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

[Struc]

Re: 4.3l Block Crack - repair options, or replace?

Re: 4.3l Block Crack - repair options, or replace?

being an '88 you have many options. find a 87-95 4.3 block, or my recommendation would be to find a low mileage 4.3 from a truck after 96 (vortec heads). then get a vortec specific intake, change the head gaskets to marine versions, change the core plugs (sometimes called freeze plugs) from steel to brass, and put in a marine cam. all your other "stuff" will change over to a vortec headed motor except your intake manifold.

Thanks for the advice! That's the info I was looking for.

However, I've got a lead on a complete motor with accessories, oil pan to flame arrestor, alt, starter, flywheel cover, etc for $800. Given that I was going to have to spend $500 on a full exhaust manifold & riser set, and this engine comes with them (and they are newer replacements), I'm not sure I can pass it up, provided it runs good and has a good compression test. It's about an hour away, so not too bad.

I'll let everyone know what happens. Even if I get this motor, I'll probably strip it down and replace all the gaskets while I have it out of the boat. Seems like cheap insurance.

 

[zbnutcase]

Re: 4.3l Block Crack - repair options, or replace?

Re: 4.3l Block Crack - repair options, or replace?

Just make sure IT isn't cracked! 4.3s will crack in the valley under the intake usually before they crack externally! Buyer beware. And a cracked engine can run good and have good compression!

 

[Struc]

Re: 4.3l Block Crack - repair options, or replace?

Re: 4.3l Block Crack - repair options, or replace?

Just make sure IT isn't cracked! 4.3s will crack in the valley under the intake usually before they crack externally! Buyer beware. And a cracked engine can run good and have good compression!

I hear you, but I would guess it's going to be hard to remove the intake while I'm there before I buy it. I will certainly check over the block and heads as much as I can, though.

And since my current engine runs good and has good compression, I'm certainly aware!

 

[Struc]

Re: 4.3l Block Crack - repair options, or replace?

Re: 4.3l Block Crack - repair options, or replace?

Stripped down the old engine a bit more today, before I go look at & possibly pick up the replacement.

Pulled the heads and just wanted to see what kind of condition everything was in. I'm amazed at the good condition of everything internal, with 2 exceptions.

#1: Found 2 pieces of impeller stuck in 2 water passages between the block and head.

#2: Found another crack. This time, in cylinder #5.

There is also a brand new core plug right outside that cylinder, so I'm guessing it froze up and cracked and then pushed out the core plug. Somewhat amazing though, as that cylinder has 180 compression, so it was still holding strong, despite the problem.

Oh well, just made my initial decision to replace it an even better one.

 

[Struc]

Re: 4.3l Block Crack - repair options, or replace?

Re: 4.3l Block Crack - repair options, or replace?

Well, scratch the replacement engine. Was just about getting ready to leave and had called the kid to confirm with him. Got a call a few minutes later while I was hooking up my trailer to haul the engine back. He found JB Weld on the outside of the block as he was looking to pull the engine. I wish he would have found it earlier, but at least I didn't drive all the way down there and find it. Maybe I'll offer to buy the exhaust manifolds off him for cheap, rather than spend $500 on a set of new replacements.

So... Back on the prowl for a replacement engine. I'm finding a few S10/Jimmy engines around in the $250 range. Maybe I'll just strip one of those down and rebuild it instead of finding a genuine Mercruiser.

 

[Struc]

Re: 4.3l Block Crack - repair options, or replace?

Re: 4.3l Block Crack - repair options, or replace?

Well, found my replacement engine - went and heard it running earlier today. It's in a 1992 Silverado that is getting parted out. The engine was replaced with a remanufactured unit at 90k, and the vehicle has 190k on it now - so the engine has approx 100k on it.

It's got Vortec heads, so I'll need a new intake manifold if I'm going to use them - I see the 2bbl version of the Vortec intake manifold for $200 new - I guess I can deal with that, since I'm getting the whole engine for $200.

Oh, and the other good part of the deal - it's about 5 miles from my house.

They are going to work on pulling it out tomorrow, so I may have it home by tomorrow night. Probably won't get to stripping it down until next weekend, though. I'll keep the thread updated with my progress.

 

[Scott Danforth]

Re: 4.3l Block Crack - repair options, or replace?

Re: 4.3l Block Crack - repair options, or replace?

if its in a 92, make sure that it does have vortec heads. the vortec heads are 96 and newer.

you will need to switch all core plugs to brass, and change the head gaskets to marine head gaskets. The truck cam will also need to be swapped for a marine cam.

 

[Bondo]

Re: 4.3l Block Crack - repair options, or replace?

Re: 4.3l Block Crack - repair options, or replace?

if its in a 92, make sure that it does have vortec heads. the vortec heads are 96 and newer.

you will need to switch all core plugs to brass, and change the head gaskets to marine head gaskets. The truck cam will also need to be swapped for a marine cam.

