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-   -   what causes this? (https://classracer.com/classforum/showthread.php?t=11822)

BIZMANRACING 07-14-2008 12:17 PM

what causes this?
 
went racing this week, everything was fine until the first round. when i pressed my line lock button, the car rolled forward a bit. kind of surprised me. i think it surprised the guy in the other lane to since we was dead late from hell (.138) to my .001. but none of the numbers on the run were any good since i went in so deep.

so my question is whats wrong? one guy told me its my shifter not putting the car "all the way into first gear" another told me that my trans is going away. yes that it does that if it gets hot. trans temp was 200???? so what the f*&k. just kind of upset. i was all up beat about the car and driving and now this. its always something.

any help please.

SSTRACER323 07-14-2008 02:14 PM

Re: what causes this?
 
Carlos the same thing happened to me second round at the Div 3 race in
Chicago.... i found out i was to high on the rpms when i hit the trans brake button ( you said line lock, did you mean trans brake?)
Check to make sure your fluid level is right and it is possible the trans is going bad, but my trans guys said he doubts any problems with the trans on mine just to high on the rpms...... hope this helps

Lee

BIZMANRACING 07-14-2008 02:25 PM

Re: what causes this?
 
YES I DID MEAN TRANS BRAKE.

i only have the rpms maybe at 1500 when i hit the button and mash the gas pedal. bad trans is not good. in a tough dollars and cents world something like this could just spell the end for 2008.

SSTRACER323 07-14-2008 03:03 PM

Re: what causes this?
 
I know what you mean..... it is getting tougher and tougher to keep racing
I hope it is not a bad trans for you...

Lee

sst3447 07-14-2008 03:20 PM

Re: what causes this?
 
check your band adjustment if it is too loose the car will roll when you apply the transbrake

Adger Smith 07-14-2008 04:36 PM

Re: what causes this?
 
In a P/G the band is applied when it is pulled into low gear. Rolling forward is usually too low line pressure at the time you apply the Trans Brk or too much clutch clearance in the rev clutches. The low(forward band) is applied and the rev clutches must apply to hold or lock up the forward movement. If they(rev clutches) are late or slow applying you will roll/creep forward.Try changing the spring pressure or the size of the boost valve (.488 dia gets the most pressure) in the valve body to raise the line pressure. You might also try going to a higher apply RPM to get the pump spinning up the pump pressure-Vol. Low vol. or worn pumps require higher RPM to move the required fluid vol to apply the rev clutches. The hardest thing to fix is the rev clutch pack clearance. (requires complete transmission disassembly)The more clearance, the more fluid vol is required to apply the rev clutches. I usually work around .060 for pro tree and around .085 to .090 on .500 tree applications. With it doing it hot I would put a pressure gauge on the rev & check the difference in hot or cold pressures. You can also judge how fast the pressure rise is when you apply the Trans brake.
Good luck, hope this helps you solve your problem.

Bryan Gillespie 07-14-2008 04:57 PM

Re: what causes this?
 
band adjustment (all the way in,then out 3 turns)
also change fluid and filter

Bob Verwold 07-14-2008 05:18 PM

Re: what causes this?
 
Quote:

Originally Posted by Bryan Gillespie (Post 75521)
band adjustment (all the way in,then out 3 turns)
also change fluid and filter

70 inch pounds in and 3 1/2 to 4 out is the way I adjust mine........

BIZMANRACING 07-14-2008 07:01 PM

Re: what causes this?
 
i adjust my low band about a month ago. turned all the way in and then 4 complete turns out. i might add that it was a bitch with the CSI cover over the trans. its a little hard getting the allen head in there.

as for the line pressure being low and increasing the rpms. that might just be the only other thing to try. always some **** for me in the 3rd round. just finished practicing on friday. back to back to back runs just to see what the car would do if it had a good drivier. everything went fine and it repeated. now this.

well it will just have to rest until friday, then will do a little maintenance and put it away again until race day. see, bad thing about race cars is that you just can't take them out into the street and try them out. hell, it would blow the tires out anyway.....lol

SlickVic 07-14-2008 08:11 PM

Re: what causes this?
 
Carlos, sometimes my trans rocks the car foward or backwards when engaging the trans brake. Ive tried adjusting an still does it. The way i fixed it was just to bring the rpms up a little before i stage. This brings the line pressure up and no rock. The nova also engages the line lock when the transbrake is engaged to keep it from rocking but becomes a pain when backing up w/ a hipster.


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