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

[CharlieB]

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

Auto engines are clockwise rotation and marine is counter clockwise, difference is in the auto world rotation is seen from the water pump side and the marine world rotation is seen from the flywheel side

NOT

All built on the same assembly line, just a few differences in the parts used/installed.

Historically, there were 'reverse' rotation engines installed in twin engine boats, now-days it is all reversed in the drives, all engines are CW from the front.

Some manuals view the motors from the rear and are then referred to as CCW, but even they are CW from the front.

 

[Struc]

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

Guys - enough already with the rotation stuff. Everyone is saying the same thing, but not understanding what the other person said. We can all agree that they all spin the same way whether they are marine or truck engines.

That said, I did some work with a wire wheel on my intake manifold and motor mounts today, and painted them. They look pretty nice and touched up the timing cover too.

My garage looks like a used parts store for 4.3l engines.

 

[DeepBlue2010]

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

What paint did you use? If not a can spary, what was your spary settings?

 

[Struc]

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

Just used some regular high temp engine paint in a spray can from the auto parts store.

 

[TomB985]

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

Just used some regular high temp engine paint in a spray can from the auto parts store.

You didn't use genuine Merc Phantom Black?

 

[gunsup007]

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

I just found your post and finished reading thru it all. Great info. as I might be heading down the same path. I am in the process of tearing down my own 4.3L right now. Your thread has helped clear up a lot of questions that I had. Thanks man, and i'm looking forward to the finished product!

 

[sleeper455]

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

bump.....

Any updates? I'm knee deep in the same process....

I have an 88 Century with a possible cracked block as well. What are the possible hazards with a vortec balance shaft conversion (other than finding an intake to fit the vortec heads)?

Also, is there a "hot cam" for these vortec motors that is a bump up from stock?

I'd imagine the smoother running balance shaft motors (along with the better flowing vortec's) would be a no brainer swap for earlier 4.3 equipped boats.

Thoughts?

 

[Struc]

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

No real updates. I've been busy with other projects, and since the boating season doesn't start for another 5 months here in Wisconsin, I have plenty of time to finish up the motor.

I did buy a new timing chain & gear set - the stock one seemed a bit loose. It might have been in spec, but it was close, so I decided to spend the whole $40 for a aftermarket double chain roller set.

I had a set of pretty nice looking heads from my parts boat, so I dropped those off at a machine shop to be checked over, but one of them was cracked, so a couple days ago, I dropped off my original 1988 heads from the original motor. Hopefully they are not cracked anywhere and I can have them cleaned up, rebuilt, and resurfaced to new condition.

I don't really know all the possible pitfalls of using a newer motor, although I'm sure I'll find out at some point. I have a 1997 Vortec motor in my storage unit that I want to rebuild someday - maybe sooner than later if I find a good deal on a boat with a poorly winterized and cracked motor. At this point, yes, the intake is the primary issue. I don't know what other parts may not match up, however - things such as the distributor.

As far as camshafts go - whatever you get just make sure it's marine rated. Most "hot" camshafts are more interested at flow at higher RPM's and can cause serious issues in a boat motor.

 

[Scott Danforth]

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

You didn't use genuine Merc Phantom Black?

That would also be PPG 9000 black

 

[Bondo]

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

That would also be PPG 9000 black

Ayuh,... Or Rustoleum rattlecan Black....

 

[Scott Danforth]

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

Stuc, I would suggest the '97 vortec heads for the rebuild. the intake is the big difference.

 

[Struc]

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

Stuc, I would suggest the '97 vortec heads for the rebuild. the intake is the big difference.

Yeah, but I don't have a Vortec intake for the boat, though. I would have to buy one. And if I went Vortec Intake, then I would need to buy a 4 bbl carb (well, I wouldn't *HAVE* to, but why go half way?)

Right now, I'm trying to do this as an economical build. Besides, the boat had PLEANTY of power for me as it was - I was very happy with the performance.

One thing I didn't mention before is that I sold the Centerforce clutch and the intake manifold + TBI that came with the truck motor, and made back more money than I bought the motor for, so thus far my budget build is right on track!

 

[Scott Danforth]

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

in case your looking for a vortec manifold

http://www.google.com/search?q=vort...iI5PegQf67bCXAg&ved=0CFoQrQQ&biw=1035&bih=811

http://boston.craigslist.org/sob/boa/2765178447.html

http://burlington.craigslist.org/boa/2711912348.html

 

[Struc]

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

Machine Shop Results:
Parts boat heads - 1 cracked, one good
My 1988 Original heads: Both cracked (around head studs on one, and valve seat on other)
Heads that came with my truck motor: Both good - I got these rebuilt

Bill ended up being $250 after trade in of the 1 good core from the parts boat. He had to go through and disassemble and check all 6 heads out, and did a full resurface and valve job on the 2 I'm using, so I feel it was still a pretty good deal.

