Beck TD, Part 44: Trimming the Ram's Horns

The Ram's Horn is an engine part in early Volvos - it vents oil fumes to the atmosphere, in those pre-emissions-controls times. I don't feel guilty for running one - it makes Beck TD look more "vintage," and I've only driven the car about 200 miles in almost two years. As the accountants say, that mileage is "not material" in terms of cleaning up the air. I think the official name of the part is "Road Tube" but Ram's Horn is a common name among enthusiasts due to its shape.


I wrote about the Ram's Horn previously in a prior post (link), when I repaired an oil leak behind the horn. These photos are from that post, showing the entire Ram's Horn to the left, and the top part attached to the engine to the right:

There's a bracket on the horizontal part at the bottom of the tube. It attaches to the block underneath one of the bolts for the oil pan. I'm preparing an engine I recently bought from Joe Lazenby. It's only two years younger (1967 vs 1965) than the engine that was in Beck previously, but in those two years, Volvo made a genuine improvement. They added a cast aluminum stiffener to the bottom of the block, and cast in ears on the block to mount it. Unfortunately, those ears made it impossible to reinstall the Ram's Horn without modification. You can see how the bottom bracket is hanging out in space here:

Well, nothing to do but ask for help. I asked some of my buddies on the Volvo Engined MG Group, and Jake Roulstone came thorough with two bits of info. He said that his Volvo-powered TD has the later engine, and the horn was modified by cutting, and then extending with a stiff hose. The second bit of info was even more important: he said that the tube works via the Bernoulli effect, the same thing that makes airplanes fly, and it is important for the tube to extend down into the airstream the same amount as the factory originally designed it.

After ascertaining with Joe Lazenby that he had extras in his collection if I ruined this one, I set to work. First, I cut off the tube just past the bracket so I could mount it in place to take stock. I'm holding the cut-off piece below the remainder of the tube:

With it bolted securely in place, I could mark a cut point on the tube just past the oil pan bolt to the left of the currently used one, so I could continue to mount it that way. After cutting, I had a shorter Ram's Horn, and a stub with the mounting bracket:

That bracket is mildly complex, with a pinned-on foot and a curve that fits the tube. I decided I could remove it more quickly than I could duplicate it, so I set to work with a Dremel tool with a thin cutting disc, and cut through the welds holding it in place. It came away very cleanly:

I remounted the now-shorter tube, and used it to mark an appropriate cut line on the down-turn:

After that cut, I reinstalled everything to check alignment. You can see how I bent the bracket to match the curve it now needed to match:

Thankfully, the Grant St. Garage photo team was on break while I welded everything up - I am the worst welder you know, no matter who you know! In this case, I installed 0.025" wire in my MIG welder, carefully set it up, and practiced on the small pieces that were cut out until I was not blowing through the pipe on every weld. After a couple of tries, and a good bit of grinding of the excess, I put the welder away. A bit more refinement, and a skim of JB-Weld to gloss over the flats left by grinding, and it was ready for paint. At 10 or more feet away as I drive by, it will look just fine!

Continue on to Part 45...