Cummins 4BT & Diesel Conversions Forums banner
1 - 18 of 18 Posts

·
Registered
Joined
·
425 Posts
Discussion Starter · #1 · (Edited)
I've been planning on doing a write-up on rebuilding my H1 turbo but ran into a few problems. But now it's done so here we go. You can download a service manual from http://www.holset.co.uk/files/4_4_1-service%20repair%20manuals.php, just choose your model. The following is to show some pics and my experience pulling it apart and putting it back together.

My 4bta came with a WH1C. It has a 12cm wastegated housing and a 44 mm inducer. It was oily on the inside of the compressor housing so I knew the seals were worn out. I ordered a repair kit here http://htturbo.com/Holset.htm and started to disassemble my turbo. The nut for the compressor wheel is opposite meaning "righty tighty" actually loosens the nut (13mm I think) and you'll need to stop the shaft from spinning. I used a pair of vice grips on the exhaust wheel. I think a 12-point should work but I didn't have one to test. The compressor housing comes off easy enough from the main body using an 8mm wrench. The bolts on the exhaust housing also did not put up a fight (I used a 1/2" wrench). What can provide some resistance is getting the main body out of the exhaust housing. Use your favorite penetrator and soak it.



Clamp it in a vice and try tapping it. Be careful because the main body can break (unfortunately I know from experience). If it doesn't come apart let it soak. This can take a few hours to several weeks.



This one took a couple of weeks. I had another one that took 2 days and one that took 5 minutes. I've tapped it out and I've tapped it to spin and then out, it just depends on how stuck your main body is to that exhaust housing. If you get frustrated tap a little harder, if you get angry leave it alone and work on something else. Finally it will come out. Be careful not to damage the blades on the turbine when separating it from the exhaust housing.



Here is the kit.

 

·
Registered
Joined
·
425 Posts
Discussion Starter · #2 · (Edited)
Just tap the main shaft out. It will pop out so don't let the turbine shaft drop and hurt any blades.



Take the circle clips out and remove the bushing.



The bushing are held in place by two circle clips and you'll see the second one after you pull out the bushing. The kit includes these clips so get it out and replace it. Flip the main body over and do the other side. Now's a good time to clean out the inside if wanted. The three I've seen haven't been bad inside. I just make sure the bushing surfaces are clean. You can check for tolerances now if you have the equipment, I just did a visual inspection and started putting it back together with the kit.

Wet your bushings, motor oil is fine because that is what lubricates them when it's running anyways.

 

·
Registered
Joined
·
425 Posts
Discussion Starter · #3 ·
Put the bottom circle clips in, slide in the bushings, and put on the outer clips.





Put the oil seal on the turbine shaft



You can munch up the seal when trying to slide the turbine shaft into the main body. The problem is that protector cup that blocks your view trying to get the seal in the hole. I bent the first seal I did and had to buy another one so take it easy and don't make my mistake. I found that as you slip the shaft in the bushings that you can get two small flat-head screw drivers in between the turbine and the cup and pinch the seal together so that is slips in the hole. If it doesn't go in with only hand force keep trying. DON'T use a hammer.

 

·
Registered
Joined
·
425 Posts
Discussion Starter · #4 ·
Flip it over and put on the bushing.



Put on the new retainer plate and screw it in with the new screws. It's either a T20 or T25 torx size. Torque specs are found in the manual you downloaded.





Put on the oil baffle.

 

·
Registered
Joined
·
425 Posts
Discussion Starter · #5 ·
Put the second oil seal on this piece and put it in the compressor backing plate.



Put in the new rubber seal



Slide it on the shaft and bolt it on the main housing.



 

·
Registered
Joined
·
425 Posts
Discussion Starter · #6 ·
Place the main body in the exhaust housing and put on the retaining clips and bolts. I reused my retaining clips because they were thicker and stronger than those supplied in the kit. **Note of advice: If you did not mark the main body and exhaust housing before disassembly then you will need to rotate the housing to match up the oil return lines. In order to make this easy make sure the mounting surface on the main body is clean and free from rust. Also make sure of the same on the mounting surface on the exhaust housing. I found using a dremel tool with a sanding roll makes quick work of cleaning up that surface. This will allow the body to spin in the exhaust housing by hand. I didn't do that the first time and end up breaking part of my main body trying to rotate it.** If it was marked align it and tighten down the bolts, if not keep the bolts loose so you can get it aligned when on the engine.

Next locate the alignment marks on the shaft and the compressor wheel. All three turbos I've seen have these marks. This is important because the turbine shaft and the compressor wheel have been balanced and that's what those marks are for.



I retained the turbine shaft with vice grips and tighten the nut (lefty loosey is tightening).



Put the new rubber seal on the backing plate and put on the compressor housing. Mine had a v-band clamp so I finger tightened it so I could rotate it later when I set-up the plumbing. I found putting the turbo on the exhaust manifold was easier for me.



Once aligned I tighened one of the bolts on the exhaust housing and took it off to tighten the rest of the bolts.

