4.3l Block Crack - repair or replace? [Decided to Replace - Adventures begin]

Struc

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Jul 27, 2011
Messages
409
Re: 4.3l Block Crack - repair or replace? [Decided to Replace - Adventures begin]

...back from the dead (or at least hibernation).

I got unmotivated and the engine sat for a while over the past few months on the engine stand in my garage. I did get a rebuild kit for my carb and did that rebuild a couple months ago. It looked pretty good, but the float adjustment was way off. Hopefully that fixes my rough idle issue.

So this past weekend I set out to get the motor back in the boat, forgetting how much work I actually had to do to the engine to get it ready to go in. The main issue was I had forgotten so much about the little things. Luckily I took lots of pictures of the motor when I first pulled it out. That did take time running inside to look at the pictures all the time, though. That, and the temp in WI was mid to high 80's this weekend, so I was moving slow.

I'll post some pictures when I get home, but I at least got the motor back to a state where it can be lowered into the boat. I installed the engine wiring harness from my parts boat, instead of the one that came off the motor. The original main connector was pretty bad, and I saw no good way to fix it, so luckily I had a spare harness. The downside of that is I needed to make some connector changes, and a couple repairs to that harness - and of course look at all the pictures to make sure I got it right.

Still have to get the wiring sorted out for my new electric fuel pump (vs the mechanical stock one). I have the oil pressure switch and fuel pump and fuel hose all ready and waiting. Just need to get a 1/8" NPT "T" fitting to hook up the pressure switch at the same spot as my oil pressure sender (or oil pressure warning switch - can't decide which yet).

So, over the long weekend I plan on installing the motor and getting it running, and ready for the water.
 

Struc

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Jul 27, 2011
Messages
409
Re: 4.3l Block Crack - repair or replace? [Decided to Replace - Adventures begin]

Stopped by the hardware store after work today and picked up a 1/8" NPT brass close nipple and female Tee adaptor, so that I can get my fuel pump oil pressure switch in place. Looks like it will fit best down by the oil filter where the low oil pressure alarm sender was threaded in.

Some engine pictures, as promised.

IMG_3063s.jpg


IMG_3062s.jpg


IMG_3064s.jpg


IMG_3065s.jpg
 

Struc

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Jul 27, 2011
Messages
409
Re: 4.3l Block Crack - repair or replace? [Decided to Replace - Adventures begin]

Well, finished up the last couple things I needed to do before the motor was ready to drop in the boat. Got the exhaust manifolds on as well as the elbows.

I took the time to hook up the vitals to the engine outside the boat, just to make sure it was going to run. I'm glad I did. Mistake #1: put the starter trigger wire on the wrong terminal on the solenoid. Took me a bit to figure that one out. DOH! Mistake #2: Should have pulled the distributor cap and checked the position. Timing was way off, so I had to adjust the distributor better. Once those two things were taken care of, it fired up. I was having a choke issue, but other than that, the engine runs great. I adjusted the base idle and set the timing properly. Figured it would be easier to do outside the boat anyway.

After all that, I set out to wire up the oil pressure switch for the fuel pump. I decided to simply use this wiring as a trigger for a relay, and I'll run the fuel pump off heavier gauge wire off the relay. The engine wiring I had to tap into for ignition power didn't really look all that heavy, and I didn't want to be running the fuel pump off of it. This way, there will be nearly no load going through the oil pressure switch, or being pulled through the ignition wiring.

IMG_3076s.jpg


IMG_3077s.jpg
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: 4.3l Block Crack - repair or replace? [Decided to Replace - Adventures begin]

You are planning on running it on the floor and making sure everything works before you put it in the boat aren't you?
 

Struc

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Jul 27, 2011
Messages
409
Re: 4.3l Block Crack - repair or replace? [Decided to Replace - Adventures begin]

You are planning on running it on the floor and making sure everything works before you put it in the boat aren't you?

Did you read my second paragraph above Don? :D

Yes, ran it in the driveway, discovered a couple errors, and then set the base idle and timing.

Engine is now sitting in the boat, and actually bolted in after a few other mistakes on my part that caused me to have to lift it up and set it back down a few times. :)
 

tpenfield

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Jul 18, 2011
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17,621
Re: 4.3l Block Crack - repair or replace? [Decided to Replace - Adventures begin]

Good to hear of your progress. I'll be doing that sort of thing in a week or so with my boat/engine. It has been sitting in the garage on a set of dollies all winter.
 

Struc

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Jul 27, 2011
Messages
409
Re: 4.3l Block Crack - repair or replace? [Decided to Replace - Adventures begin]

Well, the engine is ready to go. Finished it up late today. Would rather have been on the water in the boat, but I guess finishing it up for next weekend will have to do.

I'll snap some pictures of a few things next time I"m in the boat. Wired up a mini fuse box in the back rather than having everything going directly to the battery. Just have the new electric fuel pump and the mercathode wired up to it for now, but did run some of the grounds all back to it as a central grounding point.

As I mentioned, I wired up a relay for the fuel pump. Mounted that right above the fuse box. I had actually wired the pressure switch wrong (got the fuel pump and starter wires swapped), so I had to diagnose why my fuel pump wasn't running. Got that swapped and now it's working perfectly. Added a fuel filter that does water seperating as well, as long as I was running new fuel lines around. Turned out pretty good actually.

