4.3 V6 - Balance shaft?

What years of the 4.3 had the balance shaft and what purpose is it? Also, if i wanted to put a 4.3 in my truck (79 C10 Pickup) instead of a 305 will it bolt up just like any SBC or do i have to move the mounts back? A 4.3 is basically a 350 with 2 cylinders missing, but depending on which cylinders are missing, bolting it in the same spot might put the engine too far forward for the transmission to bolt in and hook up linkage wise. I know that 4.3s came in these older style trucks in the 80s so would i just need to snag the mounts from one of those trucks or what?


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howdy there

91 was last year of non-balance shaft in the 4.3

92-up most had one, but not every single one, it depended on the application.



the mounts differ greatly from sbc v-8

i have heard that you actually use s-10 2.2L mount setups to put sbc v-8 in place of a 4.3L

although that may only be for swapping a sbc v-8 into an s-10 however

otherwise the bellhousing pattern and other things are identical to sbc v-8 chevy

For the 1992 model year, the 4.3L had its block design modified to allow a balance shaft to be installed. [5] Even though the 4.3L is an even fire V6, the 90 degree block layout is not ideal for smoothness. The balance shaft on the 4.3L is installed above the top timing gear, and runs through the top of the lifter valley. It is gear driven off the timing chain, and therefore a new timing chain cover was designed for these balanced 4.3L V6s.

copyright wikipedia.org 2009

http://en.wikipedia.org/wiki/GM_Vortec_engine#4300

scroll down to 4300


there are some good pages out there describing which ones did or didnt have the balance shaft on the net. better than wikipedia does.
my 91 s-10 has the vin z 4.3L in it and is runnign very strong smooth and reliably every single day at 196k miles all original just some minor oil smoke puff for a second at startup due to bad valve stem seals but thats ok to me because it never needs any oil added. also have a work astro van 4.3L with 370k on it(6 digit odometer) and still running driving! the only real issues we ever see/have has been burnt caps and rotors and carboned-up IAC motors and carbon in the EGR valves(and bad fuel pumps- but not engine fault related though)

hard to kill a 4.3 engine, of all the v-6 engines gm made i thnk the 4.3 and the 3800 are the winners hands down, for reliability and longevity and power(bottom end torque), they both typically go well over 200k miles before having any real issues., and we have replaced alot of 3800 engines over the years always with extremely high mileage before getting tired and needing to be replaced. same with 4.3L too




good luck

Thanks for the reply. Its actually a full size truck (79 C10). I just edited my original post to include that. I've seen a late model 4.3 put into a 77 C10 before (i have pics of it) But they used the stock 350 mounts and moved them back and WELDED them to the frame. I want to avoid this on my truck.

Find a Chevy truck from the late 80`s to the mid 90`s with a 4.3.
They used a mount that bolted into place of the stock small block and channeled 8 inches to the rear and bolted up to the 4.3, at least this is how it`s done on my 92 Chevy.
I agree fully about how long a 4.3 will last. And you can hot rod these engines and have a high torque fast revving mill.
When I got my 92 it had 270,000 miles on it, I drove it for a while and noticed it was down on power and starting to loose oil pressure so I pulled it to get it ready for a rebuild. I took it to my machinist and he mic`d it and found all the cylinders were badly worn, the least cylinder was 4.009 and the worse was 4.015. The mysterous part about this was the only time the piston slapped was when it was cold, after it warmed up it was quiet.
If your interested in the performance aspect I can give you plenty of tips as well as direct you to a site that tells you alot about them and what parts interchange and which they don`t recommend be interchanged.

Would it be possible to get a picture of these mounts? Id be interested in what you have to say about performance, id really like to do some stuff to it to gain mainly low end power since this is a truck, and will be used as a truck (but not like ill be pulling a ton of weight or anything) but not enough to need a big V8 or anything. I have a diesel for that, but its a 6.5 suburban and some things you just cant haul in the back of a 'burb and pulling a big trailer just for something small is a little ridiculous. I'm very interested in a 4.3 after my boss had an 01 4.3 vortec put it his 77 C10 that is at the farm. Ive driven it many many times and am very impressed. It has as much or more power than the original 350 had. My truck is identicle and ive found some good used 4.3s cheap lately. The 77 has a TH3500 behind it and ive found 4.3/700r4 combos so I think I would probably use a 700r4, but would go for a V8 one for a lil extra strength. The 3.06 first gear and lockup converter plus the OD would be very nice.

So, with 4.3 engine, fuel injection, 700r4 trans, 12bolt rear (3.07 ratio now, probably 3.42 or 3.73 down the road) I think id have a great little truck. Im sure I could buy one (but not a 79) for the same price (what fun is that!!) but it wouldnt be a 200hp/260ftlb vortec. Would be decent on mileage and power, have all the benefits of EFI, and be highly unique.

My '92 Vin Z TBI 4.3 was non-balance shaft. It's easy to tell by the timing cover. Non-balance shaft 4.3 uses a standrard SBC timing cover, balance shaft engines have an elongated cover.

I'm collecting pieces to build a carbureted roller cam 4.3 to put in something old and light with a 200-4R and a 3.42 or 3.73 posi behind it.

