Stroker oil pump failure

[curamrdan]

Hi, unforutnately my recently build stroker engine have problem with oil pump.

The inner gear grinded into metal backplate.

From beginning, its forged 2.5L build in AAT block with AAT oil pump. Pump was is slightly better conditon then from car´s standart ABY. Oil squirts aby, checked all 1bar opening.
Running in oil was "premium" mineral 15W40+bosch filter, after 300km lazy driving(just few times on spring pressure to 5-6000rpm), changed to Motul x8100 10w60+mahle oc47 filter and go for more load and ecu tune.
On both oil i see quite low oil pressure on hot idle, just above 1bar.
Cca 600km overall, just after dyno session(maxed RS2 setup, stock 7200 rev limit - toutched few times) engine have ZERO oil pressure after start, when i want leave to home.

Conrod bearing survived. Pump gear has just gridned to not allowable/workable clearance(cca 0.6-0.8mm) - not able to suck oil from pan.

The backplate was surfaced before final pump instalation, surface is slightly roughter then OEM, which has also some finishning. On another non audi engines, this kind surfaced oil pump backplate work ok.

Do anybody have any inputs what was wrong or what check before instalation of my second pump(ABY)? I probably not touch the backplate now and also engine is runned up, so only quality synthetic oil will be used.

thanks

[diesel des]

Sorry to hear this. I use 3b style oil pumps on my strokers but always wondered if a tdi one would work. Maybe the tdi ones don't like high rpm?

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[quattro-nick]

i think that the damage on the backplate is not your cause for bad oil pressure,it's looking not that bad

[quattro-nick]

how much oilpressure do you have on higher rpms?

[RichLV]

I have the same kind of marks on my oil pump. No issues with pressure. Around 1.1-1.3 bar on hot idle which is normal, I've checked multiple correctly working Audi's with oil gauge, all have around 1 bar on hot idle. The pressure you're interested in is at 2000 rpm, it's the only thing Audi states in the manuals - Oil pressure at 2000rpm when at least 80C hot. I have ~ 3.2-3.5 bar at that point. But keep in mind that I use an AAN pump on stock 2.2 block.

[Cordoba16vt]

I am pretty sure diesel oil pump is not designed to take 7200 rpm .

Can you compare gearing between AAT and AAN pump? and giev us feedback?

The result from overspinning it would cause cavitation in the oil that leads to faliure .

https://en.wikipedia.org/wiki/Cavitation

there is even a video of a gear fluid pump

[curamrdan]

Hi, its not clearly visible from photos and also from first look (i expected blown rotor ect). But there is missing cca 0,4-0,5 m from wheel itself and similar amount of material is gridned off in worse markings on plate, which is also lightly bent now. My and my engine mechanic tried to suck oil before pump removal(similar way how oil up new engine) but pump doesnt suck any oil.
As i understand, there is a warning in dashboard clusters, which control minimum oil pressure at 2000/3000rpm... i never remmeber oil warning light or chime when driving or idling a car before. Only the last start when there was clearly no pressure on gauge at all even slight throttle blip 1500-2000rpm.

[curamrdan]

AAT pump and ABY/AAN? pump looks inside the same. Same colour of material, no different details inside. Measured some clearance(im not quite sure what, im not engine builder) and builder decided to use AAT, but its was just barelly better. Idea was it whole life drive just under 4000rpm, and if items are the same, will be more "fresh" - i know it can sound bit simple, but...

[Bowie69]

If it is unable to suck oil up, perhaps your strainer/pickup tube has a pin hole in it?

In other words, it may not be the pump not pumping oil... more oil not able to get there to be pumped which has caused the problem.

[bn-01-wso]

Maybe not your case but i remember seeing somewhere that the oil pump drive key got loose on the crank and therefore the oil pump stop spinning. Just a thought

[Error404]

how much end float do you have on the crank?

[curamrdan]

Pickup was cleaned before, and also now is fully clean, go through, no dirt/silicone ect on pinhole mesh, of course.
But now i remmebrer, mechanic used it also from AAT, its metal part is physicaly the same, same height as ABY/AAN. But there was some minor difference on rubber boot end. I will recheck it again later today.

[curamrdan]

Pump drive key, yes a found info on this forum also, "unfortunately" its ok.

Crank end play, dont know exact number and did not measured now. But there is no so big play to slip crank from drive key or to make axial press on pump rotor. Its not even possible, according construction, my opinon. No axial markings of touch of crank/rotor either.

[curamrdan]

I also looking inside the oil filter.

https://catalog.mahle-aftermarket.com/na/modules/mahleFilter/detail.xhtml;jsessionid=321848743ABC399C1C7CE6839DD589D6?filterId=22&d=

Is it corect filter type, with this wierd valve on outlet? It must definately make some restriction...(but not related to pump damage)

[quattro-nick]

that's a bypass valve which opens when the filter is clogged