drilling my mid section

[oldschoolfan]

Can i drill my midsection w/out removing the can. What if i use a ling drill bit and go through the can

[Raceman]

Yes, it can be done. You can greatly weaken a mid section by drilling. Even the factory drilled Merc High Perf mid sections like came on the non-offshore 260's were known to fail in the drilled areas.

So why are you drilling it? If you just want it to be loud, then it's the thing to do. If you're looking for performance from it you'll be disappointed. On SOME BOATS it may help em jump on top a tad easier, but you won't find an increase in top end. After the boat gets on top it's pretty much over with except for the loud.

[cocacola]

My mid came to me with vertical holes drilled above cavitation plate. It sounded great and not loud. I soon found out tuner was broke and sitting at bottom of midsection. After installing new tuner, it was loud as ****...really loud...especially when skiing (under heavy load). The broken tuner acted like a muffler.

I covered up those holes with plates and now I am quiet again.... and no one is pissed. The liner is removed and it does have a little racy sound at idle which is good enough for me. Performance is same either way I had it.




Yes, it can be done. You can greatly weaken a mid section by drilling. Even the factory drilled Merc High Perf mid sections like came on the non-offshore 260's were known to fail in the drilled areas.

So why are you drilling it? If you just want it to be loud, then it's the thing to do. If you're looking for performance from it you'll be disappointed. On SOME BOATS it may help em jump on top a tad easier, but you won't find an increase in top end. After the boat gets on top it's pretty much over with except for the loud.

[bulleteer]

I helped the previous owner of my boat drill the exhaust of my 225 promax back in 97. We drilled 2 1-1/4 holes in the mid and have not had any trouble what so ever. It really makes it sound good when idling around the dock. When she fires up all heads turn to look. It also has the holes under the cav plate too. Here's a pic of the drilled holes in mine. We used a hole saw so the big chunk stayed in the holesaw and had the motor trimmed all the way down.

http://i71.photobucket.com/albums/i122/bullet_20xrd/b4.jpg?t=1183745582
http://i71.photobucket.com/albums/i122/bullet_20xrd/g3.jpg?t=1183745688

[pyro]

The above photos show exactly the most troublesome of the drilling options. These are the relief holes that commonly cause cracks to develop.

[Trikki1010]

Yes, it can be done. You can greatly weaken a mid section by drilling. Even the factory drilled Merc High Perf mid sections like came on the non-offshore 260's were known to fail in the drilled areas.


Louder and weaker it is....

Mine were drilled and reinforced on an 280 SS mid along with a dry-stack. Ronnie was always busting my horns about it and I thought he was being my mother:eek::eek: ;) then Fast Phil dropped the bottom half of his mid AND the WHOLE LOWER UNIT W/ PROP bouncing about 95 across Greenwood Lake.... out 5k easy:mad: :mad: Ronnie Right:o :o

Boat now has offshore mid;)

[cocacola]

Probably right Pyro....need to fill those holes with a piece of pipe to keep them open for exhaust, then weld around pipe and opening in midsection. Strengthens opening.....should cure problems



The above photos show exactly the most troublesome of the drilling options. These are the relief holes that commonly cause cracks to develop.

Ooopsss....just read Trikki's comments. Maybe it's not enough to reinforce.

[bulleteer]

I've kept a check on it and have yet to see any cracks develope after 10 years of use.

[bulleteer]

Louder and weaker it is....

Mine were drilled and reinforced on an 280 SS mid along with a dry-stack. Ronnie was always busting my horns about it and I thought he was being my mother:eek::eek: ;) then Fast Phil dropped the bottom half of his mid AND the WHOLE LOWER UNIT W/ PROP bouncing about 95 across Greenwood Lake.... out 5k easy:mad: :mad: Ronnie Right:o :o

Boat now has offshore mid;)

Wouldn't the heat build up with it being dry stacked be the main culprit of the mid cracking versus the stock cooling of the can? I know the dry stacking method builds up more heat.

[76Stingray]

what about drillingg down lower?? Like just before the mid starts to curve back the long way?? Just above the cavitation??
CB

[bulleteer]

That would be too low in my opinion. It would be best if you were going that low to just drill out under your cav plate. You would have to trim your motor almost up out of the water to have the sound being drilled that low.

[stokernick]

want noise?Offshore midsection will give you all you need!

[Six Four]

what is dry stacking?

[oldschoolfan]

I am still wondering can it be drilled out w/ out removing the tuner?

thnks for all of the replys so far

josh

[Hydrophobic guy]

You got PM

[Techno]

Normally the coolant water is dumped with the exhaust to cool all that. Drystacking bypasses a large amount of it keeping the exhaust gas hot and this get you more power. A tiny bit is used to cool the tuner.
Heres Jays article on how to do it.
http://www.screamandfly.com/home/features/engine_tech/JSRE_dry_stacking/JSRE_dry_stacking_the_mercury_v6.htm

[whipper]

That makes more sence to me! If your going to do it do it right.

