Something doesn't seem right. (HELP)

[RKCHARGER]

Ok guys, here is the deal. I've put a ton of money into the motor of my car and feel like either its tuned terribly (by me) or my expectation of being able to melt tires on demand is off. I had help with the build and was expecting at told it should be around 500 hp/tq. It seems sluggish off idle and has 3.55 gears out back. what am I missing?

List of goodies.

Block bored 30 over.
factory crank and rods balanced.
Keith black 10.5 to 1 pistons.
Edlebrock performer rpm intake and heads ( aluminum )
Harland sharp roller rockers/springs
comp cam 292  501
holly 750 double pumper.
full tti exhaust 3in
tti headers
all arp bolts and studs.
mopar performance ignition,

Off the top of my head that's about all I remember. I can get any other information needed.

Am I crazy or should this thing be as powerful as I was hoping?

RK

[Brass]

If you have an auto, how much stall do you have?  Do you know for certain the linkage is set up right and it's not short-shifting into 2nd too soon?  I would also check the carb linkage and make sure full throttle is all the way open.

[RKCHARGER]

will check into all of them  stall 2500.....   

[John_Kunkel]

I see lots of info on how the engine is built but no mention of the engine size. 

"Melting the tires on demand" isn't a true indicator of performance, there are other factors. I'd be more impressed with a car that runs the quarter in 12.50 with minimal tire spin than one that runs 14.00 and boils the tires.

[RallyeMike]

That should put out some fun power. For starters,

Which KB pistons?
Is the car full weight?
Was the cam degreed?
What is the full advanced timing set at?

[RKCHARGER]

John,  I agree 100% but I can't do that if I don't have the power to start with  .  Getting it to the ground should not be an issue. Calvert racing in the rear with qa1 shocks and a 3.55 locker.   Mike. The car is full weight. Pistons Are Keith Black Performance with valve reliefs. 4.380 diameter I believe.  Camshaft, comp cam,  Hydraulic Flat Tappet, Duration 292/292, Lift .501/.501, taken off of summits site for the part number on the box. Timing I believe is where the problem is. When I set it for a decent idle and low end, I seem to lose the high, and vice versa. I'd have to double check but I seem to remember being at around positive 5. Stall is in fact 2500 on the converter to a fully built 727 auto. Rechecked all linkages and they are good. Transmission timing feels right. I think it goes back to timing.

[firefighter3931]

Properly tuned that combo should make 500hp easily 

The base timing needs to be approx. 20* at idle and it will want 34-35* total all-in by 2500 rpm. You need to dial in the timing curve first....then move on to the fuel curve.

What distributor are you running ? Can you adjust the mechanical advance ?



Ron

[RKCHARGER]

Ron,  I am admittedly a total newb at this part.    It is a mopar performance distributor. electronic ignition conversion part number P3690427. I think there are weights inside I can move if that is what you are referring to.

[RallyeMike]

To paraphrase Ron - "Set timing at 20 degrees BTDC at idle. Rev the engine in Park and check to see if total timing advance at 2500 rpm is 34-35 degrees BTDC."

6 of one or half a dozen of the other - I typically do it backwards and set/check full advance timing at 2500 rpm and then see where idle timing ends up.

Either way, this is your starting point.

[firefighter3931]

Mike outlined your starting point in the ignition testing : Start by bumping up the base timing @ idle to approx. 18-20* BTDC and see how the idle improves. I like to use a vacuum guage to see what effects advancing the base timing has on the motor.

Bigger cam profiles need more advance at idle and the engine will become much more responsive with the timing increased. The trick is to bump up the base timing to what the motor wants while still keeping the total timing in check. This is where the adjustable mechanical advance comes into play 


For example :  You have an engine build that wants 20* of idle (base) timing. That means you need to adjust for a mechanical advance of say 15-16* which will give you a total of 35-36* which is the maximum you want to put into the motor to avoid detonation. With closed chamber aluminum heads the sweet spot is 35-36*....adding additional timing will not make any more power and just pushes the motor into detonation.

The newer MP distributors have an adjustable mechanical advance mechanism that can be accessed internally. This requires some disassembly and adjustments. The advance springs control the rate of advance and these can be swapped out at the same time that the advance mechanism is being adjusted.

Start by mapping out the advance curve in 200 rpm increments and report back. Start at idle and keep going until the timing stops increasing. This will show us how much mechanical advance is in the distributor and how fast it's coming in.



Ron

[Mebsuta]

I see lots of info on how the engine is built but no mention of the engine size. 

I am not seeing that either.   

[69wannabe]

It's a 60 over 440 stock stroke. In his description of how the engine is built it say's factory crank and rod's balanced....

[RKCHARGER]

Yes, that is what it says. The entire rotating assembly has been balanced.  Am I missing something? 

RK

[RKCHARGER]

At any rate.  Firefighter thank you for the advice. I started over, found tdc, backed it up a bit and re-timed it. I was off. Your guesses were pretty spot on for where I ended.  right now I'm at 16 and adjusted to 33 advance and its running great. I am going to take it to the twin cities in Oct. and have if dyno tuned. It is literally a whole different car.    Thank you for the help. When I get it on the dyno in October ill post it up. Fingers crossed for 450+ at the wheels.

RK

[firefighter3931]

It is literally a whole different car.    Thank you for the help. When I get it on the dyno in October ill post it up. Fingers crossed for 450+ at the wheels.

RK

You're welcome RK....glad to help ! 

Amazing what a little tuning will do to wake an engine up 

It may want a few more degrees of total timing to make the best power number. In dyno testing I've found that 35* was the sweet spot with the Edelbrock RPM heads. You can play around with it when you get it on the chassis dyno. For now you're safe with premium pump gas. 

Good work !   



Ron

[68charger440]

It's a 60 over 440 stock stroke. In his description of how the engine is built it say's factory crank and rod's balanced....

I wonder if some of us are not seeing all of the posts, cause I'm seeing where he says it is 30 over not 60, and it doesn't explicitly say it is a 440 in any of the earlier  posts I can see.  Are you saying that based on inference from the rest of the post, or are you seeing it posted explicitly somewhere.  Just curious?

[RKCHARGER]

It is a 440, bored 30, stock stroke.  I found the dyno tuner in Hugo MN.  http://www.sharadonperformance.com/ I spoke to a few people over the weekend at the Street Machine Nationals in St.Paul. They come very highly recommended and work primarily on Mopars. I'm sure they will get it dialed in accordingly. Ill keep in mind the 35 and pass it along but the dyno will tell the tale I suppose.  Thanks again to everyone for all your help. Ill post up the dyno sheet when its done!

RK

[69wannabe]

Ron always know best!!! He helped me get my ignition system up to par!!!! Just having a little fun fellow's!! In the first post he stated "factory crank and rod's" which would mean it is a stock stroked 440 but in another post he stated it had a 4.38 bore which would be a 60 overbore. 4.35 is a 30 over bore on a 440 which would make it a 446 cubic inch engine!! And your timing is pretty much where I have mine on my 493 ci stroker engine that works great there. It's at 18 btdc initial and 34 total and that is a pretty good timing set up!!! Glad your engine is running better now, should be kicking out some good number's!!!

[RKCHARGER]

4.35 they are my bad.

[BSB67]

In the first post he stated "factory crank and rod's" which would mean it is a stock stroked 440 ...

Not all stock stroke Mopars are 440s.