4.3 vortec

[Sphinxmunkey]

I've got a quick question that has been troubling me.

I have an 88 4.3 that wasn't winterized and now I'm looking for a motor.

Going to take a truck engine and swap head gaskets and freeze plugs and was just wondering about a few things.

The gasket kits I've found usually say "Not for vortec engines" why is this? And if you could provide links to something I could use its much appreciated, head sets and what not.

Second are my exhaust manifolds going to bolt up, because I think I read somewhere they wouldn't but everywhere else points to the heads being the same other than the combustion chamber?

Just wanted some FOR SURE answers on this. I recently found a 98 model engine with 150k on it for 150$ with a blown head gasket, I figured it'd be a perfect candidate. Going to look at it tomorrow so some answers tonight would be awesome.

I'm planning on taking the 98 engine down to a shortblock, leaving the timing cover, putting marine head gaskets and brass freeze plugs in it, then swapping everything off of the 88 on it after I take it out.

Thanks for any input, I'd like to hear what everyone has to say on this

 

[Sphinxmunkey]

Re: 4.3 vortec

For instance the felpro set says, fits balance shaft models, which I know is after 92 so maybe thats what it is?

http://www.go2marine.com/product.do?no=90102F

And this one just says, not for vortec models...

http://bpi.ebasicpower.com/c/GASK-HS/Head+Sets

Just wondering why.

and if the manifolds bolt up, that's all I really need to know, do I have to spend extra or just buy another engine. The main deciding factor of course is $$$

 

[dubs283]

Re: 4.3 vortec

the "truck engine" won't last long at all in yer boat.

marine engines and automotive engines are different, no matter what people tell you.

4.3 auto motor designed cam, heads, crank, rocker arms and springs, etc. designed to run at 2000-2500 RPM for extended periods.

4.3 marine motor above parts designed to to run at 4200-4400 RPM for extended periods

auto motors, ecspecially junk yard motors last about 10 hours in a boat

 

[maxxman04]

Re: 4.3 vortec

the vortec engines came out in 1994 in the 4.3 motors. vortec refers to the heads and intake/injection system. '88 motors are diiferent than 98 motors, mainly in the heads. 4.3 from 94 on are vortec, pre 94 (except a special, few motors) are not vortec.

 

[mylesm260]

Re: 4.3 vortec

the "truck engine" won't last long at all in yer boat.

marine engines and automotive engines are different, no matter what people tell you.

4.3 auto motor designed cam, heads, crank, rocker arms and springs, etc. designed to run at 2000-2500 RPM for extended periods.

4.3 marine motor above parts designed to to run at 4200-4400 RPM for extended periods

auto motors, ecspecially junk yard motors last about 10 hours in a boat

This guy's an idiot, lots of us have hundreds of hours of automotive engines.

I have about 100 hours on an engine that had 60,000 kms on it in a truck, Still runs strong as new.

 

[maxxman04]

Re: 4.3 vortec

mylesm260, refrain from slandering on this site please. and have your facts straight before replying. otherwise, you're gonna make a few enemies here.

marine motors are in fact designed and built to run at higher rpm's for a greater length than automobiles. this assumes a stock marine motor vs. a stock automotive motor. very true that alot of marine parts are the same as cars, but not all. can auto motors survive? yeah, if they're not constantly pushed too hard. can you use car motors in boats? yes, with the right parts if you're looking for longetivity. a low compression, small valve, small cam motor won't hold up to the sustained higher rpm's, whether in acar or boat

 

[mylesm260]

Re: 4.3 vortec

You ever look at parts?

Cranks, Rods, Pistons, Rings, Bearings, Push-rods (in most cases), blocks, valves are all the exact same for GM's marine division as they are for their automotive division.

http://www.gm.com/experience/technology/gmpowertrain/engines/specialized/marine/marine_engines.jsp

Stuff like alternators, starters, head gaskets, water pumps, carbs, intake manifolds, that stuff is different.

Saying that a "truck" motor with all the exact same parts is going to last 10 hours is absolute BS.

