I just put my motor back together after having the heads and manifold sent to Golen Engine Service to make sure I was getting a good seal between the two. According to Chad, I should have no problem getting a seal now, he said it should be outstanding.

So I put the motor back together, and fired it yesterday and did some idle tuning today. It simply isn't right. I've got a mid 230/low 240 duration mid .500 lift 110 LSA (possibly 108, never got a flipping cam card) cam specced by Joe O. I have the idle set to 1000 RPM when warm, and here's the problems:

Vacuum was wavering (as expected) between 6-10 in/hg.
Plug were black as night with carbon after 5 minutes of run time.
Surging at idle.

Now here's the part that's just throwing flags at me. I leaned the VE table out in the idle areas, and got the car to actually start and idle pretty nicely now. I ended up locking the LTerms and locking out closed loop (open loop tune essentially). If I had left the car go to closed loop and had the LTerms unlocked, I'd either see a shown full rich (108/108 and 1/1) or a full split (108/160 and 1/255) in the Lterms and Sterms. So having locked those and closed loop out, I ended up leaning the VE tables out all the way down to the 25-35 range at idle.

Is it just me or should a car with that big of a cam want/require more fuel at idle?? I mean heck, a stocker has the VE tables in the 45-55 range at idle.

I just don't know what to do at this point. The car just seems sluggish, slow to rev (with a slight stumble off idle, probably a fuel thing still), and I don't trust it enough yet to drive it.

The plugs didn't look to be oily or saturated with anything, just carbon covered, black as the night. It was puffing a little black smoke at idle before I leaned it out, but now it's not smoking at all that I can see in the daytime, unless I give it a hard rev.

Thoughts?? I've been fighting this for 2+ years now.

 

Did you add timing at idle? Mine wanted 30-32 degrees warming up. Keep adding timing at the lower map values and see what happens.

 

A/F should be around 15/1 at idle.Timing should be factory.

 

The problem may be overlap.... a slug of air and fuel is flowing out with the exhaust. The O2 sensor sees the air and shows a low voltage, and the PCM say "lean" and adds extra fuel.

 

On a whim I just pulled the manifold earlier. Same freaking think, intake manifold gasket failure. EVERYTHING inside the runners was just saturated with oil.

My biggest question now is WHY do the intake manifold gaskets keep failing like that, especially after my heads/manifold were mocked up on a block @ Golen Engines. I don't believe it's going to be a block issue because this problem has chased me from the stock shortblock to this new 355.

I'm starting to wonder if a head was mis-cut.

I think the plan of action right now is going to be double stacking intake manifold gaskets. Does anyone have any suggestions other than that?

 

I use 3M weatherstrip adhesive around all the intake ports(on the heads and intake)and also both sides of the intake gasket.It seals everytime !! Its just a pita to remove intake ....but worth it

 

Woah......that's a new one.

 

Gotta be creative when you run 24lbs.+ of boost