1987 Corvette Z52

[Basement Paul]

After a failed attempt at a local auto parts store to get an in stock six rib pulley that will work for our application, I'll have to go to the internet today to find a roughly 4" pulley with a 3/8" hole in it. Most pulleys are 17mm inside, but there are conversion bushings available too. I'll get that ordered today if possible, and the A/C replacement idler should be almost good to go. But since we didn't finish that, we installed all the crap we removed on the passenger's side to gain access to the HVAC blower assembly. We also made a bracket for some sensor thingy that used to reside inside the A/C housing. The exhaust Y-pipe is cleaned up and should go back in next time too.
We're pretty close on this one assuming everything we did is good.

-BP

[Basement Paul]

I ordered a six groove pulley (about 4") and a bushing to go from 17mm (pulley ID) to 3/8" for the bolt that goes through it. We mounted it up and then did some belt measuring. Apparently the way we measure vs the way the parts store measures is different, but we got one to fit on our 2nd try. But it looks like the way we have the pulley mounted, when the pulley goes under tension, it flexes slightly in the bracket and makes the pulley slightly out of alignment. So I have to order a longer (6") hardened bolt so I can use both sides of the mounting bracket instead of just one, and it will keep it straight and true under load.
We filled the power steering fluid and the engine coolant, and as a last ditch before we were done, tried to start it. It really seems like there's no spark, but there was no time to diagnose. I most likely have something in the new distributor parts messed up. Next session we'll hook up the exhaust and the air intake box so all those sensors are plugged in and in place, and we'll then diagnose the no-start issue. Hopefully that's a simple-ish fix. At that point it should be reasonably road ready. But time will tell.

-BP

[Basement Paul]

No pictures today. Got the exhaust all back together. Worked more on the A/C bypass pulley setup, but after another failure, I stopped and looked online and I can get a bolt in idler assembly for about $38. I'm upset with myself for not checking this earlier.

We then checked for spark and there wasn't any (no surprise). Since we replaced all the parts in the distributor, we tore the cap and coil assembly back out. I put the old and good coil back in and now we have spark again. We have the timing off though, so next time hopefully we can get the pulley situation finalized and hopefully get the timing right and start the car.

-BP

[Basement Paul]

So as I was trying to order a new coil, I learned that there are HEI in cap coils with a red, black, and YELLOW wire and there are HEI in cap coils with red, black, and WHITE wire. Apparently they are different and you have to actually know which one you have before you order. There are theories, but there seems to be some confusion as to the real difference, but it is pretty certain they are NOT interchangeable. I'll have to take the cap off and check before I order a replacement.

-BP

[TireSmoker]

Thats a new one to me.. but if i had to guess, one may be the original design from 74-75, whenever HEI came out, the other may be an updated design/spec for computer control?

[Basement Paul]

From what I've seen (on different forums FWIW) these differences appear all over the 80s Vetts and although I didn't go crazy in my research, it didn't seem that there was any hard evidence of why both exist. I just bought the AC Delco one that Rock Auto said was right for the car. Who knew GM would be silly like Ford in this way?

-BP

[Basement Paul]

On the white wire / yellow wire coil issue, apparently I have a white wire coil, and the bad coil I installed was also a white wire. So I guess my new AC Delco white wire coil was garbage after all. Unreal.

On Saturday we went after starting the car and getting it running (but not driving). An after learning that I'm not real good at understanding when the distributor should be pointed at #1, I rotated it 180 degrees, and amazingly enough, the motor started right up! After installing the air intake and the MAF, we restarted it and it came down to idle right away and sounded nice and quiet like it should. I was worried about many things, but lifter tick and exhaust leaks were the majority of it. Without a functioning serpentine belt, we didn't run it for more than 30-40 seconds, but enough to be satisfied that this part of the project was a success. I have the new A/C bypass bracket now, but since every pulley that is attached to these is plastic and arrives with slop in it (not a little) I'm going to try to convert it to a steel pulley that we already have. Once that is done we should be able to drive it and start picking at the other brake and suspension bits. I have video of it running, but I'll wait until it's on the ground for a better video.

-BP

[Basement Paul]

Luckily the A/C bypass conversion went swimmingly. I basically was able to bolt my steel pulley directly in place of the crappy plastic one and it lined up perfectly. We had to open up one of the two bolt holes just slightly but that was simple. Once installed, we went back to the parts store for a couple belts to try and got it on the first try. So this part of the project is complete. Unfortunately while we were warming up the car and checking things over, we sprung a leak. A big oil leak that seems to be coming from the oil pressure sending unit at the back of the manifold. There was a puddle of oil under the car after about five minutes of run time that was at least 15" in diameter, so something there is amiss. We'll have to pull the distributor to get to it, but since I forgot dad doesn't have a timing light, we still have to time it anyway, so hopefully that all goes smoothly. We'll pull that apart on Saturday to investigate.

-BP

[MostMint]

that oil pressure switch is a bear. should have warned you about that as a maintenance item

[GMJohnny]

I have a timing light you can use. Don’t buy one!

GM

[TireSmoker]

that oil pressure switch is a bear. should have warned you about that as a maintenance item

Is it hard, or just hard if you don't remove the distributor?

[MostMint]

that oil pressure switch is a bear. should have warned you about that as a maintenance item

Is it hard, or just hard if you don't remove the distributor?

It’s behind the intake on the driver side so the distributor, TPI, brake booster and steel brake vacuum line are in the way. The actual changing out is not hard once you get access

[Basement Paul]

So really all I had to do was pull the distributor out, and had reasonable access to the pressure tree. It's an odd bit of engineering where there's a right angle fitting at the block, then a straight stalk that comes out with two holes in it for the two different sensors. But with a couple different wrenches, it all came out reasonably quickly. We pulled out everything and re-taped it, and I'll order two new sensors today. The one with the two different plugs on it seems to be the one that has gone bad. I think that's a shut off switch in case we run out of oil. The other one I think is for the oil pressure gauge and it seems OK, but since I'm looking at it, I'll replace it. Hopefully after this we can time it, then drive it. This will be next weekend hopefully.

-BP

[Basement Paul]

Got the new pressure parts installed this morning, set the timing, and topped off the coolant. We were able to get it down off the blocks and take it for a spin even. Just driving around local, we put about ten miles on it and so far no driving issues. It runs cool on the 160 degree thermostat and doesn't seem to be leaking as of now.
It does however, still have a detonation issue at WOT. The fuel that is in there (3/4 tank) is from August of last year and that tank also has cleaner in it for the injectors. We'll run that tank out and I'm going to get that new coil and hopefully somewhere between a 35 year old coil and dirty injectors, this problem will be solved. The timing is set at stock 6 degrees right now, and besides some detonation at the top of the rev range, the car feels strong.

-BP

[wxo]

It's exciting to know that your Vette is back on the road. Not so much that mine is out of commission and back in the garage.