apexFD

Hey guys,


I got my ACT pro lite machined by a shop in town... after seeing their job i was a little bit disappointed.


I guess during the machining of the lower step they managed to take some material off the ring gear for about 170 degrees of the flywheel?? Now this means the flywheel must have had a high spot, or they didnt mount the flywheel up correctly (which i find hard to do).


So tonight i bought a dial indicator with magnetic base, and i checked the runout on the flywheel after mounting it up to the engine. I torqued down the counter weight bolts in order and to 44ftlbs according to the FSM (auto tranny specs) then i torqued the flywheel nut to about 150ftlbs, just enough so it was tight. The MAX runout on the flywheel was .006", according to the FSM .008" is the max allowable runout. But should the runout be this large after being machined???

I also checked the runout on the pressure plate mounting surface... it is around .006-.007". Both high spots on the disc surface and the pressure plate surface are roughly in the same area as the machined ring gear.. So is my flywheel warped?


As far as i know the step is good all the way around though.


Here are pics:




Thanks in advance.



=Ben

apexFD

Morning bump.


=Ben

Speed of light

iTrader: (8)

I would expect the machining, properly done, to have removed any high spots or warp relative to the reference (crank flange, I assume). It is possible that the crank flange/couterweight mounting itself is off slightly. It only takes a small amount of error at that point to make a big difference at the OD. For comparison, I measured my aluminum FW [on a lathe] and it had a TIR of about 0.002".

The most important aspect is that the FW is flat; otherwise, 0.006 is OK. Don't forget that you must maintain the "step" of the flywheel, so you have to remove the same amount of material from the clutch cover mounting surface as you do from the flywheel surface since they are not in the same plane.

apexFD

Well like i say the guy from the machine shop measured the step right in front of me... I had phoned ACT to get the correct step measurement, i think they sayed +.02" at any case the step measurement was the same as what the ACT guy said on the phone.


Well ill check the counterweight and see what the run out is.


So should i run it is the runout is .006" thought? I would hate to wear out my ACT SS clutch prematurely..


=Ben

Speed of light

iTrader: (8)

I think your runout is okay. It's not enough to hurt the clutch. The main thing you want [for smooth engagement and decent life] is for the the flywheel and pressure plate surfaces to be flat and parallel (not wavy with any hard or high spots). It is likely you corrected for manufacturing tolerances with the machining you have already done to the FW.

I would personally check the clutch cover and clean it up if necessary. They are generally not held to high tolerances and can sometimes benifit from a once over similar to what you did to your flywheel.

apexFD

Well my clutch unit is brand new. That is why i say i would hate to kill my clutch with this flywheel issue.


But ha according to the mazda specs it should be fine, but i am still going to take a bunch more measurements before i put it all back together.


So now that i have my counterweight installed(well roughly, just enough to test the flywheel)... is it bad to take it back off? My engine is still on the stand, i havent run the engine obviously.


Thanks a lot for your help.



=Ben

sculptor

I agree, it should be OK as both flywheel surface and pressure plate mounting surface are essentially parallel (same high spot). It would have been theoretically nicer if they had held tolerance to about 1/2 FSM specs (i.e., around .004). You have probably already done this, but I would check for any burrs or accidental bump marks in the mating surfaces which could prevent a proper matching when torqued down.

If you are worried about warped, place the flywheel on a high quality machinist surface plate and measure flywheel surface for "out of flat".

Eric

Speed of light

iTrader: (8)

You can install and remove the CW as necessary; however, be sure to grease the neck [OD] of the counterweight when installing it (to lube and protect the seal). Before you put the CW on for the final time, you must put sealant on the keyway and taper per the FSM to prevent a leak.

I have attached a couple of photos depicting my near new ACT Extreme clutch. (only had a few miles on it) One pic shows the measured deviation and the other shows how I ground it in a lathe to make both surfaces flat and parallel. It has been well worth the effort. This clutch is silky smooth; no tendency to chatter whatsoever. The mating flywheel had about .003" TIR and I didn't sweat it.

apexFD

Wow that is quite the runout on that pressure plate! .012" in that one spot? Providing that its brand new i guess that is just the norm...


Ok, well ill measure the mating surface for the pressure plate and see how it matches the clutch disc surface.




Thanks for your posts.



=Ben