TRD/ Magnuson 4.0 Supercharger Tips, Tricks, and Mods

Everyone likes pictures:












I have a spare nose drive assembly, which is the original one, that has the first 2.85 pulley I installed on it years ago. The seal was weeping slightly so I bought a new nose drive a few years ago to swap so I wouldn't have any down time, and rebuild at my leisure. In March I decided leisure time has come to do the rebuild, bought a rebuild kit from SCOL and everything is good to go. Already have a new pulley in inventory.

I recalled that installing the 2.85 pulley the first time was a struggle with the threaded tool, so I kept that in the back of my mind. To remove the pulley I used a 2 finger pulley removal tool (3 finger type does not fit), heat (heat gun first, propane torch second) and impact driver to remove it. It was a struggle but I got the pulley off and in the process both the pulley and shaft galled. So a call to SCOL and I ordered a new shaft.

The finish in the bore of the new pulley is pretty bad, somewhere around a 125ST on my scale versus what should be 8RA max. This is were I measure the bore for the first time and find a .0025 difference between it and the shaft. This is huge for a mechanical press fit between steel components. So I chuck it in my lathe and carefully give it a light polish to clean up the finish a little.

The new shaft finally arrives, took a month for a new batch to get machined and heat treated. Got the shaft and rebuild kit installed and get set up on my press to install the new pulley. I made a tool for the coupler end of the shaft to sit on. Heated the pulley, a little lube in the bore and start pressing. Fairly quickly the press is getting heavy, fast, and the pulley will not go on any further than about 3/4 the way in. Several attempts with more heat and it does not budge. Period. It is on there.

With no way to get the pulley on any further I decide to remove it. The puller will not budge it as expected, so on to the mill to remove enough material to relax the bore, plus some cuts with a grinding disc to get as close to the shaft as possible without touching it. 30 minutes later with the puller, impact driver and torch it finally came off with the center of the pulley coming close to breaking off (picture 2).

The new shaft is damaged beyond use. Tried polishing but now the shaft is tapered (picture 3). Inspecting the original shaft, it looked salvageable so on to the lathe for some polishing and I got it almost new taking off only about .0003. The pulley, not looking so good. Ordered another one from URD and the finish in the bore is even worse than the last one. The bore is also bell mouthed .0002 on the shorter end, and .002/.0025 fit like the last one.

I turned down a barrel lap to fit the bore, then chucked it in the mill and lapped the pulley to a .0015 press fit. Ordered another rebuild kit. Anyone wondering why I would get another rebuild kit - the coupler plate in the kit is a one time use part. The plate presses onto the splines on the shaft and there is no way to realign the plate to the shaft once removed.

Reassemble everything again. This time I heat the pulley in the oven at 275° for 15 minutes, along with a steel disc I turned that will sit between the pulley and the ram on the press. The disc will help prevent the heat from drawing from the pulley when the ram touches. Some gear oil for lube (didn't have motor oil available) and the pulley presses on, a good hard press but nothing like before.

Some take aways:

1. The bore size URD specs is not correct, and the quality of the machining is poor.
2. Not sure what alloy the pulleys are made from, but they are heat treated, fairly hard and very tough. Very similar to heat treated 13-8 PH.
3. Use a press for the install.
4. That the threaded installation generally works is pretty amazing. Properly executed, mechanical advantage goes a long ways.

 

I can live with 6 psi for now lol

 

I will definitely be cutting a relief slice through pulley before I try and remove it. I'm with you on the URD bore size. Definitely did not seem to be where it needed to be, I've pressed thousands of wheel bearings and hubs over the years and this tiny little pulley whipped my ass last time.

 

Damn, even up in the corroded North land I was able to remove the stock pulley and the URD 2.825" and install the URD quick change hub; only needed the 3 arm puller and the original press fit tool. No cutting or hacking needed.
Assume variation in tolerance and ambient conditions were on my side.

 

I wonder if there was a manufacturing change. I basically did the same thing as you did 5 yrs ago. No trouble at all then. Wonder if there was a bad batch from Gadget.

 

I'm leaning towards this...

 

I've changed my pulley twice on mine own with the charger off the engine. OE pulley came off clean while URD 2.7 crushed and left indents from the back using 5 ton two jaw puller (OEM tool 25914). Plenty of people have re sold used URD qwik change hubs. So maybe it's just their stealth versions? Hoping my 2.7 smooth flow adapter comes off better than last.

 

The OE pulleys came off fairly easy on both my SC and the spare nose drive with no damage. I've installed three 2.85 pulleys and the 2nd one in the pics was the show stopper. After sizing correctly with a lap, the third one went on with no drama.

 

I had this exact same issue with the 2.85 pulley back in 2015 when I first installed my blower. Pulley seized about halfway in despite doing things right. Had to wind up basically destroy it and cut it up like a pizza in order to remove it because it would not go in or out at all. Came off in pieces. Gadget refused to accept responsibility for incorrect bore sizing and refused to think that his products had issues so I called the credit card company and got my money back like that. I have never went back to him ever since and it's sort of what led me to coming up with this thread searching for alternative solutions and sources to mods and parts.

 

That’s right. It was a huge pain. I ended up wrapping the puller with a nylon strap. Had a little bit of damage, unusable pulley after removal.

hope this helps someone in the future.

 

What's size is going back on it?

 

Hopefully, a Qwikchange Hub is going back on it, so future pulley swaps are quick and convenient.

 

Seriously.

 

2.6 on quickchange pulley… cuz I’m a URD whore... This was a few years ago.

 

Anyone had the same trouble pressing on a quick change hub compared to a black pulley?

 

I'm a boost newb and currently planning out my 1st S/C build. Sprung for the URD stealth pulley but this definitely gives me pause.

 

Who's running what belts on 2.7" pulleys lately? Mine's coming due for a change. Currently running stock length with a wrap.

 

Go with quick change all the way. Smooth flow is the way to go. I have pulley boys but they was before smooth flow had the Tacoma fitment down.

@IvanhoeTaco Also pressing on the quick change wasn’t bad at all.

 

with ALL of this. I'm running Smoothflow and had ZERO problems with the install.