Re-powering to a Mercruiser 496

[SEASTHEDAY]

Hey Team:

I'm biting the bullet and re-powering my '98 454 to a Merc 496. (I'll just say water in the manifolds and move on....)

Has any one done this?

Any gotchas I should be aware of? I'm thinking something just isn't going to line up right.... Any "heads up" is greatly appreciated. (Any ideas on how to convince the wife this is a good idea is appreciated as well...... )

Thanks
Mark

 

[northern]

Why a 496 not an other 454. Are the mounting bolt patterns the same? Is the 496 more efficent?

 

[dpmulvey]

Run Forrest, Run.

IIRC, the POS sea water pump on the 8.1 is in the same POS location as the 6.2. Lower left. It is an absolute SOB to get to and the engineer who designed it should be shot. The entire pump has to be disassembled to replace the impeller. Here are some shots of mine. Yes I know it's a V drive making it less accessable, however I have friends with I/O's who have the same complaint. You will regret buying a Merc the first time you change the impeller and every year after that.

Here are shots of mine I took last week.

The seawater pump is behind that pulley in front of my big brown shoe.

Note the proximity to the stringer.

That is the cooler above the seawater pump

The red hose is a seawater hose going into the pump.

If you are the size of the average 6 year old, it won't be too hard. It would be for the average 7 year old though.

This would be my 1st choice.

http://www.boatstoreonline.com/420_main

I know he has no 6.2L MPI's in stock. I talked to him yesterday. He may have some carb models or other sizes. Note the HP to Weight ratio.

Second would be Marine Power. It's what the local mech's are using here as drop in replacements for the Merc. Cheaper and note the placement of the sea water pump on the crankshaft. Thirty minute DIY impeller changeout at most.

http://www.marinepowerusa.com/

Third and only because I don't know if they can be adapted as an I/O would be Crusader. Again, everything is up front and easy to get to.

http://www.crusaderengines.com/index.html

Good luck with whatever you choose.

My $0.02

 

[No Name Sea Ray]

I did the same two years ago. My mechanic installed it. The only issue I was informed about was the need for a special pigtail to adapt the wiring and I needed to re-prop, so add a bit to the budget for that. Might not need props.

I do not know anything about the pump issue spoken about above.

They no longer make the 454/7.4 so your choice is the 496/8.1L or the smaller 6.2L. The 6.2 is a good motor but probably not enough for yours or my boat despite the hp being similar to the old motor.

Yes you can go rebuilt but I found it to be not a big enough money difference for me. And I wanted closed cooling. The Bravo III can handle 400hp, so no H.O. 425hp engines.

Boat runs great, uses a bit more gas and sounds a bit healthier. Not cheap, 15k all said and done.

 

[Tail Chaser 661]

Lots more TQ with the 8.1. A new prop will probably be in order. Engine is longer then the 7.4. Even more so with the front mounted raw water pump. 8.1 should get much better mpg at cruise speeds.

If you have lots of room in front of the engine. I would look at the Marine Power 8.1 also. Less computer crap then Merc.

 

[SEASTHEDAY]

Wow… GREAT responses …..THANKS VERY MUCH….

Hey Northern: I have heard 4 really bad stories about the 454s (besides my own), the most recent story was a guy at Defender (defender.com it’s in Waterford close to where my boat is… I’m there far too much…) he has a 1997 37’ Sea Ray with twin 454s. Last year he rebuilt them both; this year 1 blew… YIKES…The previous owner of my boat didn’t run the engine …he just let it sit… in 05 the manifolds were changed, but not the risers nor the elbows…. This year I started to replace everything… you should see them… I’m surprise my engine didn’t blow a long time ago…. (at this point it hasn't blown.... I haven't tried starting it ... it ran fine end of last season... but now... I had 2 different mechanics tell me either repower to rebuid.....I just can't see rebuilding....)

