Nola Mike's 3.7/470 --> 4.3L swap thread

[Lou C]

Sorry I had to be the bringer of bad news but better to find out now than later. Believe it or not my vision got better after I passed 60! Especially close up. The opposite of what happens in the 40s.

 

[achris]

.... I mentioned to you I don't have the Mercruiser 4.3L manual. ....

You do now...

Shhh!

https://docs.google.com/open?id=0B1TAvwZ3TjhfYWRiMDZmNDctMzgzZi00MmIzLTkxNGItMGY1NGExYjJmOGJh

 

[nola mike]

You do now...

Shhh!

https://docs.google.com/open?id=0B1TAvwZ3TjhfYWRiMDZmNDctMzgzZi00MmIzLTkxNGItMGY1NGExYjJmOGJh

Ha ha, I was about to hit you up next.

 

[nola mike]

None of the accessories will fit a true Vortec block. Those blocks have serpentine belts, different balancer, and different pulleys on all the accessories. I'd consider that a no go altogether. Stick with a pre-96 block and you'll save enough to get vortec heads should that be your desire.
A Chevy is a chevy is a chevy.

Well, I've never worked on a chevy...
But I have all the brackets and old accessories, what's keeping them from bolting to the block? I guess if the balancer is spaced for serp belts then it won't drive the v-belts? And otherwise what about putting a new balancer on there? Not sure when they went to the serp belts, but could I not find something aftermarket that would fit? Might be tougher to find a pre-'96, especially with low miles...

Also, there's apparently a forum bug with the PMs...Using this link gets around it:

https://forums.iboats.com/privatemessage/notification/0/1

 

[Lou C]

To answer your questions there are a lot or confusing changes made over time on the 4.3s and dome parts are not interchangeable even in the same year range depending on if the engine was built in
Tonawanda (NY) or Romulus (Michigan). The Serial # on the right front of the block will have a T or an R to designate this. Now....if you want to marinize an auto block you need brass core plugs and marine head gaskets (Fel Pro) + marine circ pump, unless you want closed cooling. I think it might be possible to put the old accessories on a Vortec. Go over to Michigan Motorz and look at customer installs. Then look up the one where they replaced a pre Vortec with a Vortec. All the OMC accessories were re used (V belts not SERP). Another think I wondered about is the flywheel, are they the same for pre Vortec and Vortec? MM lists only one as if grey are the same but that might not be right. Then this gets into can you use the same coupler, etc. makes my head hurt! I might just get a pre Vortec reman from them so all my old stuff fits. I picked up a nice fresh water used pre Vortec 12 bolt intake just in case. I’m sure by them my original will be too rusted to use. All I want to add is 1/2 sys closed cooling and a remote oil filter,

 

[achris]

The flywheel MAY be the same, it will depend on the block casting number. If the new vortec block is an 8LK or 8LJ, then yes, same as the old one. If it's 9LK, 9LJ or 0LK, then no, it's different.

The balancer (the pulley just bolts up to the balancer, regardless of vee or serp.) is also different. The vortecs have a POS composite front cover, the old (non-vortec) have a tin cover. And they are not interchangeable. I know :facepalm: And because the covers are different, the balancers are also different.

Other than those 2 items, everything else will bolt straight on.

May I suggest you find 2 engines. One of each. You pull the heads and manifold from the vortec engine and drop them, with nice marine gaskets, onto a non-vortec block that you know the flywheel and pulleys are correct for. I'm sure with your 'pick and push', you could get a good deal on 2 engines.

Chris.........

 

[Scott06]

There’s a block same vintage as yours on eBay for $275

 

[alldodge]

Ever look for a rotted out hull which can just swap everything over?

 

[Lou C]

Here are the pix, of a pre-vortec to vortec conversion...done by Michigan Motors....notice the old PS pump and alt were used with the old pulleys...I'm not sure if they had to do something special to make this work or what, but it LOOKS like it can be done!

 

[achris]

Yep, pulleys are just 'bolt-ons'. If you get a serpentine engine, just change the crank pulleys and it's ready for your Vee-belt accessories. And when I say crank pulley, I'm not referring to the balancer. The pulley bolts onto the balancer.... You'll be using your marine water pump, so the old pump comes off the new block....

​
Crank pulley (#17) bolts to balancer (#16).

The more I look at it, the more I think, if you got a Vortec 4.3 from a manual gearbox car/truck/SUV, the flywheel may just be the right one, and it doesn't matter about the belts up front, just bolt your pulleys on and you're good to go. All the bolt holes for mounting accessories are in the same place on the non-Vortec as the Vortec. The only thing you'd have to do is add en electric fuel pump.

What was the vintage of the cracked 4.3 you have now?

Chris.....

 

[Rick Stephens]

Here are the pix, of a pre-vortec to vortec conversion...done by Michigan Motors....notice the old PS pump and alt were used with the old pulleys...I'm not sure if they had to do something special to make this work or what, but it LOOKS like it can be done!

