A short while ago we scored a pulled-apart, but intact ’69 Ironhead powerplant from our long-time pal Josh Green. The engine was in great shape and it already had the top end done up with bigger pistons and a ton of machine work. The only issue was that one of the cylinders had the top fin missing. It would be a shame to put together such a nice motor and have one of the largest fins missing knowing it would stick out like a sore thumb and bug the shit out of us for eternity.
Luckily for Street Chopper, we are friends with Dave Singrey of Davey’s Welding who specializes in fin replacement on heads and jugs as well as Knuckle and Panhead case repairs. After a brief phone discussion, we putted over to Dave’s shop and he showed us how to properly replace a fin from tip to tail. Here’s how he did it. STC
Source Davey’s Welding
(562) 243-8808
[1] As you can see the whole...
[1] As you can see the whole top fin on one side is missing and needed to be repaired.
[2] Dave got to work quickly...
[2] Dave got to work quickly by sanding off any rough edges that the departed find had made.
[3] All of the surrounding...
[3] All of the surrounding areas that will come in contact with the repair were cleaned of any paint or gunk.
[4] A template was made in...
[4] A template was made in the shape of the missing fin with paper and pen.
[5] The shape was then transferred...
[5] The shape was then transferred to sheetmetal the same thickness as the original fin.
[6] The new fin was then...
[6] The new fin was then cut out on a band saw.
[7] The edges of the new...
[7] The edges of the new fin were deburred and adjusted to the shape of the where the missing fin broke off.
[8] With a little work, the...
[8] With a little work, the new fin was made to fit with little to no gaps.
[9] The new fin was slathered...
[9] The new fin was slathered with flux.
[10] The whole cylinder was...
[10] The whole cylinder was heated up with a torch
[11] Once the cylinder and...
[11] Once the cylinder and new fin were at 400 degrees, it was go time.
[12] The two parts were carefully...
[12] The two parts were carefully brazed together using a torch and silver solder.
[13] Once the new fin was...
[13] Once the new fin was one with the cylinder, it went into a heated oven for gradual cool down.
[14] In about an hour the...
[14] In about an hour the cylinder was cool enough to start shaping the new fin.
[15] To shape it correctly,...
[15] To shape it correctly, Dave marked the new fin with a paint pen using the lower fin as a guide.
[16] He then shaped it with...
[16] He then shaped it with the aid of a Bur King stationary belt sander.
[17] The edges of the new...
[17] The edges of the new fin were shaped with a small hand-held sander.
[18] Dave then peaked the...
[18] Dave then peaked the bottom of the fin to mimic the previous fin’s casting.
[19] He also gave the top...
[19] He also gave the top of the fin some good peaking to match the other side of the cylinder.
[20] Here’s the new fin on...
[20] Here’s the new fin on the old jug. It’s looking good and ready to meet the rest of the motor being built.