Since I broke my main housing I had to get another and I was fortunate enough to have a buddy who gave me his old one. This one was still and H1 but the body was alittle different. Everything still bolted right up. I ended up transfering the rebuild kit to his turbo and used my exhaust housing so now the specs are:

Still wastegated 12cm housing, 54mm inducer and a 4" intake. I've got some bloopers pics that I'll share.

 

·
Registered
Joined
·
425 Posts
Discussion Starter · #7 ·
bloopers and comparisons

Bottom left is the oil seal I mangled, bottom right is the old seal. You can see the groove worn into it and that's why it didn't seal anymore. The other seals I got out of the other turbos were worse and one looked like a strand of wire. That turbo was shot. The new good seal is on the top.



I tried rotating the housing with it bolted to the engine and it wasn't budging. Some hammer and a punch and here you go, broken housing. It's repairable but I got a good one now so I did have to worry about welding cast.





I put the housing in a vice and got my dremel tool to clean up the mounting surface. Mine also had paint on it that acted like glue.

 

·
Registered
Joined
·
425 Posts
Discussion Starter · #8 ·
Picked up this housing off of ebay for the main body to replace the one I broke. I looked alright from the outside. The ad said it had shaft play. I thought no problem since I have a rebuild kit.



That was no joke. I could literally move the shaft 1/2" for radial play. Once I got it apart I could see why. That turbine shaft was toast. Look at the wear on it where the bushing would run. No problem right, I just wanted the body anyways.



Looked at the housing and saw that I had a paper weight. The oil seal surface was non-existent and if you look hard enough you can see scoring where the bushing spins.



Here's the bushing. It doesn't have a nice smooth surface anymore.

 

·
Registered
Joined
·
425 Posts
Discussion Starter · #9 ·
These are H1 turbos. The farthest on the right is what I ended up using. It looks a little different but everything bolted up just fine.







 

·
Super Moderator
Joined
·
8,975 Posts
Excellent writeup. Thanks for sharing.

It's amazing how far dead a turbo can be before people notice something is wrong.
 

·
Registered
Joined
·
425 Posts
Discussion Starter · #11 ·
Turbine wheels are all the same and they came from three different sized housings.



Compressor wheels are different. 40mm inducer on the left, 54mm inducer in the middle (83mm outer diameter), and 44 inducer (83mm outer diameter) on the right. I used the middle one with it's matched turbine shaft.



Compressor housings. Ebay on the left, one I used on the top, my old one on the right.



The holes sizes are different depending on the inducer size of the compressor wheel. The v-band clamp backing plates were the same but the bolt on one obviously was different.

 

·
Registered
Joined
·
425 Posts
Discussion Starter · #12 ·
Thanks Dougal,

That's all the pics I've accumulated so far, just thought I'd share and I'm pretty excited to see how the new turbo will work. It should be what I'm looking for.
 

·
Registered
Joined
·
157 Posts
Excellent tech report!!!!!!!

Excellent tech report BOOTS4!!!! A couple of things ..that I might have missed reading are..

1) The turbine wheel end can be held with a 19mm 12 point socket.

2) Antiseize on the bearing housing to turbine housing diameters. Helps with the next time the turbine housing needs to be removed from the bearing housing.

3) Need to take care and ensure the journal bearing retaining clips are fully installed in each of the grooves with full expansion. An easy mistake is to leave one ear clip out of the groove which can cause the journal bearing to "cut" on the end face. I have personally seen the OAL of a bearing reduced to 1/2 of the normal length due to this issue in a short period of time.
Also, the radius edge of the retaining clip should be placed towards the journal bearing.

4) The turbine shaft can be tricky to install into the bearing housing due to the piston ring seal. Just rotate the shaft slowly as you apply a slight hand force and it should slide in. There is a faster method but it takes time to develop the "trick".

5) Be sure to oil the shaft thread prior to torquing the rotor nut to specification. Don't over torque it..there is little room for "error". Most rotor shafts can only be torqued to spec 6 to 10 times before failing!
 

·
Registered
Joined
·
1,109 Posts
interesting. what did the 40 mm one come on originally? my friend has a h1c like thatexcept its not got a wastegate that supposedly came from a 6bt but I can't imagine it'd be big enough.
 

·
Registered
Joined
·
425 Posts
Discussion Starter · #15 ·
High Pressure, great info and good details. Thanks for adding.

K204DR, It was listed as an H1 turbo so I don't know what it came out of, but I too thought they came from early 6bts. That one didn't have a wastegate. My 12cm housing is the only one that did in my pics and it's the one I'm using.
 

·
Registered
Joined
·
854 Posts
The 54mm one you posted up looks exactly like the one I pulled off of my 92 Dodge. (I haven't measured it yet)

It does OK with the stock 18cm housing but I'll be swapping a 12cm housing on pretty soon.
 

·
Registered
Joined
·
3,391 Posts
1 - 18 of 18 Posts
Top