Clutch :-(

[WVZR-1]

I would be inclined to call ARP as was suggested rather than just use the mentioned ARP product for converter. You should tell them "flywheel" and it would be good to have flywheel thickness available to pass on to them. Judging from images the ARP product mentioned has a very short shoulder and looses most/some of that with the use of the washer. I would think the desired fastener should have a shoulder that nearly matches the thickness of the flywheel or at least more than that offered by a converter bolt. ARP flywheel bolts do seem to have more shoulder but not near flywheel thickness.

ARP does a 7/16-20 ring gear bolt that is 1.20 under head for Strange rear axles. I'd ask them the details of their 250-3001 product maybe. I don't know that this Summit image is correct but you might look. It's also a 200,000 psi bolt ARP spec.

http://www.summitracing.com/parts/ar...FbTm7Aod_UsATA

There should be many sources for satisfactory product but I'd be inclined to use "branded product" from reliable sources. The finish of the bolt should also be considered.

Daniel - If you've got the 9th bolt you might confirm the shoulder length.

[A26B]

FLYWHEEL BOLTS

Cautionary advice: The LT5 crankshaft flywheel hub is blind tapped. Make sure the under head length is not too long or the bolt can "bottom out" before the full clamping force is applied to the flywheel.

Before installing the flywheel, I recommend:
1.cleaning the tapped hole out thoroughly to remove contaminants
2. install the new flywheel bolt by hand until it stops. Do not oil the threads.
3. measure the space under the bolt head/washer & crankshaft insure that the space is at minimum, 0.100" less than the flywheel thickness.
4. Use Loctite 262 or equivalent when installing the flywheel

We stock ARP flywheel bots and sell them by the set of 8. They are properly sized for the 3 different aluminum flywheels that we stock for the LT5. Offhand, I am not sure how our aluminum flywheel flange thickness compares with other brands.

You will note that hardened washers are furnished with the bolts and are recommended for aluminum flywheels.

http://jerrysgaskets.com/store2/root...roducts_id=877

PRESSURE PLATE BOLTS

A good read on the subject:
http://www.zr1.net/forum/showthread.php?t=8306

[WVZR-1]

Originally Posted by A26B

FLYWHEEL BOLTS

Cautionary advice: The LT5 crankshaft flywheel hub is blind tapped. Make sure the under head length is not too long or the bolt can "bottom out" before the full clamping force is applied to the flywheel.

Before installing the flywheel, I recommend:
1.cleaning the tapped hole out thoroughly to remove contaminants
2. install the new flywheel bolt by hand until it stops. Do not oil the threads.
3. measure the space under the bolt head/washer & crankshaft insure that the space is at minimum, 0.100" less than the flywheel thickness.
4. Use Loctite 262 or equivalent when installing the flywheel

We stock ARP flywheel bots and sell them by the set of 8. They are properly sized for the 3 different aluminum flywheels that we stock for the LT5. Offhand, I am not sure how our aluminum flywheel flange thickness compares with other brands.

You will note that hardened washers are furnished with the bolts and are recommended for aluminum flywheels.

Jerry,

What is the depth of the bore on the threaded flange on the crankshaft hub? I had never considered the after-market flywheels but I did like the possibilities of the Strange ring gear bolts if I did consider one. Your steel SMF flywheel is how thick at the crankshaft mounting flange?

[c4koh]

Jerry -

Thanks for that advice, appreciated.

There seems to be many opinions on bolts - whether to re-use, or use new, which kinds, lengths and so on... I think I have what I need all sorted in my mind at least :-)

Last but not least - I was planning to loctite red (262) the FW bolts, and loctite blue (242) the pressure plate bolts. I may have messed that up too lol.

Anyway - all good fun, and part of the enjoyment of the ZR1. No pain, no gain, right?

[Daniel_Mc]

c4koh,

The ARP bolts I mentioned are specific for the Fidanza single mass FW. That is why they are shorter.

-Daniel

[A26B]

Originally Posted by WVZR-1

Jerry,

What is the depth of the bore on the threaded flange on the crankshaft hub?

Effective, threaded depth = 1-5/16" (1.312") on the single crankshaft checked (4 bolt holes checked). I would recommend staying 0.100" off bottom, which still leaves plenty of thread engagement.

I had never considered the after-market flywheels but I did like the possibilities of the Strange ring gear bolts if I did consider one. Your steel SMF flywheel is how thick at the crankshaft mounting flange?