I'm actually running a 4.3 from a chev ASTRO AWD in my boat right now, with the stock astro cam, stock head gaskets and stock EFI system.

My boat runs better, is 8 MPH faster and gets better fuel consumption than it did with my marine engine. Granted my marine engine was non-vortec and this one is vortec.

Making statements like "truck engines are completely different that marine engines and won't last" is just straight up false.

Lots of people on these forums recommend using automotive short/long blocks as doner engines for those who cracked their blocks due to freezing, provided of course they swap over all the necessary marine parts.

 

[mylesm260]

Re: 4.3 vortec

I've got a quick question that has been troubling me.

I have an 88 4.3 that wasn't winterized and now I'm looking for a motor.

Going to take a truck engine and swap head gaskets and freeze plugs and was just wondering about a few things.

The gasket kits I've found usually say "Not for vortec engines" why is this? And if you could provide links to something I could use its much appreciated, head sets and what not.

Second are my exhaust manifolds going to bolt up, because I think I read somewhere they wouldn't but everywhere else points to the heads being the same other than the combustion chamber?

Just wanted some FOR SURE answers on this. I recently found a 98 model engine with 150k on it for 150$ with a blown head gasket, I figured it'd be a perfect candidate. Going to look at it tomorrow so some answers tonight would be awesome.

I'm planning on taking the 98 engine down to a shortblock, leaving the timing cover, putting marine head gaskets and brass freeze plugs in it, then swapping everything off of the 88 on it after I take it out.

Thanks for any input, I'd like to hear what everyone has to say on this

Okay, sorry for the ranting:

To answer you're questions:

Manifold differences: Intake only. The vortec heads have different intake manifold bolt patterns, the exhaust bolt patterns are the same, your existing exhaust manifolds are fine, but you will need a new intake.

Gasket sets:

The gaskets sets are going to be different for a few reasons, rear oil seals are different, oil pan bolt pattern is different, intake manifolds are different.


Head gaskets:
You ONLY need to change the head gaskets if you are going to run without a heat exchanger. If you already have a heat exchanger, you can leave the truck gaskets in there. If you do NOT have a heat exchanger, now would be a good time to invest in one.


Cams:
The 1996-2001 4.3 vortec cams are spot on with the marine cams, I've looked into this heavily. in fact, it's been suggested that the truck cam is a smidgeon hotter than the marine cam.

150,000 Miles: That's too many. Those 4.3's don't have the best bearings from the factory. I would look for something 110,000 or lower. You could rebuild it for pretty cheap, assuming you don't need any major work done.


What you ideally want to do is find a running 4.3 with lower miles on it, swap all the marine parts over to it, install a new intake manifold that's going to be compatible with your carb, and install a heat exchanger if you don't already have one, that way you don't have to open you're running engine.

It's the cheapest solution to you're problem, and since your going non-vortec to vortec, you're basically giving yourself an extra 20-30 HP (depending on how limiting you're carb is).

 

[Tail_Gunner]

Re: 4.3 vortec

mylesm260, refrain from slandering on this site please. and have your facts straight before replying. otherwise, you're gonna make a few enemies here.

marine motors are in fact designed and built to run at higher rpm's for a greater length than automobiles. this assumes a stock marine motor vs. a stock automotive motor. very true that alot of marine parts are the same as cars, but not all. can auto motors survive? yeah, if they're not constantly pushed too hard. can you use car motors in boats? yes, with the right parts if you're looking for longetivity. a low compression, small valve, small cam motor won't hold up to the sustained higher rpm's, whether in acar or boat

I am sure you are trying to do the right thing here. But if you take a very close look @ how a motor is built marine off road or car...there is very little difference.. Yes the bolt on eqipment is different...But even the cam is pass say...nice french huh,,.

As in all things the in this world the bubble is being busted. And with that said...Carb's... ign sys....and fuel pumps...now that is still marine stuff....

 

[mylesm260]

Re: 4.3 vortec

A low compression, small valve, small cam motor won't hold up to the sustained higher rpm's, whether in acar or boat

What you just listed there are all factors the effect performance, and have absolutely nothing to do whatsoever with longevity.

