mphox

I am installing a optima v triple disc 7.25" QM clutch in my C5Z. The bearing is a tri-lite with 1.65 piston/bearing length and I am using a stock f-body flywheel from rock auto. I just bolted up the torque tube to the bellhousing to check the clearance between the t/o bearing and the clutch diaphragm spring. QM recommends .100-.150 in clearance. I have no clearance, the t/o bearing will turn but drags on the diaphragm spring. It appears that the 1.65 bearing is the shortest tri-lite bearing QM makes. Before I mill the stand offs/legs on the the bearing mount I wanted to see if anyone that has installed this clutch has had a similar problem.

I confirmed that QM sent the correct release bearing assy. overall height is 2.80" and 165 appears on the inside of the hydraulic piston.

RAFTRACER

If QuarterMaster knew that you were installing this into a C5, you would have received a tri-lite assy that the legs were already machined .200" I believe. I also think that you need .150-.200 bearing clearance between the bearing and the diaphram spring. Make sure that you torque tube bearing adapter is not making contact with the torque tube embossments for the bolts, this will give false inaccurate clearance measurements. Also better to make these measuements from the bell housing torque tube face to the diaphram face with a striaght edge and depth micrometer as well as the bearing to the torque tube face then subtract the difference.

mphox

When I ordered the clutch I spoke with Dave at QM and he was aware the application was for a C5. I checked the bearing assy. legs and they did not appear to be machined .200. Standard height for 165 bearing assy. is 2.80 according to website and the measured height is 2.80, according to instructions sent with the 165 bearing assy. height should be 2.55. Also bearing clearance should be .100-.150 according to website and .100-.250 according to instructions sent with bearing. I checked the bellhousing/ spring measurement and the torque tube to bearing measurements and currently have -.010 (negative) clearance which confirms the interference when installed. I will call Dave tomorrow to sort out the details.

davidfarmer

I agree with Danny, and absolutely confirm they sent you the right parts. When I built my World Challenge C6 with an 5.5" Optimum-V clutch, they sent the wrong button flywheel (standard LS1 setup, NON Corvette version). I didn't bother to check, because I'd never had any trouble in the past. I torqued everything down and it literally snapped one of the clutch plates in half.

Now I stick with the old standard Pro 5.5, and I know what they look for. Flywheel and bearing adapter are perfect fits!

mphox

I have torqued the flywheel to the to the flexplate/crankshaft and the clutch to the button flywheel and did not have any issues with breaking a clutch plate (disassembled after initial install and torque to check for issues). I am curious if I have an LS6 motor with a f-body flexplate what would be difference between a standard LS1 non corvette version and a corvette version button flywheel?

mphox

Spoke to Dave at QM today the correct assy. height is 2.80. His recommendation was for .140-.180 bearing to diaphragm spring clearance for C5 application. Also indicated that typically .270 needs to be machined off of the legs of the standard 165 bearing assy. In my case (with -.010 interference) I would need to mill .150 to .190 to get proper .140-.180 clearance.

RX-Ben

Are others generally getting the correct clearance with the properly machined slave or is shimming/machining occasionally needed?

Thanks.

redtopz

I installed this clutch about a month ago. I didn't take any measurements, but everything went together fine and I tested the clutch and it worked perfectly. However, I did notice that not all flex plates are the same. I had an aluminum SFI LS1 flexplate from my GTO that I was going to use, but the button flywheel would not bolt up to it flush without using washers as spacers. So I ordered a RCI steel flywheel from Summit and that worked fine. I think the spacing will be dependent on which flywheel you use to some extent.

I just completed my first 2 races with this clutch and it takes some getting used to starting in 1st gear, but the shifting is much quicker and more consistent compared to the stock setup.

mphox

The clearance is recommended for clutch wear. As the clutch wears the diaphragm fingers will move away from the clutch discs toward the bearing. So initially even with little or no bearing to spring clearance the clutch should work fine. There could be an issue with the clutch slipping once it is worn (friction plates become thinner)