Rebuild or new engine from Blueprint?

[open_road_toad]

Good morning Everyone,

I posted a couple of days ago about my 1988 C1500 TBI not running well after replacing the intake manifold gaskets, distributor and a bunch of other stuff. It ended up being a unplugged spark plug wire (happens to the best of us).

The truck still doesn’t run “right”. It idles weird and stalls sometimes. I’m really at a loss on this. Here’s the breakdown of everything I’ve done so far:

Replaced the following:
Distributor, coil, plugs, wires, EGR valve, O2 sensor (single wire), coolant temp sensor.
I rebuilt the TBI a couple of months ago using AC Delco injectors and rebuilt kit. PVC valve and all vacuum hoses and lines.
I’ve also replaced the complete AC system, water pump, thermostat and housing, flushed the coolant multiple times, drive belt and belt tension and idle pulley.
I’ve also replaced the throttle and TV cables.
I love this truck. I use it for work everyday and I have taken great care of her. I’ve replaced all of the suspension components as well including the upper and lower control arm bushings. Truck rides great.
The exhaust is original and it’s pretty rough as you would imagine. It’s got some leaks In multiple areas. Next on my list is new exhaust manifolds, y pipe and exhaust.

I’m worried that the engine is just tired. It smokes a little when you first start it. Blue smoke so I figure it’s just the valve stem seals. Doesn’t smoke when you drive it. I’ve never had the heads off.
So here’s where I’m at; do I put the money into pulling the heads, doing a roller cam conversion and rebuild or upgrade the heads or do I just buy a ready to go longblock from Blueprint?
They have 350 engines specifically built as TBI truck replacements

 

[open_road_toad]

I wasn’t able to finish the post for some reason.
So I’ve gone back and forth about rebuild/upgrade mine or buy a new one from blueprint. Seems like it would cost about the same either way if I were to get new aluminum heads for my engine.
Any thoughts or suggestions? Any idea as to why my truck is still not running right? Could it be the exhaust leaks?
Thanks in advance!
Todd

 

[Erik the Awful]

The truck still doesn’t run “right”. It idles weird and stalls sometimes.

So here’s where I’m at; do I put the money into pulling the heads, doing a roller cam conversion and rebuild or upgrade the heads or do I just buy a ready to go longblock from Blueprint?

Replacing the engine won't fix your driveability problem. You need to get a thorough diagnosis of what's causing the idling/stalling issue.

 

[OutlawDrifter]

You've got two very similar threads, would make more sense to keep this going in the other one that is 6 pages long.

 

[VIKING_MECHANIC]

How was it running before you replaced the manifold gaskets? Like @Erik the Awful said, you need to diagnosis what's going on.

Have you done a compression test? How does it idle?

Blue smoke means it's burning oil, which could be the valve stems or the oil control rings are shot and allowing oil in the combustion chamber.

Your symptoms seem similar to what I had happen to me on my 91 S10 with the 4.3 TBI. It would run fine at idle until it got warm then would idle erratically and sometimes die when driving.

I'd start with a compression test and go from there.

 

[Schurkey]

Connect a scan tool, find out what the computer has to say about the rough running and stalling.

Verify fuel pressure. Perhaps cylinder-balance test, cranking compression test, maybe a leakdown test.

As Eric the Awful said, it would be a shame to waste money on a "new" engine, and have it run EXACTLY the same way the "old" engine runs, because something else is WRONG.

I agree with OutlawDrifter. Perhaps a moderator will combine these threads.

 

[open_road_toad]

Replacing the engine won't fix your driveability problem. You need to get a thorough diagnosis of what's causing the idling/stalling issue.

I agree. I stopped by a shop where my buddy works at. They do a lot of work on older “classic” cars and trucks. He listened to it idle and suggested the throttle position switch and/or the IAC.

I don’t like to just throw parts at a problem but he brought up a good point. Those parts are original to the truck and it doesn’t hurt to replace them. I will replace the TPS, IAC and MAP sensor this weekend.

I also agree that replacing the engine is a bit overkill for what I’ve got going on. I was looking for more power out of the truck and I would like to replace the cam with a roller. That’s what sent me down that rabbit hole.

I’ll report back on what happens when I replace the above mentioned components.

Thanks for the replies.
Todd

 

[Schurkey]

In my driveway, those parts would be TESTED before being replaced.

I'd rather have "good used" OEM parts than brand-new imported junk parts.

 

[HawkDsl]

The IAC could be gunk'ed up. Wouldn't hurt to pull it out and make sure everything is clean inside and out (including TBI where it's screwed in at). There is a way to reset the IAC, but you'll have to do a search here to find it. Blue smoke is almost always valve stem seals, but that is the first indication it's time for a rebuild IMO (if over 100k). I bought a short block from Chevy and did the roller cam conversion (it was already drilled and tapped for the spider and cam plate)... Had the heads redone with springs and screw in rocker studs. Went with CompCams for everything (lifter, roller cam, roller rockers, springs), and added a Cloyes double roller timing change set. All in was about 2k in 2004. In hindsight, I would have preferred to rebuild the original engine, but was under a time limit, and machine shop would have taken longer compared to what I did. Now, I would buy the Chevy performance 383 short block, and just throw it into the truck.

 

[BOOT]

It depends on if you trust your local machine shop or just want to diy things. Blueprint test their engines on a non running setup kinda like a spintron, they checked my shortblock before crating it up. I noticed there was signs of a cam being installed and when I asked they told me that was from testing, since they had to for oil flow. I mean they build a lot of SBC's vs how many does your local m-shop machine? M-shops round here suck! I'll link a vid of my exp and one of the Blueprint tour form another channel.

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