I don't want ti hijack this thread but I have a '93 4.3 sitting in the subframe of a '70 nova. With the stock 307 mounts the front of the oil pan is sitting on the crossmember, any suggestions?

You have to move the engine back (as mentioned) about 8" to make everything work right. Since a 4.3 wasnt even available in '70, you'll have to fabricate your own or buy some universal one that you can bolt or weld in but either way youre gonna have to drill holes or weld in the mounts. Be sure to measure twice because once you weld those mounts in you'll have a hell of a time getting them un-welded to move them again. Or you'll have to drill more holes if you bolt it in.

Why not go with a 350, or an LSx? They are alot of truck for a 305 to lug around and you're loosing around 43 cid by going with the 4.3,resell value will also be signifigantally lower. Alsso have you considered a 6.5 diesel (or 6.2 ) swap
I wouldnt even consider a 350 diesel though they were a pile from the factory

Shane

I've considered alot of options. I have a 6.5 in my suburban and I like it alot. But. There are issues with that. The price of the engine is the main thing. Then you must convert the fuel system. Shouldn't be too hard, but still the cost of the engine is crazy.

I picked up this 305 for $100. I was told it was rebuilt not too long ago and after having torn it apart I have verified that it is indeed true. The 305 is not too bad for just the truck and maybe some light hauling. According to the books its only about 20hp and 20ft lb away from a 350 which isn't too much. The only problem I see with the 305 is its limited ability to be modified and make lots of power, but that's not much of an issue for me. I was just looking for something cheap to make this truck run for a while. I have a 454 that i was going to install but i found out that it had gotten water in it and locked up so it must be rebuilt. I don't have the kind of money it takes for that right now. I do pressure washing for a living and in the cold weather work is slow so money is tight. That's also why the $100 engine sounded appealing.

Now then, Mileage was another thing I took into consideration. The 454 is going to guzzle it down, but i figured with a comp cams XE250H cam, 781 heads, RPM intake, performer carb, headers and my 3.07 gears (perhaps upgraded to 3.42 or 3.73 down the road especially with a 4.3 or something) would really do alright power wise and mileage wise.

But the biggest influences on my decision for a 4.3 is that

1) Having a 6.5 diesel burb, I don't really have to have something in the pickup that will tow or haul alot. If really needed I *CAN* use the trailers I have with the burb. I just don't like to hook up to a 16 foot utility trailer and hauling it all around town just for something that's too big for the burb but not big enough to need the big trailer. I don't mind the trailer, its just inconvenient.

2) I have found boatloads of 4.3 fuel injected engines cheap on craigslist lately. Id really like to have the injection. And with the fuel injection on these 4.3s, the numbers these things make will eat this 305 alive and have better mileage and driveability too. 200hp 260ft lb fuel injected vs 145hp 230ft lb. I'm not too concerned with the wiring, I'm pretty good at that stuff.

3) As I said above my boss has a 77 C10 with a 2001 4.3/TH350 in it and I am highly impressed with it. It runs nice, starts right up and has the same or MORE power than it had with the 350/TH350 combo (I drove the truck many times before and after the 4.3 swap) Either way A 700r4 is likely in the works no matter which direction I go, except for if I ever decide to run the 454. Right now there is a 305 with a TH400 behind it (I already had the TH400, it was behind that 454)

Finally reason #4) I'm having difficulty with this 305. I'm missing the correct power steering pump and brackets. I need headers or new manifolds. I should rebuild the carburetor, and really just need to get a new one. The one on it is a Q-jet from a 72 C10 pickup I used to have that had a 350/350 in it. I rebuilt it a couple years ago but later switched carbs and haven't used it since then. Even then i think it had typical q jet warpage and throttle shaft wear causing some undesirable effects. It worked but the idle was too low some times and other times was OK. It would stumble and bog down for a second if you nailed the throttle. All my weird issues went away after I switched carbs so I know the problem was the carb.

Now with everything Ive said, keep in mind I may, at some point down the road decide to go another direction. I'm just crazy enough to jump through hoops to get what I want, and then decide that's not the way I want to go anymore. I am 99% sure the 4.3 is what i want tho. With my 72, i had that 454 in it once, all running and everything and decided i wasn't sure I wanted to keep the truck and wasn't gonna let that engine go with it. So I stuck a 350 in it. That truck was a junk pile on wheels tho. Always working on it. Always. Anyways this 79 is a nice truck, I know I want to keep it and what I expect from it. I only bought that 72 because i got it cheap ($200).

Sorry for the long post, just figured I'd explain myself.

If you measure from the face where the transmission bolts on to the center of the motor mount holes on both engines 305 and 4.3 you will know how much you will have to move the pads back on the frame. Find a 1989 or newer 4.3 truck at the wreckers and you will see how the bracket hangs out the back of the crossmember the same amount as the measurement you first did. Don,t get paranoid about the little bit of weldin you will have to do. I went from a 4.3 to a 350 on my 1989 p/up and it works well. I had to move my pads ahead and you have to move yours back. If I can do it you can do it

Have you checked on www.car-part.com
Shane

I have a 86 with a 4.3 and 3 on the tree I'm not sure when they started putting them in these years,Haynes says 1981.Now that I've gotten some of the bugs worked out,it has plenty of power.It had dozens of vaccum leaks and the carb needed overhauled.