1969 Chris Craft Roamer 46 Refit: New Coolant Hoses, Clamps, and Coolant Test

While I wait for supplies to show up so I can finish the exhaust risers, I avoided the blistering heat of summer and headed into the relatively cool engine room to finish up the coolant systems.

Original(?) coolant hose was kinked

Original(?) exhaust manifold coolant hose on the right side was kinked; new formed hose on left won’t

Turbo coolant hose also kinked

Turbo coolant hose also kinked

Constant torque clamps eat the bands

Constant torque clamps eat the bands

Another CT clamp cannibalized itself

Another CT clamp cannibalized itself

I’ve never used Constant Torque clamps before, but I know some guys who swear by them. Clearly, Cummins likes them. But they seem to rip out the treaded portion of the bands. I suppose this could be from overtightening… Either way, I need to replace them. Like everything else, I figure out what parts I need, order them online, and hope they show up during the following week. I’ve pretty much stopped ordering parts locally, since state sales tax adds significantly to the cost of everything and shipping (even from far away places) tends to at least break even if not save money.

Out with the old, in with the new

Out with the old, in with the new

Much better...no kinks!

Much better…no kinks!

New silicon turbo coolant return hose

New silicon turbo coolant return hose

I also replaced the exhaust manifold coolant return hose

I also replaced the exhaust manifold coolant return hose

With all of the lines replaced, I tested the coolant to make sure it was within specs. From what I’ve read, the 6CTA engines have sleeved blocks and additives are required in the coolant to avoid crevice corrosion. When I drained the coolant it was extremely clean, so I ordered some test kits to check the status.

First color band

First color band shows good glycol

Second band

Second band is in the middle  for molybdate

Third band is a tad low, but within spec for nitrite

Third band is a tad low, but within spec for nitrite

Where the column and row cross is in the green

Where the column and row cross is in the green at ~1.5SCA Units/Gal

Port side was in the green, too

Port side was in the green, too

So I refilled the coolant systems, and that’s another check box on the honey-do list. I’m still waiting for my argon diffuser to arrive so I can finish welding the exhaust risers. The only things left to do on the engines is wrap up the fuel system and raw water supply.

Next up on our 1969 Chris Craft Roamer 46 Refit: Building a Fume Extractor & Paint Filter Box

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2 comments on “1969 Chris Craft Roamer 46 Refit: New Coolant Hoses, Clamps, and Coolant Test

  1. Julian Davis says:

    Many years ago an old marine engine mechanic told me to use Breeze stainless steel clamps. His reasoning was that the edges of the Breeze clamps were slightly rolled so they would not cut into the hose even if over tightened.

    I don’t know if that remains the truth or if the information is too far past it’s use by date.

    We’re loving the progress you’re making on your yacht.

    • 1969roamer46 says:

      Thanks, Julian!
      I’ve used t-bolt clamps for bigger diameter hoses and standard worm gear clamps for smaller ones, but the failure I’ve seen here are similar to ones I’ve seen for standard clamps. I’ve never had a problem with clamps cutting hoses. AWAB solid band clamps are very good and with excellent rust resistance, but since the engines came with constant torque I decided to stay consistent.
      Cheers,
      Q

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