Hey Dpmulvey : GREAT PICTURES AND GREAT INSIGHT…. I’ll check those sites for engines as well… and check out what those guys have… THANKS…. My pump from the 454 was in the same location, but I had more room to play with than what I’m seeing in your pics. Man that is tight…. I have some pics of my engine…. (it’s hauled out right now… and I’m wrenching with the gimbal) I’ll have to see what I have…. And where the stringers … I’m going to make some serious measurements now… and talk to my mechanic Eric and see what he says… he had told me the foot prints with the 454 and 496 were the same…. I’ll double check where the pump is .. My friend Rich has a 2000 340…with 454s and V-drive… it took his mechanic 8 hours to change both impellers…

Hey No Name: I had heard about the pigtail…. The prop comment is making me go “Hmmmmmmmm………”…. My friend Jon (JSea558) has the exact same boat with 22 pitch props and he likes them (his 454 is in much better shape than mine…) My props are 20 pitch props… The torque is higher with the 496; I’m thinking new props are going to be needed…. Again…hmmmmmmm……What do you think I should go with? My friend Peter has a 6.2, he re-iterates the “no replacement for displacement” phrase… I’m leaning toward the big block….. I too like the closed cooling…. As well as the Stainless Steel dry-joint exhaust…. That is interesting… ;-) Raw water cooling should only be for boats on a lake, not for Long Island Sound …what was I thinking? …… well… let’s not go there….

Hey Tail Chaser (I dig the name…..) How do you like your 26 pitch props? Mine are 20 pitch … I’m going start doing some homework on this bigtime...

These responses have certainly giving me a lot more to think about… I’m going to start with where that pump is going to be, that could be a major show stopper right there….and the props. Another thing I just learned is that the manifolds are 2 inches higher that where they were on the 454 so a 4 inch riser is needed rather than the 6 inch risers; which is extra….of course…. Oh the drama….

Anyway … THANKS again….:grin: I really appreciate it…. I’ll keep the thread going and let you know where I’m at with it all….

Thanks
Mark

 

[Tail Chaser 661]

SEASTHEDAY....
I have not tried the 26P prop yet. So many holdups last year with the project I had to walk away before splashing her. Starting to get motivated again now. :grin:

Keokie on CSR had the identical boat as I. The 502ci has the same TQ as the 496ci. I went off off his advice, since he had done lots of homework and trial and error.
His 502ci 26 DA with 2:20 GR ran 30 mph at 3000 rpm with a top speed of 53 mph. Cruise mpg was 2.0/2.3 mpg running 3000 rpm around 30 mph depending on conditions in fresh water.

Motor mounts locations are all the same. You may need a new Y-Pipe for the 496ci exhaust risers to fit.

 

[No Name Sea Ray]

Forgot to say- It is a very tight fit on the top, maybe an 1-1/2" to spare vs 4" before under the floor.

I would not worry too much about the props. Your 20" should be close. You might only need to go to 22". Once everything is all back together, run it a bunch under all conditions and see if you need a change. Just watch that you don't over rev or bog it down. You can buy good used or new props on ebay for $500-700 for the pair and sell them for the same, so no real cost. I still have some for sale in the classifieds from my experimenting.

 

[dpmulvey]

I found a thread on another site with a workaround for the POS pump. He uses a Sherwood P105 crank mounted pump on his 454 Mercruiser powered Shamrock. He posted his pix on his website. What a difference!

 

[SEASTHEDAY]

The mechanic is saying that if I'm going to go the the Merc 496, then there should not be an issue... The 496 has been used to replace the 454 for a while and the placement of the water pump should be just as difficult as it was before....but not worse... (nice wording huh?) other engines ...it depends...

Here are some pics of what that area looked like before I pulled the engine out... I'm going to look into prop pitch next....

 

[SEASTHEDAY]

Hey No Name:

That 1-1/2" to spare vs 4" before...under the floor. That is scaring me now.... Is that the clearance above the engine itself.... or about the exhaust? Any pictures of that you might be able to share? THX :grin:

Do you have risers?

