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Discussion Starter #1
I may have already asked this, but no memory, so: I have an HTT Stage II compressor to swap onto my turbo. From what I've read it's real easy, but I'm not buying that yet. Anybody have experience swapping out the Holset H1C compressor side? I'd much rather not remove turbo. Supposedly it's just a matter of unbolting compressor housing, unbolting compressor impeller [reversed or left-hand threads], and do the reverse to re-assemble. What holds shaft/impeller when removing impeller nut?

All I got was the Holset compresor housing, the Holset compressor impeller, and the steel exhaust manifold to turbo gasket, which I shouldn't need? Re-useable o-ring at compressor housing? Tips? Warnings?

This swap gives me a 16cm exhaust and a 58cm compressor, same as an HY-35 from what I'm told. Thanks....
 

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Mine wasnt hard to do, but I removed the turbo. Only takes me about 20 mins to remove and makes everything else much easier. Impeller threads are left-handed. Backup wrench on turbine side and impact on compressor side to remove nut. Backup and torque wrench to install nut, I used some blue locktight. Reuse the o-ring. Make sure everything is clocked the same and you are good to go. It was so easy I thought I had forgotten something.bounce
Good luck,Carl
 

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Just remember the torque wrench has to work "left handed" and some aren't calibrated for that direction.
 

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Woops, thanks Bob, been working graveyards and forgot that.:rasta:
Carl
 

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There are two different types of nut on them. Which one is on yours? I ask because of questionable balancing issues...
 

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Discussion Starter #6
Well jeepers, then it's as easy as I heard it was! Thanks for the replies and tech assist, guys. My torque wrench reads both directions.

I guess I will pull it off so I can clean and paint and all that. Just didn't want to leave myself stranded, new to the area and no local friends to call for a ride.

Being as I haven't taken the turbo apart I have no idea what nut is on it?? Thanks all!
 

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There is risk associated with this procedure. The balance of the rotor assembly will be a major unknown. You might get lucky but based on experience the odds are not in your favor. Ideally, the assembly needs to be rebalanced. Most reputable turbo rebuild shops have the ability to “rotor balance” the turbine shaft, oil slinger, thrust collar and impeller as an assembly. This procedure is the most basic form of rebalancing a rotor. To have this balancing done… the core will need to be disassembled… which means you might as well replace the journal bearings, thrust bearing, piston rings and other small associated parts.

But if you want to roll the dice…

The rotor nut is left hand (chances are you have a hex nut) the ideal rotor nut today is a 12 point nut. Be sure to apply oil only to the rotor shaft threads and the “rotor nut” face of the impeller prior to retightening. The basic torque spec is 13 +/- 1.0 Nm (115 +/- 10 lbf inches).

JimmieD.. You have spent a great deal of money on a new impeller & compressor housing. It may not cost that much more to insure the turbo is built correctly. Good luck.
 

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How is the balance done at a turbo shop. Meaning how to they add weight to bring in balance. How fast is the turbo spun during balance ?

Paul
 

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The most basic method (lowest cost) is accomplished on a belt driven balancer locating on the journal bearing diameters. Most don't remove material in this process... the impeller is untorqued and rotated to change the relationship of the individual components unbalance (primarly the turbine shaft & impeller). The rpm is typicaly 2,000. The amount of unbalance allowed is 1.5 gram mm (.002 oz inches)

There might be some shops that are able to perform "low speed" core balancing by locking the core assembly in a fixture and providing oil to the bearings and air driving the turbine wheel to a controlled 4,000 rpm ...again balance is corrected in the same method as described above.

The most expensive method is high speed core balancing to well over 100K rpm.
 

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I have to agree with the guys on the rebalancing. You are taking a big chance with a wheel change and no balance. If it is out of balance it could easily come apart which could not only damage the engine, but ruin your new parts or the entire turbo.
 

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I asked technician about this very thing when I purchased my comp wheel and housing. He said not a problem because stock rotating assy had been balanced and new compressor wheel was individually balanced so it would all go back together OK. The new wheel did have some material removed to indicate it had been balanced. Im running 12cm turbine housing with 52mm compressor wheel so plenty of turbo rpm. Im sure complete balancing may be better but mine has worked great for 6 months.
Carl
 

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I have to agree with the guys on the rebalancing. You are taking a big chance with a wheel change and no balance. If it is out of balance it could easily come apart which could not only damage the engine, but ruin your new parts or the entire turbo.
I have swapped turbo compressor wheels without problems. Remember all the parts are balanced individually, the process of balancing the assembly is only taking care of the small residual imbalance when everytying is bolted together.

