Importance of details & longevity, 8+ seasons Spec 3+
12-11-2015, 08:54 AM
#1
Importance of details & longevity, 8+ seasons Spec 3+ Am not sure exactly how many seasons it's been now, but, @ least 8. Pulled Spec 3+ clutch just to check it (Winter stuff). Clutch has seen multiple road course track days, 2 broken half shafts & street use. Makes in the 480 ft-# TQ range @ the flywheel.
As can be seen in the pics, there is no measurable disk wear. Measures .350", mic reads .352", but, zero on dial indicator was +.002" to start with. There's no burn from slipping the clutch on the flywheel or pressure plate. The wear on the flywheel is @ about .005"; can feel ridge w/ finger. Am sure that there is wear on the PP as well, just haven't measured it.
Proper care was taken on initial install by confirming set up dimensions, cleanliness, PP/flywheel balancing, external bleed line. Also, followed the break in procedure closely. Another benefit being that "The Munster" weighs under 2900# w/ 2 passengers & full tank of fuel. Am careful not to slip the clutch when engaging.
As can be seen in the pics, there is no measurable disk wear. Measures .350", mic reads .352", but, zero on dial indicator was +.002" to start with. There's no burn from slipping the clutch on the flywheel or pressure plate. The wear on the flywheel is @ about .005"; can feel ridge w/ finger. Am sure that there is wear on the PP as well, just haven't measured it.
Proper care was taken on initial install by confirming set up dimensions, cleanliness, PP/flywheel balancing, external bleed line. Also, followed the break in procedure closely. Another benefit being that "The Munster" weighs under 2900# w/ 2 passengers & full tank of fuel. Am careful not to slip the clutch when engaging.
12-13-2015, 11:37 AM
#2
Continuing...
Measured the PP. It is a stepped diameter & measured the total thickness since the step is machined from one piece. Did a quick search & couldn't find Spec 3+ PP thickness spec. Measured 0.740" & am a$$uming that the original thickness was 0.750". This means that the flywheel thickness was worn .005" + .010" on the PP.
Plan to clean up the flywheel some .007". Am not gonna machine the PP surface, but, will take .010" from the PP feet. Will add .017" shim to throwout bearing to make up the difference. Will re-assemble & check it again in another 8 yrs or so.
Having an adjustable master & the ability to add/check fluid through a remote bleeder are important features toward clutch longevity, as are; proper dimensional install, break in & quick engagement (slipping the clutch as little as possible).
Measured the PP. It is a stepped diameter & measured the total thickness since the step is machined from one piece. Did a quick search & couldn't find Spec 3+ PP thickness spec. Measured 0.740" & am a$$uming that the original thickness was 0.750". This means that the flywheel thickness was worn .005" + .010" on the PP.
Plan to clean up the flywheel some .007". Am not gonna machine the PP surface, but, will take .010" from the PP feet. Will add .017" shim to throwout bearing to make up the difference. Will re-assemble & check it again in another 8 yrs or so.
Having an adjustable master & the ability to add/check fluid through a remote bleeder are important features toward clutch longevity, as are; proper dimensional install, break in & quick engagement (slipping the clutch as little as possible).
12-28-2015, 01:37 PM
#4
TECH Senior Member
iTrader: (7)
You must also do a very nice job of heel and toeing when you downshift. A few years back there was a guy that built a 3rd ten RX7 with a LS swap. He did a single track day at Road America and his clutch was toast. He couldn't understand why, but after some questioning it because clear that when he was downshifting he was not rev matching. This obviously put a lot of heat into the clutch and it killed it. As I recall it was a brand new, stockish clutch with an organic disk.
People forget that the #1 enemy of any clutch is heat. If you can keep the heat to a minimum a clutch will last a very long time.
Andrew
People forget that the #1 enemy of any clutch is heat. If you can keep the heat to a minimum a clutch will last a very long time.
