Re: Exhaust Riser gasket change
 

Great point. I have a bunch of bolts... but 8 perfectly matched of the correct length, thread and size? Not so much.

I work on mine at night most of the time too.
On lots of jobs you are gonna get surprised and you will end up running for an unexpected need. Can't avoid it.

This should not have been one of those jobs. I ordered a kit that was to include all necessary elements.

At the end of the day... it was ok that a mistake was made with the order. It is not ok that the customer was treated like a piece of crap.

I'm a good customer. I only expected to get what I paid for.
Nothing more, nothing less.

Re: Exhaust Riser gasket change
 

Ok... it's my busy week.

I decided to let ebay deal with him.
They have a mechanism for "I paid but my entire order didn't arrive."

My request was that the ad be amended to show only the items that he actually ships so that future customers can have some protection.

Re: Exhaust Riser gasket change
 

Where "Less is Moore"...Now thats funny!

Re: Exhaust Riser gasket change
 

Ok... still getting powdercoating off of the mating surfaces.

Going with MCs suggestion.

Now that the coating is off I can see that one of the four castings is really cobbled. Like they had a void in the casting at the mating surface so they globbed some more metal in the spot and tossed it back on the grinder.

Took the file to it but there is way less mating surface on that one.

If he wasn't gonna send bolts... I don't suppose he is gonna ship a replacement manifold.

Maybe I will just have to put that one on the engine that is the less "popular" of the two. :D

Re: Exhaust Riser gasket change
 

Ya know... at the end of the day... nothing personal against Dennis (who I have never heard from again good or bad) but the manifold castings are lame.

The risers are actually well cast. Clean and sharp. Good consistancy of the metal. Fairly precise.
Two out of four of the manifolds are really poor castings. One is frightening. I have worked on it with a file, but I'm still scared of it. It looks like they were short on metal so the added some later. Eek.

The other two manifolds are ok. Not great.

Knowing what I know now... I wish that I had gone with stock replacements. My time in trying to make these cheap chinese castings look flat is really adding up.

Wish the manifolds had been done with the same workmanship as the risers.

Maybe the aluminum ones are better.

Re: Exhaust Riser gasket change
 

I am actually thinking about ordering an Osco to use instead of this one really crap one from Dennis. I don't think that he would replace a crap casting since he wouldn't ship 16 bolts.

For a couple hundred extra bucks in might be worth not worrying about losing a block because of a poor quality GLM manifold.

Re: Exhaust Riser gasket change
 

They are in. Went with what Dennis shipped instead of a new one.

Started bolting them up on the outboard side of the port.

By the time I got to the inboard side of the starboard I knew I had a problem. The old manifolds JUST slipped past each other in the center. There was just enough room between the other manifold and the studs on the side you are working on to slip the manifold that you are installing past the studs.
The new one wouldn't fit. So I got out my tape measure.

The EXACT REPLACEMENT manifolds from GLM (per Dennis' ad) are actually 1/4 inch wider. (each) So the "exact replacements" are not the same size. Ahh.

This means that I gained 1/2 inch in the center and 1/2 inch on the outside for a total of 1 inch lost free space.

Can't get the oil filter out from under the SB side anymore without removing a manifold.

Can't pull the engines without removing the manifolds anymore.

Had to switch from studs to bolts on the inboard manifolds to get them on.

Getting either inboard manifold off is going to be a trip.

Not sure how you guys interpret "exact replacement" but I took it to mean that they would fit in the same space... not be larger in width. Especially when dealing with twins in an 8 foot beam.

They do make my engines look bigger.

And they seem to kind of run, sort of.
(Think I have corroded points on SB)

And the stainless riser bolts give me some much needed bling. :D

Re: Exhaust Riser gasket change
 

POINTS...........

Fund, you seriously have to get rid of them, either different distributors or a points elimination kit.

Sorry to read about all the hardships on what should have been a straight up swap out.

