5.7 to 7.4 swap

[joelewis73]

Ok I have had it with the 5.7 Mercruiser that I have in my Rinker 242... I paid alot of money to have it rebuilt and guess what 3 times out on the water and I think I blew it up again today>>>WT>>> It sounded like a old volkeswagen so i was limping back into the ramp and within a mile of the ramp it made a very bad grinding sound, oil smell and smoke for days and I had to be towed back. I am going to the shopthat redid my engine and only hope that they will stand by the engine they built.
But if not I have found a 7.4 that is for sale and want to know from the people on here what would I need to do to swap out the 5.7 with the 7.4.. I have a Bravo 3 outdrive and the 7.4 has closed cooling so what else will i need. This is the 3rd time that this boat has left me and my family stranded in need of help. Any help is freatly appreciated.
Thanks
Joe

 

[Wave thumper]

Re: 5.7 to 7.4 swap

Thats bad luck, what did the shop say about it?

 

[Scott Danforth]

Re: 5.7 to 7.4 swap

the 5.7 and 7.4 share the same flywheel housing bolt patterns.

you will need a big block coupler, a bit of plumbing, and some time. I would find out why it blew if you just had it rebuilt.

 

[picklenjim]

Re: 5.7 to 7.4 swap

Exhaust manifolds unless it has them already. Does it have a flywheel? May use the same coupler. Is there room in the engine compartment in front?

 

[joelewis73]

Re: 5.7 to 7.4 swap

Thats bad luck, what did the shop say about it?

Oh the shop said the warranty was only good for 90 days even though the boat was laid up for over a year due to my deployment. I am no mechanic to say the least but I could have done a better job... The guy who owns the shop said that was his sons deal and he left and they do not do baots anymore... What a crock they have 5 boats sitting in their parking lot.... Stay away fro The Machine Shop In Va Beach Va... IMO

 

[joelewis73]

Re: 5.7 to 7.4 swap

the 5.7 and 7.4 share the same flywheel housing bolt patterns.

you will need a big block coupler, a bit of plumbing, and some time. I would find out why it blew if you just had it rebuilt.

I have plenty of time, other than I am ready to sink the boat and say to hell with it... They will not even look at it tohelp me said it has been to long even though it was laid up for so long....Oh well out $3600 on that engine guess I will get it going again..

 

[joelewis73]

Re: 5.7 to 7.4 swap

Exhaust manifolds unless it has them already. Does it have a flywheel? May use the same coupler. Is there room in the engine compartment in front?

NOt really sure about the front room will have to see what the difference is. The engine is complete I am looking at just want to seewhat would be in the process... Thanks

 

[Scott Danforth]

Re: 5.7 to 7.4 swap

$3600 is a lot of money for a motor. The big block is about 31" long from the flywheel housing mating face to the front of the coolant circulating pump. (about 2" longer than the small block)

 

[joelewis73]

Re: 5.7 to 7.4 swap

$3600 is a lot of money for a motor. The big block is about 31" long from the flywheel housing mating face to the front of the coolant circulating pump. (about 2" longer than the small block)

you are exactly right $3600 is a lot if you break it down by the hours of how much I have had it out $3600 / 10 hours wow look there $360 an hour..
I think there may be at the most 6 inches now from the front of the pulleys to the fuel tank so I will take a look in a while just dont have the heart to go over and open it up.

 

[Scott Danforth]

Re: 5.7 to 7.4 swap

you have to get back on the horse..... you may also see what went awry.

 

[joelewis73]

Re: 5.7 to 7.4 swap

you have to get back on the horse..... you may also see what went awry.

Yeah I know I am looking at new engines right now and I think while I will get it done I have to get my Chris Craft back in the water and drag this one to Mississippi when I go. I only have 18 days until move day so not alot of time to get anything really done. I will probably build it myself with some help from friends and get a reputable shop in Ms go over it really well before I do anything.

