Best way to shut down your race car after a pass

[elkymann]

Hey all, recently I have heard some things concerning how or what is the best way to kill your engine after passing the traps if a plug reading is desired, and I usually let the engine help slow me down along with my brakes but what routine do you guys do for a plug reading?

I have heard that, with a TH400, and maybe a glide as well, that you should NOT shut down the engine in nuetral as the trans pump no longer pumps oil to the trans in nuetral and you can damage the trans, is there any truth to this????? I have also heard that, if your going to do a plug reading and you need to kill the engine, to do it in gear!!!! won't this cause a problem also, although I don't know what problem it will or could cause?????

Any help is appreciated as always. and good luck this year racing guys/gals. :D

John
The Elkyman

[elkymann]

Ok guys/gals, I just called my trans guy and here is what HE had to say about the two transmissions.

A TH400, can NEVER be put into nuetral and the engine cut off as what happens is, now the engine is not controlling the drum in the case at 7000 rpm's (as an example engine rpm), and since the driveshaft is now spinning the drum at 2.2 times the speed of the engine that was, at say 7000 rpm's, the drum is now spinning at over 15,000 rpm's and BOOM, there goes your trans.

The powerglide is able to handle this type of shutdown as the internal parts connection are a little different so it is ok to jam your glide in nuetral, and kill the engie to do plug reading at the turnoff of the strip, whoo, got me to thinkin there for a minute :?

Just some info that may help others out later if they don't know what or how to do this that want to read plugs for tuning. Now I know the rest of the story, Paul Harvey, Good Day!!!! :D

Elkyman
John

[us7race]

I have done it many times with my glide. Can still read the writing on the clutches.

[russ67chevelle]

my trans guy agreed with comment dont put in neutral on a 400 @ high rpm.

[Scooterz]

Would this apply the same to the TH350 (like the 400??)

[chevyart]

be careful elkyman neutral dont live very far away from reverse. i know 2 racers who almost killed themselves (and their cars) by slipping past neutral into reverse. its not hard to do unless you have a safety valve body that wont permit this to happen. i have a hyperflow in my glide and it can go intyo reverse even if i try chevy art

[chevyfireball]

I run a glide. I can't even put it into nuetral without releasing the safety switch. Wouldn't even try. I turn onto the return road before shutdown. Can still read the plugs fine.

[OneBadGMC]

Would this apply the same to the TH350 (like the 400??)

ANY 3 speed transmission should never be put in neutral, and should only be doing burnouts in 2nd and 3rd, never first. If enough HP is on tap, do high gear burnouts only.

Doing burnouts in 1-2 can cause low clutch sprag failure, with catastrophic failure of the drum.

Chrysler 727
http://www.turbodieselregister.com/forums/attachments/other-vehicles/60687d1161537248-mopar-727-trans-explosion-727skott1.jpg

Turbo 400
https://blownalky.sslpowered.com/Turbo400_files/image008.jpg

[kicker91laser]

ANY 3 speed transmission should never be put in neutral, and should only be doing burnouts in 2nd and 3rd, never first. If enough HP is on tap, do high gear burnouts only.

Doing burnouts in 1-2 can cause low clutch sprag failure, with catastrophic failure of the drum.




This is very good to know. Is it the 1-2 shift that cause the low sprag to fail? Is it ok to leave it in 1st just to clean the tires off?

[OneBadGMC]

ANY 3 speed transmission should never be put in neutral, and should only be doing burnouts in 2nd and 3rd, never first. If enough HP is on tap, do high gear burnouts only.

Doing burnouts in 1-2 can cause low clutch sprag failure, with catastrophic failure of the drum.




This is very good to know. Is it the 1-2 shift that cause the low sprag to fail? Is it ok to leave it in 1st just to clean the tires off?

http://www.yellowbullet.com/forum/showthread.php?t=120213

We had a huge discussion about it on Yellowbullet a few months back.

I dont think cleaning the tires off ever came up, but, as in post #7 from that thread...

The low roller clutch is designed to work under load & for this reason it is highly recomended that you do not do burn outs or hard peddle the car while in first gear. The loading & unloading of the low roller clutch causes the rollers to slam against the springs & flatten them. If the low roller fails under load it will send the dirct drum to 3.25 + times engine speed, usally very bad when there is a cast drum involved.