Re: Exhaust Riser gasket change
 

Points= OMC ESA system (electronic shift assist). There are a couple of electronic ignitions that are OMC ESA friendly, but I am not sure which. They seem to fail fast enough with points.

I switched from points to magnetic breakerless on my last boat (with a merc alpha) and was very happy.


On the hardship issue: it's a boat. What else should I have expected. I'm just glad that I had enough creativity left by that time in the day to figure out how to make a sling out of bungees to hold the manifold up next to the mounting holes to use the studs as bolts.
Neither one of those inboard manifolds are coming out without using vice grips to remove the studs WITH the manifolds. :D

But I wish that Dennis' ad had said "suitable replacements" rather than "exact replacements."

They seem suitable... that's the important thing.

They are NOT exact.

But at the end of the day I am glad that I caught this because I did see a tiny bit of rust in one exhaust port in one head to go with the tiny bit of rust in the manifold. I am sure that I had a ticking time bomb on my hands.

Seems like the thing about wet manifolds is that by the time they are leaking OUT, they are already leaking IN.

Re: Exhaust Riser gasket change
 

I don't care for wet joint manifolds for just the reason you mentioned. Dry joint is the only way to go in a boat IMHO.

Re: Exhaust Riser gasket change
 

You are right.
If this wasn't a cheap, stock boat I would have converted.

Re: Exhaust Riser gasket change
 

I couldn't agree more. Yes, they cost more, but everytime I look at them I am very glad I have them.

I will not own a boat without them now.

Re: Exhaust Riser gasket change
 

Fund Razor,

Sorry to hear about the problems. Mine are aluminum look to be in better shape than yours were in. I did not think to check the size because they do look the same...Will put a ruler on them and check. The Mercruisers must be narower than your OMC's cause I had??? more room than you seem to have between the engines. I think the height will be more critical on mine because I am using the Y pipes and not going thru the hull.

Did you get on the water yet?

Re: Exhaust Riser gasket change
 

You shouldn't use stainless bolts on those risers. Stainless is actually a weaker metal than grade 8. Stainless could stretch on you. I originally had stainless in mine, actually broke one bolt tourquing it down, then switched to grade 8, got them from Fastenal.

Re: Exhaust Riser gasket change
 

Stainless is fine for the correct torque setting of about 20 ft/lbs.

Stainless is also available in grade 8 even though that is way overkill for this application. Most stainless failures are from not lubing the threads before installation causing the nut to gall when tightened with an air tool.

Re: Exhaust Riser gasket change
 

Fund,

2 Seasons ago, I went with Osco Manifolds on my stock 1987 Merc Alpha 454. They were thicker than stock (cross-sectional) and seemed well made. They bolted on great, had all of the attachment bosses and came with all the fasteners and fittings.

Last weekend, I went to start up the boat for the season and found I had a stuck #5 exhaust valve. :mad: Yes...it was ultimately due to the riser joint leaking internally. When I originally installed these new manifolds, I decided not to use the paper-type Osco riser gaskets supplied, and opted for the Quicksilver grey steelcore gaskets. I used no sealer, filed both surfaces flat, and torqued the riser bolts to 25 ft-lbs. I wonder if I made a mistake on assembly?? :( (..and guys don't say I bought the wrong type of manifold...I run a stock 330hp and in salt water - aluminum would be a disaster! and stainless would have been a disaster in my wallet!)

Anyway, I am putting it all back together this weekend (with the Quicksilver grey gaskets) and I am going to try the copper gasket spray that McCollins suggested. In addition, I am going to remember to torque those riser bolts a few times in the beginning of this season. Let's see what happens then! :evilb:

Good Luck!

-Larry

Re: Exhaust Riser gasket change
 

ljsmith1,

I actually like the OSCO gasket better than the MC. The same thing happened to mine...MC riser gasket installed by the book leaked and took out exhaust #1. The OSCO gasket I'm using came with a FWC kit. Its thicker and lower durometer than the MC and the ones I got are not made of paper.

cloudmaster_321, the stainless riser bolts should be fine if torqued properly, I used stainless fasteners for everything external on my engines without a problem.

