C-4 Build Levels

It seems there are several C4 builders out there in FordMuscle land. Assuming street/strip and DOT tire use, at what levels do you beef the tranny? For instance one fellow says he uses junkyard C4s behind 400hp motors. Really? How much hp will a pan fill C4 withstand? At what point do you break things? What mods do you suggest for 500hp? What mods are in the C4s behind the super high output BBFs?
I know Windsor Eight, C4Tim and others of you have the info. Give it up.

<font size=-1>[ This Message was edited by: R Code on 2/27/02 8:39am ]</font>

I have built many c4's for big blocks. Most of them for some of the racers in my area. I use Kevlar bands. I am now using 5 clutches in the hi/rev drum using the lower plate from a forward drum and the smooth red clutches. I use 6 clutches it the forward drum, I send the drum out and have the snap ring groove widened higher. Performance also has a kit to do something simular I use an H servo with the outer seal removes and 3 flats ground on the surface and I plug the hole in the case. I use the stock planetaries and they seem to hold up fine. I weld up the 3 peanut holes in the forward drum and machine smooth then I redrill the lube hole. I then drill and chamfer a hole the the thrust washer. You can also drill holes in the outside of the hi/rev drum to stop too much fluid from building up. Most of this stuff is basic. I have had alot of success with the C4's, most of mine are behind big blocks. The guy you really need to talk is gregaust he takes it to a new level.


<font size=-1>[ This Message was edited by: windsoreight on 2/26/02 9:28am ]</font>

<font size=-1>[ This Message was edited by: windsoreight on 2/26/02 9:29am ]</font>

<font size=-1>[ This Message was edited by: windsoreight on 2/26/02 9:40am ]</font>

That is good info. I have read the article that Gregaust has forwarded. Read and printed the stuff saved by FM in the archive thread. Just wondering what is necessary at the different power levels.
Every piece seems to have a different formula, but they don't say when the different fixes are necessary.
C4Tim has detail on the roller conversion which eliminates the thrust washers. Sounds like a great idea as one of the pieces said the thrust washers are the source of the metal in the fluid, which is supposed to be trouble. Going with the roller conversion eliminates that problem.
One of the builders likes the teflon sealing rings, but that doesn't seem too universal. Thanks again.

You might contact JPT (Jims Performance transmissions)in Eaton Falls, Michigan, home of the roller C4. He designs and builds his own planetaries. I have been running one of his C4's for 2 years, 600+ hp weekend after weekend. Never a problem.

Ron

My buildups are very similar to windsoreights.Kevlar bands,i use 5 forward + 5 hi/rev clutches,welded fwd drum and drilled hi/rev and low drum.Remove the checkball from the stator support for increased cooler flow,roller thrusts as per TimR's info.
To answer your question,It is said that the 26 spline input shaft will take up to 600 hp.The weak link is mentioned in another post here ,is the fwd drum jelly bean holes. I personanally use the steel sealing rings but some guys do prefer the teflon.I like the 'R' servos.I rebuild the front planetaries using parts from the rear planets as per the article in the archives.
The roller bearing mod also solves the problem that 89coupe mentioned a while ago about shearing the tangs from the stock thrust washers when on the gas.
A good valve body helps the trans live.I have used the transgo stage 2 kits.There are some mods in the article posted that also work well.I use those mods + a couple of other little changes in my transmissions.
Hopefully that helps a bit,i'll add any more if i think of it..

Just a couple of things I have learned over the years.
More oil volume is good, deeper pan with filter extension of some kind.
Keep tranny endplay to a minimum, especially with iron sealing rings but helps all around.
Use valve body gaskets for better sealing, has helped several different trannies seal better. Use them even with full manual valve bodies.
I like the R servoes but have used H's with good success. Do not like the servo mod where the small sealing ring is taken out. The only C-4's I see that take 2nd gear band out have this mod and I believe it is hard on high gear also. I have a theory on this I can expound on further if anyone is interested.

Theories (conspiracy or otherwise) always play in the States. Let's hear your theory and maybe one or two of the experienced ones will have a counter point or two. Bring it.

