Problems w/ new build, need suggestions

[TonyG]

I just finished up my new build, with an 04 Cobra Shortblock, TFS 44cc 2v heads, T-trim, 10% OD dampener and RR intake. It made 598 rwhp on the dyno at 19 psi/6500 rpms.

Then the engine started making funny clacking noises. We thought it was a rod knock at first, but then it mysteriously went away. To this day (a month later), the noise hasn't come back and the car has been run every day. We thought the noise was just a sticking valve or lifter which eventually "un-stuck" itself. The oil was clean, with no metals. We re-dynoed the car and this time it made 550-something rwhp on a very hot/humid day. A 40 hp loss sounds like a lot but its only 6.6% of 598 hp

Anyway, I took it to the track yesterday and made 4-5 passes. I was trapping 94-95 in the 1/8th and 114-115 in the 1/4. Obviously I am not making 598 or even 550 rwhp. 114 mph is what I used to trap when I was making 360 rwhp.

Today, I pulled the plugs and did a compression check. Compression was good, 160-170 psi in all 8 cylinders. But I did notice that two of the plugs on the passenger side (two plugs closest to the front of the car), had a much narrower gap (0.013 and 0.018) than the other plugs (0.025).

My questions:

(1) Could the narrower gap in the two plugs have caused such a tremendous power loss?

(2) Could the sticking lifter problem have caused the piston to hit spark plug and bend in the electrode?

(3) Spark plug recommendation for TFS 2v heads + 04 Cobra Shortblock?

 

[Midnight2V]

First off let me just say, it seems odd that with this build that you didn't crack 600rwhp. I can only conclude that you are maxing out the blower before you are hitting the power band of your intake, or the intake is simply choking the rest of the system. I don't remember the plenum size of the Reichard intake, but I think it may be insufficient for your build. One thing is for sure - at 6500 rpm, you have better manifold choices like Trick Flow and Edelbrock.

It's possible the gap could have caused the power loss, but that's easy to fix and see if the power returns. Swap the plugs and see what you get. You might want to set the gap as low as .018-.022". Honestly since you said it was a hot day, I am thinking maybe your power loss is due to the manifold being heatsoaked.

I don't think a lifter would cause the gap to close, but detonation certainly would.

Autolite 103 or other full head length spark, plug two stages colder than stock.

Here are my questions for you:

Where exactly are you making peak boost and torque? What's your displacement and what cams are you using.

What fuel and fuel system are you using for your application?

Exactly when did the ticking start? Initial startup after assembly, after break-in, after the first dyno flog, or after any major modification?

I am on my mobile so if any of my question's answers are in your Sig, I apologize.

 

[TonyG]

Thanks for your response, below is the dyno chart. I made peak tq at 6000 rpms. HP and boost keeps climbing, but we stopped at 6500/19 psi.

http://i132.photobucket.com/albums/q14/TonyG_2007/IMG.jpg

The Reichard intake has short runners and is more gear for forced induction/high rpm applications. They are notorious for losing low end tq, but I was told a plenum spacer would minimize that. Here is a photo of it.

http://i132.photobucket.com/albums/q14/TonyG_2007/IMG.jpg

Answers to your other questions:

Cams are HP regrinds: 531 Lift, 292 [email protected] with 114 lobe sep. They are actually quite mild...I used them with my stock heads.

Fuel system: twin focus pumps, modified FPDM, wiring upgrade, braided fuel lines, steeda fuel rail, 60lb injectors.

Clanking started after being dyno tuned. Before that, it was fine.