Exhaust Parts Compatibility Between 57 and 43

"For my repower, I ended up wi

"For my repower, I ended up with a low-hours (hopefully) mid-80s 5.7 260 HP Mercruiser engine, with manifolds and risers.

I want to install this to a late-80s MC transom assembly.

I have on hand a late 80's 4.3 parts boat (source of the above-mentioned transom assy).

It seems some Y pipes listed will work with both the 4.3 and the 5.7 - is this so for these engines?

How many of the other parts - exhaust elbows, tubes, clamps are interchangeable between the 4.3 and 5.7?

What is the common life span of the rubber tubes and the clamps in the exhaust system?

And while I'm asking, I heard that the exhaust, drive and shifter bellows are good for five years then should be changed since they are so critical - true?

This is my first Mercruiser boat project, I guess it shows…"

"The Y pipe, exhaust elbows, a

"The Y pipe, exhaust elbows, and rubber couplers are all interchangeable.
The elbow where the exhaust turns down to the Y pipe is different. The 4.3 uses a funny looking folded back elbow.
The rubber couplers have a life span of at least 10 years. They do get hard and difficult to work with after a few years of use.
The drive leg bellows are usually good for 10 years or better, depending on use. If you have the drive bellhousing off for any reason (like changing the lower shift cable), that is a good time to change them all out, including the gimbal bearing.

Rod"

"Thanks, Rod, I was hoping it

"Thanks, Rod, I was hoping it was so. But a couple things I'm not quite clear on:

Terminology. Are the common terms of this system, in order from the engine: manifold, riser, rubber coupler, exhaust elbow, rubber coupler, Y pipe?

I'm thinking I'm not real clear on other common names for what I'm calling risers and exhaust elbows… For example, the seller of the engine wrote it came with "manifolds and turndowns". So I figured turndowns could only be what are called "exhaust elbows" on the drawings on the Mercruiser parts site (since they are the only part that actually turns down). But in pictures of the engine I bought, I noticed the exhaust system stopped at what I call risers. Seller told me he calls risers turndowns and what I see is what what I get. When I looked it up, I found what I call risers are "elbow assemblies". Since he didn’t specify "manifolds, risers and turndowns", I really couldn’t argue much and it wasn't a deal killer for me - but I had seen other engines available that did come with the parts in question.

Also, if I don’t know the age of rubber couplers, is it safe to say that if they aren’t cracking or too hard to use then they are OK to re-use? Is there some sort of dressing or conditioner that can help them last longer? They seem to cost about $100 bucks minimum for the set of four, delivered. Not a really huge deal, and not something I'd want to take a risk for, but a hundred bucks could buy other stuff…

The bellows? I'm definitely renewing those, no matter what they look like. I just read that something like 44% of I/O sinkings are bellows-related.

What's the wisdom on changing the 'lower shift cable' while I have it apart?

Any other items besides bellows and gimbal bearing that are smart to replace?

The list grows."

"Your terminology is correct.

"Your terminology is correct. however, "elbow" & "riser" are commonly used to describe the riser. so be clear. I would change the shift cable. and throw away the metal clamp on the shift cable bellow. use a zip tie instead. the clamps are steel, and rust."

"Scott has you covered.

The

"Scott has you covered.

The 90 degree elbow that bolts onto the manifold is commonly referred to as either an "elbow" or "riser", or both. Risers are actually an additional straight piece that bolts between the upper elbow and the manifold.

These are available in several lengths and are used if you need more height to gain the needed clearance from water line to top of the elbows; which is usually 13".

The "elbows" actually turn down 7 degrees from horizontal on the engine block; so they could I suppose be called a "turndown" elbow.

Confusing, isn't it?

Rod"

"Rod:

What ever happened to

"Rod:

What ever happened to the multiple straight vertical flame thrower exhaust pipes used when you were a boy? Now those were some noise makers!"

"Guy;
Thankfully we all grew

"Guy;
Thankfully we all grew up, well kind of anyway.
Now most of like to try to keep it down a little in consideration of others.
You can still see what you describe at the drag strip though. Very spectacular at night!

Rod"