Hey guys
i just bought a 91 z28 with a 5.7 tpi, and it’s a mess lol. Previous owner did a manual swap which I was excited about at first but now I’m finding a bunch of shoddy stuff everywhere. I was looking at a valve cover leak on the passenger side and I noticed these 2 sets of wire clips that one is really burned from the exhaust manifold and I don’t know if they clip into each other or what they may go to. They are right behind the A/c compressor, coming straight from the wiring harness. I taped them to A/c line just to keep them from burning more. Does anyone know what they are for? Thank you in advance

 

Look like the harnesses that went to the AIR system. Probably got left dangling against the exhaust system for awhile after the PO hacked all that off of the car.

I'm gonna go out on a limb and guess you also have an oil leak down at the right front of the motor that slings oil all over the exhaust, frame, oil pan, motor mount, etc. over there, butt you have no idea where it's coming from.

 

so I have an oil leak coming from the valve cover but yes there’s an unusual amount of oil coming from that area… sounds like you know something?
Also, which air system do you mean? Like a/c? Do the plugs go into each other?

 

I wouldn't go all the way down that rabbit hole, butt yes, I've seen a thing or 2 over the years.

The AIR system. Stands for Air Injection Reactor. Commonly referred to as the "smog pump". Involves that pump, some hoses, a large valve thing, and metal lines that screw into the exhaust manifolds. Those plugs are what used to control that valve while it was still there.

The pump bolts to the motor down low on the pass side. Since yours is obviously no longer there, the bolts that held it on, probably aren't either. One of them goes right directly into the crankcase; in carbed cars, you can see the fuel pump drive rod by looking into it. In fact one of the tricks for changing the fuel pump easily involves putting an extra long bolt in that hole just finger-tight, to hold the rod up in the block and keep it from sliding down out of position and interfering with the linkage on the pump. In some blocks you can actually get a glimpse of the crankshaft by looking into that hole. Obviously if the bolt isn't there, there will be a leeeeeek.



You can see in this photo how the fuel pump drive rod passage, which is the large hole in that place in the block that looks upward at the top of that sort of chamber there, is in line with that bolt hole. To stifle the leeeeeek, put a short bolt in the circled hole, with a drop of RTV or other sealer on the threads. It's 3/8"-16, a very standard thread, and the bolt needs to be about ¾" long.

How much of the rest of that system has been hacked off of the car? Or more accurately, how much of it is left? I can see some of the lines in that photo; what are they hooked up to? Does the belt work right?

 

So, the PO was a bit of a backyard hack you say.....

Well, sorry to pile on the misery, but, in that case allow me to give you yet another thing to worry about, as if you don't have enough already

Factory manual shift cars came with a firewall stiffener for the clutch master cylinder that (of course) automatic cars didn't. When someone does a manual swap on an automatic car and does not add the stiffener the end result is that after a number of pushes of the clutch pedal the firewall cracks from being flexed. I will enclose a pic of the stiffener (Doubler) that you should check for and if it isn't in place you really should make a plan to add it (from a parted out "native" manual shift thirdgen). If it isn't there, check carefully where the MC mounts for cracks.

This is a piece of firewall from a parted out manual shift thirdgen. In the pic, the piece I refer to is under the hole where the brake booster mounts.

 

That trick unfortunately didn't work for me with my Goodwrench crate 350, as that hole is "blind" and does not go through to the fuel pump rod. I wonder the casting process is different in Mexico where it was made...

 

you said it’s in carbed cars, mine is injected….am I safe?

 

The hole in the block is in ALL blocks, subject to whatever year they quit drilling that rod passage in them... which AFAIK was well up into the 90s. You may not have the fuel pump rod butt you most likely have the passage for it. They didn't differentiate the block process between what fuel systems were installed onto them later in production, and it was probably just cheeeeeeeper and eeeeeeeezier to keep making em the same as they had been since 1955, than it was to delete the rod passage from the gang drill machine and its programming. So, no you are probably not safe. Especially if you have a mystery oil leeeeeeeeeeek that spews all down the right side of the oil pan, the exhaust over there, and on the frame. Your block needs a short bolt in that hole. Check and see.

 

SMH......

I see the OP skipped right over my post, good luck when your clutch MC rips itself outta your firewall.....

 

So i replaced my PCV hose and my mystery oil leeeeek has stopped lol. i think there was just too much pressure in the crank case and it pushed oil out.
thank you!