The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: RichardL on 06.07. 2019 21:08

Title: A quality crankcase weld
Post by: RichardL on 06.07. 2019 21:08
Though not the most critical or difficult weld on a crankcase, the local shop I've found (Mike's Welding, Aurora, IL) did excellent work in giving me the material needed to reconstruct my broken-out sump-bolt boss (landing? bump? I don't know what to call it). Now, the hand work is up to me.

It's a race to see which will occur first, the completion of my A7 barn-find build or the disappearance  of all glaciers.

Richard L.

Title: Re: A quality crankcase weld
Post by: bikerbob on 07.07. 2019 15:46
A nice quality welding job before I retired I did quite a bit of specialised welding mainly building up shafts with weld or metal spraying but I have done a fair number of casings for bikes and cars and other industrial parts similar to that crankcase the difficult part in the welding is not to undercut the weld around the edges paticularly the sharp corners. The hard part now comes for you to get it back to a good finish it is easy to take metal off but not so easy to put it back on. If that was my case after finishing I would bolt the casings together fit the sump plate then fill it as much as possible with some oil then leave it standing for a few days.
Title: Re: A quality crankcase weld
Post by: mikeb on 08.07. 2019 01:35
Bob-
Quote
fill it as much as possible with some oil then leave it standing for a few days.
what would that achieve?

Richard -
Quote
a race to see which will occur first,
the third contender being when smelly old engines like these get banned form the roads. probably after the glaciers are gone. better speed up on the a7 project!
Title: Re: A quality crankcase weld
Post by: RichardL on 08.07. 2019 04:13
Bob-
Quote
fill it as much as possible with some oil then leave it standing for a few days.
what would that achieve?

Mike,

I take Bob to mean that the quality of the oil seal should be tested with oil before committing to complete assembly. Bob will correct me if there is more to this.

Richard L.
Title: Re: A quality crankcase weld
Post by: bikerbob on 08.07. 2019 15:17
That is correct Richard at least if there is no leakage of oil out of the crankcase then you should be pretty confident that it will not leak on final assembly but if there is weepage then it can be corrected before a complete rebuild.