So I have a 'Vortec' engine. It is built into a '95 block, which is pre-Vortec with Vortec heads, 1 pc main and roller cam.. I have V-belts and a steel timing chain cover and pan. It is also no balance shaft. It's a morphodite bastard that I have to buy some parts for Vortec and some are pre-Vortec.

Was your Michigan Motor build with an aluminum or a steel pan? If I was Michigan, I'd do the same thing I did. Grab a 95 or earlier block and stick Vortec heads on it.

 

[Lou C]

https://www.michiganmotorz.com/vorte...ent-p-186.html
this is what they are showing, as a re-man 4.3 Vortec, and it has the alu pan although painted black. the one in the pix, is supposedly this engine...

https://www.michiganmotorz.com/vorte...016-p-283.html
this is a new base engine 4.3...

 

[nola mike]

Ever look for a rotted out hull which can just swap everything over?

Umm, yeah, that's what got me into this mess

Ok,a lot to digest and respond to on a phone. But Chris, my cracked block is from an 89 boat. I posted the s/n elsewhere, but it's pre balance shaft, 2 bbl carb, standard heads, roller cam,v belts. I already knew that I'd need new heads, intake, and carb (4bbl). So I guess I'm still not seeing why any vintage wouldn't work with my accessories? I have all pulleys, brackets, etc. I mean, literally we're talking about the block. I probably will have the easiest time finding an auto post '96 vortec. So maybe I need a new flywheel? Ok, cheap and easily found, right ? This seems fairly straightforward. Maybe something won't fit, but anything that I can't just buy if needed? What am I missing here?

 

[achris]

Umm, yeah, that's what got me into this mess

Ok,a lot to digest and respond to on a phone. But Chris, my cracked block is from an 89 boat. I posted the s/n elsewhere, but it's pre balance shaft, 2 bbl carb, standard heads, roller cam,v belts. I already knew that I'd need new heads, intake, and carb (4bbl). So I guess I'm still not seeing why any vintage wouldn't work with my accessories? I have all pulleys, brackets, etc. I mean, literally we're talking about the block. I probably will have the easiest time finding an auto post '96 vortec. So maybe I need a new flywheel? Ok, cheap and easily found, right ? This seems fairly straightforward. Maybe something won't fit, but anything that I can't just buy if needed? What am I missing here?

Engine mounts. The non-balance shaft engines ran fluid mounts, the balance shaft engines ran 'normal' solid mounts. I haven't tried it, but I see no reason that the fluid mounts shouldn't work on a balance shaft engine. Just be aware the mounts are a little higher (bigger), so the mount beds needs to be built up slightly lower than a normal mount.

Chris.....

Oh, one more thing. The oil pans changed from pressed tin to cast ali when the engine got Vortec heads, mid '96.
So any vortec-head engine will have a cast ali sump.

 

[achris]

....Also still can't remove the damn control box from the trim panel. Can anybody help? I can't get the handle off, it appears just pressed on, but I don't want to start prying.....

While looking for the serial number, I ran across this....

If you get down on the floor and look up at the control lever, you'll see a slot at the bottom. That's for an Allen key (can't remember the size, 3/16", I think)... If you move the lever, I think Forward, you'll see the head of the Allen key, loosen that a couple of turns and the lever should just pull off, then you can get to the screws holding the control box to the panel.

Sawzall not required!

Chris........

 

[nola mike]

Thanks! Those are pricey on eBay, will be nice to sell mine with no attached trim.
​ The fluid mounts seemed like a good thing to replace as a wear item after 30 years anyway. Although fluid mounts + balance shaft = smooooooth

oil pan I guess should be replaced with tin if running brackish water?

So bottom line...I can just start looking for a vortec long block? What would be the newest?

 

[Lou C]

Actually the alu pan might last longer. Mine has the original tin pan still but has been sprayed with Boeshield or Corrosion X every few seasons. 100% salt water use. The tin pan if putting in a reman pre Vortec engine should be painted with 2 brushed on coats of Rustoluim

 

[Scott Danforth]

I wouldnt run squishy mounts with a balance shaft engine.

 

[Rick Stephens]

I wouldnt run squishy mounts with a balance shaft engine.

There are a ton of after market mount makers, squishy or solids. Only time you want squish is with non-balance shaft motors, - like mine.

 

[nola mike]

Ok, just did some calling around, and there are dozens of blazer/astro engines at these 2 places. First place is $180 for the long block, I have to pull it myself. 6 month warranty. No way to know the mileage. Thinking I can grab the VIN on these and run a car fax. Don't know how easy it is to check compression before I pull it? Can I just bring a battery and hook it directly to the starter?
Second place pulls it, also warranty, I assume I can also car fax from the engine VIN. That's $450. Larger selection at the second place, but both have plenty.

Are the mounts the same for the boat as the trucks? Cursory search of car ones, they're cheap.