I had a motor put together by Nick and Victory Racing Engines. It has Eagle Rods and Crank, SRP -5cc Dished Pistons. LE3 Heads/Cam/Intake
37lbs Delphi Injectors, Walbro 255lph Fuel Pump, etc...
Yada yada yada...

When motor got together, there was a serious fuel problem. Ended up fouling out TWO (2) sets of spark plugs!! But we could never figure the problem out because the car would never stay on. Once car reached closed loop, it would fall on it's face and never want to stay on. You had to force the car to stay on, but if you did... it would run like pure crap. It also had nasty vibrations (Only in Closed Loop)

So we ended up swapping PCM's (1996 Stock Tune OBDII PCM) and that seemed to solve it. Car runs, you can actually drive it. Car bucks at lower rpms... but I know thats a tuning issue. The car STILL has vibrations, but only at certain rpms. But, to me, it's very hard to distinguish the difference between BAD VIBRATIONS and a car rumbling hard. I have Urythene mounts (both motor and trans). The cam is quite large with a 24x/24x duration. Low 6 lift on a 108lsa. This is the only big motor/cam car I have ever been in that wasn't solid. (I have been in only ONE (1) other big motor car PERIOD... 414 Solid Setup in a MOPAR). Plus... car doesn't vibrate at idle. Only at like 1300-1500rpms and maybe a tad above 3500... but I haven't gone passed that, and only been there once because I don't want to hurt anything.

But I want to get the car dyno tuned instead of a mail order tune because the injector size right now is untold because of the fuel problem. My tuner swears the tune is on point and something else is off. Either the PCM has a hiccup or the Injectors are the wrong size. I really don't have the time to take the injectors out and have them flowed to be completely sure. But then if it is wrong, I still need to get a new tune and make sure that it's not the tune and it's the PCM... get me?

So now I want to take it to a dyno tune... they will break the motor in and tune it for $550. Problem is, their break in methods are NO WHERE NEAR what I was told to do by my builder (Nick at VRE). This makes me very uncomfortable, but I can't break the motor by myself... They would have to do it, and it'll cost me $330 just to get a base tune to break the motor in myself, then an additional $550 when i'm ready for the dyno tune.

Their method was... turn car on and set the AFR to get it straight, then let it heat cycle once. Then from there they start the WOT pulls to get the car tuned and while doing that, seating the rings/bearings...

I was told that this procedure is normal for complete race motors, but mine is a street/strip car... more then street then anything because it is my Daily Driver but still... it has racing parts in it. It also has a brand new clutch... not sure if thats relevant though.

What do you think? Should I just get the car dynoed? Can vibrations be caused by massive amounts of fuel being dumped into the cylinders?

 

When my engine was complete, it was set up on an engine dyno. It was run for one hour at moderate load, varying RPM. After that, the oil and filter were changed, and all the bolt torques checked. Then the tuning pulls started - maybe 1/2 a dozen for NA tune (approx 500HP), then another 1/2-dozen or more for a 125-shot, and another 1/2-dozen pulls for the 275-shot (765 HP total) tune. The engine was brought to 7,000rpm many times.

Then it was daily driven for about a year, with no problems. 4 years after that, its still running like a Rolex.

I would find out why its vibrating first. No sense beating the crap out of it if its a balance problem.

 

Was the engine balanced? I've heard of clutch pressure plates being out of balance causing probs.

 

Well... the vibrations weren't there originally when the motor was first fired up. I was in a hurry before when I typed that.

The vibrations are fairly new... and it's really hard me to tell whether they are vibrations or the car rumbling.

I drove the car and it felt great... on the stock LT1 tune... I know it's a mistake.

I need to find someone who can give me a base tune in person for something less then $300 so I can break it in myself. Anyone know someone in the tri-state area? (NJ,NY,CT)

 

do the vibrations happen with it out of gear with a free rev, or in gear rolling?

 

Free Rev, didn't notice it while driving

 

Was the new motor internally balanced; if so did you get a neutral balanced flywheel? When I ordered the flywheel for my new internally balanced stroker motor (SPEC85S) it came with the external balance weight bolted to the inside. My supplier got in touch with SPEC, and they told me to remove the three allen screws and the weight, and then reinstall one of the allen screws in the center hole.

Regarding breaking in the new motor, I followed SStrokerAce and others' suggestions on this website to "...beat on it." I ran the new motor for 20 minutes, adjusting the fuel pressure, TPS and bled the cooling system. I let it cool down, changed the oil and filter. Checked a few of the spark plugs (the ones easiest to get to...they looked good) and then proceded out to a deserted hiway a few miles from my house. Then from a rolling start in 2nd gear, I ran the motor up to 6000 rpm and let back down. I then shifted easily to the higher gears (I still had to break in the new clutch) and let it cool off for a couple of minutes. I repeated this process about a dozen times. This worked for me, the engine now has about 450 miles on it, the clutch is broke in and the car absolutely flies! I'm a firm believer in the "...beat on it." break in philosophy. By the way, thanks to the three most responsible for my success: Lloyd Elliott (www.eportworks.com), Chad Golen (www.golenengineservice.com) and Bryan Herter (www.PCMforless.com).

Chris

 

Hope youre able to get it all worked out. I'm having my engine built at the moment with the exact same setup just about.

 

See if you can get someone in your area to log your car during startup, idle. Driving normal conditions, and driving at WOT. My car had some serious issues when it first was put together. Come to find out atleast 2 injectors were bad. After replacing the injectors the car was a whole new car. I then ran into the burnt plug wire problem. The car felt gutless and would vibrate bad. I then re routed the wires and havent had a problem since.

This would have been near impossible if I didnt have logging software. I have LE2 heads and GM847 cam. This is my only real high cam motor ive ever driven so it was hard for me to tell, just like you are saying.