Turbo Gurus, Excessive Oil Pressure??

[strkdblwncapri]

put this 50trim on my bone stock motor 1g with the oil feed off the head(-3) and a -10 return, and needless to say in under 500 miles the turbo took a dump, started smoking and had terrible shaft play! just wondering if its possible there was to much pressure? i just baught a new vtrim bullseye power turbo and i dont want this to happen again.

i didnt see ant blue on the turbine wheel just on the compressor side seal and the thrust bearing where the oil comes in is discolored and the holes on the thrust bearing where the locator pins go are egged out now?
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since i cant post pics here is a link with a few 106_0464.jpg picture by turbocapri - Photobucket

 

[JusMX141]

Too little pressure at the head is most likely what killed your turbo- that and the fact that it's an eBay turbo. There's definite heat scoring on the shaft and the thrust plate.

If you're still on the stock block with balance shafts in place there are more pressure outlets for the oil on the way to the head, and Garrett turbos require more oil pressure to operate properly than a MHI turbo does. The head feed works well for some Garrett customers, and for others it's catastrophic. What you're feeling here is the wrath of installing an aftermarket turbo without verifying the pressure at the source with the pressure requirement for the turbo. If your distributor cannot tell you in writing what the required pressure is for the turbo you're buying to operate, you shouldn't be buying a turbo from that vendor.

The -3AN oil supply is fine; try moving your oil source to the filter housing. If you're using a -4AN line, you will probably need a restrictor as the -4AN line provides too much volume for the -10AN drain to handle.

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[strkdblwncapri]

thanks for posting pics. i was checking it out and where the thrust bearing rides in the collar for the front seel there is no play so my guess is the play was between the front seel and the backing plate. i was thinking, to much oil pressure was causing the thrust bearing to push the front seal into the back of the back plate, cause the back of the back plate has scoring on it and the thrust bearing dowel pin holes were egg shaped like the thrust was being pushed on real hard wher the oil would enter the centersection? idk

 

[JusMX141]

If the backplate has wear, either the thrust plate and collar are worn or the spring-lock that holds the thrust plate down (yours doesn't have a bolt-down thrust plate) lost it's tension and was allowing the whole thrust plate and all to move toward the compressor wheel.

If the turbo didn't sustain any wheel damage, it can be repaired fairly reasonably.

 

[strkdblwncapri]

yes thats what apeared to be what happened. is that just turbo failure or too much oil pressure pushing everything towards the compressor housing?? its like it ate into the backplate, and the thrust bearing actually pivots on the locating pins due to the holes being egged out.

i want to figure this out before i put my new turbo on. thanks for the help.

 

[viperlp01]

I dont think it is possible to overfeed a turbo from the head.. The oil pressure i way to low unless you have some blockage issues.. You should tap the oil feed line and see what your oil pressure is. I bet at idle it is lower than the recommended oil pressure minimum.

edit: You can have to much oil pressure if your return line is not the correct size or it is kinked or blocked in anyway. The oil can't get out of the turbo fast enough when the oil pump is pushing alot of oil(High rpms). The pressure builds up inside the turbo.. Big problem with the holset turbos

 

[strkdblwncapri]

yea i guess thats what i will be doin tomorrow i guess is hooking up a gauge to see what it is out of the head. sorry for the questions but what is the norm for a completely stock 6 bolt at the head?

 

[JusMX141]

is that just turbo failure or too much oil pressure pushing everything towards the compressor housing??

No; it's a lack of lubrication as a buffer between the thrust plate and the thrust collar.

Boost pulls outward and upward on the shaft from the compressor side....the more boost, the greater the thrust loads. If you don't have enough oil to buffer the thrust plate, the collar will wear into the plate or pull against it and try to rotate it if the locating pins don't hold the plate in place.

 

[JusMX141]

what is the norm for a completely stock 6 bolt at the head?

Around 20psi cold idle, 45-50psi cold around 6k; around 10psi hot idle, 35-40psi hot around 6k.

The filter housing source can't be more than 70psi hot at 6k or you're going to destroy turbos from too much oil. In steps Mr. Restrictor:

 

[strkdblwncapri]

ok so 35-40 is to low and more than 70 is to high. i believe i read somewhere that the bullseye vtrim likes between 50-60 psi. looks like i have some work to to tomorrow. thanks