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Old 03-01-2010, 09:55 AM   #41
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Wildo, can you tell us what steps were taken in the assembly of your engine to assure that no foreign matter got left in any of the gallies? I am curious because I have an engine being built right now, and want to make sure nothing was skipped.
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Old 03-01-2010, 11:10 AM   #42
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Originally Posted by ctdrftna View Post
alot of oil filters dont. you have to do some research. look through catalogs. as long as it has a 20mm thread and the right size o-ring it will work on a miata block. i use a chevy type filter on my car, with a filter relocation kit. the bigger the filter the better.
just be aware that filters without a bypass can cause serious cold start issues.

oil gets thick when it's cold. it tends to not move. oil that doesn't move through a filter can't lubricate stuff.
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Old 03-01-2010, 05:02 PM   #43
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thats why i have an accusump
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Old 03-01-2010, 05:07 PM   #44
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thats why i have an accusump
how does it change the viscosity of cold oil?
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Old 03-01-2010, 05:17 PM   #45
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Originally Posted by y8s View Post
how does it change the viscosity of cold oil?
It doesn't, but it does pressurize the block for ~60 seconds with oil that (IIRC) bypasses the filter. An Accusump is on my shortlist.
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Old 03-01-2010, 08:48 PM   #46
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Originally Posted by JasonC SBB View Post
I measured the stock gear thicknesses of the gears from my stock 2000 oil pump, which showed 0.0025" clearance to the backplate in the case, with a Mitutoyo digital micrometer, at 3 points each :

inner gear: .37180, .37195, .37200

outer gear: .37220, .37240, .37245


Re: the loose clearance of the first set of gears I got, it was tip-to-tip clearance. I got the same measurement whether the gears were in my case or out. So it has nothing to do with the case.

Likewise my stock gears show .0035" tip to tip clearance regardless of whether it's measured in the case or not.
I received the new ones, thanks. They measured at

inner .3697
outer .3701

What's the fancy gray coating that resembles the Supertech pistons anti-scuff coating?
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Old 03-01-2010, 10:01 PM   #47
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I received the new ones, thanks. They measured at

inner .3697
outer .3701

What's the fancy gray coating that resembles the Supertech pistons anti-scuff coating?
That is an extra step we do with the gears for the pump assemblies to make sure the parts do not have burrs. We media blast the gears just before they are ultra sonically cleaned. We are now doing that for all the gears. It does make them look nice too!

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Old 03-02-2010, 03:35 PM   #48
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I put myself on hiatus after the last post and haven't checked in. I apologize for going a bit too far with some of those comments. Travis and I have shared some emails in the past week.

To continue sharing information:

Webby459 asked about the steps taken to insure debris was not left in the engine during the build. All I can say is that none of the parts were blasted in any way. All cleaning was done by either heat or clean solvents. For example, the block was baked. No media blasting whatsoever.

I should also say that there was no damage to the bearings. Upon looking at the oil pump, everyone expected the worst. I was pleasantly surprised that bearings did not show any damage similar to the oil pump, nor did they have metal bits impregnated into them. There was some light wear on the crank bearings, but all 3 shops independent of one another suggested that this type of "light" wear is common on high-RPM applications. My engine had been rung-out to 8500RPM after break-in. All also stated that if whatever took out the oil pump had come into the engine, the engine would have grenaded, which it certainly did not. Consensus is that I dodged a bullet.

Regarding the oil filter & bypass, I don't really know how the bypass works. Does anyone here? My understanding is that the bypass triggers under a pressure differential between the filter input and output. If the pressure is high on the supply side and low on the output side, the bypass opens. If, however, the filter is flowing correctly and the pressure is high on both the input and output side, that the bypass stays closed. Since the bypass is designed to prevent blockage in the filter from killing oil pressure, the above makes sense.

Also, we know that the filter was seeing a lot of pressure, as the filters were being deformed. This leads me to believe that the filter was actually in play, but again, I'm not sure how the bypass works. Considering the absolute beating the oil pump took and the total lack of wear on the soft aluminum bearings, I think it is safe to say that the damage was confined to the pump. I'm reluctant to accept that (if something is too good to be true...), but the analysis so far has all been great news.

Also, just to be clear, the photos in post #11 are not my pump. While on the subject, close-up pictures in my (post #2, pictures #1 & #3) appear to be the OTHER side of the gears, and not the same side as the pictures #2 & #4).

That said, I'm still unclear why the sides of the gears, as shown in the close-ups, took more of a beating than the aluminum pump housing. Travis and Stuart have explained it a bit, but I haven't followed the logic. Perhaps I need to re-read this thread.
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