347 stroker help

[piedraco]

hey, first let me tell you about my car:
I got an 89 vert, stroked to 347, trickflow heads and stage 1 cam, bbk 75mm TB and EGR, trickflow upper plenum with intake manifold, mac shorty headers and full exhaust, underdrive pullety, 7qt oil pan (moroso), t-56, and some other stuff that I cant remember right now.

by changing the cam on the motor, does that change the sound, because it sounds LOUD as hell compared to what it used to sound like.

I installed it last week and I finally got it to turn on last night, but there are some problems and I dont know where to begin.
First of all i think there is a vacuum leak somewhere and I have no idea where its comming from, the only thing I can think of is this junction of vacuum lines on the passenger side by the firewall, its got 4 vacuum lines merging into a rubber retainer and then 1 vacuum coming out of the top for the EGR. I dont know if it's supposed to look like that because when I took out the stock engine i didnt notice it.

another problem i am having is that its backfiring, i am thinking that this is related somehow to the mysterious vacuum leak, or my valaves arent correctly tightened down.

one more problem. as i shut off the engine I hear a whistling sound like as if pressure is being released from somewhere. I am thinking that maybe this has something to do with my fuel injectors not sitting properly, maybe an O ring is bad or something, It's loud as hell when the engine turns off. also i have a adjustable fuel pressure regulator with a gauge and the system is not holding pressure when the engine is turned off, is it supposed to?

 

[cobradvm]

You might want to post this in the 5.0 tech forum - likely will get more replies. The AFPR will typically not hold pressure after the engine is switched off if you have put in an aftermarket fuel pump. You should get a vacuum gauge and check your vacuum and go from there. I think your vacuum connections you described sound like its okay. If there is a large leak, you should be able to notice it easily.
BTW who suggested that HCI and exhaust for a 347?

 

[piedraco]

what is HCI? I am using what came with the car when I bought it, it came with MAC shorty headers and MAC H-pipe i think its 2.5" or 3" diameter. The car ran last night just rough with a backfiring that was consistent with the stroke of the engine it was on beat so that leads me to believe that it might not be a vacuum leak but something with the valves. I will repost this on the tech site thanks for your help.

 

[Yellowpnoy]

The cam can make the car louder due to more fuel being burnt in the cylinders caused by more valve duration on the cam profile. The whistling sound that you here, are all your spark plugs tightened down correctly? Have you removed them? Start with the simple things. The backfiring, when you installed the cam, you followed the instructions correct and installed the cam "straight up?" Also, did you set the timing on the motor after installing the cam at a 10* base setting with the spout out?

Anthony

 

[82blackpony]

hci=head,cam,intake//cam is basicaly what causes the exhust to sound a certain way by valve control..///

stage1 tfs cam has a nice perf sound..+what exhaust set up makes a diff..

 

[thumper460]

the More power from the engine.. the louder it will be on an existing Exhaust system... cool??

Just me..............................

Thumper

 

[5spd GT]

H/C/I - Heads, Cam, Intake

The larger cam swap you just installed allowed more air to come into the engine, which creates a more condensed explosion, which makes the car louder. A custom cam would really wake up your car's power.

Pinpoint the shrilling sound if you can.

I have an aftermarket fuel pump and adjustable fuel pressure regulator and it holds pressure for quite sometime after the car is shut off.

What is your fuel pressure set at? What size fuel injectors? What spark plugs are you using and at what gap? What is your base timing with spout out?

Stud-Mounted Hydraulic Lifter/Valve Adjustment

This is how to do it? Did you do it this way?

1. Remove the valve covers, and pick a cylinder you are going to set the pre-load on. Only do one cylinder at a time.

2. Rotate the engine in its normal direction of rotation (clockwise) and watch the exhaust valve on that particular cylinder. When the exhaust valve begins to open, stop and adjust that cylinder's intake rocker arm.

3. To adjust, back off the intake rocker arm adjusting nut and remove any tension from the push rod. Wait a minute or two for that hydraulic lifter to return to a neutral position. The spring inside the lifter will move the push rod seat up against the retaining lock, if you give it time to do so.

4. Twist the intake push rod with your fingers while tightening down the rocker arm. When you feel a slight resistance to the turning of the push rod, you are at "Zero Lash". Turn the adjusting nut down one half to three-quarters of a turn from that point for street applications. Use 1/8 to 1/4 turn for race applications. Lock the adjuster into position. The intake is now adjusted properly.

5. Continue to turn the engine, watching that same intake valve/rocker you just set. It will go to full open and then begin to close. When it is almost closed, stop and adjust the exhaust rocker arm on that particular cylinder. Loosen the exhaust rocker arm and follow the same procedure described before in steps 3 and 4 to adjust this rocker arm.

6. Both valves on this cylinder are now adjusted, and you can move on to your next cylinder and follow the same procedure again.

There may be some initial valvetrain noise when the engine is first fired up but once oil pressure has stabilized and the engine heats up, it should quiet right down to a normal level.

Remember that some racier camshafts will have a mechanical sound to them and will not be a silent as factory units.

 

[87foxstang]

as far as not holding fuel pressure, i had this same problem, however the car was running extremely rich, and it turned out to be a bad injector was just dumping fuel into the intake