'98 Vortec into a '88 K2500, retaining the TBI

[Schurkey]

The engine was a factory warranty L31 crate motor, so it would have came with a new balancer on it. I can't imagine that the Holly TC has the pointer that far out of whack.

Find true TDC #1, verify for yourself.

 

[Firewood truck]

I got the timing issue figured out. I grabbed a used, GM dizzy from a junkyard donor. It was in great condition and felt better all over compared to the aftermarket dizzy that was in the TBI engine when I purchased the truck. A co-worker lent me his Innova timing light, what a difference that made for me. At idle and a TDC groove lining up to the pointer, initially I was at 40° BTDC.. as I adjusted the dizzy, I got it around 15° before it would stall. I finally realized that I had disconnected the wrong plug
(solid brown wire). I noticed that the tan/blk plug was faded to white/blk. As soon as I unplugged that one, the timing suddenly became 10° ATDC.

I set it back to zero, then dialed in 4° advance, shut it down and plugged it back together. Instantly got the "service" light to turn on in the dash, so I knew that I got it right. She fired right up and idled around 600 rpms. Nice crisp throttle response. I need to fix the oil pan leak so that I can take it on a good rip around the area.

I grabbed a few other goodies while junkyard shoppjng- I got an air cleaner lid assembly from a vortec 4.3 truck. I think that it could choke off airflow into the 5.7, but it would solve the AC manifold clearance problem.

 

[Firewood truck]

I was doing some number crunching, the 4.3 air filter has about 40% less surface area then the one for the 57, then I saw some of the filters had CFM ratings on them ( on the rockauto site) no way would the 4.3 flow enough air at high RPMs.. this will work for idling in the drive way, more of a way of keeping anything from crawling right down the intake manifold. I will need to order some of the manifold fittings for the AC compressor mentioned by other members in this thread and make some new "custom" hoses. I've given up trying to hunt down the P/N's for the Mexican L31/TBI engine. I called a Chevy dealership new Brownsville, TX- they couldn't help me without a VIN.

Yesterday I got the front axle actuator rats nest of a wiring looms cleaned up and routed better, I replaced the backup light switch on the NV4500, so now I have reverse lights. I keep trying to talk myself into dropping the pan and replace the gasket, I've also looked at how much work it would be to drop the front diff and make it easy to change out the oil pan. It's been raining the past 2 days and will continue through Saturday, so not a lot will get done this week.

 

[Tim W]

Do you need pics of how my AC brackets are?

 

[L31MaxExpress]

I was doing some number crunching, the 4.3 air filter has about 40% less surface area then the one for the 57, then I saw some of the filters had CFM ratings on them ( on the rockauto site) no way would the 4.3 flow enough air at high RPMs.. this will work for idling in the drive way, more of a way of keeping anything from crawling right down the intake manifold. I will need to order some of the manifold fittings for the AC compressor mentioned by other members in this thread and make some new "custom" hoses. I've given up trying to hunt down the P/N's for the Mexican L31/TBI engine. I called a Chevy dealership new Brownsville, TX- they couldn't help me without a VIN.

Yesterday I got the front axle actuator rats nest of a wiring looms cleaned up and routed better, I replaced the backup light switch on the NV4500, so now I have reverse lights. I keep trying to talk myself into dropping the pan and replace the gasket, I've also looked at how much work it would be to drop the front diff and make it easy to change out the oil pan. It's been raining the past 2 days and will continue through Saturday, so not a lot will get done this week.

That 4.3L filter is the same filter as a 5.0L or 5.7L G-van. Feeding a 350 it was not too restrictive until 4,500+ RPM. By 5,500 rpm it has asthma though. That is why I searched for a year to find the 454 G-van air cleaner and ducting. Larger filter and a much larger intake duct.

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[L31MaxExpress]

Here are a few screenshots with the smaller filter in place.

Barometric pressure read as -0.6 at my altitude as I am ~1,000 ft above sea level. Under 4,500 even with a paper air filter is was only making 1 in/hg. Above 4,500 that filter and small block air ducting ran out of flow and it built another 0.4 in/hg at 5,000 and increased another 0.4 in/hg @ 5,500. In 1,000 rpm the pressure drop through the filter and ducting practically doubled. At 5,500 the map was reading 2.4 in/hg with 1.8 in/hg restriction from the air cleaner setup. Looking at it another way, that is roughly equivalent to the manifold pressure driving at ~4,000 ft elevation.

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[Firewood truck]

That 4.3L filter is the same filter as a 5.0L or 5.7L G-van. Feeding a 350 it was not too restrictive until 4,500+ RPM. By 5,500 rpm it has asthma though. That is why I searched for a year to find the 454 G-van air cleaner and ducting. Larger filter and a much larger intake duct.

You must be registered for see images attach

I never thought to look at the G vans in the RA catalogs, as every other V8 powered vehicle from that era seemed to use the 12" air filter. I also had no idea that GM had jammed a big block into the G vans, that must have been unpleasant to work on! Thank you for sharing your knowledge with me as I figure out this Lego puzzle.

 

[Firewood truck]

Do you need pics of how my AC brackets are?

Thanks but I'm ok. I was referring to the AC compressor "manifold" where the hard lines attach to the compressor, I may have caused some confusion by calling it by that name.

 

[Firewood truck]

I went for a short test drive tonight, to get some gas and for a short shake down. I know that the oil pan gasket needs replacing before I can drive it. I got a few miles into the drive, I stepped on the clutch and something let go- the pedal went to the floor. I could smell brake fluid but I didn't smell a fire so I coasted down to where I could slip the trans into 2nd gear and limped it home about 5 miles going 10 MPH. The speedo reads about 5-8 MPH faster then actual ground speed (when compared against the speed app on the phone). At least the hazard lights sorta worked.

Once in the driveway, I saw fluid in the master cylinder and at the bell housing I didn't see any drips/puddles. I started tracing the line with my hand and found the fluid mess- the damn plastic line was resting on top of the EGR pipe, apparently the heat shield on the EGR tube wasn't enough to keep the hydro line from melting. Damn it.. it just doesn't stop, ever.

I will measure the plastic line tomorrow, if its a standard sized plastic line I will get a compression union and splice it back together as a temporary "fix" so that I can keep moving the truck. Besides the clutch line, the truck really didn't drive all that well, its stumpling off of idle and doesn't seem to make a ton of power. Its still way better then it was with the sick TBI engine that came out, it just doesn't seem "smooth" if that make sense. More trouble shooting will happen next week.

 

[Tim W]

Im glad you found the problem your clutch. Have you considered changing your hydro line braided SS?

When I changed my Auto to a Tremec TKX, it came with all SS lines. I dont know if there is a reason or if its just for esthetics.