patsmx5

iTrader: (16)

There are 100x the number of post about oil pump gears breaking than evidence of failed oil pump gears with a failure diagnosis. I'm sure a few folks have legitimately had an oil pump gear failure out of nowhere (18psi has seen one as mentioned in this thread on a stock motor), even though they had a good damper and oil in the motor, etc. But as you suggest, it's a very rare failure. Most oil pump failures I see are stuck relief valves, and these are seen on stock and on modified oil pumps alike. Why does this fail? Probably debris hanging the valve, or just wore out from use since the bore is aluminum. Sticking a relief valve after tapping the oil pan while it's still on the car is something that I've seen in miata world, and other cars as well. If anything I think a better relief valve would be a better upgrade, since those seem to "fail" more than the gears. From what I saw years ago, most oil pump gear failures back in the day were tied to high RPM use + no harmonic damper at all (literally removing it for a lightweight pulley to save weight). I could absolutely see a 20 year old worn out/damaged/broken stock harmonic damper causing the same type of failure as well. And stock 20 year old dampers to do fail, even at stock power levels they have been documented to wear out and slip.

If I build another 10k engine I will change the oil pump, but with a chain driven oil pump so that crank flex has no affect at all on the oil pump. For 400 dollars I can do the fab work to put a better oil pump in the car than a stock pump with stronger gears.

I have had 3 of the 4 "bottom of your list" failures. Bent valves, throttle shaft failure, and bent rods. Valves were bent by me on assembly and not discovered for almost 2 years, throttle shaft broke at the track, rods bent from too much nitrous/boost. Never melted a piston, but have broke stock piston in half twice around 350whp each time.

Madjak

I still think the oil pump gear failure is more about the oil pressure relief valve than anything else. The valve either gets stuck, or overwhelmed at high revs and the pump builds up pressure and blows to bits or alternatively the valve chatters and generates pressure waves that blows the gears to bits. Using a good quality external pressure relief valve prevents pretty much all of those scenarios.

I'm not sure sure about the crank flex failure mode but I suppose if the crank is wobbling all over the place then it could kill the oil pump from deflection... but the pump is right next to a main bearing so the crank would have to be way way out of shape to cause an issue here and if that was the case the bearings would not be happy either. I also think it would wear away the aluminium housing around the pump gear over time than just cause and outright failure. Plus it would happen when you first reved the car.

I'm fairly sure it's a bad idea to run a BP engine without a damper. Our engines just aren't as smooth as other JDM engines. I'm not sure on how much of a requirement an ATI or SM damper helps over stock though... it comes down to risk mitigation vs willingness to spend money. I run half a stock damper to 9000rpm and haven't had issues with my stock oil pump. Out of anyone here I should be highest on list for failure if it's revs and damper related. Maybe I'll jinx myself by posting this!

codrus

AIUI, barring the cases of no or failed harmonic damper the shattered gears are mostly about RPM.

--Ian

shuiend

iTrader: (24)

So I was around when the gears first came out. This was 2008/2009/2010 time frame. They were originally made because the only option at the time to help prevent shattering gears was the ATI damper. It was a $600 part and lots of people did not want to pay that. So TravisR@BE came up with the billet oil pump gears for I think like $100-$150 in the original group buy. This was a cheaper product to solve the problem of exploding gears. He then went on to sell full pumps, and then 949 released their damper. So now there are several products on the market, at various price points, to reduce a specific failure. Any of them are good to run and it is up to you which you choose. I originally chose the gears, because they were the cheapest at the time. I now run the gears and a 949 damper. So no they are not "required", but if I was building a motor with forged rods and pistons, I would for sure make sure to have one of the solutions to minimize the chance of oil pump gears exploding.

gtred

Great discussion and good points!

In prior racing seasons I had run a porsche flat6 and then moved onto chevy-8's. Quite a disparity in the attitudes towards engine prep: The porsche crowd wanted to sell you all sorts of expensive engine jewelry, with the attitude of "only the best...only the most expensive" ...when in reality, all that you actually needed for a solid motor were ARP rod bolts, a better pan baffel and an upgraded intermediate shaft bearing.

While with the chevy ... I think on advice from "bubba"... I used the stock $35.00 oil pump with a roadracing pan and called it good! Even when I needed head work, the midwestern boys at brodix always gave me good chat and a low-down-brother-in-law good-deal on the parts.

The miata is nice, since it's so well sorted out. I'm a little leary since there is so much smack talk about some of the vendors... it kind of makes you want to investigate things for yourself. So, now that I'm well informed, I will get on with my longblock refresh! ...I hope you all don't mind, as I'll likely ask a few more questions before I'm done.

RedFox

Poor folk like me... they don't even make a pump for ... short nose 1.6. I don't have a choice . Still ok. For now.

ridethecliche

iTrader: (2)

Swap in a 1.8. Problem solved.

RedFox

No

dc2696

iTrader: (2)

If you have any money into a motor you never wanna feel this kinda pain

Art

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ridethecliche

iTrader: (2)

So you're basically implying that anyone that has ever busted a motor even with the 'upgraded' stuff has somehow messed up in the installation or motor build?

Am I reading your claim correctly?

Art

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Savington

iTrader: (31)

This is factually incorrect.

Art

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Art

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18psi

iTrader: (76)

So you come into a thread talking about a specific failure with a totally vague and redundant observation of "sometimes it's something else".

Does every thread really need to have a disclaimer?
1) if you are not a moron
2) if you know how to assemble an engine
3) if you don't pour sand into your oil fill
assuming all of the above is true............THEN let's talk about things breaking from power/heat/abuse

I mean ok, but that's...just....like....my....opinion man

Art

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turbofan

iTrader: (1)

THE POINT IS, your comments are irrelevant for the following reasons:

1. your basic premise is REALLY OBVIOUS
2. the rest of your premise is correct only in a Miata.net use case.

Sure, assembly is more important than parts choice at stock power levels on a granny driven car (see m.net comment). But for a turbo track car running lots of power, it simply isn't. BOTH are important, and no amount of careful measuring is going to make stock rods hold up to 350 whp on track.

Questions about parts failure assume proper assembly. if they didn't, that'd be a really stupid question.

"guys, If I throw together an engine without measuring anything or cleaning the block, and maybe there's some metal shavings inside, how much power will my stock rods hold?"

Art

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Savington

iTrader: (31)

actual IRL lol