Resurrecting a 2.8L?

2183 Views 56 Replies 8 Participants Last post by PeteD, 5 mo ago

DougE

Discussion Starter · 8 mo ago

I'm in the process of rebuilding an '88 S15 (new 350 engine, new 700R4 trans). I bought a second S10 for miscellaneous parts that had no engine, trans or driveshaft. I think someone had dropped a big block into it at one time. The 2.8 I pulled out of my S15 wasn't running according to the owner. So, if I strip the 2.8 down to the long block, what it the simplest way I can get the engine back into service? Is there a carb that will fit the existing manifold? Will the distributor work or do I need to drop something else in? I'm good on old school 350's but know nothing about these little guys. (Thinking of giving this to a neighbor that needs basic transportation).

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DougE

Discussion Starter · #3 · 8 mo ago

Not useful, PeteD. I've looked around at vehicles for less than $5k and there's nothing out there in reasonable condition. Do you send a truck to the graveyard just because the engine crapped out? I've got lots of left over parts from 2 vehicles that I can put to use and a vehicle with title. So with free labor how can I get this back to useable condition?

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DougE

Discussion Starter · #6 · 8 mo ago

That's good information, jimmykicker. Person I bought it from hadn't figured out it's issues. Guess I need to run a compression test on it before I get into moving to a carb and distributor option.

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DougE

Discussion Starter · #7 · 8 mo ago

Is there a good swap to carb post (without having to dig through bunches of misc info)?

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DougE

Discussion Starter · #9 · 7 mo ago

Appreciate your reference, Mad Max, but a little deficient on detail. I've spent literally hundreds of hours researching a V8 conversion with no computer, a Painless harness, Intellitronix custom gauge set, etc. Hoping to avoid that much investment of time researching this one.

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DougE

Discussion Starter · #14 · 7 mo ago

This truck has none of the computer electronics. Is there a stand alone controller for the TBI? Gauge cluster is torn out so I need to go with old school gauges.

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DougE

Discussion Starter · #17 · 7 mo ago

Per my initial post this is a 1988 S15 engine going into a 1988 S10 truck.

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I am really looking for an inexpensive way to get my leftover parts assembled into a reliable vehicle for a neighbor. I don't care what the fuel system is, I'm just looking for viable options. I will probably forgo resurrecting the AC as I could easily drop $1k in that endeavor.

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DougE

Discussion Starter · #19 · 7 mo ago

When I got it, the PO had welded in motor mounts and ran it with a big block. So I need to cut out the mounts and reinstall 2.8 mounts. Now, no engine, trans or driveshaft. I doubt anything in the engine compartment is re-useable. However, I enjoy wiring (yeah, I'm nuts), have a spare bulkhead connector now and can easily repopulate the engine side of the wiring harness. Here's where I am with the S15:

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DougE

Discussion Starter · #22 · 7 mo ago

There are so many wires associated with the stock computer that I just don't want to go down that rabbit hole. No telling what the PO has screwed with in the existing wiring system. On the S15 I'll be doing a Holley Sniper for its simplicity and ability to control 2 radiator fan circuits. On this S10 I can probably do a new carb for half what the Sniper would cost me. It seems common to adapt a Weber to these things so I'll probably investigate that a bit. I am looking for a detailed installation of a Weber so I can evaluate it.

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DougE

Discussion Starter · #25 · 7 mo ago

This is what I find when I look for computer documentation. So much more complicated than a pre-computer system.

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DougE

Discussion Starter · #26 · 7 mo ago

Just so you know guys, I really appreciate the input!

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DougE

Discussion Starter · #28 · 7 mo ago

Does anyone have a wiring diagram showing only the wiring necessary to make the engine run?

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DougE

Discussion Starter · #30 · 7 mo ago

riscy, I appreciate your effort but dang, that's a bunch of wiring connections to run down without knowing what the ramifications to the computer would be.

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DougE

Discussion Starter · #32 · 7 mo ago

Well Darn!
Compression Test:
150...120......80....1,2,3
150...120...120....2,4,6
Squirted in some gear lube and #3 came up to 150#, So must need a ring job.
Suspect I can find a 3.4 in decent shape for less than the rebuild.

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DougE

Discussion Starter · #34 · 7 mo ago (Edited)

Trying to keep this reasonably low buck but not restrained by cost when justifiable. Obviously the 4.3's are later and easier to source. The odometer showed about 125k miles and the trans had been swapped. Not settled on a course of action yet. Just looking for low cost, but reliability. All the 2.8 stuff is supposed to fit the 3.4 block but don't quite understand how the 2.8 heads could work with the extra displacement and keep the same compression ratio.
Update: Went into RockAuto and checked cylinder heads of the 2.8 and 3.4. Hidden in the Info is both heads have the same interchange number:
OEM / Interchange Numbers: 3061272B
So must be identical!

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DougE

Discussion Starter · #36 · 7 mo ago

Bore and Stroke:
2.8L: 89mm x 76mm (3.5"x3.0")
3.4L: 92mm x 84mm (3.6"x3.3")

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DougE

Discussion Starter · #38 · 7 mo ago

I'm just up the road from San Antonio, Texas. Must be someone down there that could help hook me up with a low mileage 3.4L.

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DougE

Discussion Starter · #40 · 7 mo ago

Texas goes by the 25 year rule also (yea!). If the engine comes with the harness I'll investigate using it (the multi-point fuel injection would be nice) but still, I'm concerned about what wires can be eliminated for an "engine only" configuration as I'll probably have to go with a basic hot rod gauge set. The best donor appears to be a '93 to '95 Camaro.

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DougE

Discussion Starter · #47 · 7 mo ago

The original thought was to take a relatively rust free 1st generation S10 without an engine and transmission, and put in the left-over parts from a V8 swap to make it into an inexpensive, reliable driver.
A compression test proved that the 2.8L would need a rebuild but it would be reasonable to upgrade to the 3.4L. As of now it appears that the most economical course would be to source a 3.4L short block, move all the 2.8L parts over to it and use a Weber carb.
If you upgrade to the entire 3.4L system, you face dealing with modifying the computer to work in this application and an upgrade to the fuel pump. While the engine connections are fairly easy to adopt, there is no information (i.e. a wiring diagram) to define the necessary computer harness modifications. (If you go to the next level and get a 4.3L then a replacement transmission would also be required.)

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