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Vortec LB swap into '88 with TBI

ericcarney

ericcarney

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After a series of unfortunate circumstances, I ended up overheating my TBI sbc in my '88 K5 and cracked the block. I thought it was just the head gasket, tore it down replaced them and put it back together and still blowing coolant out. So I yanked a 5.7L vortec out of a wrecked '96 Tahoe and bought the intake manifold and adapter plate so I could keep my TBI. My buddy suggested I should just keep the serpentine belt system but I have heard something about problems with the water pump set up. 1. Can it be done? I have also noticed some extra hoses that aren't on my original water pump. The plug for the alternator is also different, the vortec alternator has four prongs and my original has two. 2. Can I just rewire the plug from the vortec harness? There is also no spot for the EGR on the intake manifold but I kept the exhaust manifolds from the vortec because I read somewhere that I can use the EGR tube on them. 3. What does it take to bypass the EGR? 4. If I just cap it off and go with no EGR, will it make the motor run different? 5. What other problems will I run into while making this swap? I am sure this is old news but there was nothing specific enough to address my particular problem when I was searching for the last three hours, haha. Any advice would be awesome, thanks.
 
The vortec wp will work. The hose on the driver side of it needs to go back to the intake. The other one is for the heater hose. Then just use the stock vortec fan and clutch. The alt just run a big wire from the post on the back to the battery. Take the brown wire from your old plug and wire it to the plug on the alt.
 
Will the plug from the vortec harness have a brown wire to match up to the brown wire from my harness? And do I just cap off the hose fitting that right now leads to the heater core from my radiator?
 
Any help on the EGR would be cool, I noticed before when my check engine light would come on and throw the EGR code, it would make the engine run worse, then I could turn it off and back on, it would be fine for a while and up to speed it would come on again and you could feel the difference in the engine. Almost like it wasn't actually the EGR not working that made the truck run bad, just the ECM realizing that the EGR wasn't working. Punishment from my blazers computer. Will this be the same issue on the vortec? Is there a solution? Emissions testing is not an issue for me
 
Just ditch the EGR for now. Later on have it removed form the chip you have burned. The best way to have a chip burned is to have it dyno tuned.

Martin
 
So, cap off the EGR tube on the exhaust manifold. What about the oxygen sensor port that isn't on the vortec manifold like on my original? Emissions aren't an issue but performance is
 
I HIGHLY doubt you have a cracked block, (very rare to happen). I'll lay odds that the heads are cracked. Did you have them checked at a shop and resurfaced before installing new head gaskets? I've been building engines for 25 years and in all those years the only time i've seen a block crack was from a bad winter freeze which cracked the block and also when a piston exploded and blew out a cylinder wall.
 
Just weld an O2 bung into your y-pipe right past the exhaust manifold.

Martin
 
4X4HIGH said:
I HIGHLY doubt you have a cracked block, (very rare to happen). I'll lay odds that the heads are cracked. Did you have them checked at a shop and resurfaced before installing new head gaskets? I've been building engines for 25 years and in all those years the only time i've seen a block crack was from a bad winter freeze which cracked the block and also when a piston exploded and blew out a cylinder wall.
Click to expand...


:waytogo::deal: agreed....
 
4X4HIGH said:
I HIGHLY doubt you have a cracked block, (very rare to happen). I'll lay odds that the heads are cracked. Did you have them checked at a shop and resurfaced before installing new head gaskets? I've been building engines for 25 years and in all those years the only time i've seen a block crack was from a bad winter freeze which cracked the block and also when a piston exploded and blew out a cylinder wall.
Click to expand...


Not to go too far off topic, but we did crack 2 cylinder walls in a 20+ PSI Boosted 350 a while back. The crack were between cyls 4and 6, right under the turbo and proor timing the whole engines life...
Oh well lessons learned

That one is the ONLY one I have ever dealt with cracking
 
63chevyll said:
Not to go too far off topic, but we did crack 2 cylinder walls in a 20+ PSI Boosted 350 a while back. The crack were between cyls 4and 6, right under the turbo and proor timing the whole engines life...
Oh well lessons learned

That one is the ONLY one I have ever dealt with cracking
Click to expand...

