Replacing the Exhaust Manifolds Risers on a 5.0 V8?

[BoatMyAssOff]

My Mercruizer service center just let me know that they needed to replace the Exhaust Manifolds cause they found water on cylinder 5/7 while performing the annual.

I was quoted $1900.00 just for parts. Is this a relative simple job to do for a person with average mechanical skills?

 

[Don S]

Re: Replacing the Exhaust Manifolds Risers on a 5.0 V8?

What's the SN of your engine, year doesn't mean anything after 1998.

 

[JUSTINTIME]

Re: Replacing the Exhaust Manifolds Risers on a 5.0 V8?

holy sheet!
i got a buddy with a shop your way

 

[BoatMyAssOff]

Re: Replacing the Exhaust Manifolds Risers on a 5.0 V8?

Ok, here is the info requested:

Engine: Mercruiser 5.0L 220HP
Engine S.D. #OL949752

I was looking in my Seloc Mercruiser Stern Drive Repair Manual and they list the following for water in cylinders:

1 Backwash through exhaust system
2 Loose cylinder head bolts
3 Blown Cylinder head gasket
4 Wraped cylinder head
5 Creacked or corroded exhaust manifold
6 Cracked block in valve lifet area
7 Improper engine or exhaust hose installation
8 Cracked cylinder wall

Woohaaa.....fun times

 

[captmello]

Re: Replacing the Exhaust Manifolds Risers on a 5.0 V8?

Replacing your exhaust won't solve the knock in your motor you mention in your previous post. If you are in salt water, the engine needs only minor neglect before exhaust becomes corroded. If your in fresh water I doubt manifolds would be bad unless cracked.

I would check into the motor problems your having. Perhaps another opinion.

In your previos post you wrote:

Ok, I have just enough knowledge about egnines to really mess things up

Now you ask:

I was quoted $1900.00 just for parts. Is this a relative simple job to do for a person with average mechanical skills?

You better bring it in.

Good luck to you!!

 

[BoatMyAssOff]

Re: Replacing the Exhaust Manifolds Risers on a 5.0 V8?

I think we have limited the so-called knock to a lose lifter.....the noise went away when we increased the RPM. It was only present at really low RPM, and I have to wait a bit before it is audible.

I'm the second owner of the boat, and since it only had 64 hours on it when I bought it in 07, I'm not sure what the previous owner did with it since 02?

Mechanical skill....no engine skills, but I have built my own kit car before.

I did an annual in 09/22/07 and this was the compression readings:

1 - 200
2 - 195
3 - 195
4 - 190
5 - 200
6 - 195
7 - 190
8 - 200

So, 4/7 seems to be the ones with lower compression? Wil get the numbers from this annual and compare.

 

[Don S]

Re: Replacing the Exhaust Manifolds Risers on a 5.0 V8?

That serial number is for your Alpha outdrive, not the engine, what I really need to know is if you have the Dry Joint type exhaust system or not on your engine?

 

[BoatMyAssOff]

Re: Replacing the Exhaust Manifolds Risers on a 5.0 V8?

That serial number is for your Alpha outdrive, not the engine, what I really need to know is if you have the Dry Joint type exhaust system or not on your engine?

Don,

My bad...0M353341

PS. Where do you recommend I buy the parts from?

Edit: Just got another quote to replace exhaust manifolds - $1500, including labor. Does this sounds more reasonable?

 

[BoatMyAssOff]

Re: Replacing the Exhaust Manifolds Risers on a 5.0 V8?

Found a nice site to purchase parts from based on engine serial number:

http://www.perfprotech.com/store/catalog/Mercruiser-Parts-Finder,3172.aspx

Since they only found moisture on the spark plugs for 5/7 I'm hoping I only need to replace the gasket (cylinder head to manifold). Luckily I always run the motor at least once a month.

 

[Bondo]

Re: Replacing the Exhaust Manifolds Risers on a 5.0 V8?

I'm hoping I only need to replace the gasket (cylinder head to manifold).

Ayuh,... There's No Water at that gasket,... Only Exhaust,+ Atmosphere....

 

[BoatMyAssOff]

Re: Replacing the Exhaust Manifolds Risers on a 5.0 V8?

Ayuh,... There's No Water at that gasket,... Only Exhaust,+ Atmosphere....

