1996 4.3 Mercruiser water in my oil? Hoping not!

[Rick Stephens]

If I was doing this, I'd pull my own old manifolds and test them with acetone to see if they are cracked. If the new motor has batwings, I then have my old riser type mani's swapped while both motors are out of the boats. Let's be REALLY generous and call that an hour job. From your video, I can see the donor boat engine removal is not over an hour job itself. No idea how bad your boat is to access the motor, but if not really tough, another hour there. Drop the new motor in, bolt it up, align it, wire and plumb it and a couple hours later it fires up. If you lived next door, you and I'd I would have to drink a crap load of beer not to get it done in a day.

Personally, I don't want a rebuilt built by someone else or a used unknown motor pulled out of something or other. So I think about who is gonna help me with my machining and mic'ing, parts purchases and then I assemble my own motor. If you don't want to do that, then most machine shops will mostly assemble a motor to a long block for you for little extra cost. You can also buy a factory rebuild from a number of notable shops but have to wait on them to get delivered. No such thing as a warranty until we get to this point, where we purchase a long block or more complete motor. This costs more, but gains you a carefully built unit someone put their name behind.

I don't know what you are gonna choose. Probably not my path since you don't sound like that's your way. I didn't write this to tell you your way will be wrong, just know the DIY path is most of us on this forum, so you are getting answers resistant to throwing money at it and letting someone else do the job. I wish you best on it though. And happy to help with thoughts like how to test your original mani's.

Rick

 

[Lou C]

I looked at the tag on the flame arrestor and it said the comp test #s were 140s, those in my experience are low for a 4.3, mine has always been 165-170. Prob fine though, I'd want to see if when you removed the batwings there was any sign of water in the cyls, rust in the exhaust ports etc.

 

[Rick Stephens]

I looked at the tag on the flame arrestor and it said the comp test #s were 140s, those in my experience are low for a 4.3, mine has always been 165-170. Prob fine though, I'd want to see if when you removed the batwings there was any sign of water in the cyls, rust in the exhaust ports etc.

A standard small block will be at best 155 PSI on compression if perfect. Not high compression motors unless someone changed the pistons.

Also, I'd be more concerned with consistency across all the cylinders and not 'exactly' what the number is, as long as the number is well above 100. Consistency tells all on how a motor was maintained and whether it was built within spec. And the worst part of looking at the raw number and saying that is below the 'new' 155 PSI and thinking that means anything is most compression gauges are only roughly accurate. Most compression gauges are accurate enough to tell us that all 6 holes are near the same compression, which is the most important fact.

 

[chuckndiscs]

I am still working on pressure testing the cooling. Turned the brass block plugs back in after draining the water and the port side broke/froze. I got the case out - the plunger part won’t move back in. Question; Can I use a plastic plug same as the ones that are in the manifold holes? Otherwise I can’t hold pressure...getting there slowly.

my starter mount is cracked and broken off at the block so I’m at a new block any way you look at it now, more than likely. Therefore I’m looking for options. Testing to see what good parts I have more than anything.

A michigan motorz rebuilt 4.3 for under $2400 is a nice option - thanks for the recommendation. I might yet go that route - thanks Rick for all your input, info and advice! So appreciated.

im calling the marine tomorrow to inquire more about a warranty, changing out the batting’s on their motor and how much to install a motor from Michigan motorz...and if they will even do it. A couple marine shops around here have already said no. It has to be their motor.

thanks folks! Stick with me...I’m still trucking on this one...we’ll get there by spring here in MN!

Rick - I’m likely pulling my exhaust manifolds soon (after the pressure testing)) and will be asking for help on the acetone tests.

 

[chuckndiscs]

Ok, know what I’m doing!

Rapido marine
primarily complete 4.3 vortec engine, 230 hp engine - $3750.
1 year warranty
self install
buying a 4 barrel carb upgrade
comes with;

Distributor 160.00
Distributor Shaft 5.00
Distributor Wires 45.82
Distributor Coil 32.20
Distributor Coil Wire 45.00
Distributor Bracket 5.00
Flywheel 116.00
Flywheel Bolts 9.00
Thermostat Housing 102.76
Thermostat Gasket 3.20
Spark Plugs x 8 36.00
Intake 247.80
Intake Bolts X 8 0.00
Expansion Plugs ½ X 4 0.00
Expansion Plugs 3/8 X 2 0.00
Water Pump 111.90
Water Pump Hose 34.25
Carburetor 330.00
Carburetor Holley Fitting 9.30
Carburetor Adapter 26.00
Oil 33.00
Oil Filter 7.50
Oil Pan 64.00
Oil Pan Dran Plug/ Hose 33.86
Oil Pan Dip Stick 15.96
Oil Adapter 5.00
Oil Pan Dip Stick Tube 9.95
Oil Pan Rails 5.00
Timing Chain Cover 30.00
Harmonic Balancer 52.50
Harmonic Screw 0.00
Valve Covers 56.82
Pick Up 17.87
Oil Pump Screws 0.00
Fuel Line 39.20
Fuel Line Adapter 1.97
Starter 83.00
Oil Windage Tray 5.00
Oil Windage Tray Nuts 0.00

going to place my order after I give them a call and confirm some specifics. Looks like it doesn’t come with exhaust and a few hoses, etc. I’d be ordering a hookup gasket set as well.

can I post a direct link or is that frowned upon?

wahoo!