The bible "diesel engine reference book" says that this imbalance is mainly a noise issue and didn't use to be performed on truck and industrial turbos. My experience fits with that.
 

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Yes it is true the components (turbine shaft & impeller) are individually balanced from the factory. Some components will have metal removal balance cuts and some will not...one cannot base how well a part is balanced by the type of balance cut. A large cut could result in a part that has a very low unbalance and conversely a part that has a small cut could have an unbalance that is just below the max allowed. Some parts might only have a cut on the backface, or between the blades or only the nose. No way to know for sure in less they are measured. There are several more variables involved that effect rotor balancing and core balancing beyond the individual component balance.

Here's a link to the Holset service repair manuals and data sheets.

www.holset.co.uk/files/4_4_1-service repair manuals.php
 

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Yes it is true the components (turbine shaft & impeller) are individually balanced from the factory. Some components will have metal removal balance cuts and some will not...one cannot base how well a part is balanced by the type of balance cut. A large cut could result in a part that has a very low unbalance and conversely a part that has a small cut could have an unbalance that is just below the max allowed. Some parts might only have a cut on the backface, or between the blades or only the nose. No way to know for sure in less they are measured. There are several more variables involved that effect rotor balancing and core balancing beyond the individual component balance.

Here's a link to the Holset service repair manuals and data sheets.

www.holset.co.uk/files/4_4_1-service repair manuals.php
The reason wheels have a balance cut on the rim and the nose is for dynamic balance. Removing material from only one place (say the rim) can staticly balance the wheel, but it'll try to rotate about an axis that is different to it's centreline. Try to force it to rotate about it's centreline and it'll vibrate.

Removing material from each side (rim and nose) allows for dynamic balance that won't vibrate when spun. It's the same principle as balancing car wheels. They need to add weights to each side, yet adding weights to onl one side will give you static balance.
 

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Discussion Starter #15
Thanks for the further information! The unit I purchased came from HTT [High Tech Turbo] and comes in several versions, Stage I, II, III, and IV. I think I got a Stage II, have to double check.

Hundreds, probably thousands, or these turbo uprgrades are used by the Dodge 6BT performance crowd. I've never heard of any complaints about balance or later disintegration, and never heard a word about re-balancing at install. I don't doubt that your information suggesting re-balance is good and accurate info, just that in real world applications it seems to be a non-issue? Hopefully so, as po' folks like me can't afford such a balance job!

This upgrade takes it to 56cm compressor wheel, maybe 58 [?] but I don't know what AF ratio it is with new housing. Supposedly it comes out to an HY35, and I have a 16cm exhaust side.

Thanks all!
 

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Your welcome, I only know one way to build them. What would be a fair price for an H1C rebuilt core (minus the end housings) that had the following work done to it?

New
Journal bearings
Thrust Bearings
12 point rotor nut
Thrust collar
Oil slinger
Piston rings
Seals

Bearing housing cleaned, bore brushed to remove deposits

Turbine rotor shaft reinspected for journal size and impeller diameter runout, journals micro finished & rebalanced to less the .75 g mm

Impeller balance confirmed to be less than .75 g mm

Core reassembled to service specs & procedures

Low speed core balanced to less than 1.4 g mm in 2 planes (turbine and impeller)?

I rebuilt one 2 weeks ago to the above process...just curious what it is worth? Though I have no plans to sell it... I need it for my project. ;)
 

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i just bought a rebuild. with a larger compressor, and paid 500.
This is the very reason I prowl Ebay... Some time ago I bought a brand new H1C with 54mm inducer, 16cm2 turbine housing for 380.00 ish. This assy was built for an Onan stationary generator, the seller has had them on Ebay for some time, the price has been up and down since I bought this one. I wouldn't hesitate if I wanted another. For the price you can't go wrong and if you wanted to upgrade inducer/housing and bearing set you would have a great value.
 

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Discussion Starter #19
Have you bolted that on yet, and if so, how is it?
 

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Have you bolted that on yet, and if so, how is it?
I have not. From other folks I have talked to a 50 to 54mm upgrade most likely will not impress you. Or me... :)

It was an impulse buy. Ebay, a blessing and a curse...

I was looking for a 16cm2 turbine housing and a rebuild kit for a turbo with 275,000+ miles on it. Considering the miles on the current turbo, a rebuild kit and turbine housing upgrade compared to the cost of a whole new assy wasn't all that bad of a buy IMO. DIY turbo rebuild with that many miles on it and the thoughts of feeding compressor side parts into a non I/C intake made up my mind.
 
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