HELP! 90 Heads Reassembly - A/C brackets

[chevyaddict]

Hi All - after two long years I'm finally getting my 90 vette back together from bad head gaskets. Of course, I don't remember how most of this stuff goes back together. I took good pictures but I neglected to get good shots of the passenger side and the a/c brackets and bolts. I'm rebolting the pass side exhaust manifold back on and I have four regular bolts and two bolts that have an extra threading for nuts to receive bracket mounts for the a/c. I need to know where these two specialty bolts go - what sequence from front to back. Can someone help me? The chilton and haynes manuals I have don't really help with pics unfortunately.

 

[vetteoz]

Go either side of # 4 and 6 ports
Front one is for back brace off A/c compressor , rear one holds dipstick

Don't forget the other two compressor braces;
parts 5 and 6 in diagram below
one to fuel pump plate stud and other to water pump stud

 

[chevyaddict]

Excellent pictures!!! THANK YOU SO MUCH!!!! I've been staring at all this for an hour already...

 

[boomdriver]

I just did "battle" with the a/c compressor bracket and all the bolts. I wanted to add,. its of great help to run a tap into the thru bolts holes in the front of the heads, and all a/c bracket mounts and even run a die over the studs and bolts. The bracket is very soft aluminum as you know, and it strips very easily. Its easy to get cross threaded and screw the pooch....Same goes for the tensioner bolt. When everything is clean, bolts glide in and torque easily. Its just such a fragile bracket that I feel its worth getting the tap out and doing it right. If everything is not torqued right, the bracket can break. Thats why that lower steel brace was added. bracket loves to break east of the tensioner mount. And, these brackets are darn hard to find.

 

[chevyaddict]

I just did "battle" with the a/c compressor bracket and all the bolts. I wanted to add,. its of great help to run a tap into the thru bolts holes in the front of the heads, and all a/c bracket mounts and even run a die over the studs and bolts. The bracket is very soft aluminum as you know, and it strips very easily. Its easy to get cross threaded and screw the pooch....Same goes for the tensioner bolt. When everything is clean, bolts glide in and torque easily. Its just such a fragile bracket that I feel its worth getting the tap out and doing it right. If everything is not torqued right, the bracket can break. Thats why that lower steel brace was added. bracket loves to break east of the tensioner mount. And, these brackets are darn hard to find.

I was wondering why that little bracket at the bottom was there. Actually everything went on OK except that little heater hose that goes through the bracket. What was chevy thinking with that design....:eyerole

 

[boomdriver]

I was wondering why that little bracket at the bottom was there. Actually everything went on OK except that little heater hose that goes through the bracket. What was chevy thinking with that design....:eyerole

I dunno....they were probably thinkin...get that thing wrapped up and push it out the door! we'll never see it again...they hope ! !

Mine broke the bottom ear on the waterpump stud,so I get to order bolts tomorrow that says...bye baby ! ! !

 

[chevyaddict]

I cannot for the life of me find bracket #5.... very frustrating. I'm assuming it wouldn't be a good thing to go without it, correct? I know I had it because I have a picture showing it was there. ad

I made a lot of progress today though. Its almost entirely reassembled except for the top half of the intake & fuel injection and all the electrical, air pump, hoses/vacuum lines and belt. Next day I should have her running... hopefully. Its true the computer sets the appropriate timing correct? I just have to get it pointing at the proper cylinder, yes?

 

[vetteoz]

Its true the computer sets the appropriate timing correct? I just have to get it pointing at the proper cylinder, yes?

You drop dist with timing " near " enough to get engine started then you must set static timing using timing light .(6* BTDC )
Don't forget to disconnect the timing connector to do this and reconnect after timing set

I cannot for the life of me find bracket #5.... very frustrating. I'm assuming it wouldn't be a good thing to go without it, correct?

May get away without that one; I know the back brace to head is the most essential one.Many have had bad vibrations with that brace missing when A/c on

 

[boomdriver]

worst case make one....some flat steel thats bent to the correct angles and holes drilled right places will work just fine,..The OEM brace was just cheap steel tubing that had the ends flattened down for bolt holes.
I think that brace came later after the main bracket started to crack from the tensioner stressing in the lower a/c bracket. They love to break around the water pump studs. If you can see another place to add a support then go for it ! The benefit is in stabilizing the bracket and not letting belt torque tweak the thin aluminum around and crack it. Because the a/c bracket has so little support, 3 solid bolt positions, and handles a great deal of torque, another point of attachment will help.
I added a wider piece of 1/4" flat bar, cut and shaped to hold the backside of my alt and air pump assembly because I had broken the alt bracket twice. I was able to see the movement when the motor revved...Now, that accessory combo is solid. The bracket went to a thru bolt on the air pump then twisted around to an existing hole in the intake manifold. Just need a torch to heat, a vise to hold and a drill to make the holes. Tube steel is cleaner to look at but can be tricky when trying to est the angles where the flat part needs to be and at what angle to fit well.

It will live without a brace, just be nice to it until a brace can be installed to fit well.

 

[chevyaddict]

You drop dist with timing " near " enough to get engine started then you must set static timing using timing light .(6* BTDC )
Don't forget to disconnect the timing connector to do this and reconnect after timing set

Only 6 degrees? That is pretty low! Which is the timing connector; is that the other connection coming off the distributor itself?