 

[nola mike]

Try posting a link. Someone will scrub it if they don't like it
Who's doing the install?

 

[chuckndiscs]

Here is the link for reference. It’s the 4.3 link near the bottom.

https://www.rapidomarine.com/default.aspx?p=/complete_engines.aspx

id be doing the install myself. So I’d need to figure out how to lift it out and lift the new one in plus uninstalling and reinstalling the motor(s). I have help but it will be a learning job!

my garage has 12’ ceilings so I’d likely build a free standing lift or reinforce beams BUT it’s entirely finished...

 

[chuckndiscs]

Ok. Planning for engine removal... called and nobody locally will remove and replace unless I buy the engine from them. So, on to doing it myself!

Engine hoist I’m looking to rent can lift up to 100 inches.

https://www.abcrentalsinc.net/m/equipment.asp?action=category&category=46& key=EH

So I measured.

garage floor to clearing the boat = 57”
depth of motor (measure from boat bottom to 2” over the top of the motor) = 37”

total = 94”

that gives me 6”+ to work with. Hope that includes the hook and chain!

what am I missing?

 

[chuckndiscs]

Long time in the works but the powerplant is OUT! Its in the shop, I decided to go with a shop as I dont know this boat at all and I just want it done right. Hopefully this motor will be my 20 year motor! The shop is giving me a one year warranty and has stated that as long as he can remember who I am he wont let my motor fail on me if I keep up the motor. I know that is an easy statement to make but this is a 3 bay auto and marine shop, so a little more trustworthy as he relies on reputation. Diagnosis so far is water intrusion from the exhaust manifold on the port side. Ordered a new long block, new lower exhaust manifolds. Sticking with the 96 Vortec as the new one will bring 215HP and I dont need 230HP for the cost of switching out the intake manifold, etc.

During the motor replacement we are planning on checking the gimble bearing, flappers, ujoints, change the impeller, check whatever the hell is at the back of the motor that you grease that I cant think of right now.

Thanks for all the help a couple of months ago! Took me awhile to get it going but the motor is out and we are on the way to a repower!

 

[wshekar]

I don't get it. You replaced your entire engine because the exhaust manifold had a leak? Was the cylinder rusted or the compression poor?

I assume the leak in the manifold was confirmed. In that case, I would also change the riser so they have the same life expectancy. I am also sure those risers have seen better days.

 

[chuckndiscs]

I don't get it. You replaced your entire engine because the exhaust manifold had a leak? Was the cylinder rusted or the compression poor?

I assume the leak in the manifold was confirmed. In that case, I would also change the riser so they have the same life expectancy. I am also sure those risers have seen better days.

Nope!

I noticed the milkshake oil upon my first oil change after purchase. I changed it and was trying to start the motor and run it to see if the oil milkshaked again and I had issue with the starter. Upon inspection the starter had cracked the mount on the block. Boom - new block.

so...trying to deduce water entry as long as I’m replacing the motor anyways and it appears due to rusty exhaust manifold ports on the port side that it has something to do with that.

starter cracking the block is a believed hydro lock issue, something has to give right?, due to the water intrusion. Inspection is still underway!

 

[chuckndiscs]

Cleaned and buttoned up! Awaiting the motor....

 

[Scott06]

Looks good when is the engine coming ?

 

[chuckndiscs]

Looks good when is the engine coming ?

Motor is on order, expected next week...and not soon enough! Although with the temps as of late and snow I really dont have a rush....yet! This will change once the temps warm up

 

[Lou C]

For a starter mount to crack it almost has to be a hydrolock situation but starter bolts that are too long, or loose can cause that as well, due to allowing the starter to shift under torque.
It may be that the engine sat with water in one or more cyls from the leaky exhaust and the cyls rusted locking up the engine.
Here in salt water land we change manifolds and elbows every 5-7 years, doing that I have never had water in a cyl from the exhaust and my first 3 sets of manifolds were the OMC style batwings. They never leaked! Last set I converted to the later 2 piece style.

 

[chuckndiscs]

For a starter mount to crack it almost has to be a hydrolock situation but starter bolts that are too long, or loose can cause that as well, due to allowing the starter to shift under torque.
It may be that the engine sat with water in one or more cyls from the leaky exhaust and the cyls rusted locking up the engine.
Here in salt water land we change manifolds and elbows every 5-7 years, doing that I have never had water in a cyl from the exhaust and my first 3 sets of manifolds were the OMC style batwings. They never leaked! Last set I converted to the later 2 piece style.

Thanks for the info / heads up!
I wonder...how easy is it or how likely is it that a fast stop would get water to rush the rear/transom and come in the exhaust to the motor? I know the flappers are in there to stop this and mine are too but they are FULL of exhaust...so maybe slow to close?