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

[L31MaxExpress]

The front area of my engine is a bit more cluttered, mainly from the AC lines so it' not ideal to use the TBI housing and hose. I found 2 more possibilities for T-stat housings in the 4 Seasons catalog, my local Napa will have them in tomorrow so I can see if either one gives me some clearance over the EGR tube. I also tried the upper house from the 4.3 housing, it actually fits a bit better then the Vortec hose.

I'm at a cross roads as far as the AC goes- the receiver/dryer for a '98 doesn't really bolt up to the line from the evap core in my '88, and it seems that '88 was it's own odd ball year for that dryer. As I look at the '98 dryer that I have on hand, it's not going to be easy to adapt so I'm starting to think that I need to use the one for the '88 and have a hybrid hose made for the suction line from the compressor. The easiest way will be to cut off the hose with the dryer fitting from the '88 and have it spliced crimped onto the hose assembly from the '98.

Just looked in the pictures I have taken. The factory Mexican L31 Vortec TBIs appear to have used the factory TBI neck and hose. This was GM engineered not a swap. Manifold hose does appear to have been specific to the TBI Vortec setup as the suction line has a revised angle to clear the aircleaner.

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Same setup, different truck. This one was on Facebook marketplace in my area. I do find it odd that some of these have top post 48 series batteries. The 250 inline 6 Grandblazer did too.

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[Firewood truck]

That's pure gold right there, thanks for posting the pics! Now I can scan the catalog and try to find that suction hose assembly. It's frustrating sometimes playing the manufacturers "lego" game.

 

[Firewood truck]

The truck in Dallas, was that a Marketplace ad? I'd love to have a VIN in order to look up the oddball factory parts for that engine.

 

[L31MaxExpress]

The truck in Dallas, was that a Marketplace ad? I'd love to have a VIN in order to look up the oddball factory parts for that engine.

Yea it was on market place along with a 2 door Tahoe at the same time. They odly badged the Tahoe as a Silverado in Mexico. Neither posting had the VIN. Both were in really nice shape and kind of surprises me that neither had the engine bay cleaned up before photos were taken. Representative of the culture owning them though unfortunately. The exterior and interior are immaculate and the engine bay is neglected as can be. I have seen fresh paint, chrome wheels and new interiors in vehicles that barely run and leak fluids from everything here. Not hating at all just do not understand it myself. I can deal with a paint issue, a torn leather seat or a cracked dash pad provided the engine and drivetrain is in good shape. I like keeping my engine cleaned ever so often as it makes maintenence on the vehicle a cleaner job.

I will add that the Mexican trucks do not have EGR or a catalytic converter on them. The manifold itself is cast iron and uses a large IAC footprint 454 TBI unit.

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[L31MaxExpress]

This manifold came on both marine application and some of the later Mexican trucks. The ~96 mexican trucks still had a TBI long block with Vortec accessories. The heat sleeve actually covers a metal coolant line. The coolant line is the coolant bypass to the water pump and the manifold has a water jacket in the plenum under the TBI openings.

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[Firewood truck]

I picked up a 4 seasons housing 84846 ( 65-73 GMC) which fit pretty well, the rad hose was barely touching the heat wrap on the EGR tube. This is probably the one that I will use, but I am trying a 84987 tomorrow ( 90° straight up, the stock TBI hose should fit right one) then it would have the routing like your van. There's a few interesting housings in the 4seasons pdf catalog for vans, I just want the cleanest routing possible.

All 3 of the pics from you show the rad hose routed under the AC line, I could see how that was going to work with the hoses/housings that I was trying out. MY stock TBI housing pushes the hose towards the drivers side and kinks against the mounting bracket. It will be interesting to see what the hose routing will be with the straight up housing.

 

[L31MaxExpress]

I picked up a 4 seasons housing 84846 ( 65-73 GMC) which fit pretty well, the rad hose was barely touching the heat wrap on the EGR tube. This is probably the one that I will use, but I am trying a 84987 tomorrow ( 90° straight up, the stock TBI hose should fit right one) then it would have the routing like your van. There's a few interesting housings in the 4seasons pdf catalog for vans, I just want the cleanest routing possible.

All 3 of the pics from you show the rad hose routed under the AC line, I could see how that was going to work with the hoses/housings that I was trying out. MY stock TBI housing pushes the hose towards the drivers side and kinks against the mounting bracket. It will be interesting to see what the hose routing will be with the straight up housing.