 

[boomdriver]

Only 6 degrees? That is pretty low! Which is the timing connector; is that the other connection coming off the distributor itself?

This is the single brown or tan wire thats somewhere near the wiper motor or brake booster on the harness that passes toward the distributer. Keep all the normal distributor connections plugged in, but pull the "timing wire" to set the timing. .If I remember correctly, this sets 6* base timing open loop operation and closed loop then goes to whatever is required. Much more than 6 but its done internally.

 

[chevyaddict]

This is the single brown or tan wire thats somewhere near the wiper motor or brake booster on the harness that passes toward the distributer. Keep all the normal distributor connections plugged in, but pull the "timing wire" to set the timing. .If I remember correctly, this sets 6* base timing open loop operation and closed loop then goes to whatever is required. Much more than 6 but its done internally.

EXCELLENT! THANK YOU!!!

 

[vetteoz]

This is the single brown or tan wire thats somewhere near the wiper motor or brake booster on the harness that passes toward the distributer.

.If I remember correctly, this sets 6* base timing open loop operation and closed loop then goes to whatever is required.

Spark advance by ECM is independent of closed loop operation.
Put a timing light on a cold engine before it goes into CL and you will see 32+ degrees of advance .

 

[chevyaddict]

YAY! I found the bracket!!! I forgot though to put that tube that hooks on top of the water pump that goes from the driver's side exhaust to the emission thingy... big faux pas as I can't go back and insert it. But luckily I can fashion a new hose to connect the two so no worries. Otherwise I'm almost there!!

 

[chevyaddict]

And the trouble begins...

Is there a straight forward way to determine if fuel is getting to the fuel injectors without having to unbolt the fuel rail lines? I'm trying to fire her over and nothing is happening. I've double-checked the distributor and firing alignment and I have it correct so that isn't it. Its just turning over and turning over at this point so I need to see if the fuel system is working. I know having completely torn this apart there "could" be a multitude of problems (especially since the car sat for 2 years) but I want to diagnose the easy stuff first. Never played with fuel injection before.

 

[vetteoz]

Is there a straight forward way to determine if fuel is getting to the fuel injectors without having to unbolt the fuel rail lines?.

Put a fuel pressure gauge on the test port on fuel rail; should have 45psi (ish )
Pull a spark plug and see if it is wet
Have you got good spark?

 

[chevyaddict]

I don't own one of these gauges unfortunately; was hoping there was another way. I was searching the forums though and it seems this is what I'm going to have to do. Spark is good. Car was running fine upon disassembly, however, I'm wondering if having the fuel injectors sitting open the past two years has messed them up. I hope not!

 

[vetteoz]

I'm wondering if having the fuel injectors sitting open the past two years has messed them up.

Check the resistance of the injectors
Should be around 16ohms and all in similar range.
One bad ( grounded ) injector will take the whole injector bank out ; no fuel to one side

 

[boomdriver]

I don't own one of these gauges unfortunately; was hoping there was another way. I was searching the forums though and it seems this is what I'm going to have to do. Spark is good. Car was running fine upon disassembly, however, I'm wondering if having the fuel injectors sitting open the past two years has messed them up. I hope not!

Having a gauge is not absolutely necessary. When you turn the key to ON, that should trigger the fuel pump to run for 2 seconds. This is to prime the injectors before cranking. So, you should have fuel pressure before the starter is engaged.
Just push in the needle valve on the rail to see if there is fuel. The pressure should remain for at least 20 minutes. A good system will stay pressurized for hours after 2 seconds of pump running.
If there is enough pressure to run, gas will try to spray out of the needle valve when depressed.,. if the pressure is poor in the rails it will dribble or not be there at all. That needle valve is exactly like a tire valve.
A Schrader valve.

If there is Good fuel pressure at the rail, move on to the injectors. A "noid-lite" is helpful here. That will show the pulse of the injector as it fires. If there is fuel pressure, the fuel still has to get thru the injectors. I doubt that all 8 are plugged up from sitting but they may have a common problem like no signal. Since they all fire together, what effects one will effect all 4 on that side. You can also use a volt meter or even a test lite, but it takes 3 hands to do that...be sure to look at the injector fuses as well as the fuel pump fuse/breaker.

Without the noid-lite or volt meter, check for wet plugs. Dry a couple real well, then use those to see later if there is any difference. Old plugs look wet all the time (from oil) after sitting for a few months.

If you're certain the pump is running and you still have no real pressure at the schrader valve on the rails, then look at the filter. You can check for voltage to the pump by unplugging the fuel pump relay and probing the plug.

2 other easy things to check.....

1. make sure the fuel-pump relay is plugged in. Its near the wiper motor and that distributor wire.

2. make sure both oil pressure switches are plugged in. One is for low pressure and will cut off the fuel pump if there is no oil pressure, the other sends the signal to the oil press gauge. The switch has 2 wires and should have power to one side all the time(key on).
As long as this oil pressure switch is plugged in and working the fuel pump relay is not critical.

Hope this helps. To see some good electrical drawings, search other fuel issue post. VetteOz has posted the fuel system electrical in several places and they are very clear drawings out of the service manual.

 

[chevyaddict]

Wow Thanks!! I will check all these things tomorrow. The fuel gauge was $45... for someone who is out of work that is expensive if I don't "need" to have it.