1990 vs 1992 4.3 block swap

[achris]

Leave all the surfaces painted, put your graphite gaskets on dry, bolt it up...

 

[Chris51280]

Elbows are on and torqued to 25ftlbs. Hoses and wiring is on. Hopefully I will be able to start it this weekend. I will shoot a little video of it

 

[Chris51280]

Its alive. Still needs some fine tuning but its promising. Ran for a couple seconds since no water was hooked up

https://youtu.be/CiC6HAR8qgo

 

[Chris51280]

I received the shutters 807166A3 from sierra and when i put them in the flapper doesn't move and close as it should. The ears on the side are squeezed inward and prevent the flapper to work properly. It appears that I have to grind the top about 1mm each side to make more clearance. My Y pipe seems to be about 1/4" thick where the holes are.

 

[Chris51280]

I did grind the sides a little and the flappers work freely now.

I started the engine again but noticed oil coming from the NPT threads from my offline oil filter kit. I used permatex aviation gasket on there which I thought would seal it better than pipe thread. I was planning on taking it apart and clean it. What is the best way to seal these and is there a torque spec I should follow?

 

[Scott Danforth]

pipe threads seal by the crush/interference of the threads. the sealant is more of a lubricant than sealing medium. there are torque values.

 

[Chris51280]

Thanks Scott, I will look it up. NPT always scare me because I don't want to over tighten these

 

[Chris51280]

Item #20. Why is there a rubber grommet between the bolt head and the anode?

 

[Chris51280]

I have two outdrive assemblies. both are gen1. The difference is the spare one has these two bolts on top and my current one does not. The current one is faded and pitted from being in the water for long periods of time. I'd like to use the donor with the two additional bolts. Is this the only change? They are interchangeable, correct? I would just drill the holes through the transom. Would be a better setup since it has more bolts and the it will definitely be sturdier.

 

[Bondo]

I have two outdrive assemblies. both are gen1. The difference is the spare one has these two bolts on top and my current one does not. The current one is faded and pitted from being in the water for long periods of time. I'd like to use the donor with the two additional bolts. Is this the only change? They are interchangeable, correct? I would just drill the holes through the transom. Would be a better setup since it has more bolts and the it will definitely be sturdier.

Ayuh,..... The Gen.I Alpha does Not have those studs,......

Yer spare must have started out life as a Gen.II,.....

 

[Bondo]

Item #20. Why is there a rubber grommet between the bolt head and the anode?

Ayuh,..... So it'll come Off, when necessary,.....

 

[Chris51280]

Ayuh,..... The Gen.I Alpha does Not have those studs,......

Yer spare must have started out life as a Gen.II,.....

thanks. I looked and they are the same. It looks like its the very top but its actually the inner mounting just below the arm for the steering. All good. my fault. Should have looked closer.

 

[Chris51280]

Ayuh,..... So it'll come Off, when necessary,.....

There is actually another rubber washer between the bolt and the housing. was a little hard to find but I got a set on fleabay. It is to seal the square drive off. A little 99 cent washer and your boat constantly leaks.

 

[Bmaverick]

Boat engine cams have a different lift and duration than automotive cams. They also use brass freeze plugs, stronger valve springs, and marine accessories like starter, distributor, carb, alternator, water circ pump. It is unsafe to use non flash proof automotive parts in these areas from automotive. They get more power because of mainly water cooled exhaust, sometimes bigger valves, and more air flow.

 

[Chris51280]

Boat engine cams have a different lift and duration than automotive cams. They also use brass freeze plugs, stronger valve springs, and marine accessories like starter, distributor, carb, alternator, water circ pump. It is unsafe to use non flash proof automotive parts in these areas from automotive. They get more power because of mainly water cooled exhaust, sometimes bigger valves, and more air flow.

3 months later but ok. the heads are the same as automotive ones. Water cooled exhaust does not make much of a difference other than making sure the inside of the boat doesnt get red hot. With the rest I agree

 

[Chris51280]

I splashed today. Everything seemed good with all being water tight. The boat only got to 3000rpm wot. Maybe need another prop with a 19pitch. It reved up to 4000 without the prop engaged.
after about 20 minutes driving we went swimming for an hour and then the boat would not start anymore. I bypassed the new filter I installed with no luck. I could see the priming when you push the throttle down in the carb. It ran for 2-3 seconds and then it shut down.
it is a mechanical fuel pump on a rochester 2bbl carb that i rebuild over the winter.
the gas was fresh from the gas station from the same day. The tank was empty otherwise.
Will bring to a mechanic tomorrow.
My guess is the fuel pump or the carb not working right anymore. Any input from you guys?

 

[havoc_squad]

I splashed today. Everything seemed good with all being water tight. The boat only got to 3000rpm wot. Maybe need another prop with a 19pitch. It reved up to 4000 without the prop engaged.

I hope you at least did that in the water and not on muffs.

Also, running any boat engine without a load at or above 3000 rpms is inviting trouble. Engines like to self destruct/throw rods/or run away when they are reved with no load near or above WOT RPM of the motor. (I think 4.3L V6s are around 4200 to 4500 RPMs).

 

[Chris51280]

They are 4400-4800 typical wot from mercruiser. I did rev it in the water to see if it will rev up that high.

 

[Bondo]

They are 4400-4800 typical wot from mercruiser.

Ayuh,....... Under Load,..... not free-wheelin' in neutral,......

 

[Chris51280]

Just did a short burst to see if it goes that high since it would not with the prop engaged. I think i may have heard some pinging at wot and let off the throttle then. Boat is still at the marina.
Still don't know why it would not start again and only run for 2-3 seconds