the problem area... Most likely side load the distributor shaft and wear the Bronze Alloy bushing (Sintered Bronze) at the base of the distributor... Then your dist. gear and shaft will be "doing a little dance, make a little noise... get down tonight"... Ooops, the 70's just came back... :?

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