2G HELP...blew the engine after Holset install need advice/opinions

[kmetiuk]

Had a late night dealing with the engine so I need a sanity check please.

I'm prolly over thinking this but I really don't want to hurt my 6-bolt. Thanks in advance.

Installed the Holset HE351VE a few days ago and setup speed density with vanes 0% closed. No real issues everything went very well. Boost never got over 22psi and was very flat and good power. Oil pressure seemed a bit low (sensor sender tee'd into the oil feed line just before the Holset. At startup it was 40 psi ish and at idle was down to 7-10 psi. Reving it up i would see 20-40 psi from about 3000 RPM to 5000 RPM. When driving it's hard to look at it but it seemed to be kinda low in the top end...never really gets over 40 psi.

Then last night I was testing my controller at various vane positions to find the initial "curve" to put in my controller's tables. Tested vane positions from 40% shut to 100% at increments of 5% (all logged in DSMLink) and did not have any real issues until I was testing 40% closed at the end of the night. I originally started at 50% and went up to 100% so then figured I should log from 40% down to complete my data set. The last pull before the motor blew was rev'd to 6500 RPM then let off to cruise to the parking lot to analyze logs. As I pull up I hear the dread rod knock when you've blown a bearing (or its in the process of degrading). Drove it as far as I could as I was close to my house (and I have a 6-bolt nearly ready to go in anyways) and she seized hard when idling at the light just before my house. Can't even turn the crank (either way) with a socket on the end so she's fcuked.

When testing the controller I was watching EGT's and they never got over 1500 F which was at 85% shut (anymore closed and it was choking the shiit out of it and wouldn't build enough boost). So I am confident that it's not an EGT temp problem melting shiit.

Just before I did the last run I noticed that in as I was leaving the lot, the engine sounded off....like rod knock-ie but not full blown. Gave her some rev's at the next light and it was sounding funny in the 1500-2500 RPM range then after that it seemed okay. Checked the oil gauge and saw that I was getting 1-2 PSI at idle and would not go over 15 PSI at any RPM. I Figured it was gonna die so headed back home and was literally a block away from my house when she finally gave up the ghost.


TL;DR: Oil pressure seemed low earlier in week just after initial install. Then were very very low just before I heard rod knock. EGT's were in check the whole time I tested various vane positions.

My Holset is fed from the oil filter housing using the stock 2G hard line that was there and then a -4N adapter/Tee/Oil Pressure Sender to a -4AN braided line to the -4AN banjo that is spun directly into the CHRA oil feed.

Holset stock oil feed adapter bolt (OEM) in the top of the CHRA: ID=4.1 mm
2G OEM turbo feed hard line from the OFH: ID=4.6 mm
-4AN stainless line: ID= 6.3mm
Banjo ID>>4mm

For comparison the 14B CHRA oil restrictor hole in the feed "port": ID= ~ 1.9mm (hard to measure but it's pretty damn close)


My main question is could the low oil pressure from:
- the way my Holset was fed oil was not creating restriction thus not pressuring up the rest of the system?
- the age of the motor and stock parts and the clearance/tolerance's being super sloppy?
- the sender reporting low pressures b/c the ID's of all the lines basically meant there was no restriction in the feed to the turbo?


The main concern is if I put the 6-bolt in and it still is showing the same pressures I'm going to hurt it prematurely.

Setup Details:
- Stock 7-Bolt head and block with 103,000 miles
- Compression test shows 162,132,152,157
- No issues at all when playing with the 14B upto 22 psi
- all mod's to support the Holset to 800hp
- Balance shafts and oil squirter's still in
- Holset boost set to 22 psi (verified in all log)

 

[SasaniFab]

Looking at everything it seems as though the pump was on its way out before you installed the new turbo. I dont believe the oil distribution change caused the problem, you probably finished her off with the power increase. You went from a hair dryer to a leaf blower.

 

[GST with PSI]

I dont believe the oil distribution change caused the problem

Agreed.

 

[kmetiuk]

Looking at everything it seems as though the pump was on its way out before you installed the new turbo. I dont believe the oil distribution change caused the problem, you probably finished her off with the power increase. You went from a hair dryer to a leaf blower.

Shoulda stated the 14B and the holset were both set to 22 psi. So the car was used to that boost level. Maybe both of them hurt the bearings causing low pressure?

