I got my bearings for my rebuild today so im going to have a machine shop press them in. This worry's me because every single time ive taken anything rotary anywhere, they end up screwing something up. Therefore i'd like to be educated on the procedure first. When pressing the old bearing out, what is the proper method? Do they need to have a corect size head for the press, and old bearing, or do you just press in the new one, which will press the old one out at the same time (what i think they might do). Are there any tricks to this that i should tell them about? i know about the draw two lines straight down from the indexing tab with a sharpie to help alignment, and will probably do this for them before i take them, anything else? I'd love to take it to a good rotary only shop, but i honestly dont know of any in the bay area. Thanks.



edit: they are main bearings.

 

I gave up and bought my own press. I made the pushers to drive in the bearings.



The first (Removal) pusher should be just a few thousandths smaller than the bearing ID and have a shoulder on one end to just drive the bearing but not touch the ID of the stationary gear.

This pusher should be as long as the bearing plus the shoulder length, maybe another 1/2"



Another pusher that is just a few thousandths smaller than the ID of the bearing but has a shoulder with an OD larger than the bore in the stationary gear to act as a stop when the bearing is flush with the end of the bore. The OD of this pusher should be twice as long as the bearing plus the stop shoulder.



Do not push out the old bearing with the new bearing. It may be ruined.



I would call up a builder and see if they can do this for you. It may be cheap insurance and could be out and back in a week with UPS.



Replace the rear seal when you get them back or have the builder do that too.



The picture is the chassis for the 95 RX-7. The idiot on the left is Engineer Craig Rhine. The idiot on the right is me. The bare chassis weighs 134 pounds (SAE 4130).



Lynn E, Hanover

 

Gas or TIG welded?

 

I TIG where the thickness piles up a bit. Gas everywhere else. You can drape a gas weld in 4130 and get it to cool very slowly. With a TIG you should heat the area with a gas torch before you weld, and then drape it. So I use just use gas where I can.



I know that 4130 is very forgiving but I have also cracked pieces right beside the weld with TIG, because I did not preheat.



Lynn E. Hanover



The pix is the modified counter weight to fit a chevy (Tilton 5.5 inch button clutch) bolt pattern. Yes I wipe off the paint before I bolt on the flywheel.

 

The preceeding was just a test



Glad to here you are gas welding the 4130.

 

I am a little confused here. Tig uses argon gas. TIG = Tungston Intert Gas. Soooo what do you guys mean when you say gas?

 

"GAS" is Oxy-Fuel welding, the fuel being Acetylene, Propane, Propolene or Natural gas. Oxy-Fuel welding 4130 gives better control oner the HAZ (Heat-Affected Zone) which is critical in 4130 structures due to brittlement issues.

 

From the TINMAN:



What are the pros and cons of welding 4130 with tig or gas? There seems to be alot of controversy on stress relieving etc. Thanks John



The Tinman Respondeth:



John, Briefly stated are the following pros and cons on Tig vs Gas on 4130:



Gas will enter into a narrower angle.

TIG may use a little less rod.

Gas headgear is smaller, enabling head entry through tight spots.

The postweld gas flow from TIG can quench and harden the weld, whereas the gas torch may be played over the weld for a moment after welding, to enable stress relief.

TIG can encourage the use of insufficient filler. Trying to make the daintiest appearance welds is actually detrimental to weld strength. This is something a torch guy is less tempted to do since it goes against the natural welding process of the gas torch.

The gas torch is less expensive to buy and operate.

It can be used for brazing, soldering, annealing, bending, and forming - which the TIG cannot.

And...in a breezy hangar, shop, or out doors the torch is unaffected by 30 MPH gusts. The TIG's delicate inert gas envelope, on the other hand, is adversely affected even by sighs of relief.

And for other alloys: For perfect penetration on aluminums and stainless, the TIG requires a complete argon backpurge, or at least a backup flux. The gas torch, on the other hand, uses a flux and makes a flatter bead with perfect penetration anyway.

 

Sorry, I have done quite a bit of TIG welding on aluminum. There is no way I would ever want to use a flux setup with a torch. ICK But then again I have never tried it



But thanks for clearing that up. We just call it a "torch"



Gregory

 

go to the site and look at the TIG vs OFW ALuminum pics