lost my tune up

[coffeehound]

I have a 482bb.chevy,DartBigM,Pro1-345 w/871andEnderle bird.This motor ran 7.50 right out of the box, off idle.Blower set at 1to1.It would run 7.50-7.60 all day on this safe fat tune until I got cocky and decided to turn up the wick,got completely lost and ended up in the low 8s.Jim Blake ("Cape Codder") gave me some  track side help,and in 2 pill changes got me to 7.75. Pill now 170.Plugs are white and oil is clean.Is this too lean?How much total timing should I use?We built this motor to run 7.50-760 index with out having to kill it,so I/m trying to get the most out of it w/ 1to1 I/m sure there is a lot more in this motor but I/d be real happy to get back to 7.50 consistently! Any sugestions?gddyxp

[masracingtd1167]

Coffee hound Great looking car ! Nice to see another 7.50 car in the north east ! Can you go back to your original tune up ? When I get lost I always find it best to go back to square one and start over again .I have no experience with a blown car but there are some guy's on here that do and I am sure they can help you .

[coffeehound]

I wish I could.The motor was given to me w/out this info and I was so happy initialy with the 7.50 out of the box that Ididn/t pursue it.Then I ventured past my Knowledge and experience and lost it

what happened to FEDA., Front Engine Dragsters of America. I was a member since 1990 and N.E. rep. Then life happened and I lost touch in the last 10 years. Aren/t you familiar with them? they were the first FED club that I know of and sponsored the first "Sling Shot Nats" at Cordoba in the late90/s. Jim Post was the founder and raced a 60/s Woody Gilmore rail w/ a sb chevy on nitro. He was a passioned  fed owner and driver  and one of the first to promote feds, long before the current nostalgia movement. FEDA was formed in 1998 by Jim. I find it hard to believe that FEDA is no more. Any info on them? By the way, my first and prior car was a 1967 165" Woody Gilmore, SB chevy w/enderle stack inj on alcohol. Thanks for listening to me babble, Ralph

[Draw 3D]

So what changes did you make when you got "cocky" and what was the original main pill?

[coupemerc]

Is that you Ralph? That motor should go easy 7.0's. Did the speed drop way off too? I don't know what your total nozzle area and fuel pump numbers are but a 170 jet size is way out of the range (BIG) that we used to run. Without further details, it sounds to me like it may have went fat for some reason and slowed down. Then Jimmy went to the 170 jet to get it back. If that is the case then check to see that the burst panel has not cracked or maybe your blower studs cracked and is allowing the boost to going somewhere it shouldn't be. Maybe your fuel pump is going away? Ignition weak. I'd probably have the timing around 30 BTDC. Is it burning any cad off of the plugs? Is it widening the top rod bearings at all? Those would be symptoms of a lean condition. I would also check out all of the mechanicals (valve springs, leakdown, etc) and make sure the fuel system is clean and poppets are all opening properly, installed in the correct orientation and location. Good luck!
Chuck

[coffeehound]

Its been several years(didn't race for a while)soI/m not  sure what the original pill was.This was my first bln/inj motor and I was learning as Iwent.I started w/overdriving the blower a bit and fattening it up at the same time.I was only running 28 to 30degrees timing.Every thing went south from there.I also think I may have been way off (to fat?) on the barrel valve from what it had set at originaly.At the time it was acase of just enough knowledge to be dangerous.Another lesson learned

[coffeehound]

chuck with a w?

[coupemerc]

Yeah!

[coffeehound]

thanks for your input chuck.Bearings are mint,plugs are good.Ithink you are right about it going way fat.mph  was down as well.I don/t think its a mechanical issue as everything is fresh and I was surprised how quick Jim got me back in the ball park.I/m using a gasket between the blower and manifold.should I be using an o-ring setup instead?the fuel system was set up as simple as possible w/ no high speed bypass and I/m returning the fuel to the inlet side of the pump instead of the tank.Any suggestion for best barrel valve setting, or where to go from the 170 pill?Thanks again.

[coupemerc]

Ralph, I sent you a pm. Chuck

[Curly1]

That is a really nice car. Okay on the tune up I would say go back to original tune and go from there. So you do not know where that is then my thinking is to fatten it up and see what it does. Will not hurt it as much to be fat.  If you have a 170 in there then I would put a 150 in there and see what it does. 
Barrel valve, how I set mine is adjust it to where it spits and stumbles at idle when I give it gas then fatten it up a little from there. Then I do a leakdown test on the barrel valve to get a baseline to return to.
Watch everything you can water temp, EGT, O2 if you have it and see what it is doing. There should be clues as to what it needs.

But if your car has been sitting a while I would say do a complete clean out of your fuel system before you do much. The alcohol can sometimes turn to a gel and that makes it act stupid. If you have trash in the lines then one cylinder may look lean while the others are fat and it will slow your car down. I had a problem with my car recently on the dyno and luckily my dyno guy had 8 O2 sensors. We were able to determine the cylinders were not all tracking the same. The dyno session was a success so I called it a day but it tells me there is a little more there. Some were getting richer while a few cylinders were getting leaner my thinking is it had some gel in the lines.  I cleaned all of the nozzles real good and have flushed a full gallon of alcohol through the lines to get everything out. Will test to verify this weekend to see if it did the trick.

Now I have had the alcohol turn to get several times with my carbs and I always use top lube. I really do not know what causes it or how to prevent it. Of course our injection systems with very small nozzles may be more sensitive to it even though they work at much higher pressure.  Do not know for sure but something to consider.

As I think about it more I would look closer at trash in the system than the tune up itself.

There are several places like Spud here that may give you a baseline tune up as a starting point if you can give them all of your information. I think there are many variables though and would be hard to get it perfect with out dyno or testing.

[32bantam]

What are you using for and ignition? Do you now what the pump flows? Not advertised but from having it flowed? What pump is it?
If you know the fuel system is functioning and you have a tune-up you know goes 7.50 and you have made two big main fuel changes and it does not improve 90% it is a bad ignition. I chased a 3 tenths slow problem for two races...I tried everything...including checking the cam timing. Finally I threw on the spare Super Mag III from spud ...put the original tune up in and went right back to where it belonged.
Hope this helps.....

[coffeehound]

Thanks for all the help.Because  I could not answer some of the questions due to lack of info/knowledge,I have sent the mag and fuel system to Spud for testing and service to insure the mag is100% and give me a good base tune and info to help me get back on track.This is my first bln/inj motor and I realize its an ongoing education ,but I wouldn't be able to get down the track without the help and support of like- minded racers with much more experience than I have who don't mind helping the new guy.THANK YOU , Coffehound

[32bantam]

Excellent choice.....your system will come back ready to go....and information for your to make changes.