Engine Options for Repowering my twin 350 Mag MPI

[Hai Nhi]

Hello everyone.

I'm in the research phase for my repowering work on my new-to-me 1999 Cobalt 292. Currently it has twin Mercruiser 350 Mag MPI with Bravo One's. Engines exteriors are very rough & rusted. Hand crank can't turn them over. So it's definitely time to go.

I'm checking around for some reman but I heard a lot of you (from this forum) saying that new is better. Well of course I'd like to agree too except new ones are more expensive . So I'm here asking for your advice & input on how to soften the pain as much as possible.

Assume all options below are complete drop-in.

1) Option #1: I ran into some listings for a brand new set of Mercruiser Sea Core engines, but it's only a 5.0, with possible discount. My question for this option is: how would a twin 5.0 compare to a twin 5.7 for this size of boat (in term of power, ...)? Most of my boating time would be touring places, possibly carrying 10-12 people. If I go with this option, how much per engine would consider a really good deal? How much is fair market price for this?

2) Option #2: I read in some of the posts that GM employees can get discount on Mercruiser??? I don't know anyone @ GM, but my uncle works at a mechanic shop. He asked the shop owner and it seems like they're not sure how, if it's at all possible, to get Mercruiser at a discount. One of my friends also work at some dealership (I need to find out which), and the other friend owns a mechanic shop. Any tips & advice on how to utilize any of them to possibly get engines at discount prices?

3) Option #3: go with Reman. I saw videos & advertisement about Mercruiser own lines of reman's. Look pretty promising. If this option is advisable, which dealers get reputable service & fair/good pricing? Is there any other company that makes good/reliable reman other Mercruiser?

Thanks in advance.

Nhi

 

[alldodge]

Option 1 - no way, no how
Option 2 - I doubt it but it's worth a shot to see.
Option 3 - Reman's are a good way to go if you can either do it your self (best) or can trust your rebuilder.

I like option 4 - buy new marine crate motors

 

[Scott Danforth]

I would start by pulling the drives. Would hate to have you replace a motor because of a seized drive.

If it were me, I would build a pair of 383 or 396 stroker motors. sort of option 3.1

 

[Mischief Managed]

I would only go with new if the entire engine is shot. Were they underwater? Do you need all new engine electronics too? If so, new makes sense. If the bolt-on items are ok, then go with a pair of rebuilt long blocks and re-use the bolt on stuff. I'd go with at least 5.7s, nothing smaller, but that's me. I'm sure the boat would be fine with a pair of 5.0s; they came that way from the factory and Cobalt does not have a reputation of building price point/under powered boats.

 

[biggjimm]

Beings it is fuel injected I would think the 5.0's would not run 100% correct with the ECM & everything programmed for the bigger 5.7's. The cams & intake & exhaust runners in the heads are different sizes also & I would expect the 5.7's to perform much better besides the obvious increase from being larger displacement engines. Just my thoughts. Good luck with it. Jim.

 

[Hai Nhi]

Thanks everyone for your quick & great respond. I've looked up the 383 Stroker and liked it a lot. It's ~$10k/ea though. Hahaha.

Right now what I can tell from looking at the engines, there's lots of rusts. I will try taking some photos and load them up. In the 2nd week of August, I plan to setup some hoist framing in the back yard to haul both engines out to inspect further. And pull the drives while I'm at it for inspection & service as well.

I have a 4x4x12' steel tube. I was thinking about using it as the cross bar with some 4x4 supporting posts. Any suggestion on this would be appreciated as well.

How to determine which bolt-on components are worth keeping? I'm willing to spend time and my elbow grease to salvage parts. But at the same time, if it makes sense to replace new, I'm ok spending extra too - within reasonable limit. Since this is a twin set up (double the $), I'd like to look for deals to minimize the total bill.

So far, I've searched through prefprotech.com, and eBay.com listings for 350 mag mpi & 383 stroker mpi. eBay has lots of vendors and I'm not sure who's selling their own reman or Mercruiser dealership.

 

[biggjimm]

Just sent you a PM regarding a source for replacement engines. Good luck. Jim.

 

[Hai Nhi]

Thanks Biggjimm.

I'll check them out to see what they have.

​

 

[Scott Danforth]

If you have a good working relationship with your local machine shop, building a stroker vs a 350 is about $800 more per engine. About $1700 to rebuild a 350. About $2500 for a stroker. Assume $500 per motor for new manifolds and risers.

However if you haven't pulled the drives yet, you can't be certain your motors are shot or your drives are shot. If your drives are locked up, the motors won't turn

 

[nateo]

If engine is on the compression stroke you won't be able to turn crank by hand.

 

[alldodge]

I see your in CA and next to the coast. So unless you have closed cooling the salt could be a real issue with trying to rebuild them. New crate motors are in the 3000 range give or take. They can also be picked up at your local GM dealership, just make sure to specify marine type

 

[Hai Nhi]

ok I'll pull the drives and try again.

The boat was driven in salt water for sure.

AllDodge, when you said ~$3000 range, do you mean just the short block?

 

[Hai Nhi]

Just pondering: what it takes to make a boat like this smart craft and axius joystick equipped? . Can someone pls list a "menu" of things to buy/replaced with close estimate on costs to see what it's like?

I'm always wanted the luxury of joystick handle so my wife can drive it too, without lots of training.

Thank you.

 

[alldodge]

No long block
This one is from GM Direct but is an auto engine, this includes UPS freight to a hub. BTW crate 383 is in the 5000 range
http://www.gmpartsdirect.com/results.cfm?singlepart=1&partnumber=12499529

Call your local GM dealer and ask, never know what they will sell it for

Here is Michigan Motors
http://www.michiganmotorz.com/350ci...t-p-109.html?gclid=CKX3m9r7hccCFQczaQodKmgDZg

 

[Scott Danforth]

It is cost prohibitive to update to axius. Smartcraft gauges would require newer or brand new engines, controls, wiring. If you really want to go that route, sell your existing boat and buy one running with the smartcraft setup or axius.

 

[Bondo]

It is cost prohibitive to update to axius. Smartcraft gauges would require newer or brand new engines, controls, wiring. If you really want to go that route, sell your existing boat and buy one running with the smartcraft setup or axius.

Ayuh,..... Exactly,.....

 

[Hai Nhi]

I would imagine so. Just curious what it takes to have luxurious stuffs .

I heard you also need bravo iii too, right?

 

[alldodge]

I would imagine so. Just curious what it takes to have luxurious stuffs .

A large bank account

I heard you also need bravo iii too, right?

Don't think its a "have to" could do it with B1 or B2, but current models I've seen all have the B3. You get far less crabbing with the B3

 

[Hai Nhi]

I saw some listings on eBay for axius. Some of them in the $1400-$1700 range, some only ~$700. Are these complete joystick system (other than the newer engine with dts requirement, or possibly the B3 requirement as well)? I thought it would be in the ~$5000 range or more.

Large bank account I don't have, but if total extra to bring it up to axius equipped (including dts upgrade, additional for engine upgrade, and the axius system itself) is less than $5k, I might be able to pull it off. Just wishful thinking though, I think....

Counting down till engine work start date (after 8/10) - can't wait!!!

 

[biggjimm]

So have you decided what route you're going to go with your boat?