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

Scott Danforth

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Chris, there is a reason that I sell speed parts to hot rod folks in Australia........
 

nola mike

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Yeah, pump isn't going to break the bank. achris, any knowledge on the composite cover/pump interference? I know you're a huge fan of the cover...
I had spoken to Michigan, they asked me to send pics, said if I ordered the pump and it didn't fit then I could send it back
 

achris

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Never seen an issue between cover and pump like your photo... Sorry, I know that doesn't help...
 

nola mike

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This is strange. Well, at some point the pump changed and has a water bypass hole. It looks like that hole needs a corresponding hole in the block? If anything though, that looks like that would reduce clearance even more. My block doesn't have that hole at any rate...

https://www.ebay.com/itm/233468141133
 

nola mike

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Another 2 steps forward 1 step back day. Finally got the mounts glassed in. Not pretty, but hopefully will do the job. God I hate fiberglass. Then went to change shift cable and completely rounded the nut. Pb,heat, 13mm 6 pt socket hammered on. Rounded completely. Cable 2 years old and permatex applied prior to install, so not sure why so difficult. Outer sheath is fine, so I think I'll just replace the core for now and leave this job for another day. Pains me to do that, but I can't handle yet another complication at the moment.
 

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achris

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yes, motor mounts were a pain. you should round those edges and corners really good.

Agree. Hard corners on the mounts will make it impossible for the glass to stick and conform properly.

Chris......
 

nola mike

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It laid down well, I had the mat cut so it didn't stress around the corners. It's in there now, seems solid. I feel like this isn't the thing that keeps this project from working, but points taken...
 

Rick Stephens

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Mike. not to be a after the horse is out of the barn kind of guy, but thought I would mention a couple things.

First, the only way glass adds strength is the fibers are unbroken across a stress area. When the glass is cut for a corner, the glass isn't doing anything, all you have is wood and some resin that is breakable. That's why pretty much all corners are rounded is so the glass in one long piece can tie components together. When I did my mounts I tied them all the way into the transom. I ran one piece of mat from the furthest front part of the stringers I could reach, unbroken around the new mounts, and back bending across the transom itself after radiusing the stringer to transom area with PB. The engine applies torque over that space. Your setup might be fine, I just want to make sure before you hammer down the motor that the twist put on mounts by the motor is sufficiently accounted for.

Second thing is glassing over gel coat. When I sold the interior out of the donor boat I got my power package out of, the guy who bought it spent an hour with me looking at and talking over my half finished glassing in of the new mounts. He had just done that to his boat to install a V8 where a 470 had been. His story is hair raising. He sanded and chemically washed down his gel coat, but didn't take it all off. After all done, and cured, he stepped on one and it broke loose from the hull entirely under his foot. He took a hunk of wood and knocked the other one off as well. I can't speak to his methodology, I wasn't there and I didn't really get all the details. But the point is that the wax that is in gel coat is death on adhesion.
 

nola mike

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Appreciate the feedback. A few things--those cuts were around 2 corners on the last layers, there was one that went all the way around. There were continuous layers running along the stringers, parallel to the stringers, and perpendicular. That seemed like it would take up all the stresses that would be applied to it. If not, perhaps wrapping around the corners would work? Moot point to some extent anyway. I didn't wet the mat on the inner vertical surface, so didn't cure right. Going to tear out what I can anyways. Looking at other peoples' mount setups, I really think I should be OK. Most didn't do that much extension. That wood encased in PB seemed pretty damn solid as it was. I did round the other block off, it came out much better. As far as the gelcoat, well, I did what I could do. A lot of roving, so like I said in a prior post, I sanded as much as I could. There was a ton of bare FG exposed over a large area, so I'm hoping that will be sufficient. I can say that the second mount seemed very well adhered and rock solid. Not sure if there's any way to test that. Any suggestions at this point welcomed. Did I mention how much I hate fiberglass?

The one hopefully positive thing is that I got my new water pump today, and it does look like there's a difference between the 2 that will allow it to clear the timing cover. If you look at them, the new pump is flat up to the hose outlet, while the old one is slightly bulged. Going to try to fit it tomorrow.
 

