Slow out of the hole

[KPoole9008]

I have an all steel C Cab that I used alot of TBucket info to build. It has a GM Performance crate engine with 290 hp, timed at 10 degrees with 32 degrees advance, a Holley 600 cfm carb with vacuum secondaries, a Performer intake, a Mallory Unilite distributor with their coil, and headers. The tranny is a Turbo 400 with a 2000-2200 stall speed torque converter. The total weight of the car is 2820 with 1060 on the front axle and 1760 on the rear. The rearend is a 3:42 ratio. I am running B.F. Goodrich T/A 2.75/60/15 radial tires on the rear. I can't get the rear tires to break loose no matter how hard I try. I've even put a linelock on the front brakes and with it engaged the front tires slide. Any ideas why it's so slow out of the hole.

 

[ruggs]

I have an all steel C Cab that I used alot of TBucket info to build. It has a GM Performance crate engine with 290 hp, timed at 10 degrees with 32 degrees advance, a Holley 600 cfm carb with vacuum secondaries, a Performer intake, a Mallory Unilite distributor with their coil, and headers. The tranny is a Turbo 400 with a 2000-2200 stall speed torque converter. The total weight of the car is 2820 with 1060 on the front axle and 1760 on the rear. The rearend is a 3:42 ratio. I am running B.F. Goodrich T/A 2.75/60/15 radial tires on the rear. I can't get the rear tires to break loose no matter how hard I try. I've even put a linelock on the front brakes and with it engaged the front tires slide. Any ideas why it's so slow out of the hole.

KP,
The list is long for possible causes, I don't feel comfortable giving you advice but, I gotta see pictures of this C-cab...........ruggs

 

[one finger john]

Try setting initial advance @ 16*, all in by 2500 rpms, shoot for 36 - 38 * total, hook up the vacuum advance (for better fuel economy [with these fuel prices an extra couple mpg won't hurt]).
2820 lbs., 3000 lbs. w/you in the driver's seat is about 1000 lbs heavier than the average T. That's a real difference. I think more horse puppies are in order.
Any way, get the timing figured out first. Then attack the carb. 600 cfm is fine for that engine. Is the carb stock? Is it second hand and seen a few owners? Find out what stock settings are and use that as a staring point.
What is the loaded diameter of the rear tire? Maybe a shorter (or narrower) tire is in order.
You didn't say how the car runs. Get the ignition fixed first, then the carb. If you can't do a huge smoky, there are worse things in life.
If you want to do burnouts, then more H.P. will be required.
2x Ruggs request for pics.
This is where "tuning" comes into play. 90% of carb problems are in the ignition.

John

 

[railroad]

I agree with one finger john. Great advise on the ign timing. A lot of pep to be found in the optimum ign timing. On the carb, make sure the secondaries are opening, although this may not happen at lower rpm. Vacuum advance is your friend on the street. Probably more transmission than you need, but that is way down the list. Sounds like a great ride. You may not like the ride, but air up the rear tires real tight, after the ign adjustments.

 

[RPM]

I agree you need more timing

 

[fordsbyjay]

Maybe you should have put a Ford in it.

 

[KPoole9008]

I will try resetting the timing. The info sheet that came with the engine said to set the initial timing at 10* before TDC. and 32* total so that is where I am now.I am assuming you are saying 16* BTC. How is this done as the timing tab only goes to 12*. Do I estimate by moving past 12*(sorry, but I guess I am not as smart as I thought I was)? The carb is new and is stock. I have 11 inch wide fenders so a more narrow tire is nearly out of the question. The info sheet said not to use a vacuum distributor and if I have one not to hook the vacuum up. (GM go figure). Other than no hole shot the car runs great.

Try setting initial advance @ 16*, all in by 2500 rpms, shoot for 36 - 38 * total, hook up the vacuum advance (for better fuel economy [with these fuel prices an extra couple mpg won't hurt]).
2820 lbs., 3000 lbs. w/you in the driver's seat is about 1000 lbs heavier than the average T. That's a real difference. I think more horse puppies are in order.
Any way, get the timing figured out first. Then attack the carb. 600 cfm is fine for that engine. Is the carb stock? Is it second hand and seen a few owners? Find out what stock settings are and use that as a staring point.
What is the loaded diameter of the rear tire? Maybe a shorter (or narrower) tire is in order.
You didn't say how the car runs. Get the ignition fixed first, then the carb. If you can't do a huge smoky, there are worse things in life.
If you want to do burnouts, then more H.P. will be required.
2x Ruggs request for pics.
This is where "tuning" comes into play. 90% of carb problems are in the ignition.

John

 

[KPoole9008]

I will take your advise and add more air to the tires. They are at 27 psi. now. I like the 400 tranny because of the electric passing gear.

I agree with one finger john. Great advise on the ign timing. A lot of pep to be found in the optimum ign timing. On the carb, make sure the secondaries are opening, although this may not happen at lower rpm. Vacuum advance is your friend on the street. Probably more transmission than you need, but that is way down the list. Sounds like a great ride. You may not like the ride, but air up the rear tires real tight, after the ign adjustments.

 

[KPoole9008]

OOCH THAT HURT!!!!!!!!

Maybe you should have put a Ford in it.

 

[2old2fast]

Yea. ya'know those ford guys, they take every opportunity to be obnoxious, but the congregation still won't listen..hee hee.....

dave CHEVY'S RULE !!!!

 

[fordsbyjay]

Yea. ya'know those ford guys, they take every opportunity to be obnoxious, but the congregation still won't listen..hee hee.....

dave CHEVY'S RULE !!!!

Hahahaha Dave you crack me up.

 

[RPM]

Maybe you should have put a Ford in it.

Built Ford tough with Chevy stuff.

 

[benT]

Maybe you should have put a Ford in it.