THX
Mark

 

[No Name Sea Ray]

Not sure what kind/size of risers are on it.

The engine cover panel is the highest part.

 

[SEASTHEDAY]

Okay... Thx.

Spoke to mechanic again..... I must have misheard him the first time... he said the impeller "is" worse to change because it's further back ....closer to the mounting bolts.... I might have been laughing at the comment about "….should be just as difficult as it was before….” to not catch the "worse" statement .....I don't know...

Also, found a 2000 Sea Ray 270 online in New York (recently sold) that had a 496 installed.... saw the pics of the engine.... looking at those pictures made me feel a little better about the whole deal...It looks like it’s going to work… :thumbsup: I’m going to try to contact the broker……


I’m adding what my engine looked like….. and the pics from the online ad …. Any observations …..please share…THX

Here is my old engine.

Here is the 496

...looks do-able.... no riser on this one.... would likely need to add that... hmmmmmmmmmm........ what-cha-think?

 

[Cool Runnings]

I did that in 2005 on my '94 290 Sundancer and it is a better boat now. It's a tight fit and hard to get into the bilge for maintenance. In fact it just fit sinced the fuel tank is just fore of the engine. I have a Bravo 3 outdrive and need to replace that now.

 

[SEASTHEDAY]

Yes, it is a tight fit…Moving around the engine is definitely different… I pulled the trigger and did it.. ordered it ...($13,000) it arrived within a week.... ... and we put it in the hole... did a new gimbal as well.. that was $1700 (should have bought a package... for 21,000 and worked a deal with "cool runnings" for the outdrive...bad timing....).. Wasn’t planning on the gimbal assem, that sorta happened at the last minute...... I have a 2006 outdrive... hope that lasts.... I was worried about the raw water pump there for a bit... but that fits okay ….. phew.. ...I got the pig tail to convert to a 14 pin; from the 9 pin…put in the new steering arm and the new trim pump. Need a pig tail for the trim pump now..... also need risers.. they are 4.7 inches and are $683 for the pair... The wife is just about ready to shot me...(really... she really is...) they arrived 2 days ago.... by then I made other non-boating plans for Memorial day... so didn’t make it for this weekend… oh well……. The risers will go in next week.. I'll take pics and update.....

Hopefully I will be in the water soon... Everyone else is floating by now... it's just killing me...

 

[CAGE RATTLER]

Did you have to change the Ypipe for the 496?

Im about to order a 496 as well to replace my 350 MAG MPI and trying to find out if i will need a new ypipe as well. From what ive been able to find out... the 350 mag and the 454 uses the same ypipe. Part # 807130A4

I checked the part numbers on mercruiser parts.com but they dont even list a y pipe for the 496. What gives there??

 

[SEASTHEDAY]

Hey there Cage Rattler:

Good ole Mercruiser .... with their part numbers .... real PITA... The Y pipe I took off had part number 861229-c on it...

No, I didn’t have to change my y pipe. I did… I replaced it with exact model….well… my friend Jon give me a "barely used" new Y pipe... same exact model as the one I had. (Jon has same exact boat '98 Sea Ray 270; his engine is running fine...) My old was was 12 years old... The one Jon gave me had less then 10 hours on it... it was very clean He had 2 newer ones... kinda forget why... but he install one of them on his engine a year back and offered the other one to me. I owe him big time.... :grin:

One thing to note... if you are ordering the "engine package"... it comes with a new trim pump and a new steering actuator... one guy told me the engine package only has the engine and if I wanted the other 2 parts, he "can get the for me..." for a good price... at the time said something like between 500 - 1000. I kinda forget. He mentioned that would have to be a "separate sale".... so, go with a good dealer.
(I think I paid $13,774 that was price with tax… did I mentioned the wife wants to shoot me??? …gimbal was ~ $1800)

We thought we order the 4.7 inch risers for the 496; when they came in they were 6" risers... which made it too tall... Then we found out that the 4.7 inch risers were only for the 305, 350, and 377 engines, not the 496.... (oh the drama...) They only make 6" risers for the 496. The manifolds are already 2" higher on the 496 than the 454. We ended up sending those 6"risers back.... and ordered new elbows that were 2" higher than standard rise (stand rise in the elbow is 3";...we order the 5" overall...) We ended up cutting about 1.25 inches off of the exhaust elbows..(the ones that connect to the Y pipe) to make the whole thing work..

