TH400 build-pictures
- Thread starter 87buickracer
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blackplague
Are you watching Phil?
- Joined
- May 25, 2001
- Messages
- 472
It's 4140 pre-heat. It's a great material for valvebody valves and other things.
Mike.
thanks mike.i used it for those stagerite valves as well.after grinding i put them on center i put them in a v block and they were unmistakably 0.it was impressive.the grinder did a good job and we left .002 per side.great material,and priced reasonably.mike when you use that 700 bearing on the rear of the pump support you must grind off the lip or relieive the front bore on the drum.i have also been having great luck using the new style 4l80e support rings in the 400.they are a plastic/graaphite combo and have a unique interlocking desin that seals and doesnt shrink and also doesnt erode the drum bores.they are shown in the photos from turbobitt
I not clear on what you mean, .002" per side. I hope you're not talking about a total valve to bore clearance of .004".
I keep finding new mods for the 400 all the time:
http://www.bdub.net/tranny/TH400SuperBeefing-text.pdf
The pump drilling was new to me. I already knew about the .072" steels.
Also, a guy on the RealOldsPower board found this in his 400 oil pan:
http://img174.imageshack.us/img174/1376/vxlqa0.th.jpg
ImageShack - Hosting :: vxlqa0.jpg
"The center part is rubber..
The other part is aluminium, not the sprag then."
Time for a new case for him?
Definitely overhaul time!
http://www.bdub.net/tranny/TH400SuperBeefing-text.pdf
The pump drilling was new to me. I already knew about the .072" steels.
Also, a guy on the RealOldsPower board found this in his 400 oil pan:
http://img174.imageshack.us/img174/1376/vxlqa0.th.jpg
ImageShack - Hosting :: vxlqa0.jpg
"The center part is rubber..
The other part is aluminium, not the sprag then."
Time for a new case for him?
Definitely overhaul time!
I keep finding new mods for the 400 all the time:
http://www.bdub.net/tranny/TH400SuperBeefing-text.pdf
The pump drilling was new to me. I already knew about the .072" steels.
Also, a guy on the RealOldsPower board found this in his 400 oil pan:
http://img174.imageshack.us/img174/1376/vxlqa0.th.jpg
ImageShack - Hosting :: vxlqa0.jpg
"The center part is rubber..
The other part is aluminium, not the sprag then."
Time for a new case for him?
Definitely overhaul time!
That's the int. pack case lugs. The rubber is a piece off of the int. piston.
The pump drilling they showed is what's called in the industry a 'full time lube' modification. You must be very careful doing this mod. If you do this in addition to installing a restrictor orifice in the converter feed passage, then no worries. If you drill this full time lube passage without the restrictor orifice, you could be adding to the chance of having a crank killer 400.
87buickracer
Member
- Joined
- Dec 2, 2004
- Messages
- 798
I'm running the 4l80e drum/sprag..
don .002" per side is the amount left for the grinder to grind off to bring the valve to the proper dimension.this means if the part finished od is .750 its diameter is machined to .754 "after turning in the lathe .the final material removal to get to required diameter is done on a grinder while the part is supported on both ends from a center point machined into both end faces..002"per side removed generates .750".besides other things it allows "exact finishing and alignment between centers.
Good. I was hoping that was what you meant.
Slick chirping 3rd on a sticky track with a checkball in the aluminum piston. 2-3 shifts have been as high as 7,800 rpm. This is in addition to a bleed hole (not .060"), commonly recommended to relieve trapped or crossfeeding oil, drilled in the high drum. I think the reason for this extra hole has been covered. The high drum is not rotating in 2nd gear and begins to rotate only after the pressure has seated the check ball, acted on the direct clutch piston and the clutch pack has engaged. Maybe at a lower line, the checkball can unseat due to rotating speed?
There is a better intermediate sprag setup, but I don't think you'll need it for your level.
Testing i have done in the past has improved clutch apply with balls omitted in high rpm applications.Oil does momentarily exhaust out the ball on apply and it is this motion that partially pulls the ball into the pocket to create the seal.Hi rpm can throw the ball up the curvature of its pocket and away from the center and unseat it.Oil pressure acting on the balls minute cross section in psi is minimal at best,and there comes a point where rpm beats psi.
At what rpm did you notice the checkball having a problem staying seated?
