2.8L rebuild in a 1985 4x4 Blazer

[TechRod]

And I have a complete distributor from a 1992 S-10 2.8 that I could sell you.

[Baja Blazer 85]

Hmm, ok. So I would need to get these things plus wiring harness, distributor, and I assume an OBD II computer and an electric fuel pump to use TPI? I might just stick with the carb then, I hate dealing with wiring stuff. Thanks for the offers! What I think I might do is save up for the crate motor and I'll run it with my carb plus a jet size.

Oh, and this reminds me of another question I had; how do I figure out what size jet to use?

[geoffinbc]

It depends on how the carb was set up stock. It may be just fine without any changes. Carbs are self compensating when sized appropriately to the displacement and operating range of the engine. I would leave it stock for the first drive and install a wide band O2 monitor to check that everything is working right.

[Baja Blazer 85]

Okay, that makes sense with the carb. I rebuilt my carb about 6,000 miles ago, I think it'll be okay, would you agree?

Wait, a wide band O2 monitor? You mean an O2 sensor. what do you mean by wide band? How would I specify this when I go to the parts store counter?

And if I'm getting a larger O2 sensor, would I have to flash the OBD I computer or chip it or somthing like that?

[geoffinbc]

No the monitor is a separate gauge all together. You install a wide band O2 sensor after the Y pipe in the exhaust and it will tell you your air/fuel ratio on a gauge you mount in the truck. It is very handy and the best way to know how your carb is running. Here is a new one from Innovative that is only about $200 http://www.innovatemotorsports.com/products/MTXL.php

[Baja Blazer 85]

Oh thats really cool! Is it required that I install the O2 monitor behind the Y pipe? Just curious because my passager side manifold has a spot to put an O2 sensor in it (with a non operating O2 sensor plugging the hole) and just out of convenience, maybe I could use that hole.

[geoffinbc]

Yes you could. You would only read one bank but it is better than not knowing how the engine is truly running.

[Baja Blazer 85]

But that reading would have to be the same as the other side anyways, since the one carb supplies both banks.
Unless a cylandar on the other side isnt firing for some reason, but that would be noticable anyways.

On a slightly different note, I think I may build a coffee table out of the ol' 2.8



Yea? Yea? I'm doing it.

[Baja Blazer 85]

So I'm reading over the manual for the 3.4l crate motor. I found this .pdf through s10 forum:

http://www.tricky6.com/S10files/3-4%20Instructions.pdf

It included a list of parts that I need to buy seperately. Most of it is understandable and makse sense to me, except for the following:
It says that I need to purchase, seperately, an oil pan for the 4x4 trucks. But why cant I just use the old one off my truck?
It also says I need to get a bunch of stuff for an "in line electruc fuel pump." I would figure getting it direct from GM is pricey, so where can I source one of these?

And about the O2 monitor. My truck is a California truck, fitted with an AIR system for emissions. Because part of the AIR system pumps fresh air into the exhaust manifold (for some god-awful reason), with this emissions system operating, isn't it going to throw off my O2 readings?

Thanks so much for the help guys, greatly appreciated!!!

[pocket-rocket]

Where does your AIR system pump the air in at? I've seen cats with tubes for AIR injection. As long as the air is injected after the O2, but before the cat, it should all be fine (and read correctly).

[Baja Blazer 85]

Air is injected right at the header in each of the three individual header pipes, before it even gets to the collection pipe

[Baja Blazer 85]

Also, that conversion manual says I need a Oil Pressure switch, part number 12353512. I cant get anything on google except that its a bad part number. What is this? oil pressure switch?

[pocket-rocket]

You could always reroute the AIR injection into one of those cats with the AIR tube on the side to get around it. The oil pressure switch... you could probably get a sender like any of a majority of the 60v6 cars have. It's a 3 wire deal. It has a sender for a gauge in it, and a switch to power the fuel pump if for some reason the ECM output for the fuel pump quits. I would need to see a schematic or read a bit more on it to be sure though.

[geoffinbc]

Stop worrying! You don't need anything you don't already have. The only reason you need the electric pump is because there is no fuel pump mount on the engine block. But all you need is one of the hundreds of electric pumps designed for a carb'd engine.

[pocket-rocket]

But all you need is one of the hundreds of electric pumps designed for a carb'd engine.

My 83 and 85 dual side draft carb'd Honda Preludes had an external electric pump... It was under a cover right in front of the rear drivers tire up under the body just inside the pinch weld...