We just fired it up yesterday for the first time... the engine alarm kept going off…. 2 beeps every minute or so… just a warning… ….Eric (mechanic) hooked up his merc tools and it said it had 50 psi for oil pressure… while running… then we shut the engine off… and it stayed at 50… it should have gone to zero. He then found the oil pressure sensor was installed incorrectly on the engine from mercury … (more drama) .. unplugged it …turned it …plugged it back in…. and it worked… went back to the break in sea trail… running it at 1500 RPM for a while… THEN it started to whistle… Eric immediately said… sounds like a bad IAC. (Idle air controller) which it was… so… he is getting a new IAC as part of the warranty … (wife still isn’t happy….. She still can’t go for a ride… MORE DRAMA… just a few more days……..)

Anyway, I ramble when I’m tired… good luck with your purchase. I’ll upload pictures soon. Other than those 2 things… the engine ran great… I’m looking forward to using it… It wasn’t as loud as the 454; and felt good ….a new engine should feel good right?

L8R
Mark

 

[CAGE RATTLER]

Now your scaring me ... lol

I ordered mine friday and feel i got a very good price.

Hopefully i wont run into the same problems you have or worse!!

I kept looking around online at prices but wanted to buy local from a merc dealer in case there are problems. We have a local dealer with 3 different locations and the one location near me is turning into a repower center. I went there a couple times to get some prices and found that these guys dont know a whole lot about boat engines. Their just salesman and it was like pulling teeth to even get prices from them. I had to keep pointing out the right motors that i wanted prices for out of their catologue cause they had know idea what i was talking about. They kept wanting to give me prices on CPO engines (which are used engines). By the way ... the price they gave me for a CPO 496 Mag was 11,700.

After about a week going back n fourth on the phone and them giving me prices of CPO engines, I finally told them I could get a 496 MAG online for 12,000 and if they could match that i was ready to write the check. They called me back an hour later and said since they were just starting out repowering they would get me one for 12,000 and that they were only making 1% on the deal.

I was up there an hour later to give them a deposit and when they ordered the engine, merc only had 1 in stock and it was setup with 2inch risers which would make it an additional $200. they told me if I didnt need the risers they would buy them back or swap them out with what ever size i need. So with tax my bill came out to $12,932.

Your comments about them only haveing 6 inch risers for the 496 mag has me wondering. Guess i'll find out when it comes in.

They did tell me the engine comes with the new tilt & trim pump Which i didnt realise) but nothing was said about the steering actuator. Guess i'll find out about that as well when it comes in too.

Pulled my 350 MAG this past saturday and getting ready for the new engine to hopefully go in this coming weekend.

Im worried about the elbows & Y pipe fitting as well. I was told they should work and hopefully it does.


Im hoping to splash the boat on the 26th so hopefully all goes well.

My prop got ruined by corrosion last year and will need a new one anyway but I have no clue what size to start with after the new repower. any clues??