So, dont sound like a good idea to me.

[elkymann]

be careful elkyman neutral dont live very far away from reverse. i know 2 racers who almost killed themselves (and their cars) by slipping past neutral into reverse. its not hard to do unless you have a safety valve body that wont permit this to happen. i have a hyperflow in my glide and it can go intyo reverse even if i try chevy art

I'm the same as chevyfireball, my trans won't go into rev unless I flip a lever, then squeeze another lever, safety feature :D ain't no ding dong here, I did my homework with my trans, and not to sound like a smart fart either, I just did the footwork with some of the best trans guys I know here in Detroit, but thanks for your input and thoughts :wink:

ElkyJohn

[RAPPTOR23]

I HAVE A BTE WITH NEW PUMP OIL ROUTING.. WHEN I PUT IT IN NUETRAL AFTER RUN,ITS TAKES 5 SECONDS TO FREE WHEEL. BTE SAID NOT TO DO THE NUERAL ,AFTER RUN.. ALSO, TRANS BRAKE RELEASE IS AS SLOW AS STINK!! THANKS

A TH400, can NEVER be put into nuetral and the engine cut off as what happens is, now the engine is not controlling the drum in the case at 7000 rpm's (as an example engine rpm), and since the driveshaft is now spinning the drum at 2.2 times the speed of the engine that was, at say 7000 rpm's, the drum is now spinning at over 15,000 rpm's and BOOM, there goes your trans.

The powerglide is able to handle this type of shutdown as the internal parts connection are a little different so it is ok to jam your glide in nuetral, and kill the engie to do plug reading at the turnoff of the strip, whoo, got me to thinkin there for a minute :?

Just some info that may help others out later if they don't know what or how to do this that want to read plugs for tuning. Now I know the rest of the story, Paul Harvey, Good Day!!!! :D

Elkyman
John[/quote]

[shawnp]

A TH400 should never be put into neutral. When you does this the transmission spins at 2 times the rate of the engine rpm. They are not designed for that.

However, you can get a "clean neutral" valve body. This is available from most companies. It adds and extra neutral gear that allows the car to safely be shifted into a neutral gear while release the high gear assembly so the transmission does not spin at twice the rate of the engine RPM.

[olds48]

Sorry to bring up an old thread,but I've been away for a while.I run a TH400 and my transmission guy told me the same thing about the high gear burnout,so that is what i do. My question is about the guys saying never put one in to neutral.Now,I'm not trying to split hairs here,but after you do a burnout and put the trans into to neutral,i usually rev mine at the prestage light to clean it out. Nothing crazy,just 1 or 2 quick raps to about 4 grand or so. Is this a no-no?

btw-my th400 had 186,000 miles on all original parts when i put a good set of clutches and a reverse pattern valvebody in it.All other parts are still original.I've put alot of passes on this transmission and am very amazed at its reliability.

[shawnp]

your fine with the quick rpm spike when cleaning it out before staging.

[olds48]

Cool! Thanks for the reply

[Loren1968]

Hi guys I'm new to this site and was looking over the Form on the hole trans burnout. Now I'm not a real expert on trans, but I did rebuild them for 7 years and what I under stand Is don't let the trans shift in a burn out. It's very similar to reving an engine with no load on it. Also as the trans shifts in a burnout the wheels can momentary change direction as the no load shift happens this will hurt a sprags, drums , and also differentials. The way I was told is the trans is to help push the car and in a burnout your really holding all the weight back So everything turning has no load on it. Also with the shutting down and neutral in the traps I agree with that, but if you have a old and I mean old trans with a rear pump in it you technically could do this without blowing it up. But then you could also push it to start it like a stick, but most don't have that but I thing a glide does if I remember correctly. Not sure. All I do know is that my car with 800hp and a 727 not shifting in a burnout does not blow up. Thank you for hearing my thoughts on this hope it helps.

[fast75vega]

but if you have a old and I mean old trans with a rear pump in it you technically could do this without blowing it up. But then you could also push it to start it like a stick, but most don't have that but I thing a glide does if I remember correctly. .

yes....the old cast iron glides had the rear pump and could be push started like a standard :wink: