Chrome moly pinion bearing nut

[Thomsen]

How much hp can the stock type-1 pinion bearing nut handle?
The trans is for a 200hp NA full weight bug for street/limited strip use

[Bruce2]

I highly doubt you'll find even a ball-park guess.
Spend the $40 and get the good nut.

[dangerous]

Shock load is the killer not HP.
If you use a stock one, make sure it is the FAG steel one, and not a cast one that came out in the first type available(SKF?).
I have used a stock FAG one with over 450hp and no probs ,
yet stripped one with less than half that power, when using a normally aspirated engine with 2-step launch.
...so for racing use they are worth the extra dollars.
I am always a little worried about using them for a high milage combination,
unless I have fitted a positive method to lock the chromoly nut.(NOT LOCTITE!!)

[Casting Timmy]

So does everyone usually just do the chromoly nuts on rebuilds, or at least a new stock nut?

I really don't see a down side to the chromoly as a lot of the stock ones come off so easy, I really don't know how many of the stock ones I want to reuse assuming that they come off easy from jumping a thread already.

[Pablo2]

The stock nut is fine for all stock applications. The stock one will only expand a thread if subjected to shock loads. HOWEVER, I did have the stock nut jump a thread on my very heavy Syncro Westy with 240 hp SVX engine .. surprised the heck out of me.

The only downside is occasional seizure of a chromoly nut on the hard threads of the pinion bearing (the hardness of both is similar). Threat of this occurring can be eliminated by careful inspection of BOTH threads before installation. The bottom thread of the nut usually needs cleaning up, and some micro swarf can usually be found on the threads.

[Casting Timmy]

Do you reuse stock nuts though? I'm kind of leaning of using even a new stock new on mild applications as I like tightening without the previous pings messing with it.

[Pablo2]

Used OE nuts are good for trial assembling. Chromoly nuts or new OE nuts should NOT be used for trial assembly.

A single tiny burr on the pinion bearing thread can damage the threads of an OE nut, so close inspection of all threads prior to use is a smart idea.

[Casting Timmy]

Thanks Pablo.