Car Not Running Right...

Det_Riot

Det_Riot

Forum Member
Huge thanks to anybody who can help me out....

Well first let me give you guys the background story. I bought a set of twisted wedge heads for my 94 gt over the summer and planned on putting them on this winter. Well school started, I got bored, so the swap started early.

Everything went in correctly, everything was torqued down and replaced, upon initial start up, there was horrible valve train noise, after re-adjusting rockers a number of times, i finally decided to check the geometry and the push rods were too short.

Fast forward to this past week. Got everything buttoned back up, started it back up and it wasn't idling very well. Got it to warm up without touching the timing and it was at like 2* Well after adjusting the timing to 14* where it was before, it started randomly popping/backfiring really sporatically and randomly while idling. I took two videos of the car idling. the first was before the pushrods were changed. The second was taken yesterday.

http://www.youtube.com/watch?v=KxnIIM9_UZA

http://www.youtube.com/watch?v=Hi5-1qaB_uA

Here's the modlist:
94 GT
Stock block~freshly honed
Mystery Cam (cam with car p/o didn't know what it was)
Trickflow 170cc Twisted Wedge Heads, 2.02/1.6, 7-angle valve job
.650 lift anderson motorsport springs
6.75" trickflow pushrods
1.6rr's
trickflow street heat upper & lower
1"intake spacer
75mm throttle body
msd dizzy
accel coil
autolite 3924's
stock fuel system
all accessories
 
Three thoughts:

1. I've heard this happening back in the day when valves stick on new heads. We used to bop them each with rubber hammer before installing them.
2. Are you sure the timing is correct, and the distributor is not off?
3. Did you check valve lift with a dial indicator at all? Did you check piston to valve clearance? It's really not the smartest thing to put a 2.02 valve head on a stock shortblock with a mystery cam unless you check for clearance. You could have bent some valves if it has too much cam since the stock piston won't have the reliefs in the right spot.
 
Det_Riot said:
If the clearance wasn't there, wouldn't it be hitting on every rotation? Not just sporatically?
Click to expand...

Not if you improperly adjusted the rockers the first or second time. I'm just throwing out ideas for you. I can't watch the video here at work on my phone.
 
You should start by doing a cylinder pressure test on each cylinder. This will help identify if you have any bent of sticky valves.
 
i didn't think you could go w/ a 2.02 valve without hitting the piston. I'd check piston to valve clearence asap-and don't fire it back up. I'd go with a cam you know the specs on too. You have to match the cam w/ the correct valvesprings.
 
Is it a intake back fire. Is the Idle high? Intake leak??? But if its a 2.02 valve head deff bar it over and check for sticking or not closing valves. It could hit for sure. I know this is after the fact but Always check PTV. A comp test is a good idea. Hope its a leak hate to see new heads get messed up.
 
I listened again the video is tough to make out. It is a loud pop. A lean condition could cause this. Would not expect that at idle but a VAC leak makes it lean. re torque the intake like 4 times over the pattern.
 
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