Flywheel "Thickness Tolerance"

[JohnnyC]

Toyota gives parallelism and runout specs but NO "thickness tolerance"

manuals say if the parallelism and runout specs are bad....to replace the flywheel.

I know many of us have had flywheels cut...however...it would be nice to know a thickness tolerance in order to tell if a flywheel would be able to be cut.

Destin has an issue now that maybe a situation of being cut too far.

I figure if we can find an uncut flywheel to measure...we could use that as standard to check flywheels...and avoid future problems.

would this "thickness tolerance" be measured from crankshaft bolt surface to the clutch surface?

I know F and 2F are going to be different...Destin has an F

Thoughts? Ideas?

 

[antFJ]

I think this would be some good info added to the site.... Im curious how my flywheel will compare to a stock one

 

[destin]

Thanks Johnny

Yes I think this would be good data, might even save people money

 

[cuencanolenny]

This is a very good question. As noted above the FSM says NOTHING about minimum thickness. I have had my rig for 2 1/2 years now. The first 15 months it was in the shop as it failed inspection, miserably, the day after I bought it. The transmission and transfer case had been leaking and were covered in crud. So while they were out I of course wanted a new clutch. I ordered the CCOT complete clutch kit, it is a three finger unit. I requested that the flywheel be resurfaced. Once the vehicle was put into service in March 2014 I was never happy with the clutch, it wasn't smooth. Mentioned this to the mechanic, who speaks no English, but it seemed to fall on deaf ears. So, at this time I am having my F engine swapped out for a 2F. When he pulled the flywheel off we found why my clutch sucked, it wasn't the throw out bearing. The springs on the disc were hitting the head of the flywheel attach bolts! In hindsight, I believe a "knowledgeable" mechanic would know to put the lock strips and bolts into the flywheel (on the bench) and lay the disc on to check for clearance.

 

[shelfboy1]

i have a pile of flywheels but never had any cut since i had so many i never needed to .what measurements do you need ?

 

[cuencanolenny]

While my issue is being addressed, although as a retirement machinist, tool & die maker, tool engineer I shudder to think of what that repair will be. I think the numbers that would be important for us to know is the distance from the machined contact face (3 spd/deep step) to the attach flange. That figure will naturally become less anytime the flywheel is re-surfaced (lathe turned). It is easy enough for a machinist to maintain the 16mm step, however, once the disc contact surface has been machined too far, the springs on the clutch disc can contact the bolt heads. Since the Land Cruiser is unique in that the rear motor mounts are attached to the bell housing and the flywheel and clutch assembly are installed from underneath the housing and lifted into place, typically when the engine is in the car, it is much more difficult to see what is going on that with a "typical" installation. So this information and observations may be of value to another mudder to verify whether all is good before putting it all together since to correct the condition requires removal of the transmission, transfer case, etc. A major chore.

 

[west aussie]

'tolerances' usually depend on how 'tolerant' you are JohnnyC. im pretty tolerant as a rule...

...but clutch is needed. pulled this old f motor (for the bellhousing) last night and was going to pick the 'better' flywheel of the two; but have already turned my nose up at this one. you can clearly see where clutch has been hitting the flywheel bolts. and there's cracks aplenty.

 

[cuencanolenny]

Yep, the bolts look like mine but fortunately my flywheel is in much better shape. I think they are going to sand the contact surface and cut the heads down on the bolts. A jury rig way to fix the problem, but if it gets me on the road I can pursue other options. Since I would have to go back in to replace the flywheel I think I will be looking to upgrade to a 4spd unit.

 

[1962fj40]

Any updates on flywheel thickness by chance? I'm in the same boat and having the clutch disc springs contacting the flywheel bolts.

Robert

 

[cuencanolenny]

Any updates on flywheel thickness by chance? I'm in the same boat and having the clutch disc springs contacting the flywheel bolts.

Robert

This is a very challenging machining job due to the step nature. Conventional blanchard grinding won't work.

 

[cruisermatt]

Any updates on flywheel thickness by chance? I'm in the same boat and having the clutch disc springs contacting the flywheel bolts.

Robert

Are you sure you have the clutch disc installed the correct direction?

 

[1962fj40]

Are you sure you have the clutch disc installed the correct direction?

Yep. You can see pics from the other thread I started. White lettering on right says flywheel side. And if you zoom in just below the top spring you can see it as well. Note the wear marks on the spring and flywheel bolts.

Clutch woes

Tearing the clutch down after release bearing issues. I noticed some cracks on the flywheel and wear marks on the flywheel bolts as well as wear on clutch disc springs. Evidently there is a clearance issue between the two. This is on my 1962 FJ40 F engine with a SM420 conversion. Any ideas what...

forum.ih8mud.com

 

[TheBussman]

Thickness info still needed. I'm working on a columbian truck that's been worked on alot. Flywheel was really rough worst I've seen. took .035 to clean it up. if this is the first time it's ever been machined it should be fine but it's a old truck and may have been machined a few times before or may have had 10 clutches though it. Current measurement is 1.310" thick on the step. If anybody was able to measure their 2f flywheel that would be great.

 

[pb4ugo]

It's a stepped flywheel?

 

[charliemeyer007]

I can't seem to find a spec for minimum thickness - .035 is just a few percent of the total you have. I would put it in and see if it works. I saw 2F remanufactured flywheel for sale $250 with $125 core and shipping too I bet.

 

[pb4ugo]

Idk, if this helps, but it seems credible.

https://ace-mfg.com/wp-content/uploads/2018/05/EZRider-HotSheet-Flywheel101-digital-copy.pdf

 

[TheBussman]

It's a stepped flywheel?

yes

 

[TheBussman]

Idk, if this helps, but it seems credible.

https://ace-mfg.com/wp-content/uploads/2018/05/EZRider-HotSheet-Flywheel101-digital-copy.pdf

thanks for posting, I'll measure from the face to the top of the bolt heads tomorrow.

 

[TheBussman]

I have the 5/16" clearance. Put extra washers under the bolts as a test and clutch springs still don't touch so I'm probably OK with this one.