Water entering motor - 4.3L Mercruiser

[Spiderhole]

Are all Vortec heads the same? Meaning they will bolt onto any block?

 

[achris]

Are all Vortec heads the same? Meaning they will bolt onto any block?

No, V8 vortec heads will not bolt onto a V6 block. You need to use V6 vortec heads on a V6 block....

Chris........
;-)

 

[Spiderhole]

Sorry, I was making the assumption of a v6 head to a v6 block. Basis of my question is that I currently have non-vortec heads. My local u-pull-it auto yard has vortec heads for $35. I will have to buy a proper marine vortec manifold for my old two barrel carb, which I have seen so I assume that's enough fuel for these heads otherwise they wouldn't make it?

https://www.ebay.com/itm/NEW-4-3L-V...AOSwKtVWv1Xk:sc:FedExHomeDelivery!75050!US!-1

 

[achris]

A 4.3 litre engine with maximum revs of around 4600 will only pull about 300 cubic feet of air per minute. Those 2bbl Rochesters are good to about 425 CFM....

Chris....

 

[Spiderhole]

So I've been tearing down the top end of my motor. As part of doing this, I was hoping I may find some indicators to exactly what is going on to cause the issues I was experiencing... running terrible, water in oil, etc. So far I have removed the manifold, and the starboard side exhaust manifold/riser and cylinder head. I also pulled the plugs on both the starboard, and manifold side of the motor. I do not see any obvious cracks in anything, anywhere. I am wondering if the previous owner just poorly sealed everything and that is the source of the water breach, most likely in the manifold. I do see one area where the head gasket was cracked, but it was near the piston, and I don't see anything that looks like water was going though there -either way, it will have to be replaced. Second, this is no doubt at least part of why my motor was running terribly... I had very recently replaced all the spark plugs, distributor cap and rotor... the spark plugs on the starboard side all look almost brand new like they are not firing at all. There was some water in the chamber when I pulled the head. I am not sure if they were not firing because of the water, or something else. The port side plugs all look black and normal like they are all firing. Also, whenever the previous owner replaced the block, they did not install a thermostat at all which I know is not good! Any thoughts on any of this?

I do want to throw up my hands, but I am this deep at this point...

 

[Rick Stephens]

I bought FelPro marine last time from Summit for my 4.3L. I had to mix and match since I have a pre-balance shaft block with Vortec heads and Edelbrock intake. And yeah, Mercruiser shipped 4.3L with carbed 4Bbl Vortec engines.

You definitely want to install a thermostat. Motors will run hot in some places and too cool in others without a thermostat.

I had a 4.3L full of water when I bought it. Without thinking I tore it down. The time to figure out where a leak is is when it is still fully assembled. Then it is so easy to pressure test. Lots harder once it's torn down.
Rick

 

[Spiderhole]

I bought FelPro marine last time from Summit for my 4.3L. I had to mix and match since I have a pre-balance shaft block with Vortec heads and Edelbrock intake. And yeah, Mercruiser shipped 4.3L with carbed 4Bbl Vortec engines.

You definitely want to install a thermostat. Motors will run hot in some places and too cool in others without a thermostat.

I had a 4.3L full of water when I bought it. Without thinking I tore it down. The time to figure out where a leak is is when it is still fully assembled. Then it is so easy to pressure test. Lots harder once it's torn down.
Rick

This thing with the plugs is kind of throwing me off though. I wonder if they are actually not sparking because of water entry on that side only, or if it's something else...h

 

[Rick Stephens]

Presence of water will flash off any carbon that is on the plugs. The plugs will look too clean when they are wet.

 

[Spiderhole]

Presence of water will flash off any carbon that is on the plugs. The plugs will look too clean when they are wet.

OK, that makes sense. I think then what this tells me is that most likely the water is only entering the starboard side. Would that mean that more than likely something with the starboard side head is in fact the issue?

 

[Rick Stephens]

OK, that makes sense. I think then what this tells me is that most likely the water is only entering the starboard side. Would that mean that more than likely something with the starboard side head is in fact the issue?