Re: Exhaust Riser gasket change
 

Hi IT.

The mercs are a tiny bit narrower, but the stock OMCs were narrower than the repros.
I think that my engines/drives are closer together than some twins I have seen.

I am not thru hull either, I came out to the stock couplers and pipes.

Got the boat in the water Friday. Everything seemed ok and it didn't sink in the slip so I took her out for a real shakedown Saturday. Too many boats out for me to really get a good reading on a new WOT speed, but I was out for about 90 minutes and I think that I have a small gain.

I was seeing 33 mph at 2800 and 52 mph at 4200.
Just a little trimmed out but not trimmed to the moon.

I was having a little trouble with the idle. They didn't want to stay running below 1000 rpms. Passengers would never have know what was up, but the skipper always knows.

I am gonna run out some of this old gas before I start changing things. Good chance that with todays fuels separtating so easily when not kept mixed... could very well be old gas.

Re: Exhaust Riser gasket change
 

I am thinking the same thing Mark. The rusted ones that I removed were grade 5. Most broke off.

The torque on these riser to manifold bolts is 14.

Hard to get exact with my needle style T wrench, but I am guessing they are between 15 and 20... hand tightened and triple stepped.

I consulted with a metal guy before I did it.

He said NO WAY use stainless studs for the manifold to block but absolutely ok to use stainless for the risers.

Re: Exhaust Riser gasket change
 

I really trust MC. Not only does he know the theory behind every piece of advice he gives... he has actually DONE it. (Over and over.) I went with the copper spray a gasket and coated both sides of the metal crush gasket and both mating sufaces. We shall see what happens.

If he says that the Copper spray a gasket is "magic" then I believe him.

So far so good, but I am gonna check those bolts periodically.

Good luck right back at cha! :D

Re: Exhaust Riser gasket change
 

Thanks for all the input guys.

I appreciate it.

Re: Exhaust Riser gasket change
 

Hey Fund,
How are the manifolds working out for you?
I haven't bought a set yet, but I'm planning to soon.
Mine are shot.

Paul

Re: Exhaust Riser gasket change
 

They seemed to work out ok once the mating surfaces were cleaned up.

Ended up running the boat for a few hours (enough to know that the job had beed successful).

Then last week I sold the boat.

Have been too busy to use it.

My only advice to someone considering the GLMs would be that they should expect to have to clean them up and that they are slightly larger (in my case anyway) than the stock. Be aware in tight twin apps.

Also... supply your own hardware.

I had to change a set of studs to bolts to get one side on.

I also would recommend using the Copper Spray a Gasket to help fill small voids in the castings on the mating surfaces.

Re: Exhaust Riser gasket change
 

Thanks for the info.
Were you able to use the studs from your original manifolds, or were they the wrong length?
Are you going to be getting another boat?

Paul

Re: Exhaust Riser gasket change
 

Fund Razor,

Guess your out of boating for the season...Didn 't take to long to sell it.

Did you notice any speed or performance improvement over the stock manifolds?

Re: Exhaust Riser gasket change
 

I used the studs, but backed them out using a second nut and slipped them into the manifold before I tried to line it up.

I used a sling made of bungees to suspend the manifold near the block so I could have a hand free for getting the "bolts" started. Only had to do this with one manifold. One of the inners obviously.

I'm sure that I will get another boat sometime.

Not sure what it will be.

Re: Exhaust Riser gasket change
 

Yep. Taking the rest of the season off. Maybe catch a couple rides.

I would say that the cast ones that I bought didn't exactly hurt the performance but there wasn't a huge gain. Didn't get the chance to trim the boat to the moon and go for ultimate max WOT but my sense from running it a little is that I picked up one or two mph maybe.

Might have gone from 52mph to 53 or 54, on gps. All other things being equal.

I can only assume from the reduced weight that the aluminums would have a larger gain.