There are many transmissions that use airbleed checkballs for the same purpose as the airbleed checkball in the direct drum or piston of the turbo 400, including the 200-4R. What other transmissions have you found this to be a problem?
right about 8000 rpms with a TH400.more prevelant with the 4l60 series where the drum is already in motion in 2nd gear.many have been doing it on torqueflites forever.even if you pump up a 400 or 4l60e drum with 200 psi you can easily push the ball off seat with little effort.the ball check is a very effective but when parts have hi mileage ball seats are worn out and then high rpm just aggravates it.
all of our stage 2 units are built with no ballchecks and the bleed hole regardless of rpm.it has worked well,whether its because of the ballcheck absence or not we dont have direct clutch problems.Don I suggest you try it and see if it improves your already functional situation.Its an easy enough thing to do.Some things have been passed over form one design to another without checking the value of their presence in a functioning system.Based on design standards currently in use ,most non rotating clutch housing wont employ a ballchecks,while rotating housing do.some rotating housing that dont use ballcheck will use a ball check and bleed hole in the case or valve body.this seats the ball on apply and bleeds off oil at an orifice next to the ball check to exhaust.as soon as pressure is dumped at the manual valve the ball drops and the ballcheck seat becomes the 3rd and second largest ehaust point in the circuit.But in most manual shift custom vbodys the clutches exhaust at the manual valve (except for the direct after brake charge is dumped.)applying the clutch as fast as possible is enhanced by its removal when used with a bleed.One of these carried over things has been the reverse boost circuit in a th400.it isnt needed in a manual shift brake equipt 400 with max line and we have left it non functional for the last 5 years.we also grind a slot into its land in the boost valve so it doesnt become hydraulically active from the common x leaks at the boost valve. why a ballcheck in the forward drum and none in the center support?it seems the non rotaing drum / piston rule has become standardized.no its because the forward drum can remain applied momentarily while shifting quickly to reverse and drive such as when you are stuck in the snow.the main thing to realize is that without testing some of this stuff may just be along for the ride,and the given application is the foundation the final result is supported by.
Holy cow Chris. You made my head hurt. Ouch!
The constant bleed hole, especially if it's 1/16" is more than adequate to take the place of the checkball airbleed and exhaust any residual during unapplied conditions. I'm not saying it won't work. It does. Just make sure you do have that bleed orifice, constant or checkball airbleed.
I use both.
OK. I'll explain why I do it the way I do. Not saying my way is better than anyone elses. Like I stated in an earlier post, every builder has their own way of doing what turns out to function the same.
I drill a constant bleed orifice too. In the same place everyone else does. I don't drill it to 1/16". I just feel it's way too much of a constant bleed. I use a smaller size.
I also make sure I have a checkball airbleed. With both the checkball airbleed and the small constant bleed orifice that's positioned to relieve any trapped oil from the outermost point of the piston cavity, I have very adequate air bleed capacity during the initial feeding of the direct clutch. After the clutch housing is bled of air and the fluid slaps the checkball orifice closed, I will still have the constant bleed orifice bleeding off oil while the high clutch is applied and holding 3rd gear. Understand that any fluid that is bleeding off while a clutch is trying to hold is the same as if you took a razor blade and cut a bit of the clutch piston seal away. It makes no hydraulic sense to have an excessive bleed off going on when the clutch is applied. There you have it.
The constant bleed hole, especially if it's 1/16" is more than adequate to take the place of the checkball airbleed and exhaust any residual during unapplied conditions. I'm not saying it won't work. It does. Just make sure you do have that bleed orifice, constant or checkball airbleed.
I use both.
OK. I'll explain why I do it the way I do. Not saying my way is better than anyone elses. Like I stated in an earlier post, every builder has their own way of doing what turns out to function the same.
I drill a constant bleed orifice too. In the same place everyone else does. I don't drill it to 1/16". I just feel it's way too much of a constant bleed. I use a smaller size.
I also make sure I have a checkball airbleed. With both the checkball airbleed and the small constant bleed orifice that's positioned to relieve any trapped oil from the outermost point of the piston cavity, I have very adequate air bleed capacity during the initial feeding of the direct clutch. After the clutch housing is bled of air and the fluid slaps the checkball orifice closed, I will still have the constant bleed orifice bleeding off oil while the high clutch is applied and holding 3rd gear. Understand that any fluid that is bleeding off while a clutch is trying to hold is the same as if you took a razor blade and cut a bit of the clutch piston seal away. It makes no hydraulic sense to have an excessive bleed off going on when the clutch is applied. There you have it.