Ayuh,.... In 92, the heads were Vortec in Name only, count the number of intake manifold bolts...
'n,...
The truck cam is just fine, No reason to change it...

 

[joewithaboat]

Re: 4.3l Block Crack - repair options, or replace?

Re: 4.3l Block Crack - repair options, or replace?

Yea like these guys are saying, it might even say "vortec" on the valve cover and not have the actual vortec heads. Count the intake bolts... 12 bolts for regular... 8 bolts for vortec.

Here is that link again to tell you what year stuff you are looking at.
http://www.hotsixes.com/index.php?option=com_content&view=article&id=14&Itemid=12
Good find and good luck!

Oh and if it is a vortec head, dont buy a 2 barrel intake ...get a 4 and a new carb!!!

 

[Struc]

Re: 4.3l Block Crack - repair options, or replace?

Re: 4.3l Block Crack - repair options, or replace?

if its in a 92, make sure that it does have vortec heads. the vortec heads are 96 and newer.

Ayuh,.... In 92, the heads were Vortec in Name only, count the number of intake manifold bolts...

Thanks - I was very confused about that. I questioned the kid about it too.

Here is that link again to tell you what year stuff you are looking at.
http://www.hotsixes.com/index.php?op...d=14&Itemid=12

I scoured that document again last night, and was looking for any reference to a pre-1996 Vortec head, and didn't see anything, so I figured they weren't really Vortec. Then again, it was a rebuilt replacement engine - didn't know if something else was put in there, or if cars were different than boats. One of the kids selling it to me said that 1996 was the first FUEL INJECTED Vortec when I question him. This thing looks like it has a carb on it (maybe TBI?), and he made it sound like it was some sort of pre-Vortec, Vortec or something. I honestly didn't care. Figured if they were Vortec, it would be a bonus I could either use, or just sell for the price I paid for the whole motor.

It does have Vortec valve covers, but I didn't count the bolts on the intake - I will figure all that out once I get it home. Either way, I'm happy with my purchase. At this point, I would have been really happy for a block in good condition for $200.

I'll pull off all the numbers (block, intake, cam, etc), and compare it to the website, and see what all I got. That website is VERY confusing - not because it's poorly written or anything - just because GM made so many #$(@!* changes to this engine over the years.

The truck cam is just fine, No reason to change it...

I'm going to be tearing down for a full inspection. Don't want to get it back together and be sorry mid-season. If inspection shows anything worn, I'll buy a full engine rebuild kit and will be pulling the cam to replace the bearings. Is the truck grind the same as marine? The cam in my old engine looks fine, so I could swap it in there if there would be an advantage.

Oh and if it is a vortec head, dont buy a 2 barrel intake ...get a 4 and a new carb!!!

I thought long and hard about it, and at the moment, doesn't seem like it will be an issue, but I'm quite happy with the performance of the 4.3l with 2bbl carb. I don't think I could justify spending an extra $250 (used) to $500 (new) for a 4bbl carb. Maybe someday in the future I would sell off the 2bbl setup and put a 4bbl one on - hard to say. Just not ready for that now.

 

[Scott Danforth]

Re: 4.3l Block Crack - repair options, or replace?

Re: 4.3l Block Crack - repair options, or replace?

if it is truly a 92, non-vortec, it would be the same castings/parts that you have, just non broken.

Bondo, you may want to double check, the cam part numbers and profiles are different between the truck and the industrial/marine engines. if you are pulling the engine apart, a new cam and t-chain are fairly low cost.

 

[Bondo]

Re: 4.3l Block Crack - repair options, or replace?

Re: 4.3l Block Crack - repair options, or replace?

if it is truly a 92, non-vortec, it would be the same castings/parts that you have, just non broken.

Bondo, you may want to double check, the cam part numbers and profiles are different between the truck and the industrial/marine engines. if you are pulling the engine apart, a new cam and t-chain are fairly low cost.

Ayuh,... I didn't say it's the Same, just that it don't matter...

The tear-down tells the story,...
If the present cam is Good,...
No reason to swap it....
If it's Wiped,... I'd go abit hotter than stock marine maybe...
if yer spendin' on a cam in the 1st place...

 

[joewithaboat]

Re: 4.3l Block Crack - repair options, or replace?

Re: 4.3l Block Crack - repair options, or replace?

I agree if neither of those roller cams is good id get an aftermarket that's a little bigger. Replacement will be $300.00, give or take, either way.
Truck cam specs are very close to the marine cams from what I've seen folks post previously.

 

[Struc]

Re: 4.3l Block Crack - repair options, or replace?

Re: 4.3l Block Crack - repair options, or replace?

OK, pictures shortly.

