Just wondering what everyone here thinks of what might have happened last weekend with our dragster. Ran 1.08 60' 4.83@142.80 1.077 60' 4.80@143.00

Then a 1.25 60' 4.98@142.84 then 1.21 60' 4.948@143.00.

Both the last two runs, the car looked and sounded the same, lifted the front on both, didnt see any hint of spin or trouble, but both passes and oddly fell off .13 and she was quite red on both which is also very inconsistent. Sadly no 330 timers to get split times from which might help some.

The track is an old airport. Could the setup of the lights and crown of the road factor into this? Not sure where to even start looking. So strange those two passes were so consistent but off and the first two were so consistent and quick.

Possibly camshaft or lifter issue. Maybe intake gasket got sucked. I have seen this happen before. You will probably get told its the converter usually 100 times or more and it is possible. But I would not check there 1st. I forgot I would look at the valve springs 1st. you.ll get it.

This message has been edited. Last edited by: Footloose,

There’s no way the 60-660 times and MPH would be the same if there was a mechanical issue costing you .1+ of ET to 60’.

Starting line timing system issue, period.

When I lost a converter it was similar but worse. Stall went from 6400 to 4400 and if I remember right ET was off about .30. You would probably notice if stall dropped that much. When I lost a 7AL-2 box it was about .4. Being that little could be any number of things.

I would start with checking rotor to see if it is broke or loose, check distributor for slop which could be rotor or worn bronze gear, run the valves and look for anything unusual. Clean carb real good especially air bleeds. Check float level. Change oil and cut open filter to look for any metal. Like Footloose said could be sucked a gasket check it. Also it could be a bad spark plug, I have seen where it does not have an obvious miss but does not run right. When you look at it plug looks good but it is not.

You are looking for a clue of what it is or what direction to look. If it is a mechanical issue like lifters, cam or bearings it will get much worse quickly so sooner you find it the better.

I am not leaning toward mechanical, as the run looked identical and both of them were still at 143 mph (1/8 mile) and to me, just too consistent with the numbers for mechanical.



There was nothing else even close in numbers to us, the next closest was a 5.9 second dragster. So I am fairly confident it is something with the timing, but am trying to figure what it could be to make changes to the car to prevent that in the future.

How Red, exactly?

Car backed out (or steering wiggle, etc.) of the beam, starting the clock. I'm guessing about .2xx red? Could be when a SLE triggered?
Only way this happens.

I had this happen years ago, car was pulling front wheels out of the beams try putting some weight in the front end.

The car was lifting the front then. the lights, one was quite red but she did go in a bit deep I saw. the other she was quite careful but was still red and swears she saw yellow before letting go.

I had seen that video about how the lights work, and going red without moving. I forget what the reason was, but wondered if there could be something related to that and the crown of the track surface.

Possible stage to shallow and backed out if no stage lock in the timing system

not sure why the image wont show. I will try this way.
Photo

The car was lifting the front then. she was quite careful staging but was still red and swears she saw yellow before letting go.

I had seen that video about how the lights work, and going red without moving. I wondered if there could be something related to that and the crown of the track surface.

This message has been edited. Last edited by: TD6297,

quote:

Originally posted by diceman1530:
Possible stage to shallow and backed out if no stage lock in the timing system

definitely would not have stage lock. But would this cause nearly identical .13 increases in the 60' and ET?

Question; is the car popping the wheels straight up our of their beams or does it drive out and up?

Straight up. the wheels are not turning till touching down

Shortest way out of the beams is up. Red. Maybe put some weight up front see what it does. Just my opinion. Try to get it to go out and up. Should help the lights and inconsistencies.

Are the slicks getting old or the side walls getting weak?

I agree with BP (Barry), throw some weight on the front end to stop the car from lifting the front tires directly out of the beams. The reaction times will slow a bit but become more predictable and consistent. This will also make the ET's more consistent. You will have to play with the front end weight amount it depends on the length of the car as well as several other factors, the key point is to use just enough weight to stop the front tires from lifting straight up out of the beams. Every car is different, as a starting point try using 20# and see if that is enough.

Good luck.

Bob

I do not think popping front tires out of beams has anything to do with car going from 1.08 sixty foot to 1.25 sixty foot. That is a lot of change, I would look for something else.

I did have to move weight to nose on my Front Engine Dragster because it was popping tires out of beams and simply did not have enough weight over front tires under full power to steer car. Moved battery up front and added about 20 Lbs and drives great. Do not remember much sixty foot and et change at all and certainly no where near what TD6297 is experiencing.

MPH is the same so I would check things like loose or broken rotor, worn bronze gear on distributor.

I do think it is a good idea to make it do same thing every time for consistency. If it takes adding weight up front then do it but I do not think that is enough to make that big of difference in sixty foot and ET. Now popping out of beams does effect reaction times. I think it was about -.030 red when my car pops out of beams.

Had the same issue but severe. Would hike the wheels a foot. Straight up. I put 40 Lbs in the front. Still red. Had to put a rear bar on it and work from there. HT car.

quote:

Originally posted by TD3550:
Had the same issue but severe. Would hike the wheels a foot. Straight up. I put 40 Lbs in the front. Still red. Had to put a rear bar on it and work from there. HT car.

^^ This….
Even if a dragster/ altered does not wheelie- bars can make a car deadly consistent.

quote:

Originally posted by Curly1:
I do not think popping front tires out of beams has anything to do with car going from 1.08 sixty foot to 1.25 sixty foot. That is a lot of change, I would look for something else.

Sure it could. When the tire stays on the ground and rotates through the beam, the car gets a “head start” as the car drives through the beam before the timer activates. If the tire pops straight up out of the beam, the ET timer starts earlier, before the car gets the rolling “head start.” The reaction time would be quicker by the same amount. So if the 60’ went from 1.08 to 1.25, I would expect the light to be .170 ish red.