And, since everyone loves pictures...

 

[Struc]

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

Fired up the garage heater yesterday and got to work putting the new heads on. For anyone looking to do this, I'll outline a few extra steps I took that may not be "normal procedure" when doing something like this.

Obviously, the surface needs to be cleaned up. I went at it with a wire wheel. Some people say that's too harsh for the surface, but I've never had any issues in all the motors I've worked on.

I ran a tap through all the head bolt holes to clean them up, and then blew them out with compressed air. I also spun the motor upside down on the stand and blew out the water passages. Since this was a truck engine with actual antifreeze in it, there wasn't much junk in there, but there was some. Better to just get it out now. A boat engine will likely have a lot of sand and other sediment in there to blow out.

Once cleaned up, I took some brake cleaner and wiped down the block mating surface to remove any oil or other grease, grime, etc that may be left.

Then, I took some thick assembly lube on a paper shop towel and wiped the cylinder wals with it. This will put a thin film of oil on the walls so that they stay lubed after you bolt the head down. You can see the red hue on the first cylinder in the picture. It'll smoke a little more on first start up, but it's good peace of mind.

Since I didn't have the block resurfaced, and it was not a perfect mirror surface like it should be, I used some of this on the block surface.

And then fitted the head gasket on top. Let it get a little tacky before you put the head gasket on.

Since there are pins in the block for alignment, there are no issues aligning the head gasket on the block.

 

[Struc]

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

Since the heads were rebuilt and had just been resurfaced, there was no need for the copper spray on the head surface. Lined it up and set the head on the block & gasket.

I cleaned up the copper gasket over-spray later with some brake cleaner on a paper shop towel.

I re-used the head bolts - they were all in pretty good shape. I ran them through a thread die to clean up the threads, and remove whatever sealant they had used when this motor was previously rebuilt. It looked and felt like plumbers pipe sealant, but whatever - it came off when ran through the die.

I coated all the threads with aviation sealant, as is usually recommended in this forum and snugged them all down lightly.

Working off the torque sequence in the manual, I started at 35 ft/lbs for each bolt, and then ran through at 55 ft/lbs, and then finally finished up at 75 ft/lbs per the manual's torque recommendation.

Oh, and this picture gives a good shot of the new double roller timing gears & chain I installed a while ago.

 

[Struc]

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

I went on to install the intake manifold as well. I used the same aviation sealant on the intake manifold gaskets to hold them in place on the head surface. On each end of the block you have to lay a bead of black silicone to form the gasket that seals the lifter galley. Sorry, forgot to get a picture of the bead, but here is one of it with the manifold on.

I did go for new intake manifold bolts - mainly because they dress things up a little. It is certainly not a requirement, but they were only like $15 or something.

 

[tpenfield]

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

Looking good . . .

When I rebuilt my 454 this past Fall I noticed how 'sloppy' the timing chain was, and replaced it as you did. I used the copper gasket spray on the exhaust and intake gaskets. I put the head gasket on 'dry' as it felt 'tacky' enough to get a good seal.

Take a video when you get it all done and you are starting it up . . . .

 

[gunsup007]

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

MAN!!! That is looking good Curt... Great pictures!

I have been following along because I too, have a cracked block among other things.

Curt did you spray the mating surface with the copper spray (noticed some over spray) or did you actually spray the gaskets themselves?

The aviation sealant you speak of, is that the Permatex Aviation Form a gasket? Just wondering for when I put my manifold back on.

 

[Struc]

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

Curt did you spray the mating surface with the copper spray (noticed some over spray) or did you actually spray the gaskets themselves?

I sprayed it right on the block. Figured it was the best way to get it in the little imperfections of the surface.

The aviation sealant you speak of, is that the Permatex Aviation Form a gasket? Just wondering for when I put my manifold back on.

Yeah, that's the stuff. I bought a little bottle of it at Amazon. You can use a variety of different things to put on the intake manifold gaskets to keep them in place. I don't personally think it's that necessary from a sealant perspective, but more just to hold the gaskets in place while you lower the intake manifold down. I just happened to have that sealant handy since you use it on the head bolts to seal them.