Andrew
12-29-2015, 10:45 AM
#5
490 ft/lbs at the flywheel vs Spec Stage 3+ rated to 900+ ft/lbs...big mismatch. Without something to soften the hit of that clutch, OP is going to see very little clutch slip. Mess up a little on the rev-matching, much more likely to find weak links in the drivetrain or break the tires loose.
12-29-2015, 11:09 AM
#6
People also forget that the #1 enemy of the of the rest of the drivetrain is the clutch. A little clutch slip may have saved the OP from two broken half shafts.
490 ft/lbs at the flywheel vs Spec Stage 3+ rated to 900+ ft/lbs...big mismatch. Without something to soften the hit of that clutch, OP is going to see very little clutch slip. Mess up a little on the rev-matching, much more likely to find weak links in the drivetrain or break the tires loose.
490 ft/lbs at the flywheel vs Spec Stage 3+ rated to 900+ ft/lbs...big mismatch. Without something to soften the hit of that clutch, OP is going to see very little clutch slip. Mess up a little on the rev-matching, much more likely to find weak links in the drivetrain or break the tires loose.
Always an internet genius ready to f'ck up a thread meant to help others. Why don't you ask, rather than assume simply to post as someone who thinks he knows what he's talking about?
The half shafts broke the 2 only times the car saw the drag strip. We were invited by a manual shift drag racing group & went for fun. The COBRA 31 spline "super duper" alloy half shafts broke due to the combination of wheel hop & torque @ launch (IRS).
A 3+ was not originally rated for 900 Ft-# & was used for the full face friction plate design because the feel of a puck style plate is terrible, IMO.
The weakest link in our drivetrain was the combo of OEM spec'd ATF & the tiny roller bearing that plugs into the the back end of the input shaft. High RPM driving & ATF lube will wear that bearing down in a hurry. As long as the blocker rings have been upgraded, use a high pressure rated GL4.
I do & will always rev match. Have never broken anything due to rev matching.
12-29-2015, 03:11 PM
#7
Always an internet genius ready to f'ck up a thread meant to help others. Why don't you ask, rather than assume simply to post as someone who thinks he knows what he's talking about?
The half shafts broke the 2 only times the car saw the drag strip. We were invited by a manual shift drag racing group & went for fun. The COBRA 31 spline "super duper" alloy half shafts broke due to the combination of wheel hop & torque @ launch (IRS).
A 3+ was not originally rated for 900 Ft-# & was used for the full face friction plate design because the feel of a puck style plate is terrible, IMO.
The weakest link in our drivetrain was the combo of OEM spec'd ATF & the tiny roller bearing that plugs into the the back end of the input shaft. High RPM driving & ATF lube will wear that bearing down in a hurry. As long as the blocker rings have been upgraded, use a high pressure rated GL4.
I do & will always rev match. Have never broken anything due to rev matching.
The half shafts broke the 2 only times the car saw the drag strip. We were invited by a manual shift drag racing group & went for fun. The COBRA 31 spline "super duper" alloy half shafts broke due to the combination of wheel hop & torque @ launch (IRS).
A 3+ was not originally rated for 900 Ft-# & was used for the full face friction plate design because the feel of a puck style plate is terrible, IMO.
The weakest link in our drivetrain was the combo of OEM spec'd ATF & the tiny roller bearing that plugs into the the back end of the input shaft. High RPM driving & ATF lube will wear that bearing down in a hurry. As long as the blocker rings have been upgraded, use a high pressure rated GL4.
I do & will always rev match. Have never broken anything due to rev matching.
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12-30-2015, 12:47 PM
#8
11 Second Club
Do you wait for a rev match on upshifts? Quick lockup is why your clutch shows little wear, it's also what caused your half shafts to break. Your engine does not make enough torque to break half shafts by itself, it got help from a release of inertia energy that was stored in the rotating assy. The quicker the clutch locks up, the larger the inertia induced torque spike the rest of the drivetrain will see. That small bearing you mentioned sees an intense load spike because of this, as do your half shafts.