If you compensate for emissions, marine and automotive engines almost always put out the exact same HP and torque.

There are only 2 factors that effect a motor's longevity. Metallurgy and oiling.

And by metallurgy, I'm referring the bearings and the rings, of course, and by oiling, I'm referring to the oil pumps.

So what you're saying is true, than GM is putting sub-standard oil pumps, bearings and piston rings into their truck engines, because they don't want them to last that long.

How much sense does that make? Why would they produce two identically sized parts and make one out of better metal than the other? Especially considering how cheap it is to produce bearings and rings in the first place. Ever go on Ebay? You can get high performance marine/automotive rings and bearings for dirt cheap.



Also, consider engine life.

A typical boat motor could go 1000 hours and die with high rpm usage (say 3000-4000 rpms)

Whereas a truck engine could go say 250,000 miles of low rpms usage (say 2000-2500 average)

200,000 miles, at an average of 20 mph (city/hwy driving) is 10,000 hours.

So the engine lasts for 10,000 hours in a truck and you're telling me it can't last 1000 in a boat, one tenth of the amount of hours it sees in a truck?

If you want to get technical, engine wear occurs at the square of the engine RPMS, so if you start crunching some numbers, it makes perfect sense.


Also, I beat the @#$#@ out of my automotive 4.3, and it's still holding up fine. About twice a week on average for the past 4 weeks or so I"ve been doing runs of about 15 minutes at 4000 rpms to get to my favorite wake-boarding spot on a workday before the sun goes down.

 

[mkast]

Re: 4.3 vortec

the "truck engine" won't last long at all in yer boat.

marine engines and automotive engines are different, no matter what people tell you.

4.3 auto motor designed cam, heads, crank, rocker arms and springs, etc. designed to run at 2000-2500 RPM for extended periods.

4.3 marine motor above parts designed to to run at 4200-4400 RPM for extended periods

auto motors, ecspecially junk yard motors last about 10 hours in a boat

So you are telling me that when GM builds an engine for Mercruiser or Volvo, they use different crankshafts, cylinder heads, rocker arms and springs?
Tomorrow, when you take a break, call the engineering division at Mercruiser in Fond du Lac, Wisconsin. Then you will find out what I already know.
I'm kind of surprised you didn't throw in the "Marine cylinder blocks have a higher nickle content than automobile blocks."
By the way, how many bone yard engines have you bolted in to know they last only ten hours in a boat?
Your statements lead me to think you are kind of new at this.

 

[mylesm260]

Re: 4.3 vortec

Thank you, Mkast.

 

[fabrimacator21]

Re: 4.3 vortec

Well I was gonna post but it looks like myslem and mkast corrected him.

Dubs283: That is pure bs... Please don't post if your just doing it to look like you know what your talking about because you could end up costing someone alot of money if they take your advice. Would you want someone on here feeding you bs because it "sounded good"? If it was simply a mistake then try to do some more research next time.

As for the 150k motor I say don't do it. Especially one with a blown head gasket... chances are the bearings are wiped... antifreeze strips oil away from bearings. Those 4.3's are great motors though... my brother literally ran his 4.3 jimmy out of oil and drove about 2 miles without knowing it. It did lose a little power but still ran like a top. Tough little motors.

You should be able to find a decent 100k motor for 500 or so complete... just make sure you do a compression test on it. Might want to throw a timing chain in it too.

 

[Bondo]

Re: 4.3 vortec

the vortec engines came out in 1994 in the 4.3 motors. vortec refers to the heads and intake/injection system. '88 motors are diiferent than 98 motors, mainly in the heads. 4.3 from 94 on are vortec, pre 94 (except a special, few motors) are not vortec.

Ayuh,... The Vortec name was used on the Valve covers then,...
But,..
The Fast Burn, Vortec Heads weren't introduced til 1996...

 

[Sphinxmunkey]

Re: 4.3 vortec

Yeah I may as well get a rebuild kit, just the $ lol

"Marine cylinder blocks have a higher nickle content than automobile blocks."

I busted out laughing at that, excellent.

