Duh, yeah. I was faultily remembering that the same gear drives the distributor.
Of course the dist. has it's own gear...

_________________
--> Check out my FI Turbo build <--
--> And the race truck build project <--
--> The Diesel Corvette <--

There is still an interesting detail, with this new oil pump gear design, that I am trying to figure-out...
Hint, The SL6 cam gear has 13 teeth.
DD

Okeh, so if the cam worm has 13 teeth and the OE oil pump pinion has 13 teeth, that means each oil pump pinion will always only ever interface with one specific cam worm tooth. That won't be the case with the new pinion; each pinion tooth will interface with a given cam worm tooth only once every…I guess 14 revolutions. I don't know enough about gear engineering to know the implications.

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

Heck yes I will try it! I have a worn out 225 in my 76 D100 that only makes 20 PSI of oil pressure hot at 2500 RPM. I don't really care if it gets oil starved because I have a freshly rebuilt slant under the workbench in my garage. Since it is a truck it is a breeze to swap out the oil pump, too. I would then have an excuse to finally install an oil pressure gauge in the truck as well.

If you truly need a guinea pig, let me know. I will be happy to try it out.

DD,

more teeth and thinner but also shorter teeth, it looks like the material between the base of the teeth to the ID of the hole is thicker than a stock one, is that also true? if so, though thinner they should be plenty strong.

Brian

_________________
https://tinyurl.com/yynpj4v2

Gear OD, "root" diameter, tooth width, tooth contact angle and pitch all change in order to "cram" another tooth into the existing footprint.
As for the new "hunting" gear set, the 14T pinion finds (hunts down) the same starting cam tooth, after 14 camshaft revolutions and 28 crankshaft turns.
DD

Sorry if I am a bit slow on the uptake, but am I correct in hypothesizing that the purpose of this new gear design, specifically adding another tooth, is to reduce the RPM of the oil pump and thereby reduce the load on the oil pump gear and decrease the potential for gear failure?

The main goal is to reduce / prevent SL6 oil pump pinion gear failures.
I admit that low HP / "stock" engines do not seem to have many failures... but I do still hear about them.

This problem has been "with us" for a long time. It would be nice to find a good solution, outside of installing an after market, belt driven oil pump.
https://slantsix.org/articles/oil-pump- ... report.htm

Slowing the pump down and getting the oil pump drive gear set to "hunt" is the concept.
We just spent a bunch of time and money to see if making those changes will solve this problem.
Here's to hoping it does,
DD

Cool. Sounds like a very interesting project.

That's why he has authored a book and is called Dr.


Greg

_________________
http://www.youtube.com/hyperpack

Indeed.

While helping with the 3D model for this project and taking measurements of existing hardware, it's pretty clear that Chrysler kept some fairly large tolerances on this oil pump gear interface. Some gear efficiency is lost with such later tolerances but comes with notable manufacturing cost savings. I'm sure Chrysler agonized for choosing between cost savings and gear efficiency but their choice was beneficial to this project.

It's in these large tolerances and messing with the tooth geometry, we found a little more space for the extra tooth we slipped-in.
When hand building engines, in low volumes, the tighter tolerance of a 14 tooth gear doesn't pose much of a down side but comes with many possible upsides.

Allen D

_________________

That's a joke, right? Pretty good one! Chrysler never met a penny they didn't try to pinch in half.

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

Doug, if you need a test motor I'm your huckleberry. I spin mine 6300ish. I am running a completely stock pump. (One of the Autozone $12 sale pumps) I cut the filter open every change and haven't found any junk yet.

_________________
Official Cookie and Mater Tormentor.

Could be worse. We could be discussing Ford Falcons.

_________________
Joshua