:win: we have a winner! Just kidding....

I agree on putting more timing into it. I've had that same problem before

 

[Ted Brown]

I have found that setting the timing correctly for each car is a bit hard in a noisy open T Bucker or any Roadster for that matter, because if you are like me, and can't hear with a darn, I have to have my Wife in the car with me, so she can hear when the engine when it pings... I like the timing to be set at where the engine when running at say 30 to 40 MPH and it will ping once or twice just before it down shifts... That way it has as much timing in the engine, that it can stand... Best for HP and mileage... That is how I do it, no timing lights except for the very first engine start up... and make sure everything as at normal operating temp when you set that timing...

 

[CrAlt]

I have an all steel C Cab that I used alot of TBucket info to build. It has a GM Performance crate engine with 290 hp, timed at 10 degrees with 32 degrees advance, a Holley 600 cfm carb with vacuum secondaries, a Performer intake, a Mallory Unilite distributor with their coil, and headers. The tranny is a Turbo 400 with a 2000-2200 stall speed torque converter. The total weight of the car is 2820 with 1060 on the front axle and 1760 on the rear. The rearend is a 3:42 ratio. I am running B.F. Goodrich T/A 2.75/60/15 radial tires on the rear. I can't get the rear tires to break loose no matter how hard I try. I've even put a linelock on the front brakes and with it engaged the front tires slide. Any ideas why it's so slow out of the hole.

I got a GM crate engine last year and also had problems at 1st with it being dog-ish off the line and real bad on gas.. Turns out the balancer I had got was the right size but had the marks in the wrong spot. Different cars have the timing marks in different locations.I had to time it by trial and error until I had gotten the right timing marks.

 

[Differen T]

I have found that setting the timing correctly for each car is a bit hard in a noisy open T Bucker or any Roadster for that matter, because if you are like me, and can't hear with a darn, I have to have my Wife in the car with me, so she can hear when the engine when it pings... I like the timing to be set at where the engine when running at say 30 to 40 MPH and it will ping once or twice just before it down shifts... That way it has as much timing in the engine, that it can stand... Best for HP and mileage... That is how I do it, no timing lights except for the very first engine start up... and make sure everything as at normal operating temp when you set that timing...

Like you , I don't have all of my hearing left so I also use extra ears and a lap top for my K2500 mildly modified TBI. I found that before anyone would hear the telltale ping the engine had already knocked 50 or more times when load tested. You might want to consider that when tuning by ear. I also found that most unheard knocks could be eliminated with a small amount of additional fuel in the enrichment circuit (a lot harder to do with a carb as it is easy to make it too rich ) rather than retard timing.

Al

 

[Mike]

I found that before anyone would hear the telltale ping the engine had already knocked 50 or more times when load tested.

Ding, ding, ding, we have a winner.

Advance her 'til she lifts the ring lands, then back her off 2° and stick two numbers of jet in her.. That's like the old joke about how to torque bolts. Tighten her 'til she strips and then back off a 1/8 of a turn, after you insert a heli-coil and replace the fastener.

Yes, maximum timing can be a wonderful thing, but if you're going to time an engine in that manner, please make sure you have an extremely sensitive knock sensor in the head before you start. If you can hear the death rattle, it's already been rattling for a while and cylinder temperatures are already far too high.

 

[one finger john]

That is why I advised my friend Jim to replace the balancer for his 327. The old one's outer ring had moved and the timing marks were WAY off. He had been timing the engine by ear and the performance was not consistent. After replacing the harmonic balancer along with the timing chain (it was worn to the point that there was almost a 1/4 in. of slop on the slack side), properly positioning the distributor with the vacuum advance on the passenger side of the manifold and dead sticking the timing, the engine fired on first crank and it was simple to set the initial advance @ 16* btdc and KNOW that was what it was (and is). Jim made a couple of calls to the Edelbrock tech line and was able to get the dual carbs ALOT closer to optimum performance. The carbs are 500 cfm and by optimum I mean both in starting, idle, cruise and upper end. Jim has an Edelbrock Street Tunnel Ram that lives in the upper end of the rpm range (7500) so the next purchase will be one of those dual quad manifolds that have the divorced plenums. That should boost the bottom end considerably. Of course that means that the carb settings will have to changed, but that's why it is called "tuning". Might also freshen the top end (no, that will not blow out the bottom end). That will put extra stress on the TH350 (starting to weep from both ends) and the u joints. It is never ending.

John

 

[Ted Brown]

I have had very good luck with timing this way, running my engines very hard for more than 40 years... I have even torn down a few of my engines to see how they were looking and working inside, all was in very good operating order, (except for a couple broken valve springs over the years) I also keep an eye on my spark plugs and read the header tubes, close to the ports, as you can see how hot things are running very nicely this way, touch also works, just never grab a header tube, as they will end up keeping your skin... Time tells the tale for me, I am an old fashion person, if you never break anything, you are not running it hard enough to learn a damn thing and just who benefits from all this breaking stuff??? the CUSTOMER... Just ole Ted here at least I use my real name...

 

[Old Rotor Flap]

My opinion.... for what's it's worth..... Yes Paris, not much I know.

I think your street converter is not a benefit at the track. You need to come out much harder.... like a two-step and a 4000 + rpm converter. And, after market rear axles. You could probably survive a drive shaft failure, a broken axle threathens everyone.

My fear, my dear is the gear in the rear. Not knowing the tire diameter qualifies my opinion, however I'm guessing with a 28 or 30 " dia rear, you might need a 4.11 or 4.56 or taller.

Admittedly, I didn't read all the posts, but it sounds like I can save face by agreeing on the timing comments. Does the throttle response seem lazy? Yup. It's timing.

Let's not forget good tracks are prepped. Bite quality at the line is not generally understood by some racers.