From everything I've looked at you guys have told me pretty much what I knew/read, just wanted to be spot on before I do this and ask more knowledgeable people than myself on the matter.

Thanks

 

[180shabah]

Re: 4.3 vortec

Marine cylinder blocks have a higher nickle content than automobile blocks

...and don't forget the forged steel pistons.

 

[mylesm260]

Re: 4.3 vortec

Yeah I may as well get a rebuild kit, just the $
Thanks

Honestly, if the motor's got a blown head gasket, don't even bother.

As was posted earlier, the anti-freeze could have easily caused a hydro lock, or a water in the oil situation. Either one of those could have cause or contributed to a bearing spinning.

The second you spin a bearing in a 4.3, the cost of the rebuild goes up by a couple hundred dollars. (look up line boring)

Running, low mileage 4.3's are a dime a dozen, you just need to look around a little.

I paid 250 bucks for mine, complete with everything (starter alternator, EFI system, ECU) from a u-pull place with 60,000 KMS on it (about 40,000 miles)

 

[Fix'em]

Re: 4.3 vortec

WOW! I scanned through the replies above quickly and from what I see there are some major misconceptions out there about this. It is apparent most who voice their opinions have not actually opened up these motors to compare the parts side-by-side.

I can tell you from a VERY recent experience that there are significant differences to be found between the truck and marine 4.3. I just installed a rebuilt 4.3L two days ago using a 4.3 block from a 97 Astro van, but, it was ONLY the block that I used and this is why.

- The crankshafts are different. Side by side, and confirmed with the machine shop, the marine crank is weighted a lot heavier to maintain more rotational inertia.

- the connecting rods are the same, as are the wrist pins

- the pistons are COMPLETELY different for marine application. They are a heavier casting and the compression and oil ring grooves are much wider to accomodate a much heavier duty set of rings than the truck/van motor to beable to withstand sustained high RPM load for longer periods.

- The oil pan will not fit from your 88 marine engine onto you newer truck engine. 96 and up 4.3 used an aluminum oil pan, so the block flange and bolt patterns are completely different. You will have to weld up some aluminum to the outside of the pan to thicken it so you can tap it to fit your dip stick/drain fitting from your metal pan.

- the camshafts are slightly different in profile. Although you could use the truck cam, the marine cam has a little more low end torque than even the truck cam does. Again, you can measure the lobes when you have them both out.

- the timing covers are different. 96 up 4.3 engines use a composite timing cover that again has a completely different bolt pattern and a different mounting flange. The block castings are different. Not because of marine use, just because of the different years.

- Your marine water pump will not mount over the composite timing cover unless you change one of the bolts to a machine screw or similar with a flat head to clear the pump and you CANNOT use your truck pump. Very different style/shape.

-you can order a complete upper gasket set for marine use from several aftermarket suppliers. Mine was from Victor I believe. However, the rocker cover gaskets you get will not fit for the Vortec rocker covers. You will have to buy those seperate or re-use the original ones if they are in good condition.

-the rear main seals are the same, provided your marine engine used the one piece and not the 2 piece

So, to sum it up. You can use your $150 donor block only. Take the entire rotating assembly out of the marine motor and swap it into the new freshened block. I'd recommend at least new rings so they seat properly into the new cylinders after you hone the linings and to be safe, put in new bearings. They are cheap insurance to avoid problems.

Oh, and don't forget to use all of the marine spec accessories (starter, pumps, altenator.....)

If you have any questions let me know. Hope this helps.

 

[scipper77]

Re: 4.3 vortec

Sorry but you are wrong. The internals of the engine are identical.

I've never taken either apart but I thought that the cam was different??

 

[Fix'em]

Re: 4.3 vortec

Sorry but you are wrong. The internals of the engine are identical.

Sorry Bubba1235, but you are dead wrong. Their are major differences in the rotating assembly. I've had both in my hands side by side for comparison and measurements. Read my post above.

I've never taken either apart but I thought that the cam was different??

Scipper77, you are right. There are differences in the camshaft profiles as well, although very slight. The marine cam provides a little more low end torque than the truck/van camshaft. But not a big difference.