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View Full Version : Holman Moody exhaust weld-repair question



Craig S
08-27-2016, 09:49 AM
I'm sifting thru my exhaust stuff, trying to find 2 sets for my sbf Nova.

I have 2 very clean (like freshwater) sets, both with cuts and repairs on outside of one log manifold each.

Should this be a worry, or not? Is this a common permanent repair for what was probably a freeze issue?

Thanks
Craig

Ghost
08-27-2016, 11:06 AM
I'm sifting thru my exhaust stuff, trying to find 2 sets for my sbf Nova.

I have 2 very clean (like freshwater) sets, both with cuts and repairs on outside of one log manifold each.

Should this be a worry, or not? Is this a common permanent repair for what was probably a freeze issue?

Thanks
Craig

Craig, good to see you around here.

To your q, I dunno, but I wouldn't trust any manifold without a pressure test, particularly an old and repaired one.

Mike

yeller
08-27-2016, 01:53 PM
I had the same thing done to my Glenwoods and they lasted for years after the repairs. They were still on the boat when I sold them.

I had cracked the manifolds internally due to freezing, so I cut out a section of the outside so I could get them welded on the inside; then had the outside plate welded back on.

It all depends on the quality of the weld as to whether yours are good or not, but if they pressure test ok, then I would think they are good.

gcarter
08-27-2016, 02:06 PM
What Glen and Mike said. OK, but a test is called for.

A 4-1/2" right angle grinder and some 80 grit paper
would do wonders for the aesthetics of them.

The gimbal housing on the TR was corroded through.
After welding the area, filling, and judicious grinding
and sanding, it looks and works great.

yeller
08-27-2016, 02:11 PM
Normally, I would agree with you George, but those haven't been TIG welded, they've been arc welded. Aluminum arc welds can be very porous. I'd be concerned he may open up a hole if he grinds it.

Craig S
08-27-2016, 08:46 PM
Thanks all!!!!!

Pressure testing....with air? How long?
Positive or vaccum?

Or plugging and pouring acetone in open end to hold for a while?

I'm not planning to grind it pretty...just prep to paint Fomoco dark blue. I dont want to risk it.

Slow project. Still have to finish paint and all.
Craig

yeller
08-27-2016, 11:22 PM
Just plug it and fill with a few pounds of air and submerse in a tub of water. You'll know right away if there are any leaks.

Ghost
08-27-2016, 11:51 PM
She's still a looker! :)

Craig S
08-28-2016, 04:55 AM
Thanks for the kind words. Im pretty anxious. And amazed at my costs :-(.

Luckily, the restoration shop i have much confidence in. And we're good friends.


So, just pressure up with a few pounds of air (5?), and look for bubbles? Not looking to hold 20 pounds for 36 hours solid or whatevever?

I can do this.

I want to accessorize one engine this month (and break in the cam) to install in the boat. And get the 'engine turning'/jeweling sorted on the stainless dash plate.

We need the engine cams broken in and engines (418cid 351w) sitting on their beds by end of October so that we can re-shoot the Awlgrip hull and deck in November.

Then onto upholstery/windshield detailing/fuel system/tabs/steering/wiring/sole/rub rail/wood and chrome trim during winter. Goal is 5.1 for floating running boat show. Keels and Wheels 2017.

The stringers/transom/and detailing of main bulkhead were pretty big accomplishments over the past year or two. Or three. We chose to glass, finish and prime the multipiece control Station and reinforce with glassed CoosaBoard on the cabin side...bonding to the deck and liner. Its a very clean look that Brownie probably couldn't warrant on the production line. And it will eliminate several feet of Taco riveted aluminum moldings. And the long deck has become shapely and rigid. A weak point. Thanks also to a relatively massive glued lamination stretching from hull/deck to hull/deck below base of windshield.

All the underwater gear and v drives are installed with new seals. We made custom ss saddles to protect their 4 mounts (and the 6 from the engines) from Coosa. Barrier coat is on.

mattyboy
08-28-2016, 09:17 AM
I have seen a test using acetone in the manifold water chamber with the water inlet plugged with a log style just stand on end

a good test

https://www.youtube.com/watch?v=8D16i68nHmE


a bad test

https://www.youtube.com/watch?v=6AW8i97UYg0

gcarter
08-28-2016, 09:18 AM
Lookin' good Craig!

yeller
08-28-2016, 01:47 PM
I've never heard of using acetone.
What if there is just a very, very minor crack? I'm talking about just enough for the acetone to dampen the other side of metal. Couldn't that go unnoticed, where air would cause bubbles?

Craig S
08-28-2016, 05:51 PM
All four passed my test using acetone. I'm going forward.

Thanks!