Milky oil

[Lou C]

Turns out they are completely different. I'm hearing that 1996 in boat talk is 1995. I was aware it was pre Vortec, but I thought they swished half way through the year. I have another thread going on the valve issue. Wasn't sure if I needed to start a new one or not.

Ken

It is really easy to tell though, just count the bolts on the intake manifold!
12 bolts is the Pre-Vortec (better sealing in my opinion)
8 bolts is Vortec (better heads, but intake sealing, well you gotta be careful)
Also:
the torque specs changed, there was actually a mistake in the Mercrusier manual about this:
Pre-Vortec 30-35 ft lbs depending on where you look
Vortec 10-15 lbs, that is much lower, if you torque the Vortec to the old Pre Vortec spec you might crush the gaskets and create a wate leak!

 

[SeaRayboater95]

Hey, one more question, hopefully. Can I reuse those head bolts? Shop manual says I can except for Gen +. Not sure what that means.

Ken

 

[Lou C]

Ok Gen + I think is Merc speak for the 96 and up Vortec. I think you have the previous version so you can probably reuse your head bolts. I would:
Clean clean clean the theads in the block and on the bolts. Mine were pretty rusty so I used new ARP head bolts.

 

[SeaRayboater95]

Ok Gen + I think is Merc speak for the 96 and up Vortec. I think you have the previous version so you can probably reuse your head bolts. I would:
Clean clean clean the theads in the block and on the bolts. Mine were pretty rusty so I used new ARP head bolts.

That's what I thought.

Thx

 

[SeaRayboater95]

Hey Guys and Gals, did I just find the smoking gun? Not sure how much water could get through that.

Ken

 

[Lou C]

I think you may have, that's what my cracks looked like when they were cleaned up.
See that's why I said what I said (heads have to be checked by a shop) that boat may have been overheated at one point in the past.
If you show the owner that, he might be convinced, if he wants to keep the boat.
It might be possible for a shop to weld the cracks, but I don't know how likely that is to be successful.
When I did mine, my total parts cost for the heads, bolts, gaskets and complete exhaust conversion (from the old Batwings to the 2 piece later style) was about $2,000 USD. That was 9 years ago so of course it's more now, even just the exhaust kit went from $720 to about $1,100.
Keep in mine if he does decide to go forward, there are no "marine" heads for a 4.3, they are nothing more than a standard Chevy 4.3 automotive head.
You of course do need marine head gaskets.

 

[SeaRayboater95]

Here's another intake hole. Pretty sure that's a crack

 

[Lou C]

Sure looks like it.
Since one shutter is missing, they don't just disappear, they get melted from an overheat, does the other one look melted, or OK? If melted that suggests it's overheat damage....

One of mine was vaporized, (landed in the bottom of the Y pipe) the other got melted, I had to pull the outdrive to get the remains out.

 

[SeaRayboater95]

Sure looks like it.
Since one shutter is missing, they don't just disappear, they get melted from an overheat, does the other one look melted, or OK? If melted that suggests it's overheat damage....

One of mine was vaporized, (landed in the bottom of the Y pipe) the other got melted, I had to pull the outdrive to get the remains out.

Just starboard side was missing, but the other side was pretty limp. These pics are from the port side. I'm checking starboard side now.

 

[Scott06]

Here's another intake hole. Pretty sure that's a crack

you have to have it magnafluxed or pressure tested to know. In the grand scheme of things neither are expensive. Its done this far would be foolish not to confirm

 

[SeaRayboater95]

you have to have it magnafluxed or pressure tested to know. In the grand scheme of things neither are expensive. Its done this far would be foolish not to confirm

Any chance those are casting ridges? All three intake holes on that head have those marks in the same place.

 

[Scott06]

Any chance those are casting ridges? All three intake holes on that head have those marks in the same place.

That would be my thought that they are casting ridges, but you are chasing an issue , so if it were my show I would be using some tests. Either go back in with rebuilt heads or have they magged or pressure tested. Any time on engine work like this where I took a short cut it later bit me in the a$$

 

[Lou C]

The lines inside the valve port could be casting ridges but the one going in between the intake & exhaust valve seat areas looks like a crack, that’s how mine were in the center cylinder of each head.

 

[nola mike]

Any reason not to go to your local pull a part and grab a set of heads for $50?

 

[Lou C]

You certainly can do that, but keep in mind that you'll probably see mostly Vortec heads that won't work with the pre-Vortec intake manifold.
And, I'd still take anything I was going install into an engine I wanted to be reliable to a machine shop to get magnafluxed.