[Raceman]

I am still wondering can it be drilled out w/ out removing the tuner?

thnks for all of the replys so far

josh

I already said "yes it can" on the first page.

That having been said, here's WHY I'm negative on drilling mid sections: 1. No significant increase in performance
2. Possibility of cracking and/or breaking off
3. In an environment of increasing regulations, anything that annoys other people and causes complaints has a REAL POSSIBILTY of stimulating new laws and even more BS for high perf boaters to put up with. As a lake dweller myself, there's not much more annoying that somebody coming by with relieved exhaust either real early or real late, or just continually riding back and forth by the house at any time for that matter. Most all of my Merc stuff has either offshore or champ type open exhaust snouts, but I try really hard not to annoy the neighbors with it. Unfortunately too many people don't show the same considerations and sooner or later we'll have stricter laws because of it. In any case, relieved exhaust draws more attention from water cops, 99% of who don't seem to have a clue what high perf boats are all about and don't like em period. There's no doubt that you can get by with running faster quiet than you can loud.;)

[cocacola]

Great point. While on my 8 year hiatus from boating, I turned to RC boat racing. We had approved access to many of the nicest ponds to run our 40-80mph (depending on class) boats. Many of them city parks with little to no homes near them. Most of us ran open expansion chambers on these 1 cylinder 2 stroke gasoline and nitro methane engines. Lots of fun until you loose your pond and have no place to run your $1500 toy boat. Lakes aren't suitable for these either. We were screwed by ourselves due to excessive noise.

Currently...muffled pipes are mandated, but we still have those occasional loud one's. I loved a quiet boat to be able to hear the roostertail land in the water long after the boat went by me.


I already said "yes it can" on the first page.

That having been said, here's WHY I'm negative on drilling mid sections: 1. No significant increase in performance
2. Possibility of cracking and/or breaking off
3. In an environment of increasing regulations, anything that annoys other people and causes complaints has a REAL POSSIBILTY of stimulating new laws and even more BS for high perf boaters to put up with. As a lake dweller myself, there's not much more annoying that somebody coming by with relieved exhaust either real early or real late, or just continually riding back and forth by the house at any time for that matter. Most all of my Merc stuff has either offshore or champ type open exhaust snouts, but I try really hard not to annoy the neighbors with it. Unfortunately too many people don't show the same considerations and sooner or later we'll have stricter laws because of it. In any case, relieved exhaust draws more attention from water cops, 99% of who don't seem to have a clue what high perf boats are all about and don't like em period. There's no doubt that you can get by with running faster quiet than you can loud.;)

[Trikki1010]

Wouldn't the heat build up with it being dry stacked be the main culprit of the mid cracking versus the stock cooling of the can? I know the dry stacking method builds up more heat.

As stated above by Techno, water is diverted to "cool the can" but that heat isn't the source of the "weak link". In a surfacing applications, there are increased loads upon the lower motor mounts and the casting around them that is not as strong on the SS Mids. The Offshore mids are required to be a bit tougher as they leave and re-enter the water constantly and was part reason for their original design (along with the "at idle" noise compliance snout;) )

[Little Jon]

The mid section we have has what skip had done to his.

[oldschoolfan]

I am an ocean boat run around w/ guys running twin 502s and play in the open ocean. noise bans are not as much as a problem as you lake guys have to deal with i love the idea of sounding louder at idle and such just makes the boat look meaner when i am paling around w/ the big block boys thats all

josh

[stylishskier]

I am an ocean boat run around w/ guys running twin 502s and play in the open ocean. noise bans are not as much as a problem as you lake guys have to deal with i love the idea of sounding louder at idle and such just makes the boat look meaner when i am paling around w/ the big block boys thats all

josh

you just listed your reasons for not doing it... ocean boat means mid section is subjected to more abuse than usual... you drill your mid, it gets weaker, as everyone has said, it gets weaker and you hammer on it in the ocean, it could break... why risk it? sound louder? who cares, you'll be a 'sleeper'

[hosejockey4506]

dont drill your mid it will attract more unwanted attention then you think, i can hardly go out on any area lakes any more with out getting pulled over or people complaining.

[STVmod]

i am a member of the unfortunate club!!

I had a mid that was drilled with the big holes in the back. I also had a NEW 20 min old CLE that is now at the bottom of the savannah river somewhere with a nice 30 chopper and part of a midsection... all i have left is a broke asssss midsection that is broke off at the nice big holes that were drilled in the midsection fo noise.

its ok though its just a big hole in the water to throw money into.

if you want noise get a off shore mid it is the way to go.

[hydro-cat]

The only time I ahve seen any acheivment on drilling mids was on the old 2.4 chrome bore 200's. It's been my experience that they need all the help they can get, on exhaust relief. Just to get a good hole shot and usally, just drilling the mid, thru the exhaust releifs at the upper end of the mid was enough. This means thru the can and into the tuner. This has been only on the bass boat stuff. There are some other things that are required also. Old service bullitens will tell you to place restrictors in the bleed lines. This is just my 2 cents worth. Good luck with your engine.


Tim