Seems like a likely theory. I can see a head problem maybe causing that.... seems like it would likely limit itself to a couple cylinders though. All 3 wet seems tough to accomplish with a simple head crack or gasket. Take a lot of crack or a total blow out of the head gasket.

 

[Spiderhole]

I thought it might help if I give you all a visual on what I am looking at. On closer inspection, I believe it's only the number 2 and 4 cylinder that are not firing - number 6 is OK I think. It seems the water was also only sitting in number 2 and 4 when I pulled the head off. Please note the rip in the gasket on the number 2 cylinder - it was like this when I pulled the head off.

I have not taken the port side head off yet. I still do not see anything that jumps out and shows me where the leak is. I am not sure if it was just bad seals or what. I am trying not to throw any more money at this until I am going to repair this correctly.

 

[tpenfield]

I know I'm late to the party here . . . But . . . from what I can tell - you had an engine that was leaking water internally. You replaced the block and manifolds, but not the cylinder heads. After all that work you still have an engine that leaks internally.

My guess is the cylinder heads.

Could be getting a small amount of water in the area of the exhaust and that is getting sucked back into the cylinders during idling.

 

[Lou C]

When I was getting water in a cyl, I rigged this up to test it for combustion gas getting into the cooling water (which will often allow water into a cyl as it cools down). If you watch it till the end of the vid, you can see bubbles in the starboard side funnel, showing that combustion gases were getting into the cooling water. This was an engine that had a bad overheat about 3 years before this point, when I took it apart there were slits in the head gasket fire rings. I took the heads to a machine shop and the center cyls both had cracks in the exhaust seats but the water was all from the HGs, not those cracks because the only water was in #2 and a bit in #1.

https://www.dropbox.com/s/8lz4p4e7pdrtqr2/summer and fall 2016 232.MOV?dl=0

 

[Lou C]

https://www.dropbox.com/s/55j6h4dd1u..._2273.MOV?dl=0

up and running after the repairs (re-man heads, Fel Pro gaskets, new Volvo style center riser exhaust, rebuilt Quadrajet)…...

 

[Cashs Eliminator]

Years ago, I replaced the heads on my small block powered Bayliner. I was advised that the replacement heads should not have valve seats installed as the differing expansion and contraction of the seats and head were adversely affected by the rapid changes in temperature for direct sea or lake water cooling systems.

 

[achris]

Years ago, I replaced the heads on my small block powered Bayliner. I was advised that the replacement heads should not have valve seats installed as the differing expansion and contraction of the seats and head were adversely affected by the rapid changes in temperature for direct sea or lake water cooling systems.

That would only be true if you ran without a thermostat... A correctly working thermostat's job is to regulate the temperature of the water in the engine and reduce those very variations you're referring to...

Chris..........

 

[Spiderhole]

Guys, thanks again. I was going to take the port side head off today, but it's pouring here in Dallas. Question - when I reassemble everything with the new heads and intake manifold, I know obviously there is a sealant I need to use for the manifold, but what about around all the gaskets, including the head gaskets? Thankfully, I have the enormous summit store right up the road here in Dallas so I can probably get the Felpro marine gaskets right here locally. I am beginning to believe that the primary leak was due to the head gaskets, especially since that obvious rip is right between the two cylinders that clearly were not detonating properly. I need to order a new thermostat as well.

 

[Spiderhole]

...and another question... when I go to the vortec two barrel manifold, what is the correct thermostat that I need to order? Is my old thermostat housing going to fit the new vortex manifold - I think yes?

 

[Lou C]

With the Fel Pro gaskets you don't need any sealer on the head gaskets at all, but for sure get a thread chaser and clean out the threads in the block to ensure that you get proper torque on the head bolts, also cleaning off all the old gasket material is a major part of this job. You also will need to use sealer on the threads of the head bolts because some of them thread into water passages. I replaced mine because the orginals were so rusted due to salt water use. I used ARP head bolts.
On the intake gaskets, I used some Permatex aviation on the water transfer port area because there is usually a bit of pitting there. Thermo I can't answer for sure not having a Merc but I'd guess it fits right in the Merc thermo housing so the intake does not really matter.