Sorry guys. Ive just been busy. Haven't been around much. If you need to get in touch with me Zabac should have my number as does spltime. Or PM me.

 

Well maybe if they are made from steel instead of "billet" and not coated.

But seriously does everyone want super fancy tripple platnim coated dry friction reducing coated titanium series gold plated anodized gears, pay $$$ and wait longer or does everyone want durable affordable gears? **** coatings someone just get a run of these made!

 

Agreed. Make them out of any steel. It's not like they aren't running in a nice soothing oil bath or anything. Whatever it is will be tougher, harder and less likely to fracture than the sintered ones. I couldn't believe how soft they were.

 

Where you been hiding? haha

I agree, anyone can get them coated at a later time if they really want it...I just need some damn gears now, the cheaper the better, I'm about to get some free time soon and will be tackling my motor build head on...I need gears!!!

 

I am in for some if the price is resonable. I am looking to to do a engine rebuild this fall and oil pump is one of the last thigns I am pricnig out right now.

 

anyone have an engine out of the car that will be willing to try the first set? I won't have mine out again for a while (i hope).

 

if they are made exactly like the origanls then WTF is a test needed for. Make a set, put them in a pump, if it spins freely and has proper clearances then its good to go...

 

I am in the process of building a semi-forged motor, I am shooting for high 200's, maybe break into low 300's if all goes well, I think that is a decent test for the gears.

I doubt we'll have issues, it's pretty much a carbon copy of the stocker, only made out of a less brittle material, what could go wrong (as teeth nervously chitter)?

 

The tolerances are the problem. Most mill work is +/-.0015 at best, that’s actually fairly wide. The lathe work you can hold to +/-.0001. We don't have any idea which measurements are critical and which are not. My guess is since they are sintered it’s all fairly loose at least mill quality loose, but generally things are machined after sintering, so who knows what features got what treatment.

 

The rotor tip clearance measurement is probably the most critical; too loose and oil pressure is too low, too tight and you'll have excess pressure and premature gear wear (possibly breakage as well). Are the stock gears cast or a powdered metal "forging" (powered metal is fused in molds under high temperature and pressure to very close tolerances)

 

Yea thats called sintering.

sin·tered, sin·ter·ing, sin·ters

v. tr.
To cause (metallic powder, for example) to form a coherent mass by heating without melting.

Sometimes if its a very good tool they might be able to skip some additional refinement, but thats the reason a lot of rods are bushed, or they have additional machining, because the criticals arn't met. That has to do with the inability to control pack which changes the thermal shrinkage of the part when they bring it back down to ambient

The part I was most worried about was the O.D. of the big gear, what class of fit is that?

 

Damn, I didn't realize the Miata oil pump gears were such crap (any shock can cause them to shatter like glass!). I'm looking at the FSM for a '91 and it is showing the outer rotor to pump body clearance as .22mm (.0087) max. Weird thing is, they show the clearance being measured with a feeler gauge stuck between the outside edge of the rotor and the inner ID of the pump body; you'd think the proper measurement would be to mic the OD of the rotor and compare that to a inside mic or dial bore gauge measurement of the pump body ID.

FWIW, here's the 1.6 oil pump clearances (don't know if the 1.8 is different, I only have FSM for 1.6)

Outer rotor to pump body clearance .22mm (.0087) max
Tooth tip clearance .20mm (.0079) max
Side clearance .14mm (.0055) max
Pressure spring 45.5mm (1.791") free length

 

Great, So if I'm understanding you right those are diametrical clearences then? Anyone have the FSM on the 1.8L? I don't even know if the pumps changed. Maybe a part number search?? Also, can anyone get those actaul measurements? The only spare block I have around has more then 200k miles on it...

Oh yea I appologize to you guys my machinist didn't have time to look at it before the weekend he's been swamped I think I can beat a price out of him on monday.

 

all longnose crank oil pumps are identical.

 

and here you go. 2001 service manual.

 

Nice to see the new FSMs have a range of tolerances vs. only a service limit. It is a little unsettling to see the relatively wide range for rotor tip clearance (this clearance influences oil pressure the most). Has anyone dis-assembled a new stock pump to determine the "new spec"??

 

Alright, it did take me a couple more days then I would of liked to get the qoute.


Minimum first order: 18
Price Per Part: 149
Material: 4340 Hardened to 32 Rockwell
Shipping Included To the U.S.A.


I'm making 0 Dollars on this deal, if someone qoutes you a lower price they are made in china. This is all American made hardware with domestic materials and thats the only way I roll.

 

Travis, great job, but I would not mind paying more to see something in the RC50 hardness...ask SN95 to share a link with you talking gears in much greater detail than I could ever pronounce in english...
I would assume that would increase the cost by $10-30 at the most...see what you can do about that, but at $149 I would even buy the 32's you have a quote for.
Thanks again...

($149 per set of gears I assume)

 

I agree with Travis' suggested range of 32 Rc. Good combination of hardness and toughness. Remember, the stock sintered gears don't even register on the Rc scale. Damn soft. This is where I would make them. You will give up too much toughness going that hard in a case where it isn't warranted. If they were "wearing out" instead of breaking, there may be an argument for it. In this case, it is not.

 

The RC50 is overkill. Think about it this way. the stockers are down in the B rockwell range, and these are at 32 C, and the only thing hardness effects is the wear life of the gear. The stock gears were still cranking in my 200k+ stock engine I pulled out last year, so the only thing we need out of the gears is a better crystal structure from the metal so it can take the hits from the crank of a modified motor. A 50 rockwell rating could do damage to the pump housing, because the housing wasn't designed to deal with that. Tribiology is a very delicate thing and we're probably already upsetting it running 32C. I'm curious if the guys who bought into the 500$ gears that are ultra mega-post processed are going to have housing problems. I used 32 C because while it is alot harder then the stock gears and will probably last 500k miles, it still wasn't quite into drill bit or end mill hardness territory. There is also the matter of durability vs hardness. If you make that initial modulus of elasticity too steep the area under that curve to absorb impact gets smaller and smaller before permanent deformation occurs. That basically means the pump is going to take less abuse before it wears out structurally.