3b precup questions (1 Viewer)

[bj70cruzer]

Hi so i was just reading that another forum member here had a precup failiure and someone mentioned that it may have been a cast pre cup

I bought new pre cups for my 3b which were going to be installed tommorow but know that i look at it i think it may be cast instead of machined from billet?

When i purchased it i asked what material its made out of and was told 310 stainless which i believe is correct but havnt checked with a magnet yet

The outside looks turned down but the inside looks cast with a rough surface


People that have changed there pre cups what did the inside look like? Machiend or rough?

How can i tell as i dont want an early failiure to occur.

I have attached a few pictures of it

 

[gerg]

That was me that raised that casting question. I think I might have stirred up unnecessary fears. Sorry bout that. Ive never seen a precup cracked and fail like Gengis's did. I guess I should have called its quality into question as opposed to it being "cast". It clearly need to be cast to achieve its original shape. I thought perhaps the whole thing was a low quality cast item devoid of machining.

My precups appear exactly as yours do. I think his might be a lower quality stainless or a form that can melt with diesel? Our fuel would be hard pressed to melt quality stainless.

 

[bj70cruzer]

Thanks for the clarification gerg i got these cups from engine australia so it should be decent quality. Time will tell i guess.

Before they go in i will be taking those sharpe edges out just to minimise hot spots hopefuly reducing cracking.

 

[gerg]

I did the same with mine actually. It looked like it would interfere with the flow of the gasses.