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Discussion Starter · #1 ·
I have a '94 SS that I need to rebuild because #6 rod bearing was starting to fail. It was my father's last vehicle and he loved it. He actually ordered it, when you could still do that. I want to get it back into good running condition and improve anything I can but don't want to "hot rod" it. I know that there were a lot of changes being made during that time period.. The block is stamped 10227196 and GM 4.3LG, CFD1. It is CPI (which has been replaced once) and has a balance shaft.

I've rebuilt a lot of engines but never one of these. The first thing I learned is that it is a terrible job to remove the engine. I certainly don't want to to that again. I disassembled the engine and found #6 rod bearing starting to thin out which must have been the noise problem. It appears to be in good shape other than that with no noticeable ridge. I'm taking the engine to a machine shop to to clean up the block. There is quite a bit of deposits inside the water passages and they will clean that out by baking it followed by some chemical treatment. The soft plugs and cam bearings will be replaced. I intend to re-use the cam and lifters with new gear and chain as well as the balance shaft. I'm sure the machine shop will want to bore the cylinders and replace the pistons and maybe the rods and some decisions will need to be made. Of course all new gaskets will be used as will be new bearings.

I'd like any advice you may have beyond what I have planned. The timing chain had a lot of play in it and I assume that will be better. I've read here that there are some problems with excess play even with new parts. What else should I look for or be concerned about? What can be improved.

BTW, it has a 3.42 limited slip differential. Was that standard for this model?
 

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2004 Avalanche. 2001 V6 Extended Cab ZQ8.
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First bit of advise... REPLACE THE CAM AND LIFTERS!

You are rebuilding everything else, the cam will have been worn in the 26 year the truck has been doing it’s thing. Stock cams are not that expensive and can be had at any auto part store. I would get a Melling. Also new oil pump to go with everything. The oil pan will need a super good cleaning as will ant parts that live inside the engine. Surgical room clean 🧼. New oil pans are not cheap but they are worth it.

It also wouldn’t hurt to service the heads, new guides and a valve job. It’s a couple hundred but worth every penny on a new engine.
 

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Discussion Starter · #3 ·
First bit of advise... REPLACE THE CAM AND LIFTERS!

You are rebuilding everything else, the cam will have been worn in the 26 year the truck has been doing it’s thing. Stock cams are not that expensive and can be had at any auto part store. I would get a Melling. Also new oil pump to go with everything. The oil pan will need a super good cleaning as will ant parts that live inside the engine. Surgical room clean 🧼. New oil pans are not cheap but they are worth it.

It also wouldn’t hurt to service the heads, new guides and a valve job. It’s a couple hundred but worth every penny on a new engine.
Thanks
It has roller lifters that appear to be in good condition, I'll look at them closely. I'll do the heads myself. I do have a problem with the pan, the plug leaks and is already oversize. I need to fix that or get a new pan.
 

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It has roller lifters that appear to be in good condition, I'll look at them closely. I'll do the heads myself. I do have a problem with the pan, the plug leaks and is already oversize. I need to fix that or get a new pan.
A Time Sert kit will fix the oil pan plug problem.
 

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Thanks
It has roller lifters that appear to be in good condition, I'll look at them closely. I'll do the heads myself. I do have a problem with the pan, the plug leaks and is already oversize. I need to fix that or get a new pan.
A Specrta pan is like $100 from most of the auto part stores. I dont know what the cam measurements are supposed to be but I would recommend looking them up and getting a mic on them to make sure. The cam is the heart of the engine and it is a critical piece. OEM cam is about $200, and OEM lifters are $150 for the full set. There are some regrind cams out there for less, but as you know a regrind is someone else's old cam, and the hardening may or may not have been returned to the lobe after the grind. The cam I priced was a Melling and brand new, OEM spec. Just givin you some options.
 

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Pay special attention to the area in the block around the roller lifter bores. I had a bad crack that had to be pinned and welded in my 1994 S-10 CPI block. Maybe have it magnafluxed to be sure. If it cracks bad enough there could be a coolant leak. We did an overbore, balance and blueprint on the engine.
 

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I'm a little confused by your post. On the one hand, you say you've overhauled a bunch of engines, and on the other hand you're sending the engine off to get a machine shop to overhaul it, which is not what I think that most people who overhaul engines would do.

Personally, I would've lifted up the engine enough to get the oil pan off, pulled the pan and replaced all the bottom end bearings and inspected the oil pump to see if that needed replacing (probably). If it wasn't burning oil or had bad compression, I would leave the pistons and top end alone. I would also leave alone the cam and especially the counterbalance shaft (that's a zero wear item).

Since you haven't taken it to a machine shop yet, I would suggest that you hold off on that plan. Instead, call around and visit your local pick-a-part yard and see how much it'll cost you to get what complete engine with what mileage. Look for remanufactured block tags on side of engines at the yards. I'll bet you can get an entire used 4.3L engine in the 200-500 range. Any counterbalanced 94- 4.3L will do; just swap your intake onto the long block. Also look at your local Craigslist and FB marketplace to see who's got a 94- engine in a vehicle with a bad transmission that they want to get rid of. You can usually pick these up under $500, harvest the good engine and core transmission and part the rest to pay for your swap. There are in a bunch of vehicles in the GMT400 platform, the S/T trucks and the Asstro/Safari vans, so there are a LOT of them out there. Next, put together a parts list of what you think you'd like to purchase and call up the machine shop to see how much they're going to charge you for their part of the rebuild. I think you'll find that your used-engine path is about 10% of the rebuild path. These trucks are so plentiful that a $3000 rebuilt engine isn't going to make it into a $4000-5000 truck, and a running $300 used engine isn't going to devalue it! I usually try to pay $100-200 for a running motor, but the last one I bought was a running reman that I paid $400 for and it's in tip-top condition.

A numbers-matching S10 isn't worth a dime more than a numbers-not-matching s10. Maybe less, even!
 

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for the amount of engines are in the parts yard and all over craigslist, id never rebuild or put any money in to a V6 or 4 cylinder. $500 should net you a great condition running V6 ready to go, that will last years. Personally, on your engine, i wouldve installed new rod bearings, and ran it for another several years.
 
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