Block is casting 10172756 after I ate through the layer of oil junk with brake cleaner & wire brush. The other casting number that sometimes matters is 756.

It's TBI. It uses a single wide serpentine belt configured entirely different than the boat, and I have a LOT of spare parts to deal with getting off. No balance shaft (no extra plug in the back).

Oh, and yes, it's a 12-bolt intake manifold with valve covers that say Vortec. Ok, whatever.

One problem is that the fuel pump hole casting is there, but not machined. So either I need to figure out a way to make it machined, or get a electric fuel pump (more likely scenerio).

I'll work up some pictures and post in a bit, provided the wife doesn't get antsy with me on the computer. :redface:

 

[Struc]

Re: 4.3l Block Crack - repair options, or replace?

Re: 4.3l Block Crack - repair options, or replace?

Pictures!

Pulling the engine off the trailer. Notice all the extra crap they didn't bother to remove, including the clutch, A/C compressor, alternator, PS Pump, fan, etc.

Pseudo Vortec valve covers

Casting number. Per the V6 web site, it's of the same family as the engine I have, listed right after my original engine's casting number.

Sad excuse for a fuel pump mount.

Overall, minus the lack of a fuel pump mount, I'm very happy with the purchase so far. We'll see where I am when I get it stripped down. For $200 I really can't complain. It ran great, and I should actually be able to make back my money with selling off some of the used parts on Ebay or something.

Next step - strip it down to the shortblock and take some cylinder measurements, check out the cam, timing components, and whatever else I can see. If everything checks out, I'll have to make a decision on if I want to rebuild it, or just run the shortblock as-is.

 

[Struc]

Re: 4.3l Block Crack - repair options, or replace?

Re: 4.3l Block Crack - repair options, or replace?

Cripes - I didn't realize how expensive electric fuel pumps were. Geez.

Anybody ever hear of or use the Airtex Electric Fuel Pump, model E84389?

I saw some cheaper ones on Ebay, but they looked like I would get what I paid for. This one looks decent, and I can get it with a coupon for around $55.

What's the thought on wiring in a electric on a previous mechanical setup? I guess I could mount a relay someplace that is triggered by the ignition switch, but I've read they are usually wired through a oil pressure switch of some sort. Necessary?

 

[joewithaboat]

Re: 4.3l Block Crack - repair options, or replace?

Re: 4.3l Block Crack - repair options, or replace?

Congrats on your bargain find!!
You might break even selling the extra stuff on ebay!

As far as the fuel pump goes, you would be best served wiring it as close to how mercruiser would have. I dont know enough about factory wiring and changes from year to year to tell you how. There should be others that will, Don S, Bond-o, or Chris maybe.

That pump is USCG approved and meets the fuel pressure requirements so it should work.
Good luck!

 

[thumpar]

Re: 4.3l Block Crack - repair options, or replace?

Re: 4.3l Block Crack - repair options, or replace?

Also check out Astro/Safari engines. Those are 99% 4.3l and there are tons of them at junk yards.

EDIT: Not sure why this got posted so late. It was typed before the engine find was posted.

 

[300sflyer]

Re: 4.3l Block Crack - repair options, or replace?

Re: 4.3l Block Crack - repair options, or replace?

I just went through this same thing after discovering a cracked block on a friends 18' Searay. We found a low milage 4.3 out of a 91 Chevy pickup. After all was said and done, it runs well, and we are pleased with the results. We put new head gaskets, [Felpro] changed the frost plugs to brass, and added an electric fuel pump. [Carter]

http://www.carterfueldelivery.com/fuelpumps/universal_fp.php

Keep the pictures coming.

 

[Struc]

Re: 4.3l Block Crack - repair options, or replace?

Re: 4.3l Block Crack - repair options, or replace?

and added an electric fuel pump. [Carter]
http://www.carterfueldelivery.com/fuelpumps/universal_fp.php

Yeah, saw that one, and it looks identical to the Airtex one I asked about above. One must be an OEM of the other one. I guess that's the one I'll go with. They have it at Advance Auto Parts, and they always have great coupon deals there. It's listed for $85 on their website, but using the BIG30 coupon, I can get $30 off anything over $75, so that brings it down to $55 - a bit more reasonable.

Thanks for the confirmation on the swap - good to hear some others have done it too, although I don't forsee too many issues.

If I leave the bottom end as-is, I'll buy that same Fel-Pro engine rebuild kit that you mentioned. Advance Auto has it for like $75 vs the Marine version which is like $200. What a waste. If I end up rebuilding the bottom end, Ebay has rebuild kits with pistons, rings, full gasket set, timing gear/chain set, etc for $250.

Keep the pictures coming.

I will. I plan on turning this thread into a bit of a "how to" thread with pictures on the work I do. I gotta think this kind of thing will continue to come up as these 4.3's get older and older.