 

[joelewis73]

Re: 5.7 to 7.4 swap

Well just got word today from the shop I took my boat to down here in Mississippi that the crank shaft along with 2 spun bearings. He told me that I need a engine or rebuild this one with a new block. I have to get this one going I sold my Chris Craft and now I am living on the Gulf of Mexico with no boat at all. I am loosing my mind fishing from the bank. I just spent 260 for a new rod and reel for surf fishing....LOL...Anyway I am looking at buying a engine and swapping all of the required parts from my old engine to the new engine and having the shop put the new engine in the boat for me. That way i do not screw anything up with the installation. I think I can handle the swap out of parts and such to save me a little cash. Any words of wisdom as far as a good place to get a good engine that will not kill me in the wallet. I have a call into the Boat Yard down here in New Orleans to see if they have a engine that can be tested and dropped into my boat since that is what the mech told me to try first before we do anything else. Thanks in advance for any help.
joe

 

[RollinEarly99]

Re: 5.7 to 7.4 swap

How is your swap coming? I recently took my boat out last weekend and with 7 adults I could barely get my boat to plane... I could definitely use some extra power! I'd love to swap a 454 in her.

 

[Walt T]

Re: 5.7 to 7.4 swap

You might try a 383 "stroker" motor which is a 5.7 with a 400 crank in it. Those have a great deal of torque due to the longer stroke and you can specify pistons, heads, etc. Would be easier than a big block changeover and probably less expensive. However, there is no substitute for cubic inches and the 24 is a fairly big boat.

 

[Bondo]

Re: 5.7 to 7.4 swap

Ok I have had it with the 5.7 Mercruiser that I have in my Rinker 242... I paid alot of money to have it rebuilt and guess what 3 times out on the water and I think I blew it up again today>>>WT>>> It sounded like a old volkeswagen so i was limping back into the ramp and within a mile of the ramp it made a very bad grinding sound, oil smell and smoke for days and I had to be towed back. I am going to the shopthat redid my engine and only hope that they will stand by the engine they built.
But if not I have found a 7.4 that is for sale and want to know from the people on here what would I need to do to swap out the 5.7 with the 7.4.. I have a Bravo 3 outdrive and the 7.4 has closed cooling so what else will i need. This is the 3rd time that this boat has left me and my family stranded in need of help. Any help is freatly appreciated.
Thanks
Joe

Ayuh,... The very 1st thing to do is figure out what's killin' yer motors,...

If for instance, yer fuel system isn't workin' correctly,...
No matter what motor ya put in there is gonna Burn itself up from a lean condition induced Detonation,...

 

[Wave thumper]

Re: 5.7 to 7.4 swap

Ayuh,... The very 1st thing to do is figure out what's killin' yer motors,...

If for instance, yer fuel system isn't workin' correctly,...
No matter what motor ya put in there is gonna Burn itself up from a lean condition induced Detonation,...

This must be all sorted by now.

What is the current state of the boat Joel?

 

[Bondo]

Re: 5.7 to 7.4 swap

This must be all sorted by now.

What is the current state of the boat Joel?

Ayuh,.... I guess yer Right,.... I missed the Date,.... :facepalm:

How is your swap coming? I recently took my boat out last weekend and with 7 adults I could barely get my boat to plane... I could definitely use some extra power! I'd love to swap a 454 in her.

Welcome Aboard RollinEarly,...... Did you happen to notice the Big Red Banner askin' ya Not to post in the archives,..??

Please read, 'n abide by Our forum postin' rules, 'n guide lines posted at the top of the forum main page,...

Thank you,...

 

[RollinEarly99]

Re: 5.7 to 7.4 swap

Welcome Aboard RollinEarly,...... Did you happen to notice the Big Red Banner askin' ya Not to post in the archives,..??

Please read, 'n abide by Our forum postin' rules, 'n guide lines posted at the top of the forum main page,...

Thank you,...

Their wasn't a red banner... Thanks though!

 

[RollinEarly99]

Re: 5.7 to 7.4 swap

It's only been two months, what's so wrong with asking for an update either way? I didn't ask a question specific to my problem... Simply looking for an update

 

[Bondo]

Re: 5.7 to 7.4 swap

Their wasn't a red banner... Thanks though!

My Bad again,.... Truely sorry,.... Joel reopened the thread,.....