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nola mike

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Ok, so another 2 step forward 1 step back day. Haven't had much time lately. First, the good news!

1. Got the heads on. Need to install the pushrods, rockers, etc. New vortex heads are different from the most recent mercs, the lash doesn't appear adjustable.
2. The balancer...IDK, I checked the bolt today, and now it seems long enough. I haven't done anything since last I checked. Still going to get a longer one.
3. The water pump. It fits! New one is indeed slightly different.
4. A few other misc odds/ends.

Bad news:
1. Installed the intake manifold. A few differences between merc and GM instructions. Merc told me to use perfect seal on the mani, mahle specifically said don't. I didn't. I got new bolts, and wasn't sure what to torque them to. Merc says 35 ft-lbs, GM says 11 ft-lb. I ended up trying 35 ft-lb. Thought it might be because the GM manifold was composite v. the cast iron that I was installing. Well, snapped the 2nd bolt that I tried to tighten. Nearly at the head. I don't know how, but for some reason I was able to get it out with needle nose pliers. Because of this, I'm going to consider this day a win. Anybody have any insight into the bolts? I didn't think 35 ft-lb was that much considering that the head is iron. But I guess we do 11? How can that possibly be enough to keep that thing secure?
 

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Scott Danforth

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Vortec heads have non adjustable valvetrain unless you convert them

The 11-15 lb-ft is correct for the intake
 

nola mike

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Vortec heads have non adjustable valvetrain unless you convert them

The 11-15 lb-ft is correct for the intake

So I think that's a typo in the mercruiser manual. Rereading it it appears that 35 was for the old heads, but the instructions specifically say gen+ and earlier get the same torque unless I'm misreading.
 

achris

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So I think that's a typo in the mercruiser manual. Rereading it it appears that 35 was for the old heads, but the instructions specifically say gen+ and earlier get the same torque unless I'm misreading.

You are misreading...

From Merc manual # 18 (4.3L 1993-1997). And 'GEN +' is Vortec heads.

Click image for larger version  Name:	intakeTorq.JPG Views:	1 Size:	167.2 KB ID:	10875386
 

nola mike

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achris , here's what I'm looking at in #18 and 25
 

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achris

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achris , here's what I'm looking at in #18 and 25

You are looking at an out of date manual. The revision of your manual #25 is Aug 1996, it was re-issued in Nov 1999, with the revised torques for the Gen+ engines. PM me for a copy of the new one. ;)

Gen+ engines didn't come out until after your manual was released.

Chris.....
 

nola mike

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achris , I think I'm in the right manual (s). That screenshot has the '99 date and the diagram is the 8 bolt manifold. Same with #18, which covered both. I have the same page you posted with those torque specs at the beginning of the chapter in both manuals. At any rate I'll do the correct torque, hope it doesn't leak. Going to have to wait till Monday. This weekend I'll reglass that one mount, install the transom shield bolts and gimbal bearing, and maybe see if I can free that shift cable with a ½ socket pounded on. Otherwise I'll just replace the core.
 

achris

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achris , I think I'm in the right manual (s). That screenshot has the '99 date and the diagram is the 8 bolt manifold.

Your manual has not been updated with service bulletin 97-1. Some service bulletins come with an instruction to mark up a page in the manual, and add the SB to the manual. I have done that with my manual. See below.

Same with #18, which covered both. I have the same page you posted with those torque specs at the beginning of the chapter in both manuals. At any rate I'll do the correct torque, hope it doesn't leak. Going to have to wait till Monday. This weekend I'll reglass that one mount, install the transom shield bolts and gimbal bearing, and maybe see if I can free that shift cable with a ½ socket pounded on. Otherwise I'll just replace the core.

Not sure what you mean by 'transom shield bolts'. Merc Gimbal Housings have the studs already screwed in and the gimbal bearing already installed in it, so all you have to do is make the cutout in the transom, drill the stud holes in the transom and then offer up and install the gimbal housing to the transom. Then from the inside of the boat, place the inner transom plate over the studs, fit and tighten the nuts.

If you have a problem with the lower shift cable, as the gimbal housing is currently off, don't muck around trying to fix it, just replace the whole thing with a new kit.

Chris......

intaketor.JPG
 
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