I'm sure it also had more to do with the boost and possible thin cylinder wall than an overheat job.
 
To be perfectly honest, no, I was not sure that the block was cracked. I know that the heads did not look cracked but neither did the block. Yet there was still coolant coming out of my exhaust on the drivers side only, the same side as before I replaced the gasket. Either way, at this point the vortec engine is in and I just got back from the muffler shop getting the exhaust refitted to the vortec manifolds. I just need to tighten the motor mounts, install the lower radiator hose, figure out how to cap off the egr tube outlet on the manifold, and change the oil/filter and I should be ready to start getting into the timing. I am just still thinking about the egr issue, and how permanent I want the cap on the egr tube port to be, cause I have a crappy little welder and some halfass know-how to cap that thing off...
 
I would not suggest deleting the EGR. The EGR system helps to reduce cylinder temps which in turn helps to eliminate detonation.
 
Yeah, I have heard that, does it make a huge difference? I dont go crazy with my truck and I have heard that the risk of detonation is usually with sustained high RPM.
 
ericcarney said:
After a series of unfortunate circumstances, I ended up overheating my TBI sbc in my '88 K5 and cracked the block. I thought it was just the head gasket, tore it down replaced them and put it back together and still blowing coolant out. So I yanked a 5.7L vortec out of a wrecked '96 Tahoe and bought the intake manifold and adapter plate so I could keep my TBI. My buddy suggested I should just keep the serpentine belt system but I have heard something about problems with the water pump set up. 1. Can it be done? I have also noticed some extra hoses that aren't on my original water pump. The plug for the alternator is also different, the vortec alternator has four prongs and my original has two. 2. Can I just rewire the plug from the vortec harness? There is also no spot for the EGR on the intake manifold but I kept the exhaust manifolds from the vortec because I read somewhere that I can use the EGR tube on them. 3. What does it take to bypass the EGR? 4. If I just cap it off and go with no EGR, will it make the motor run different? 5. What other problems will I run into while making this swap? I am sure this is old news but there was nothing specific enough to address my particular problem when I was searching for the last three hours, haha. Any advice would be awesome, thanks.
Click to expand...


Dude

I have a few questions about the motor swap. I didnt know that you can run this motor and keep your TBI system. Do you keep the intake and ECM setup etc? If so, how?
 
ericcarney said:
After a series of unfortunate circumstances, I ended up overheating my TBI sbc in my '88 K5 and cracked the block. I thought it was just the head gasket, tore it down replaced them and put it back together and still blowing coolant out. So I yanked a 5.7L vortec out of a wrecked '96 Tahoe and bought the intake manifold and adapter plate so I could keep my TBI. My buddy suggested I should just keep the serpentine belt system but I have heard something about problems with the water pump set up. 1. Can it be done? I have also noticed some extra hoses that aren't on my original water pump. The plug for the alternator is also different, the vortec alternator has four prongs and my original has two. 2. Can I just rewire the plug from the vortec harness? There is also no spot for the EGR on the intake manifold but I kept the exhaust manifolds from the vortec because I read somewhere that I can use the EGR tube on them. 3. What does it take to bypass the EGR? 4. If I just cap it off and go with no EGR, will it make the motor run different? 5. What other problems will I run into while making this swap? I am sure this is old news but there was nothing specific enough to address my particular problem when I was searching for the last three hours, haha. Any advice would be awesome, thanks.
Click to expand...


GalDemSuga said:
Dude

I have a few questions about the motor swap. I didnt know that you can run this motor and keep your TBI system. Do you keep the intake and ECM setup etc? If so, how?
Click to expand...

He answered your question right here.
 
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