I do not have any steel billet flywheels in stock, although we can get them from RAM. Assuming they are dimensionally the same as our aluminum billet flywheels, the thickness of the flange under the bolt/washer is appx 0.387". The flywheel total flange thickness is appx 0.583" thick. The difference is the counterbore depth of the bolt holes (appx 0.196" deep)

If you are referring to the iron SMF I have in the webstore, the flange is 0.432" thick with no counterbore for the bolt hole.

I think another important consideration in comparison of different bolts, i.e. Grade 8 and ARP for example, is the threading method, cut vs rolled. There is a significant difference in fatigue resistance in favor of rolled threads.

[WVZR-1]

Originally Posted by A26B

I think another important consideration in comparison of different bolts, i.e. Grade 8 and ARP for example, is the threading method, cut vs rolled. There is a significant difference in fatigue resistance in favor of rolled threads.

Yes there's a dramatic difference in threaded integrity "rolled vs. cut". That is often overlooked by many when buying hardware. Curious about the counter-bore in the flywheels. Is there a reason? It seems that many of the ring gear bolts with something near 1" UHL might be a good fit for the thinner thickness at the flange. I would guess only the OD of the washer would be of concern.

Some of the flywheels without the counter-bore then the Strange bolts look like a good choice. The only exception could be is that if the bore of the flywheel is done to only match the major diameter of the rolled threads and NOT the shoulder. You might just try a conventional 7/16-20 bolt with a shoulder and try it for fit.

Bolt choice I guess is dictated by the flywheel choice.

[rkreigh]

OP

I feel your pain, my clutch exploded after 1500 miles on the first burnout and I'm kinda wimpy on my burn out compared to most

about 1/3 of a mcleod disk roached and came off

drove it all the way back from BG that way

the broken burn clutch material stinks like nothing else and it took a long time for that smell to go away

I'm interested in the RAM dual disk, Bob G turned me onto it, and now local folks are stepping up

still has the gear rattle, I'm saving my old dual mass as that rattle is really starting to annoy me more and more

the car has so much power already, the fidanza really isn't worth that much to put up with the "rox anne rox anne, your tranny sounds like gravel rattling in a can"

I've caught more than a few laughs, hey dude, your engine spun a rod bearing

sheesh..........

[HIZNHRZ]

Seem like a lot of this going around:


Pretty much the same story, less than a handful of 7K RPM shifts on a brand new Carolina Clutch kit and BOOM! I now have a Marc Haibeck RAM push type clutch setup modified for use with my factory dual mass flywheel.

[c4koh]

Originally Posted by HIZNHRZ

Seem like a lot of this going around:



... less than a handful of 7K RPM shifts on a brand new Carolina Clutch kit and BOOM! ...

That picture looks like the Stage 1 / Stock (which is what I had) from Carolina Clutch - correct??

Tom @ CC explained that my original dual mass flywheel may not have been damping well enough, due to age and wear, which on a high-rev shift basically can put far too much through the clutch disk, and as can be seen it's a very thin piece of backing plate, and there's no spring dampening any chatter, so I can imagine that it's fairly sensitive... From my "simple" point of view, that Stage 1 clutch seems fairly brittle without any dampening springs... does that make sense?

Given the high revving and high mass of that original DM flywheel, it's done a lot of work over its 61,000 miles and 22 years of service... so if that internal dampening isn't working as well (not that I could hear / feel any issue), perhaps there was just too much deviation from spec, passing too much on to the clutch disk, and boom...

Good to at least write down potential causes for the failure - if anything I've learned poring through the forums, the more we write the better and more useful it is!

So - moral of this story is probably replace that original dual mass flywheel if car is 22 years old & 61K original miles while doing the clutch! Of course, it can be replaced by a new DM flywheel (expensive, and 35-36lb or so), a steel single mass (24lb or so) or lightweight single mass (14-15lb or so)...

And now in hindsight, lots of folks (not just on Corvette sites) discuss changing a dual mass flywheel in tandem with a clutch... hmmmm... perhaps every second change... I wonder....

Anyway, for me, I didn't replace the flywheel through reliance on past experience... on my prior 91 ZR1, I replaced the clutch with a LUK 04-114 in 2004, being then a 13 year old vehicle and 45K miles at that time... had no problems with that setup with the original flywheel remaining... so, I thought, I'd be fine with the same (clutch kit only - retain original flywheel) for my 92...


Anyway, live and learn ...