when is a billet oil pump needed
#21
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I think the whole oil pump exploding thing is a bit overstated. Miatas / MX5s have been raced since they first come out and a very large percentage of them don't run billet oil pump gears. The billet gears have only been available for the last 8 years or so anyway so what did we do before they existed? On here it's quoted as if it's a given that if you are building a built engine then you _have_ to run a billet pump or you'll destroy an engine. I would guess that in Australia, less than 1 in 20 built engines have them and we don't see massive numbers of destroyed gears, in fact I can't think of one I've seen in Oz.
The question comes down to how much do you like insurance... are you willing to spend a some extra coin to reduce the chance of grenading your engine. If you like to be safe then go for it... but you may as well buy a better throttle body, race bearings, ATI / SM damper etc etc as well. There is a point you have to stop.
How many shattered oil pump gears have there been? Anyone keen to take a shot at the total number of failures?
What about throttle shaft failures?
Melted pistons from bad tunes?
Melted / bent valves?
Failed rods? Failed bearings?
I would guess that the bottom four items on that list would outweigh the top two by an order of magnitude or more... if not two.
If I was building a $10k engine from scratch it would be a no brainer... put one in, budget isn't a concern. If I'm on a budget there are certain parts I'm willing to go without for other more important things, like dyno time or driver safety. Of course I haven't destroyed a oil pump yet... so my opinion on risk might change abruptly at any moment, but I like living on the ragged edge!
The question comes down to how much do you like insurance... are you willing to spend a some extra coin to reduce the chance of grenading your engine. If you like to be safe then go for it... but you may as well buy a better throttle body, race bearings, ATI / SM damper etc etc as well. There is a point you have to stop.
How many shattered oil pump gears have there been? Anyone keen to take a shot at the total number of failures?
What about throttle shaft failures?
Melted pistons from bad tunes?
Melted / bent valves?
Failed rods? Failed bearings?
I would guess that the bottom four items on that list would outweigh the top two by an order of magnitude or more... if not two.
If I was building a $10k engine from scratch it would be a no brainer... put one in, budget isn't a concern. If I'm on a budget there are certain parts I'm willing to go without for other more important things, like dyno time or driver safety. Of course I haven't destroyed a oil pump yet... so my opinion on risk might change abruptly at any moment, but I like living on the ragged edge!
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.
#22
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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!
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!
Last edited by Madjak; 03-31-2017 at 02:20 AM. Reason: minor fixes
#24
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I think the whole oil pump exploding thing is a bit overstated. Miatas / MX5s have been raced since they first come out and a very large percentage of them don't run billet oil pump gears. The billet gears have only been available for the last 8 years or so anyway so what did we do before they existed? On here it's quoted as if it's a given that if you are building a built engine then you _have_ to run a billet pump or you'll destroy an engine. I would guess that in Australia, less than 1 in 20 built engines have them and we don't see massive numbers of destroyed gears, in fact I can't think of one I've seen in Oz.
The question comes down to how much do you like insurance... are you willing to spend a some extra coin to reduce the chance of grenading your engine. If you like to be safe then go for it... but you may as well buy a better throttle body, race bearings, ATI / SM damper etc etc as well. There is a point you have to stop.
How many shattered oil pump gears have there been? Anyone keen to take a shot at the total number of failures?
What about throttle shaft failures?
Melted pistons from bad tunes?
Melted / bent valves?
Failed rods? Failed bearings?
I would guess that the bottom four items on that list would outweigh the top two by an order of magnitude or more... if not two.
If I was building a $10k engine from scratch it would be a no brainer... put one in, budget isn't a concern. If I'm on a budget there are certain parts I'm willing to go without for other more important things, like dyno time or driver safety. Of course I haven't destroyed a oil pump yet... so my opinion on risk might change abruptly at any moment, but I like living on the ragged edge!
The question comes down to how much do you like insurance... are you willing to spend a some extra coin to reduce the chance of grenading your engine. If you like to be safe then go for it... but you may as well buy a better throttle body, race bearings, ATI / SM damper etc etc as well. There is a point you have to stop.
How many shattered oil pump gears have there been? Anyone keen to take a shot at the total number of failures?
What about throttle shaft failures?
Melted pistons from bad tunes?
Melted / bent valves?
Failed rods? Failed bearings?
I would guess that the bottom four items on that list would outweigh the top two by an order of magnitude or more... if not two.
If I was building a $10k engine from scratch it would be a no brainer... put one in, budget isn't a concern. If I'm on a budget there are certain parts I'm willing to go without for other more important things, like dyno time or driver safety. Of course I haven't destroyed a oil pump yet... so my opinion on risk might change abruptly at any moment, but I like living on the ragged edge!
#25
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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.
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.
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#31
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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?
Am I reading your claim correctly?
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You can buy all the aftermarket forged gears and pulleys and still kind of botch the engine assembly and end up with a failure. Or you can check twice and put everything together correctly (clean, torqued, correct tolerances) and minimize your chance for any failure, whether you decide to use the 'upgraded' stuff or not. The specific assembly of the engine and car is probably a much larger factor than parts choice by a large margin.
#36
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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
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
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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?"
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?"
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