Well, once I get to see one of these things, my understanding should improve So much to learn....

 

[Don S]

Re: Replacing the Exhaust Manifolds Risers on a 5.0 V8?

My suggestion would be to download the oem service manual for your engine from the adults only sticky at the top of the forum. There is a section in it for the exhaust system. I have to assume (by the prices you were quoted) that you must also have exhaust riser extensions. Is this true?
You do not have the "Dry Joint" type manifolds so just the standard manifolds risers, etc. Also, in your price quotes, was the price for only manifolds and risers, not only the extensions, but shutters, hoses, anything else they were adding into that parts list that you aren't telling us? Did the Merc shop pull the risers and inspect things, or just assume that water in 2 cylinders is from faulty manifolds and risers.
Yes, that 0M number is the engine serial number.

 

[BoatMyAssOff]

Re: Replacing the Exhaust Manifolds Risers on a 5.0 V8?

My suggestion would be to download the oem service e
.........
Yes, that 0M number is the engine serial number.

Yes, the price was for Manifolds, Risers and Elbows....and no, they did not pull the risers. I will run it tomorrow and then pull the 5/7 plugs to see if they are wet, then proceed from there. Thanks for the help.

 

[JustJason]

Re: Replacing the Exhaust Manifolds Risers on a 5.0 V8?

I'd throw a set of new plugs on that side (cyl's 1,3,5,7). Take the boat out for a hard run. And if you can.... chop the engine at high rpms and float in/get pulled it. Let the plugs sit for a day or two then pull them and see if they have rust on them.
There's more than 1 way to get water in the cylinders.... i'm surprised they didn't visually inspect let alone pressure test the manifolds.
It's not a very hard job changing the manifolds/risers.... the most time consuming part of it, if you don't have an aircompressor, is stripping off the old manifold to block gasket.

 

[Don S]

Re: Replacing the Exhaust Manifolds Risers on a 5.0 V8?

Take the boat out for a hard run. And if you can.... chop the engine at high rpms and float in/get pulled it. Let the plugs sit for a day or two then pull them and see if they have rust on them.

What are you trying to do, intentionally get water in the cylinder?
Come in dock the boat normally. After an hour or so, then pull the plugs and look at them. Why wait for rust to build up on the cylinder walls along with the spark plug. Just pull the plugs out and look for indications of water.

 

[JustJason]

Re: Replacing the Exhaust Manifolds Risers on a 5.0 V8?

What are you trying to do, intentionally get water in the cylinder?

Eagh.... Your right.... as you usually are

I had OBs on my mind for some reason when I wrote that.
Still.... if the I/O is in good tune it shouldn't experience reversion or deiseling if you chop it....
But if it's not.... Your right.... It will probably suck like a hoover.

 

[BoatMyAssOff]

Re: Replacing the Exhaust Manifolds Risers on a 5.0 V8?

Well, they just did the annual, and this shop is known for being on the high side when it comes to boat issues.

I'm taking picking it up tomorrow, going to run it for a bit (wait till it cools down), and then pull 5/7. If I detect any moisture, we will pull of the risers and proceed from there.....the boat is in excellent conditon, I'm rather surprized at this finding.

I think the fact that it all started with the "knocking noise"(lifer noise) is sending the mechanic on a goose chase. Worst case senario, valve job...at that point, I'll out window!!!

 

[Fishermark]

Re: Replacing the Exhaust Manifolds Risers on a 5.0 V8?

I think the fact that it all started with the "knocking noise"(lifer noise) is sending the mechanic on a goose chase. Worst case senario, valve job...at that point, I'll out window!!!

No offense, but there are quite a few "worse case scenarios" than a simple valve job. I didn't see your other post, but a knocking noise can be many things... in fact most of those things relate to the bottom end of the engine - a "worse case scenario" than a valve job.

 

[BoatMyAssOff]

Re: Replacing the Exhaust Manifolds Risers on a 5.0 V8?

**** FEEDBACK ****

Completed the annual, and the compression looked fine. They did found that sparkplugs 5/7 had some moisture. I had another shop pull the risers and inspection showed some water got it in.

Problem: This boat is my first inboard and I would stop by pulling the power. Apparently water can get in past the flappers. They did check the flappers and they were ok. So, if I drive it properly, it should be fine.

Thanks for all the help.....throwing money at it helped