Another Clutch Problem Thread. Chevy 350 to 3 speed.

[Adam Ogilvie]

Hey all,

I really did all the research I possibly could before posting but I just can't seem to find what I'm looking for.

So i recently rescued a 72 FJ40 from the jungle of Puerto Rico that has already had the Chevy 350 engine swap to it. It has a 3 speed transmission with a diaphragm style clutch on it (unsure what kind of clutch exactly). Its got some sort of chevy bell housing (assumption because its painted the same as the engine block) while running the Toyota 3 speed fork, TO bearing and clutch hub. The truck has been having trouble shifting as it doesn't seem there is enough throw to fully engage/disengage the clutch so I removed the cannibalized clutch fork (pics to follow) and looking to replace the majority of parts underneath.

I believe the CA5473 Pressure plate is what I need but I'm lost as far as fork, TO bearing, bearing hub, etc I need to finish the job.

The hardest part about this is I really don't know what I'm working with as far as bellhousing, current clutch, engine, or anything really. Any help is greatly appreciated.

-Adam

 

[cult45]

Best grab a good half dozen pics. At present, our guess is as good as yours.

 

[Adam Ogilvie]

Here is the clutch I've got. Throwout bearing and fork removed

This is a side view of the bell housing. I included it to help with identifying what kind it is.

This is the old fork (rough looking I know) and old throw out bearing/ bearing hub

I bought a cast iron GM fork to replace the old one with but as you see it doesn't fit the old bearing hub.

Engine pic to show the mess I need to clean still. Posted to see if anyone can tell what kind of engine it is. I'm told it is a 350 but I don't really trust the guy I bought it from.

 

[BrianSanDiego]

Can't help with the clutch but your motor looks like a 350. Not a 327 because yours has accessory mounts in the heads. Has a HEI distributor, good, mechanical fan, good, pcv, good, electric fuel pump, not as good.
Could be a 383 which looks three same, but probably a 350.

Edit: is there no vacuum advance line from the manifold to the distributor? You need that one.

 

[Adam Ogilvie]

Yeah the engine runs alright despite the "professionally installed" carb needing some attention and the electric fuel pump is a bummer but right now just focusing on getting the rig moving.

 

[BrianSanDiego]

Yeah the engine runs alright despite the "professionally installed" carb needing some attention and the electric fuel pump is a bummer but right now just focusing on getting the rig moving.

...yep, just throwing some more info in the hat.

 

[Downey]

Ok, here's what you got- - -""totally home made conversion"". but help is on the way:
(1) First, most adapters (spacer plates) go between the tranny and bellhousing, your's goes between the bellhousing and engine. That spacer was used to space the tranny rearward since the Toyota 3 speed input shaft is too long for the Chevy engine. Now that you have it, and it's bought and paid for, go ahead and keep using it.
(2) You have a problem at the throw out bearing because (a) the previous owner used a Toyota 3 speed bearing since the throw out bearing retainer tube on the front of the tranny had not been machined down for the smaller I.D. Chevy bearing. Then (b) previous owner had to use a Toyota shift fork to match the Toyota bearing. Again, you should keep using those items since they are bought and paid for, and they work with your bellhousing and shift fork pivot ball.
3. Stock Chevy clutches do not work with your Toyota hydraulics (clutch master cylinder and slave cylinder), Toyota hydraulics do not have enough travel to disengage the Chevy clutch (they take .500" travel to disengage, your hydraulics only produces .420" of travel at the bearing). Additionally your hydraulics are very border-line at being able to disengage a Luk Clutch that many claim works ok (takes .400" of travel to disengage, your .420" hydraulics barely gets the job done on a good day). What you actually need in my Chevota clutch that takes only .375" of travel to disengage.
Soooooo, I'd say use your bellhousing/ spacer plate/ Toyota 3 speed T.O. bearing/ Your modified Toyota shift fork- - -they will work, they are not the problem- - -then talk to me about a new clutch that will work, mine is $262.00 plus the ride.

 

[Adam Ogilvie]

That was the wealth of information I was hoping for! Thank you!
Honestly the old clutch fork is so worn and beat up I do not want to put it back on (plus the pivot ball clip on the back is broken). I'd rather replace the fork, bearing, bearing retainer, clutch, etc so I can have something that I know will work. If you were to replace everything from the slave cylinder to the clutch itself, what would you recommend?
I got a pretty good deal on the rig so I have no problem putting money into it to get it working right. Also it is my only car right now so I want it reliable.

 

[Downey]

Then use cast iron shift fork in your photo above, with Chevy T.O. Bearing, with Chevy pivot ball inside your Chevy Bellhousing, THEN have a machined shop machine down the T.O. Bearing retainer mounted onto the front of your transmission to take the Chevy T.O. Bearing. While your at it, install a new oil seal and gasket when re-installing the bearing retainer back onto the tranny.

 

[bikersmurf]

I don't know the availibility in Puerto Rico, but if possible, I'd track down an SM420 or SM465 Chevy Trans... or a Toyota 4 Speed. Three speeds aren't overly strong and can fail if abused behind a 350. That said, it's bought and paid for, and many have used them for 20 years behind a 350.

 

[Adam Ogilvie]

I would love to put a new transmission in it but I plan on waiting until I'm back in the states to do something that major. Also shipping a transmission this far is $$$$$$$$.

Is there a different bearing retainer i could use instead of machining down the Toyota one? Machine shops around here are few and far between. Could I just cut the fork tabs to fit the Toyota bearing hub or would that interfere with the structural integrity of the fork?
Also what clutch do you recommend, Downey? Should I consider upgrading the master cylinder to the newer style Toyota for a little bit more travel?

 

[melvinjo]

Go to advance adapters com and ask for their tech line. Have your pics ready to send to them by email. These guys are THE most helpful, friendly, and know the 350 to 3 speed setups when it come to clutches, TO, pressure plates, you name it

 

[bikersmurf]

SOR.com used to list diameters... but I cannot find them anymore. I lucked out and the stock Master and Slave have been working great with a Luk clutch for 22 years. I’m also running a braided Stainless Steel line so all the oil moved by the master translates to movement in the slave.

If I recall correctly the ‘74 master has a slightly larger bore than the master used with the ‘75 and newer diaphragm type clutch slave.

 

[Downey]

Hold your Chevy shift fork up to your Toyota T.O. bearing, see if grinding off the two inward pointing nubs on the Chevy fork will make it fit the Chevy bearing????? If so, home run.

 

[bikersmurf]

Following from Jim’s (Downey) idea you could also buildup the outside to create surface area for the Toyota retainer clips.

Depending on how much meat is left, it could be fine without adding material on the outside.

 

[Adam Ogilvie]

I went with Melvinjo's advice and called Advance Adapters and they were a big help. They had a throwout bearing specifically designed for the cast iron GM fork and the Toyota 3 speed tranny. I'm getting a new Pressure Plate and clutch disk from them as well. Still trying to figure out what flywheel to get but there will be a new one of those too.

Thanks for all the help from everyone who has responded. Ill be sure to post pics and updates of the fix once parts arrive.

 

[shelfboy1]

i used to use the 4 speed to bearing its bigger in diameter and pushes further out on the diafram and gives more throw .then i found you could drill the chevy flywheel and use the stock toyota clutch and parts.30 some v8s later no problems