Welding Tips and Tricks

A potential customer contacted me asking about welding this cast aluminum engine part, he needs the ring welded on this side (as you're looking at the photo) of the hole.

Since the ring is so degraded I suggested making a new one.

My question is what filler would you suggest, I'm thinking 4943?

Any other comments are welcome, thanks

That 'ring' looks like a valve seat to me.
Is it off a single cylinder engine? Or, would you have other cylinders to reference?

I have experience machining heads for new valve seats. I never did any of the welding, just the machine work.

I think 4943 would be a good choice for build up of the seat area. Another one worth looking at might be 5554.
Call me

After looking at the pictures some more, I take back what I thought it was.
Can you show us some wider shots?

A little more info on the nature of the part would help - I think it unlikely from the pic that it is a valve seat or any top end engine part with what appears to be a needle roller bearing next to it - if we assume this is some sort of gear case & the bearing is an end support for a shaft then logically the larger bore houses a larger bearing & the ring is likely a stepped diameter to retain / locate said bearing - if this is the case I would not re-weld it or replace the ring but bore out the previous weld repair & build up new material with sufficient thickness to allow setting the casting up on the mill & re-boring the hole to correct diameter - one would require the bearing dimension - as to filler I never tried 4943 as it will be a long wait for it to cross the pond but I've heard very good reports on it - if I have a totally unknown casting I tend to try 4047 first but if it's possible to do a test weld somewhere that does'nt matter I'd try any alloy with magnesium in & if it takes then go with it for strength - I would also add that if this is a bearing retaining step that has been damaged / repaired already unless the cause of failure can be determined any repair however well executed will likely fail again.

I'm somewhat familiar with Harley Davidson's aluminum cases from '70s era Sporsters...... where it is common practice to add a re-inforcement ring around the countershaft bearing. This case isn't one of those but it is vaguely close enough for me to suggest:

that item looks like a motorcycle transmission case (I don't know the make) ...... where the tranny mainshaft fits thru the large hole, & with the tranny countershaft fitting in that needle bearing.

I suspect some type of needle/roller bearing on the mainshaft would fit inside the proposed re-inforcement ring...... which might necessitate line boring by the customer, before use. A conversation with the customer regarding how they intend to re-establish correct alignment, following welding, might be in order.

I don't see it in the pic, but just a heads up..... there's usually an oil passage to feed lubrication to the countershaft bearing. Any welding might block this off, in which case your customer will need to re-create that oil passage. Something your customer probably already knows or maybe not.

Sorry, I have no experience when it comes to welding cast aluminum so I won't go there.

And of course I might be wrong, but I don't think so. Anyway, I hope that helps some.

VA-Sawyer wrote:After looking at the pictures some more, I take back what I thought it was.
Can you show us some wider shots?

I don't have the part yet, so the pics are what was sent to me.

noddybrian wrote:A little more info on the nature of the part would help - I think it unlikely from the pic that it is a valve seat or any top end engine part with what appears to be a needle roller bearing next to it - if we assume this is some sort of gear case & the bearing is an end support for a shaft then logically the larger bore houses a larger bearing & the ring is likely a stepped diameter to retain / locate said bearing -

You are right, my mistake to call this an engine part, it is part of the transmission. It is from a 1966 BSA A65 model Hornet

I was told it doesn't seal but holds a bearing in place

sportster wrote:I'm somewhat familiar with Harley Davidson's aluminum cases from '70s era Sporsters...... where it is common practice to add a re-inforcement ring around the countershaft bearing. This case isn't one of those but it is vaguely close enough for me to suggest:

that item looks like a motorcycle transmission case (I don't know the make) ...... where the tranny mainshaft fits thru the large hole, & with the tranny countershaft fitting in that needle bearing.

I suspect some type of needle/roller bearing on the mainshaft would fit inside the proposed re-inforcement ring...... which might necessitate line boring by the customer, before use. A conversation with the customer regarding how they intend to re-establish correct alignment, following welding, might be in order.

I don't see it in the pic, but just a heads up..... there's usually an oil passage to feed lubrication to the countershaft bearing. Any welding might block this off, in which case your customer will need to re-create that oil passage. Something your customer probably already knows or maybe not.

Sorry, I have no experience when it comes to welding cast aluminum so I won't go there.

And of course I might be wrong, but I don't think so. Anyway, I hope that helps some.

You are right about this being a transmission case, my mistake to call this an engine part.

I appreciate your response and I'll let the owner know of your suggestions and concerns, thanks!

looks like the engine case. the part that is chewed up is some type of thrust/crush washer that carries the trans drive shaft. 4943 will get you flow and some strength but that area might need more wear strength from torque. You can look up that engine case to get an idea of location.

That'd scare the bejesus out of me. Is the part replaceable? Cast poses cracking risk, and won't weld cleanly. You might have better luck building up the casting then machining rather than welding a piece to it. I also wonder if 210 is enough amperage without helium.

He can replace the part if necessary, but wants to try to keep it as it's serialized and wants to restore with the original parts.

Clean with all you got, then clean more.
Preheat with as much as 700 F.
I wonder if you might need some helium. Mine is primitive. I have a Y on the back of my welder. Each tank connects to it. I use 10 CFH argon, 4 CFH helium. The effect is amazing!

I'm concerned you will change the shape of the casting. Precision measurements are needed before, machining may be needed after.

If it is important, I would chicken out and search out an expert.

Depending on the casting thickness, how about going with a mechanical fix rather than welding ? The LH crankcase half of an A65 also has the LH crank bearing and mating faces for the RH case and cylinder barrel.

Clean up the damaged inner surface and machine a ring from 4140 , retained with 6, US made, 10-24 countersunk socket screws. The ring may have to be relieved for the thrust washer,and have the selector shaft bores, but would still be stronger than an aluminum build up.

There is a circlip groove on the outer end of the bearing bore which could be used to reference the end of the bearing bore for the facing operation.

If welding is the only option, machine a bronze plug of the bearing OD / length, to go in the bearing bore and another to go in the needle bearing bore. Keep the temperature under 250F during welding to minimize the heat treat loss, weld short runs and use the maximum % of helium you can with adequate cleaning.

Edit; just found this, the second pic down is the before...............A picture's worth a thousand words.

http://www.britbike.com/forums/ubbthrea ... ber=483690

An undamaged case would be a useful thing for comparison purposes, for the bearing shoulder thickness.

Thanks for the detailed responses, I'm waiting on the customer to let me know if he wants to proceed