 

[SEASTHEDAY]

KEWL… Congrats! Good price as well…:grin: Did it come in?.. Is it in the hole? Don’t rush it…. I found out.. doing a re-power… you want to make sure everything is done right…. I had 5 different launch dates…. ( I have to sign up on a schedule.. whatever is available..) 1st one was May 9th I think… just don’t rush to meet a launch date… focus on getting it 100% the way you want it…

The best CPO price I heard was $11,500. I almost went for it…..I did hear a horror story that Eric told me, one of the CPO’s that was ordered in 2009, when the engine came in… it had a DOM of 2005… the guy was not happy…with CPO they are supposed to … rebuild it .. or whatever…. They did nothing… then what do you do… there is a restocking fee for it to go back…. No thanks… I wasn’t sure if it was the same guy… but another story I had heard was that the engine came in with aluminum exhaust… yikes….a guy in Florida said he could get me new one (not CPO) below 12.. with warranty.. wanted all the $$$ up front… didn’t feel right…

I talked to Eric last Friday… he said he was still trying to find an IAC…… so.. no boating over Father day…….. Today he says … it’s back-ordered… (MORE drama) not one of his Mercury contacts had one… (that is kinda …giving me some pause…hope this isn’t the Achilles heel for this engine….) I’m going to start looking up the IAC info… he also told me he had the gaskets for it, but didn’t have the IAC itself… he said he would let me know more this week… he got off the phone with the final remark that was something like… “don’t worry .. we’ll have you running by end of August…”… GREAT!!! THANKS BUDDY!!!!

I had learned a lot just putting the thing in the hole… One nice thing about Eric is that he will work “with you”.. and will basically let me know…. “okay.. I’ll do this….. YOU do that…” you don’t need me to do that and charge you for it when you are perfectly able yourself… he did the heavy lifting… I did all the cosmetic stuff… I did have an issue with the starboard side ground… my deep socket was too big… I couldn’t get it to fit ..something was in the way… I ended up using a 5/8” spark plug puller… to tighten it up…then… I dropped it …it went all the way down to the “v” part of the Y exhaust…. Wasted about 2-3 hours trying to get it… then went to Home Depot… and got a magnet on a swivel head…and was able to pull it out...nightmare…

I have bravo 3 with 20 pitch props…. My friend Jon (same exact boat with “working fine” 454) has 22 pitch props and loves them.. Someone suggested I should start with 24 pitch… but… I am staying with my 20 pitch for now… (cuz I’m broke…) I think “No Name Sea Ray” had some insight here….

Anyway… GOOD LUCK RICK! I hope you are floating soon… :thumbsup:

 

[CAGE RATTLER]

Picked up the engine this past saturday and was going to drop it in sunday but decided i want to do some work in the engine compartment 1st. Doing a lil glass work and then a fresh coat of bilge coat. Im also moving the batteries, trim pump & some wireing around as well. I spent most of saturday just staring at it and checking everything out on it ... lol.

Im off all next week and hoping to at least get it splashed before the 4th of july for the fireworks on the water.

I think im going to be ok with the Y-pipe & elbows. The new motor that was originally supposed to come with 2 inch risers came stock so that saved me another $200. They didnt even charge me the refundable $300 for the crate fee.

About the CPO engines .......... I was completely turned off on those after reading mercs site.

"CPO products will show some evidence of use: scratches, cosmetic corrosion, and any number of hours are possible"

My boat has a Bravo1 and i have a 19 Pitch prop to try out 1st. Then i can adjust from there i guess.

My boat is on a trailer in my back yard so a launch date is no big deal. I just want to make sure its right before i even start it. I plan to have service tech from the place i bought it check everything out and go on the trial run with me.

The steering actuator did come with it along with the new trim pump and new alarm kit.

I read in the installation manual that they reccomend using an exhaust tube instead of the exhaust bellows on the bravo drives so i'll be changing that as well. Something about it causes a vaccum at the prop decreasing some performance.

Quick question .......... I noticed the sea water inlet hose has quick connects on them but unfortunately they didnt give me a quick connect to attach to the transom inlet. Did you put one on yours or did you just pull off the quick connect and connect the hose to the old transom inlet? Im not quite sure i'd feel comfortable with that setup anyway and may remove all those quick connects. The sea water hose is actually 2 hoses with 2 quick connects. it would make it an easy way to add a flush valve though.