replacing small section of hot exaust with 1" pipe instead of 1&1/4th" pipe

[LemonShark2]

Hi A's.

I had a rusted pipe break, and am trying to replace the end section of piping, past the elbow section. My problem was the Home Depot and Lowes only had enough black iron piping to replace with 1" sections, they didn't have 1.25".

I found an 1.25" to 1" converter, and bought the supplies to replace the end of the system with 1" piping.

Before I do this, I am hoping you could advise if this will have negative effects?
Too much pressure in the exhaust system due to smaller fittings?

Piping in red is the area I'm replacing, at a total length of about 12 inches

Thanks!

[Peter]

Lemon,

excessive back pressure is not good - I recall the manual suggesting that they suspect most A4's run with too much bp - MMI even sells a bp measuring kit to diagnose this issue.

Go to a plumbing supply store - probably cheaper than Lowes/Home Depot and they will have the sizes you need.

Peter

[LemonShark2]

I had a feeling that might be the case, but was hoping otherwise. Whats up with the big stores never having quite what you need??? sigh

[toddster]

My irrigation supply house has all the black iron stuff I need. Barring that, there's always Grainger or McMaster-Carr.

[JOHN COOKSON]

IMO is is rather useless to replace the iron plumbing "due to a rusted pipe breaking" because what you don't replace now will fail sooner rather than later.
How do you plan on loosing the threads to remove the section that failed? Bet you can't do it.

TRUE GRIT

[LemonShark2]

I think I got a bit lucky. It broke half way through the threading on a connection of two pipes, and the left over 1/2 inch of threading looks to be salvageable to connect a new section to.

Ill have to replace the whole thing eventually, but hopefully the quick fix will last through the summer, and I can do the complete project in the winter.

[romantic comedy]

I bought black iron online for a much better price then the plumbing supply.
Dont recall the vendor. Plumbing supply .com?

They also had SS for a decent price. Brass was more then SS.

[edwardc]

I think I got a bit lucky. It broke half way through the threading on a connection of two pipes, ...

This isn't luck. Exhaust pipe nipples almost always fail at the threads. The thickness of the pipe wall is at a minimum there due to the depth of the threads. That's why everybody recommends schedule 80 pipe. The walls are thicker, but the threads are still cut to the same depth, so you get the benefit of all the extra thickness.

Sch 40 1 1/4 pipe is 0.140 inches thick, while
Sch 80 1 1/4 pipe is 0.191 inches thick.

(Source: http://products.anssteel.com)

[goodoldboat]

cooling system

Grainger has it .. just ordered it on Friday they are shipping to my local grainger for pick up

[sastanley]

GOB, thanks for the info..maybe LS2 will order some too!

[LemonShark2]

I ended up going to a proper plumbing store, they had everything I needed including some rust buster to clean the older threading. They managed to get the fitting that the soft hose attaches to off, which saved me $23 of buying a brass fitting, which was the only one they had!

[LemonShark2]

I think my total was less than $25.

[LemonShark2]

Bump / update with new question

When I originally created this thread I was looking into replacing all of the hot section piping on the boat from where it had rusted to the point of breaking at one section and onward.


I was able to find the correct pipes to replace the old piping, but i have an issue of not being able to connect them to rusted threading on the old pipe section. I'm not able to disconnect the old pipe.

I'm looking for a solution to joining two pipes together without having to thread them together. maybe a flexible section that I can use hose clamps to tighten onto each pipe. Needs to be heat proof so it wont melt!

My final important caveat - this is super temporary, I only need to be able to motor the boat 5 miles, at which point I am passing it off to a boat yard to be chopped up and parted out. (I already own the next boat)

Any advise is welcome...