Do oil pumps also go bad by losing pressure?

I always thought they broke teeth off or cracked in two (seen both during my Honda phase) not got loose and lost pressure.

 

[GST with PSI]

I wouldn't worry too much about the cause at this point. You'll figure it out indefinitely when you tear the motor down. Until then, there is only guessing.

You could find any number of things wrong when you tear down, to include a bad oil pump.

Besides, rarely will two motors will build oil pressure the exact same way. Meaning your 6 bolt isn't likely to have oiling issues just because your 7 bolt is (if it is). If you plan to transfer any components from one motor to the other, make sure the components check out and are within specifications.

Bottom line, I find it unlikely for the turbo to be the cause of oil starvation unless the turbo itself is physically pissing oil out of the motor.

 

[kmetiuk]

I wouldn't worry too much about the cause at this point. You'll figure it out indefinitely when you tear the motor down. Until then, there is only guessing.

You could find any number of things wrong when you tear down, to include a bad oil pump.

Besides, rarely will two motors will build oil pressure the exact same way. Meaning your 6 bolt isn't likely to have oiling issues just because your 7 bolt is (if it is). If you plan to transfer any components from one motor to the other, make sure the components check out and are within specifications.

Bottom line, I find it unlikely for the turbo to be the cause of oil starvation unless the turbo itself is physically pissing oil out of the motor.

Nah, she was tight as a drum. Took it semi apart after 100 miles of use and it was super clean inside the comp and turbine.

I'm not gonna tear it down. Literally pull it take off the head and other bits and sell the block for scrap. No point in rebuilding a trashed 7-bolt when you have a 6-bolt ready to go and a spare 6-bolt block.

I get what your saying though....very improbable that the oil pressure issue was from the turbo.

For my own benefit, what would cause the low pressure then? Would bearing wearing out cause it to drop as well? Or simply worn oil pump?

 

[GST with PSI]

I'm not gonna tear it down.

For my own benefit, what would cause the low pressure then?

That's what I'm saying...Tearing it down is for your own benefit. It's the only sure way to figure out what caused the failure, and answer all the questions you're asking definitively. The motor has to come out either way. Another 30 minutes is all it takes to pull the pan and pop off all the caps.

 

[kmetiuk]

That's what I'm saying...Tearing it down is for your own benefit. It's the only sure way to figure out what caused the failure, and answer all the questions you're asking definitively. The motor has to come out either way. Another 30 minutes is all it takes to pull the pan and pop off all the caps.

Fiiiiiiiine. hahaha. You make a good point....I'll tear it down.

How can I tell is the oil pump is bad? I know bearing and rings and stuff inside and out, but the oil pump in the DSM is new area for me.

 

[SOADweskey]

A lot of times when oil pumps go bad the gears gouge into the front case. It's pretty obvious when the front case comes off.

Also your engine saw a whole hell of a lot more air flow and thus cylinder pressure with that Holset at 22psi then it did with the 14b at 22psi. Just because the boost level is the same doesn't mean the amount of air crammed into the cylinders is.

 

[c2ypt1c]

Just curious, what type of fuel? Mind posting the log?

 

[kmetiuk]

Just curious, what type of fuel? Mind posting the log?

94 octane....log doesn't show anything. No knock no nothing.

I was still using timing tables from the 14B and at 22PSI it was blowing a lot of hot air so I was knocking a bit and had to do some conservative tuning. I used the EVO8 mod 1 map and retarded the timing a bit in a few areas.

I could post a log but who knows which one was the one that damaged the rods....i have about 15 of them from that night from various vane settings.

 

[kmetiuk]

Also your engine saw a whole hell of a lot more air flow and thus cylinder pressure with that Holset at 22psi then it did with the 14b at 22psi. Just because the boost level is the same doesn't mean the amount of air crammed into the cylinders is.

True. I guess if its the same VE for both (which it should be damn close) then IAT plays a role with density hey? The GMIAT was showing a cool 17C last night and the sensor is very close to the throttle body. Never measure the 14B air temp as I went SD after it grenaded...but it HAD to be super hot as it was nohwere near an effiecent island that high of boost. I checked the logs and it was 33 lb/min for the holset and 29 lb/min for the 14B at ~5500 RPM....but the 14B had dropped to 19Psi by then and the holset was holdign 22 psi still.