EXHAUST RISSERS

[enterprise]

This will be my first post, new to the forum, so please forgive me if the subject of exhaust risers has been "done to death".

The £1200 question is after ten years used in salt water (approx 6 weeks per year)do the manifolds & rissers of a 4.3L mercruiser engine require replacing ? .

I have sought advice from several sources, including marine engineers that I use for regular maintenance.

There seems to be divided opinions.

One will say in 17 years of trading they have never replaced worn out exhausts or rissers,the other, that to remove and inspect them would cost (with gaskets ,time etc) almost as much as just to replace them.

As expensive as it may be, is it worth £1200 for peace of mind?

Thanks in advance.

 

[mtb]

Hello
no mate if it aint broke dont fix it !!
The fella who says he has never replaced a worn out exhaust has my vote .
There would be more risk of breaking the manifold or studs just to look at it !! IMHO

Cheers
Mick

smile you'l be on your boat soon ;-)
<A target="_blank" HREF=http://homepage.ntlworld.com/boats/>http://homepage.ntlworld.com/boats/</A>

 

[yoda]

I agree

Yoda

 

[oldgit]

Worth a look is www.yachtsurvey.com.The badly designed rubbish quality leaky risers mentioned throughout this web site may just possibly be made by an engine manufacturer known to you.Only a most basic knowledge of mechanics are needed to get the things off yourself,but be warned as the other posters have stated all sorts of things may need replacing ie studs will shear etc.It will all depend on what the previous owners have done.My risers frequently clogged due to scale/rust blocking water passages,in the end I could take them both off in minutes.You can buy good quality replacement parts from www.keyparts.co.uk or ring em on 01923 221490.they will prob be cheaper and faster to supply than M*******r.Do not forget new gaskets etc etc.You can forget about them and keep a constant beady eye on the temp gauges or .......... sort em first during winter.
As the TV programme stated...Do them before they do you. IMHO.

Oooh look its still not dark and its nearly 5pm

 

[neale]

I would say that 10 years could be considered very good service and replace them as a precaution. Shop around and you will do better than £1200 I'm sure. I replaced Manifolds and risers on a V8 for around £500. It may have been less, but I did have to ship them from USA and fit them myself.

In the US the general concensus seems to be that for saltwater use manifolds have a useful life of around 5 years with risers lasting only 3.

 

[enterprise]

Thanks all,
The advice has made up my mind.

I will purchase and fit both exhausts and risers, £500 seems worth the piece of mind.

Was the fitment of these straightforward, or will I need special tools.

Any problems with importing parts?
They sure look better prices.
Do original parts fair better than third party manufacturers?


Thanks again.

 

[oldgit]

Re: exhaust risers.

First. you will need 3 large containers of ready to use patience
Second. you will need the skills of a circus acrobat.
Third. you will find it usefull to have eyes on stalks.
Ps. your arms will require at the very least 2 extra sets of joints.
A couple of gallons of WD40 applied at least 1 month before starting job is also
V. good idea.
Once you have got that lot together we will begin.Be aware that none of your spanners will fit down in narrow slot between the well hidden nut and the riser.ditto.your socket set. Thats even if you can see the object of your desires which will be located in some impossible to get at place somewhere under the transom...........As for time about 8hrs to around 6 weeks should see the job done.

Oooh look its still not dark and its nearly 5pm

 

[enterprise]

Re: exhaust risers.

Thanks oldgit.

Humor will make make all the difference.

Nursing skinless knuckles on the three remaining fingers holding my sore head after falling into the bilge trying to reach the socket wrench that just sheered from bolt no'1

Why do all simple jobs take longer to complete?

 

[neale]

Fitting is in fact very easy. It is the removal of the old ones that could be a problem. The bolt heads on mine were rusted to rounded lumps which I could not get a grip on. I had to cut through them with an angle grinder (make sure there are no petrol fumes lurking).

I beleive that the aftermarket manifold people such as Osco and Barr actually provide the manifolds for the engine manufacturers so you may well be getting exactly the same product. You would need to confirm this but it makes sense.

I had no problem with shipping even though it is a very heavy package. It had to go surface mail which takes around 6 weeks but wasn't too expensive. I have exact figures of the total cost somewhere, I'll see if I can dig them out.

Neale

 

[ccscott49]

Re: exhaust risers.

Oh! it's a bit awkward then is it?

 

[Russell]

My V8s are getting on for 13 years old now, so I took the elbows off to replace the water shutters which I thought were rattling. Turns out that the ends of the risers had corroded and snapped off and thats what was making the noise! I've bought pattern risers here in Holland for €206 each, which is way cheaper than I was quoted in the UK. In fact I've also bought genuine stuff over here cheaper than I could buy pattern stuff in the UK.........rip off England again ? Let me know if you want any contacts over here.
The manifolds still look good though, probably because they stay full of water, whereas the ends of the risers dry out. I took them off anyway to check them, and yes, loads of the bolts sheared but only where they go through the manifold, so they unscrewed out of the head OK. The worst problem was the weight of the manifolds, lying down between the engines trying to get them out was a nightmare.
I've also bought the new plastic water shutters, which should be a big improvement on the old metal ones which were also destroyed.
The plan is to put it all back together this weekend, I'll let you know if they fit.....

 

[oldgit]

Re: exhaust risers.

Nooooo Nooooooo Mr ccscott.dead easy job and if you feel like popping round and taking mine off for something to do,while i nip off doen to Spain for a spot of sun.........................................

Oooh look its still not dark and its nearly 5pm

 

[ArthurWood]

My 454s don't have risers, only elbows. I check to see if there is seepage from the gasket and change the gasket about every 100hr. There may be plugs in the manifold which you can remove to take a look inside and make your own determination as to whether to replace them. Mine were replaced at 1100 hours - 5 yr in salt water. You might want to visit Boatdoctor.com for tips on how to change the manifold.