Welding on a Briggs 5HP aluminum block

As you stated. Its not a racing engine. If and how much it warps is, a guess at best . Spec's and tolerances can be quite different.
Aluminum blocks , can be bored quite large . if a suitable piston is located .
 
Flathead Builder said:
Soooooo....
Is the general consensus that I am likely (or it is at least possible) to have the bore warp out of round when the 2 fins are welded? I really do not have anything to lose right now (except the $ 70.00 welding charge) to just go ahead and give it a try. If it fails (warps) I'll just go ahead and find another good block or have this one resized and honed.
Michael
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Some like to bet on the come.

Some like to go straight to the sure thing.

YMMV
 
Flathead Builder said:
Thank you Brian- much appreciated and duly noted! I hope that I do not have to this time, however, it is very nice to know that I can use your services if the welding results in a failure (warpage out of round) of the cylinder. Do you have an opinion as to the chances there will be any warpage for this type of welding repair?
Regards,
Michael
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In post #18, you mentioned measurements of .005 & .001. If those are in thousandths of an inch, (accurate and what you meant,) then it's already badly out of round. I will "assume" you meant .0005" - .001" which would be acceptable for your application.
WILL the welding change the bore? That depends on the localized heat and how hot it gets. If you stuff the cylinder with cold wet rags would help some. Torque up the cylinder head and sidecover as well. Keep the weld cool (you're not looking for deep penetration and strength.) That's your best shot if you don't want to rehone it.
Question: Was it honed on a rigid (Sunnen) hone, or a ball/flex hone? Only a rigid hone will make the cylinder perfectly round.
Give the welding a try if you like, otherwise, replace the block with a similar model year.
 
Yes, Brian you are correct. it WAS .0005"-.001" and i went back and edited my post # 18. As far as what type of hone the machine shop used I do not know. They are very reputable and have been in business since 1965.
Michael
 
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Update:
SUCCESS!!
The welding repair was completed today and there was no warpage of the bore. Everything is still within specs just as it was before the welding. The engine has been tested and it runs great. I feel that I got LUCKY...
Thank you to all that took interest in my project and provided opinions along the way. Even though I am not a racer or high performance engine builder I am hoping I can come back and post questions to you all as needed on my vintage flathead projects. The collective knowledge and experience on this forum is pretty amazing.
Michael
 
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