Oil pump gears........

[J20]

Nothing wrong with a little rant. I just strikes me odd as I found this forum in search of high volume oil pump gears. I was actually looking for extended gears with an extra plate. The real funny thing is, my fears of poor oiling may be unfounded. I've been told the stock AMC oil pump gears will pump just as much oil as a big block Ch#vy pump given the same RPM. No one complains or worries much about the big block. And that the real problem is the AMC oil pump is so good, it empties the oil pan during sudden acceleration and the engine then starves for oil until the oil drains back to the pan. I don't know. Regardless (until someone convinces me otherwise, any takers?) I will sleep better with a set of high voume gears and high capicity oil pan installed during my 401 build. I just need more oil in the pan than the pump can pump out while oil is draining back to the pan.

[jeepsr4ever]

I am hoping for a summer sale on these but will be decreasing them to around 10% over stock..Like the crank pulley's they originally were sold as 10-20and 40% under drive but we found that the 10's are the way to go for the daily driver. A hint on the gears is that they are not helical and to incresase oil flow we drew them up missing one tooth...a six tooth oil pump gear

[J20]

Thanks for sticking with this. 10% over stock would be good. You must have a good reason for decreasing the output from 20% over stock to only 10% over stock. I'll trust your work. When these come out please let me know. I hope to have the 401 build to a point ready for oil pump/timing cover this summer. Target install date is Aug 04.

[jeepsr4ever]

Yes their is very very good reason to go with 10% and we may even decrease it to 8.765% over stock due to guys with tighter tolerances installing these and overdoing the pressure spring....

[J20]

Could tighter tolerances, a high-pressure spring and increased volume create enough pressure to pop things? How many gallons per minute is the stock AMC V8 oil pump capable of at say idle, 1500, 2000, 2500, 3000, 3500, 4000....? Has anyone ever done test to determine? Another thing, if the oil pickup tube is empty, pump housing drained and channels to bearings are empty, the engine must turn a few revolutions before the pump can deliver oil to cam/main/rod bearings. The question is how many. If the tube leading from pickup to pump is 18 (guess) inches long (includes travel through block) and .5 in inside diameter (3.534 cubic inches), and the pump cavity and housing holds a cubic inch or two, and the oil must fill the channels leading to the bearings, another 3 or 4 cubic inches, the oil pump must pump 7.5 to 9.5 cubic inches of oil before all the bearing get oil. How many revolutions does the rotating assembly rotate before all bearings get oil? How many revolutions before operating pressure is reached. Something to ponder.

[jeepsr4ever]

Those are just a couple of considerations and we have numbers for every 800 rpms. We found that the efficiency of the pump vs. volume vs. oil consitancy changes with heat and rpm...its a complicated mess. Its rocket science when we are talking about the dynamics of fluid control in the AMC V8

[Lifted79CJ7]

MC, too bad you are in Minnesotta, I would love to help ya out in the shop. Listening to you talk makes me wish I had finished my mechanical engineering degree instead of changing to Hotel/Restaurant Management after 3 years. Oh well, keep up the good work!
Jack

[J20]

How are you doing on the oil pump gears? Have you thought of creating and marketing a package deal - new cover with new high volume gears, fixed spring and high capacity oil pan? Seems you could at least eliminate some of the problems you mentioned. Just a thought.

[jeepsr4ever]

The more I explore the reasons somone would want to buy high flow oil gears the less I want to market them here are reasons why:

1. People who think this is a fix for a engine with bad bearing clearances.
2. The oil supply issue (gears should include oil pan)
3. The current nickle plating and midplates keep the stock oiling system up to par.
4. The AMC oiling system is adequite when you do a couple of oil mods.
5. Product liability. When you buy high flow oil pump gears and the oil runs out of the pan extremely fast you end up with dry pump and microwelded bearing surfaces.

I hear of aluminum oil pump gears that are supposed high flow and here are the problems I know of them.

1. We did the aluminum gears
a. they dont last with the amc's oiling system
b. they bind when hot and are innefficient when cold (thermal shrinkage)
c. they also warp when cooled and this causes major wear due to the changes in the wear patterns
d. they cannot be coated with a hard material because of a wear pattern that must happen (this is common with all gears (Randy's ring and pinion had super smooth gears that didnt call for a break in.....to my knowledge they bombed))
e. to obtain a tolerance where the aluminum will expand and not cause binding leads to a undersize gear that at full expansion will fit close to the cover and that is around 200 degrees...Look back to letter c. for the wearing issues.
f. aluminum comes in various stages of heat treating but cast aluminum in this case 356 cast (amc timing cover) is chosen because of very minimal expansion and its economical savings. to make a gear that will not cause binding would mean the gear must be cast (which all steel gears are) Billet aluminum expands at a much faster rate than cast aluminum.
g. The current timing covers have a tolerance that doesnt allow tight gear tolerances. We have measured .003 difference in 2 covers coming from the same batch (that is why we go through our covers before they are sold) these covers are all over the board in some cases. it takes a keen eye and alot of expensive measuring tools to ensure a good cover.
h. with a aluminum gear a steel shaft is still needed or by the rules of physics the shaft will spin in the drive gear. with aluminum shaft it will bind in the cast hole through the timing cover.
i.the aluminum shaft-gear will cause elongation of the entire assembly and cause binding.
j. aluminum expands at .000013 per degree-per inch so you start out at 30 degrees and let the engine heat up to 190 (winter time) with aluminum shaft will expand over .01248 in length...this is perposterous and would bind a oil pump


2. for alot of the same reasons steel billet gears cannot be implemented.

?'s

[Pheonix]

that was a set of 318 oil pump gears with a stainless steel adaptor, ive seen this but reguard it as homo because of the extra plate......LOL

Why is it bad because of the extra plate? Don't YOU sell a midplate? Isn't it kinda the same thing? I suppose the midplate expands different than the cover and then looses tolerences huh? Couldn't you make a new kinda oil filter adapter that is thicker and is recessed for 318 gears?
I personaly think the AMC Oiling is fine. Have you ever taken apart a Ford or Chevy pump? Those gears are small!!
My 304 had 85,000 miles and when i first rebuilt it the crank and rod bearings didn't even need reground, only polished. To me that is a sign of a good oiling system, and that is without the intake valley line kit.
Honestly, what have you got to loose with the Oil Gears MC?