Since I had plenty of room above the compressor and was making ac hoses anyway, I used a generic Four Seasons manifold setup. I had actually seen these on a 454 or 8100 motorhome a while back at the wrecking yard. The manifold is 3 pieces and kind of a pain to assemble but did work. I hit everything with a UV light the other day, no signs of leaks anywhere yet. What I learned is if the universal ac manifold assembly is listed for a R4 it will fit an HT6 style compressor by using the correct sealing washers and a bolt long enough to properly engage the compressor threads. Probably simpler to just make your own ac hoses and you won't have to deal with clearence issues with the stock manifold setup. Unless you swapped to all the R134a components the accumulator and condenser ends are the wrong thread anyway.

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If I were going to do it over again I would use a threaded manifold and 90* female fittings on the end of the hoses because that Four Seasons 12034 manifold set is kind of a pain to install and I did worry about the semi-circular clamping plate with the open slots providing enough clamping force to seal or breaking at some future time. This fitting set is a good buy though. The sealing washer kit is like $18 by itself. If your evaporator, condenser and accumulator is still the R12 stuff the discharge hose is #8 fittings and the suction hose is #10. I bought a budget hydraulic ac hose crimper from Amazon and hoses and fittings from Cold Hose out of Florida. It was cheaper making my own hoses than I was quoted to make a pair of hoses and they wanted the van for a full day to do it as well as for me to pay them to vacuum and charge it. Thanks but no thanks.

Vintage Air GM R4 A6 Air Conditioning AC Compressor Hose Fitting Manifold -8 -10

Vintage Air GM R4 A6 Air Conditioning A/C Compressor Hose Fitting Manifold -8 -10

www.ictbillet.com

 

[Firewood truck]

It's been a few days, I've gotten a bit of work done during the week after work. Trans, t-case, engine crankcase and radiator are filled with fluids I'm just running water for now in the cooling system in case any leaks appear after I get it started.

Does anyone have a pic of the headlight wiring harness routing? I didn't get any pics from when I took mine apart ( I was sure that I took some but I can't find them on the phone) I am not 100% sure how the ground wire gets routed around/through the passenger side of the core support I know that it gets fed under the battery box and up onto the fender to a sheet metal screw, I just can't remember how the loom gets routed.

I settled on the 4 Seasons 84846 T-stat housing ( '65- '73 K series trucks) it gave me a bit of upward angle to clear the EGR pipe. There is also an unmachined boss on it that gives me options for a better place to mount a temp sender if the need every arises. I also just cut down a tiny bit off of the 57 Vortec upper hose, it clears everything pretty well and will be an easy hose to get down the road.

I lost the baggie with the tiny retainer clips for the throttle and CC cable, I need to swing by a dealership and hope that they're still available. If not, it's another quick trip to the pick and pull.

It's getting closer. I picked up some new battery cables tonight, they will get installed tomorrow. I need to stop at a Speed shop tomorrow and get a AN 3/8 npt x -8 straight nipple, the port in the GMPP for a vacuum source is in a dumb spot, the fuel lines for the throttle body are right on top of the port location. I need to plumb the brake booster and the small EVAP vacuum lines then it will be ready to turn the key. I made an oil pump priming tool from the old Vortec dizzy, I just ground down the drive teeth off of the gear and chucked up the 20volt battery drill right on the shaft. Once I get power installed, I will turn on the key, turn on the video on the camera and aim it at the dash. I will prime the engine for a minute then check the video to see if I have oil pressure showing, that way I will know that the engine is primed and if I wired the 3 wire sensor correctly.

I really want to try to bend a metal tube for the vacuum line for the brake booster, I don't have anything that will bend the 1/2 steel line, I only go up to 3/8 line.

 

[Schurkey]

I really want to try to bend a metal tube for the vacuum line for the brake booster, I don't have anything that will bend the 1/2 steel line, I only go up to 3/8 line.

You don't need steel for a vacuum application. Copper would do nicely. And easier to bend.

But doesn't the brake booster use smaller tubing than 1/2"?

 

[Firewood truck]

You don't need steel for a vacuum application. Copper would do nicely. And easier to bend.

But doesn't the brake booster use smaller tubing than 1/2"?

I measured 7/16-ish last night, it's an odd size of steel tubing for sure. I grabbed the flare fitting from the TBI intake and tried to match it to some pre flared brake line tubing, the 3/8 line nuts were too small I don't feel like trying to decipher GM's "lets confuse the hell out of them" sizes/ thread pitches- switching to a -8 will be easy. The vacuum hose says 15/32, so by using a -8 nipple it will be a nice snug fit.