Chev clutch question

[beechnut]

Greetings, I've got a '74 40 and am in the process of repowering with a fresh 383 SBC, i just had the transmission rebuilt and am working on a clutch setup and have a few questions....

Is it a no no to run a chev clutch with the toyota input shaft, it fits ok but the spline profiles look different, do most people with chevotas run this?

The collar around the trans inputshaft was turned down to fit the chev TO bearing, again do many of you run this setup? The tech at the trans shop said it was a bad idea as it weakens it too much but it doesn't look like a big deal to me, its just keeping the TO bearing located right?

I've been searching through the forum and have been sifting through lots of info some clarification would be appreciated!

 

[Poser]

I would get a Toyota disc so that you do not ruin the splines on the input shaft since the Toyota and GM do have different profiles...


You should not have a problem with that modified trans input bearing retainer...



Good luck!


-Steve

 

[dgangle]

Is it a no no to run a chev clutch with the toyota input shaft, it fits ok but the spline profiles look different, do most people with chevotas run this?

The collar around the trans inputshaft was turned down to fit the chev TO bearing, again do many of you run this setup? The tech at the trans shop said it was a bad idea as it weakens it too much but it doesn't look like a big deal to me, its just keeping the TO bearing located right?

Looks like you have an early Downey kit. I ran one of these for 15 years with no problems. Yes, you use the GM TO bearing with this. As Poser states, no issues there. Make sure you put a new seal inside the bearing retainer while it's apart. I have run GM 3-finger, diaphragm and the Chevota Centerforce clutches with no problems. Search Pgbottle (Jake) for the thread on the GM parts to use. I found these to be less expensive and certainly more readily available in Everytown, USA. In driving V8-powered FJ's since the 80's, I have never had a problem with any engagement issues using any combo of the above.

 

[Bennett]

What I did.. i have the same Downey setup and had to pull my motor several times before I got it right.
Chev splines are cut different than a Toyota so do no use.
I tried a Toyota disc( with rubber instead of springs) and the inner hub would rub on the pressure plate. ( It was facing the correct side)

I had a toyota ( spring type) splined inner Clutch disc hub mated to a chevy clutch disc. Custom deal but no problem for any good clutch shop and same price. I used the chevy diaphram type pressure plate becasue it takes less throw from the slave to operate and chevy T/O bearing. I also used a curved cast clutch for to get the position closer to the slave as I used a AA slave bracket on the Chevy. Make sure you have good tight connections and no free play, with a good strong clutch return spring pulling straigh back perpindicular wtih the fork. it will save you alot of time. Ask me how I know.

What I forgot to do was put in a new chevy ball pivot $10 on the inner bellhousing. Mine was worn and caused lots of end play when the fork would pivot and try to "walk".
Ball Pivots wear and cause longer throws than needed, small Item that gets overlooked. You need all you can get .. I have seen many a sbc conversion throw out bearing spinning away cause they are too close to the clutch fingers and touch and begin to spin and sing to you.

Lastly I used a pre 69 brake master cylinder ( as per Mark Whatleys years of experience ) to give me longer slave throw. Pre 69 Brake master bolts right up and to the clutch mount .THe diameter slightly larger than the slave diameter resulting in about a 1/2" more throw when the pedal is depressed.

As was said before.. you should have no problem with that retainer.


bennett.

 

[beechnut]

Right on, thx for the good info!
Along these lines, how many people run high torque (400+ft/lb) engines in their fj's and what seems to be a commen weak link? I'm running a orion, stock rear end and 85 fj60 front axles/birfields/mini truck hubs? Is this style motor mount part of the downey kit? It looks kinda hokey to me and i'm going to switch to conventional mounts i think.

 

[camcruiser13]

i got the same motor mounts, hate them in the way of everything

 

[dgangle]

That front mount was billed as their "bolt on". It attaches with (4) 3/8" bolts into the front of the block and uses stock engine mounts to the stock locations. I am unsure if it is even still available. Pretty much sucked in that forget about power steering and you only have one specific location for mounting the SBC. But it did simplify the install for some. Buy their weld-ins and be done with it.

 

[dgangle]

Here's what you need in the FS section

https://forum.ih8mud.com/showthread.php?t=132569