Swapped out my trim pump while I was working on the boat too. The old reservoir must have a crack in it - all the fluid leaked out over winter and made a heck of a mess. Tested and good to go there.

New engine starts up and purrs like a kitten. Can't wait to see what she'll do on the water.

Alignment is all done, but a storm ran through before I could get the Alpha One back on the boat. I need to get it back on the trailer, get the lower unit back on, and filled with gear oil, and it's ready for the 2012 season.
 

joewithaboat

Lieutenant Junior Grade
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Jul 3, 2011
Messages
1,172
Re: 4.3l Block Crack - repair or replace? [Decided to Replace - Adventures begin]

Good work! Congrats! :)
 

Struc

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Jul 27, 2011
Messages
409
Re: 4.3l Block Crack - repair or replace? [Decided to Replace - Adventures begin]

Well, I still haven't snapped any pictures, but I did get the boat out on the water today. It runs and idles SOOO much better than the old block did. Probably mostly has to do with the carb getting rebuilt, but whatever it is, I like it. Starts right up every time without any extra gas too. Still having choke problems, so I just adjusted it pretty much open all the time. I doubt I really need it. I'll just pump the accellerator a couple extra times on the first start of the day.

I did hear some noticable lifter / rocker noise at higher RPM under load, so I guess I didn't get that lucky to get them all adjusted perfectly while on the engine stand. I don't have any noise at all at idle or even higher RPM with no load. I'll have to research how you guys adjust them while running without getting full of oil. I seem to remember reading about using a spare set of valve covers and cutting holes in them for putting a socket through. Might try that.

My tachometer wasn't working - I think it probably has to do with the new main engine harness I put on, or the connector, so I'll have to research that.

All in all, a very successful day for the maiden voyage of the year.
 

Struc

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Jul 27, 2011
Messages
409
Re: 4.3l Block Crack - repair or replace? [Decided to Replace - Adventures begin]

Here are the pictures I promised.

Engine sitting back where it belongs, lookin not too bad

IMG_3083s.jpg


New electric fuel pump and water seperating filter setup, mounted on the fuel tank bulkhead

IMG_3084s.jpg


And hiding in the back here...

IMG_3081s.jpg


Is the new fuel pump relay and fuse box / ground bar setup

IMG_3080s.jpg
 

joewithaboat

Lieutenant Junior Grade
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Jul 3, 2011
Messages
1,172
Re: 4.3l Block Crack - repair or replace? [Decided to Replace - Adventures begin]

Great work Struc...

Your a great example of what a little sweat equity can provide.
Hope you have fun with it.
 

jon705

Petty Officer 2nd Class
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Aug 26, 2009
Messages
101
Re: 4.3l Block Crack - repair or replace? [Decided to Replace - Adventures begin]

I may have missed it earlier in the post but what type of setup did you use to lift/remove and reinstall the engine into the boat?
 

Struc

Chief Petty Officer
Joined
Jul 27, 2011
Messages
409
Re: 4.3l Block Crack - repair or replace? [Decided to Replace - Adventures begin]

Standard automotive cherry picker (which I already had - bought it for like $150 on sale).

http://www.harborfreight.com/2-ton-foldable-shop-crane-35915.html

I did have to get it down lower to the ground (off the trailer), and even then it only cleared by about 1" or so, but it works!

You can see my wood boat supports and the cherry picker above in post #83.
 

Struc

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Jul 27, 2011
Messages
409
Re: 4.3l Block Crack - repair or replace? [Decided to Replace - Adventures begin]

And I guess while I'm here... I can update the thread a bit.

Had the boat out last weekend for the 2nd time. Still running great. I did readjust the valves non-running and it is absolutely better. Now, instead of hearing a bunch of valve rattle under load, I only hear one clanking. I'm wondering if it is a bad lifter, or it really is just the adjustment. Not too worried about it, though. It's not severe, but is noticable.

Nothing else to report engine wise. All is well!
 

tpenfield

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Jul 18, 2011
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17,621
Re: 4.3l Block Crack - repair or replace? [Decided to Replace - Adventures begin]

Good to here that the engine is back and running well. :)
 

ricohman

Lieutenant Commander
Joined
Jul 30, 2011
Messages
1,631
Re: 4.3l Block Crack - repair or replace? [Decided to Replace - Adventures begin]

Great thread. And as a former GM mechanic, I like threads like this.
With some sweat equity you can get back on the water cheap.
And as for the miles on that motor? I have personally seen 4.3 with over 400 000kms that needed nothing more than a timing chain to keep running. Although the cams were getting pretty worn by then. And I've seen plenty of remans bored 60 so I wouldn't lose any sleep over that.
As mentioned above, I also recommend the Astro vans for 4.3's. There are plenty of them and lots were family trucksters with low miles.
 

Struc

Chief Petty Officer
Joined
Jul 27, 2011
Messages
409
Re: 4.3l Block Crack - repair or replace? [Decided to Replace - Adventures begin]

Thanks! It was a pretty cheap build. Of course, $500 for new exhaust manifolds & risers hurt the budget a bit, but I knew I needed those when I bought the boat. With the parts I sold off, I'm probably into the motor for about another $500, with the head work, electric fuel pump, carb rebuild kit, and gasket kits, etc. All in all, a very reasonable motor replacement. I'm very happy with the $$$ / reward factor.
 
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