A few holset hx35 hx40 answers

[Aaron91RS]

My hx40 is out of balance and went to hell because of it (I'll just ignore the fact two people on the boards owned it prior)

I found a local guy here who rebuilds them and has been doing it for 30+ years. You'd be jealous of all the turbo cores he has piled around.

Anyway feel free to take this how you want. Considering he's been doing this longer then most of you have been alive I'm going to trust him.

First thing I asked him was should I run a restrictor.
He said no.
I said well what about if I am pushing 70-100psi.
He said it won't hurt the turbo, worst case it pushes some oil past the seals.

Second thing I asked him since it's a currently a huge thread on here.
My drain tube is only 14.5mm and some are saying I should get a bigger one.
Again he said mine was fine.

He asked what boost I pushed and I said 30psi because some people said the shafts were weak past that.
He said the shafts are fine and what happens is it gets in and out play on it.

My oil flingers were so tight he had to heat up the shaft and press them off.
Then he told me he was going to turn the shaft 5000th's of an inch and put undersize bearings in.
Again I said is that going to weaken the shaft should I buy a new shaft.
He said no the shaft will be fine, he does this all the time.

Again you can decide how to take it.
I have to go back because I just dropped it off today to rebuild so if you have any worthy holset hx40 questions you want me to ask post up.

 

[Strm Trpr]

1st, I'd say run the restrictor if you're feeding from the OFH.
2nd, Holset recommends 19mm ID minimum for drain lines.

If you want to stay with the 14.5mm return line, then do yourself a favor and
run a restrictor in your feed line.
If you don't run a restrictor, you will flow too much oil into the CHRA that the
14.5mm oil return line won't be able to flow out...

You will a) blow out the seals eventually, and b) you will keep hot oil in the
CHRA longer than intended leading to further damage...

Ask him how much oil pressure these CHRA's see when used in their stock
applications such as Dodge Pick-Ups.
Chances are they see a max oil pressure of 70psi...
You could throw 100psi at it for extended periods of time, remember that.

And, it's not really the pressure, it's the Volume of oil that's being pushed into the CHRA.
You could literally fill up the entire cavity of the CHRA to the point that the
feed line is backs up and puts stress on the oil pump.

These are water cooled no, so actually less internal volume for oil as an oil cooled CHRA.
So, hot stagnant oil surrounding the shaft getting hotter with every second of
full boost, ultimately leading to "Shaft Failure", and/or Journal Bearing Failure,
not to mention premature thrust bearing failure too.
The seals are gonna get cooked, and you'll blow oil past them in no time...

You have a unique opportunity to work closely with your rebuilder, so take
advantage of this, as you are doing.

Oh, and FYI, 5000ths of an inch is usually .005"....

 

[Aaron91RS]

These are water cooled no, so actually less internal volume for oil as an oil cooled CHRA.

actually most all of them(at least on here are oil cooled only)

Anyway their still debating all these things in the other threads but I talked to the guy again today and I'm satisfied my setup is fine.
I probably annoyed him asking him repeatedly.

The one thing he said will cause them to fail (and until now I don't think it's ever been explained this way)

Is when the turbo is sucking in air at high boost the compressor turbine is like an airplane propeller. It want's to move forward and puts a lot of stress on the thrust bearing trying to go this way.
On the opposite end is the exhaust turbine and it's trying to go the opposite direction.
So with these two things pulling against eachother the thrust bearing just kind of holds the shaft in the middle without much pull one way or another.
Up the boost and it pulls harder on the compressor side and will wear the thrust bearing out, thus in and out shaft play and eventually something breaks and we get this 'weak shaft' talk which isn't accurate.

Again i can see from the lack of responses to this thread and the page after page of responses in the other holset threads that everyone is still going to debate the oil feed, oil drain, and 'weak' shaft, but in my mind the issue is closed.

 

[JusMX141]

I found a local guy here who rebuilds them and has been doing it for 30+ years. You'd be jealous of all the turbo cores he has piled around.

I have been rebuilding for over five years now; I've acquired almost (50) cores at my shop of various sizes and brands.

First thing I asked him was should I run a restrictor.
He said no.
I said well what about if I am pushing 70-100psi.
He said it won't hurt the turbo, worst case it pushes some oil past the seals.

Not necessarily. More often that not the excessive pressure being blasted into the housing will cause the journal bearings to contact the housing rather than "float" on the oil. Too much oil is as bad as too little oil....I do not agree with his answer.

Second thing I asked him since it's a currently a huge thread on here.
My drain tube is only 14.5mm and some are saying I should get a bigger one.
Again he said mine was fine.

Fine to what level of incoming pressure? The point of that thread is to say that *if you're firing 100psi of high-volume oil pressure into the turbo, the drain must be larger in order to handle the additional oil or it will dam up inside the cartridge*.

It's not a question of how small it can be and still work properly....Holset specifies a drain that is a minimum of 19cm ID, so anything under that is asking for trouble; ESPECIALLY if you dare shoving more supply pressure into the turbo than the manufacturer specifies.

He asked what boost I pushed and I said 30psi because some people said the shafts were weak past that.
He said the shafts are fine and what happens is it gets in and out play on it.

Anytime excessive boost is seen, the turbine shaft is loaded in a way that lifts upward and outward on the compressor wheel. This is indeed rough on thrust plates and collars, but the Holset thrust plate is 360* standard and has two large oiling holes.

I can't vouch for Holset shafts....I had a customer send me a 6152S with three miles on it the other day and the turbine wheel snapped right off. I suppose some turbos are built on fridays.

My oil flingers were so tight he had to heat up the shaft and press them off.
Then he told me he was going to turn the shaft 5000th's of an inch and put undersize bearings in.

I'm confused....the dynamic seal collar ("slinger") does not touch where the journal bearings ride, so why is he undercutting your shaft? Is the shaft scored or out-of-spec? Normally it can worn be as much as .002" where the bearings contact the shaft without translating into enough shaft play to allow the wheels to hit the housings.

Again you can decide how to take it.

I will. Not to discredit him in the least, but Holsets on DSM's have only become an option in the past five years or less. Everything he knew about Holsets on diesels is thrown out the window when it comes to these cars. DSM's have been known to destroy turbos that some consider bulletproof in a very short time and without any logical reason.