Heat tape on exhaust elbows

Hey Guys,

I recently replaced the exhaust elbows and mixers on my Yanmar 4LHA-STPs. The elbows have a thermal jacket on them, that is made of some sort of fiber insulation. Mine are starting to disintegrate, but I put them back on to get me through my next trip. Now I realize that you can't really slip on replacements without taking off the elbow. It's a royal PIA to take off the elbow, so I'd like to avoid that. Two questions:

1. What purpose do those jackets serve?

2. I seem to recall seeing some sort of heat tape at an auto parts store. Would it work for me to pull off the old jackets and wrap the elbows in that tape?

Thanks,
Doug

Since those elbows aren't jacketed (except for the final mixer) they get very hot, up to almost 1,000 degrees at wot. So you need insulation to protect adjacent components and yourself from all of that heat.

Shops that build marine exhaust systems can build insulation jackets that fit and tie together around the elbow with monel wire. They cover the elbows and you don't have to remove them to install. You can use the auto parts wrapping but it will be messier and will all have to be stripped off if you ever need to remove the elbows.

David

Doug, at 12 years old I would think about replacing some of your exhaust components. At least remove and inspect. Then you could do a proper job of installing the insulation jacket.

Hey Don,

I just replaced both elbows and both mixers and inspected the hoses. They were ready. I should have replaced the jackets then too, but I didn't.

Thanks David. Maybe the Yanmar jackets wire together? I'll check with my parts guy. That would be ideal.

When I bought my boat the elbows were exposed. We measures 608 degrees. The recommended max is 200 degrees. I used a wrap that I got through Amazon. It was easy to put on. They recommended wetting it out before installation. I used stainless steel tie wraps to secure it to the elbows. Works great. I think the wrap is rated to 11 or 1200 degrees if memory serves me correctly.

Comodave said:

When I bought my boat the elbows were exposed. We measures 608 degrees. The recommended max is 200 degrees. I used a wrap that I got through Amazon. It was easy to put on. They recommended wetting it out before installation. I used stainless steel tie wraps to secure it to the elbows. Works great. I think the wrap is rated to 11 or 1200 degrees if memory serves me correctly.

Click to expand...

Any chance you still have a link?

Thanks.

It was Ledaut 2" by 50' Titanium Exhaust Heat Wrap. I was wrong about the temperature rating, it is 1400 degrees. I put 2 layers on just in case.

Goggle "Sure Marine Insulating Blankets W001-884 or W001-886". These can be removed for inspection and reused if they have a size that will work for you.

I have a dry exhaust wrapped with blankets. The whole thing is removeable and I have done so to parts of it. Approach a truck or industrial exhaust shop and talk to them. That's how I got mine done in '95 so they last.

But those elbows and parts will get HOT. My EGT has often registered 750oF although it is right at the end of the exhaust manifold.

My old lagging was waterglass and asbestos tape. The new tapes I believe are fiberglass which can still be done but I doubt you will get decent stuff at an auto parts store, more for a temp. patch.
Get good stuff what ever you do,

You do know the dangers of asbestos? Take great care removing old material containing it. Anything available now should not have any asbestos in it.

Good advice about the asbestos! Sadly, Canada's contribution to world health!

The hotter you keep the exhaust elbows the faster salt crystals will plug the innards.

Thanks for all of your responses. I'll do some research and see what I can find out. The OEM jackets are pretty thin and flimsy, I doubt they are rated up to 1400 degrees unless they are some miracle fiber. I also wouldn't think they are asbestos, my motors are 2005's, I think asbestos was done by then.

Doug,

I believe the main reason for jacketing is to stop the engine room heating up too much and prevent burns if you/hoses/wires touch the hot bits. I have Yanmar 4LH-DTE's and used header-wrap on my new risers. It works fine, but the blue tends to rubs off on anything that touches it. There may be more expensive wraps with patterns and/or colours that don't run. I was not in a position to find out.

More details of my little project here.
http://www.trawlerforum.com/forums/s6/make-your-own-exhaust-risers-mixers-23031.html