MR drive bell housing engine mounts

I currently have a project going where I am putting an engine with V8 flywheel and bell housing bolt pattern in place of a 3.0 L engine. Obviously the 3.0 bell housing will not fit over the larger flywheel (I already tried). I have a later style bell housing off of a 5.7 V8; however, the bell housing is from an Alpha 1 Gen 1 motor. I discovered tonight that the motor mounts on the MR drive are farther apart (wider) than the motor mounts on the Newer bell housing. My question is: Does the V8 Bell housing from the MR years have the same spacing (width apart from each other) as the 3.0 GM 4 Cyl would, or were the transom mounts different for a V8.

Re: MR drive bell housing engine mounts

I discovered tonight that the motor mounts on the MR drive are farther apart (wider) than the motor mounts on the Newer bell housing.

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You are just getting started with your problems. What about the Exhaust Y going down to the transom shield. What about the gear ratio in the outdrive? Changing props isn't going to work. What about the front engine mounts?
PS over the years lots of things have changed. You mention nothing about make, model, year, SN of anything.

Re: MR drive bell housing engine mounts

Don S said:

You are just getting started with your problems. What about the Exhaust Y going down to the transom shield. What about the gear ratio in the outdrive? Changing props isn't going to work. What about the front engine mounts?
PS over the years lots of things have changed. You mention nothing about make, model, year, SN of anything.

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Exhaust is going through transome with plate blocking off old "y" pipe. gears have been accounted for. Frone engine mounts are custom and fit perfectly onto stringers. I am replacing the Gas engine with a I5 diesel engine with the exact same HP output and a little more torque and has similar max RPM range. Drive is a 1978 SN have been destroyed. I guess they weren't called the MR in 78' but its the 140. And i assume that people on here would know what make an MR drive is but just in case its a Mercruiser.

My only issue currently is the bell houing motor mounts everything else is lining up perfectly including electronics.

Re: MR drive bell housing engine mounts

Anyone have any ideas? Through some reading on this forum I have discovered the old mounts (one i have) are approx. 14" apart where the new style alpha is approx. 10" appart. Not sure what flywheel housings will fit over my V8 flywheel.

Re: MR drive bell housing engine mounts

polarisrmk said:

.... My question is: Does the V8 Bell housing from the MR years have the same spacing (width apart from each other) as the 3.0 GM 4 Cyl would, or were the transom mounts different for a V8.

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Just did a look-thru on the histories... The narrower mounts started in 1983. From then to now all inner transom plates are the same. Yes, the same from 'R' to 'Alpha one Gen II'. You need to find a flywheel housing from before 1983. For the SBC the part number is -76773A1, but is NLA from Merc. Just find a V8 before 1983 and you should be good to go...

'MR' refers to the drive, not the engine. All engines in 1985 had an 'MR' drive, regardless of size. That, in turn, means all engines produced in 1985 use the same inner transom plate (the one that the engine rear mounts bolt onto)...

Please don't use the term 'Pre-alpha', it's quite meaningless in terms of what will fit and won't fit...

Using the correct references will make it easier for everybody

1967 -> 1982 is called a 'Mercruiser 1' drive (MC-1 for short)
1983 -> 1984 is an 'R' drive ('Redesigned')
1985 - is an 'MR' drive ('Mercruiser Redesigned')
1986 -> 1991 is an 'Alpha One'
1992 on is an Alpha One, Gen II

Chris........

Re: MR drive bell housing engine mounts

achris said:

'MR' refers to the drive, not the engine. All engines in 1985 had an 'MR' drive, regardless of size. That, in turn, means all engines produced in 1985 use the same inner transom plate (the one that the engine rear mounts bolt onto)...

Please don't use the term 'Pre-alpha', it's quite meaningless in terms of what will fit and won't fit...

Using the correct references will make it easier for everybody

1967 -> 1982 is called a 'Mercruiser 1' drive (MC-1 for short)
1983 -> 1984 is an 'R' drive ('Redesigned')
1985 - is an 'MR' drive ('Mercruiser Redesigned')
1986 -> 1991 is an 'Alpha One'
1992 on is an Alpha One, Gen II

Chris........

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I thought forums where for helping people not criticizing people.... At any rate I am aware that the MR was the same for all engines as well as the alpha and so on..... however the "flywheel housings" (as they are called in the parts fiche) are different sizes depending on the engine.

I am requiring a V8 flywheel housing for an MC-1 drive- vintage 1978.
I am using the information that i have and trying to simply get help.
I am a Mercruiser, Mercury, Volvo, Suzuki, Yamaha, and Honda certified tech just don't deal with much old stuff. But thank you for the lesson.

This was posted before an edit by chris... Thank you for the information on the pre 83' engines and drives, that is exactly the answer i was looking for ... now i can look for one.

Re: MR drive bell housing engine mounts

polarisrmk said:

I thought forums where for helping people not criticizing people.... ....

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Are you saying I criticized you???? Where? I believe I have answered your question and given you exactly the info you asked. By your own admission you were sketchy on the history and I have cleared that up for you.... If that's what you interpreted as criticizing, then may I suggest you go talk to a Merc tech, and pay the $100/hr I'm not charging you!

Please re-read my post....

Chris.....

Re: MR drive bell housing engine mounts

achris said:

Are you saying I criticized you???? Where? I believe I have answered your question and given you exactly the info you asked. By your own admission you were sketchy on the history and I have cleared that up for you.... If that's what you interpreted as criticizing, then may I suggest you go talk to a Merc tech, and pay the $100/hr I'm not charging you!

Please re-read my post....

Chris.....

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I did not use the term "pre-alpha" that is what got me.... I could wait till monday and find out at work but where we charge $120 an hour and I am a Merc Tech. But I was trying to get a faster answer to keep my weekend project going. You gave me that answer after an edit to your post and i responded before i saw your edit so yes i did feel as though you were criticizing me.

Re: MR drive bell housing engine mounts

Does the pre 83' bell housing fit a 14" flywheel? cause from what i am reading it will not.... not sure if it the same on the v8 engine though?

Help!