All right you asked for it.
My thought is if the small sealing ring is removed on the servo piston and some oil transfer slots cut the pressures on both sides of the piston will be the same. The problem with that is if the valvebody does the same thing as a stock one when the tranny goes to high gear the apply pressure on the servo piston is not released. This means the only thing moving the piston up and disengaging the band is the spring. I have never seen this tech tip come with the advice to use a heavier spring.
Using a H servo for an example there is a 4.4 square inch area difference between the two seal areas. If line pressure was 150 PSI, with both seals in use there is 660 lbs of force pushing the piston up the bore.
The band disengages quickly and the pressure gets to the direct clutch quicker and with less lag.
There is a 8 sec Fairmont running here that has the servo mod done and the band lasts about 10 runs. While I only run high 10's I have never killed a band.
I believe Dynamic has a valve body that releases the 2nd gear pressure when high gear comes on. I spoke to them at Epping and they use stock servos with the letter machined off and he said the servo makes no difference in their trannies.
This is my theory and I am sticking to it. Poke enough holes in it and I will try the mod late in the year just to prove my point only with an A servo so I do not waste my good servos.

I think it depends on the valve body too. I do the mod only on the C4's I build with manual valve bodies. I have been using TCI or ATI valve bodies and all of them want you to do this mod. I have not had a broken band yet. I Have a C4 in a friends 67 mustang with a 429 running 10's and in 4 seasons he has not broken a band. Same with the others I have done. I have seen some of the stock bands come apart though, with ruaway line pressure. I am using Kevlar bands and they seem to hold up well.

More C4 info for you all
I use as many as 11 clutches in my C4 transmissions and I do this by using thinned stock steels. I take large batches of them to a machine shop that can surface grind them with a magnetic chuck surface grinder and have them take them down to .061-.065 and then use smooth surface forward clutches that are .061 thick in both clutch packs, final clearance is set at .o20-.025 in both packs and this is done by machining the stock pressure plate down to a thickness that gives this much clearance and don't worry about it being to thin as there are stock ones that are listed at only .141 thick so you can make them pretty thin without trouble and I usually don't need to take them down that far usually about .160 or so, but be sure to check yours before you machine it unless you have lots of spares. Gregaust and others here have suggested that you can also machine just the edge of the pressure plate to create a lip for the snap ring to set in and I think this would work well to just watch out for clearances of the assemblies when this is done.
And a word of caution I do not believe it is a good idea to machine the snap ring land higher in the drum because you may raise the pressure plate out of the locate lands in the outer perimeter of the drum and this will allow it to turn in the drum and not drive the drum as it is supposed to along with the steels in the pack.
Interesting note in the current issue of Muscle Mustang and Fast Fords April 2002 There is a artical about PA C4 build up and in it they show at least 2 more places to put bearings in the trans other than the places that I already do, I have seen bearings used in these places before in other companies transmission builds, but never had the sizes of the bearings so I had never put them there, but now I may try these places as well, they use the same Turbo 350 pump bearings there too, at least it looks to be the same ones in the pictures.
I think it is a good idea to weld or braze the kidnee shaped holes in the forward clutch hub to prevent them from braking out as this is a known weak spot.
I have used only cast seal rings like stock with very good luck, but feel that there is some merit to the teflon ones and some day will try them myself.
Use of aftermarket hardened input shaft is only needed for the very high powered cars and heavy trucks etc. Up to 450 HP is fine for stock one. above that it would be good insurance.
There is some debate as to need for high dollar clutches and bands I have used new rebuilder kits for most of my builds with no problems mostly Raybestos, Borg-Warner others etc.
I have used the servo mod on many of my builds with only one that ever gave me any trouble and I think that the cover is flexing on that one so I plan to build a girdle for it and see if that will help.
I have pics of the bearing mods that I do and can send them to those that are interested or don't already have them on a limited basis as I don't care to be overrun with email requests for this so if it gets out of hand somone will need to help me post them so all can find them.
I only use good manual valve bodies and transbrakes for my modified trans builds so there is no comparison of the shift quality of them and shift kit or stock builds etc. mine all shift hard and firm and no slip.
anything else I can share just ask.
Tim R