Alternate 240Z rear brakes...?

[JeffYoung]

I'm on the ITAC; we recommended to the CRB that they turn down this request. The reasons are:

1. Ron Earp is a racing buddy of mine; I work on and drive his 260z, and I also know several Z racers very well (Steve Parrish, David Spillman, Jay Miller, Mike Mackaman, etc.). The drums are still available, you can occasionally find an alum one on ebay etc. Steel drums are still available at your local parts counter. Plus, i think there is some discussion about having new ally ones machined.

2. IT class philosophy -- perhaps the strongest one we have -- is that we don't make line item exceptions for IT cars for parts that are NLA, or unsafe, etc. You choose your car and the warts that go with it (and I'm certainly in that boat with an ITS TR8). At some point, some cars naturally age out of IT due to lack of parts (I think RX2/3 rear brake parts are totally gone). At that point, you go vintage or build a newer IT car (I have a 300zx sitting in a shed waiting for the day the 8 can't run anymore).

3. As Kirk indicated that exception for the Calais/etc. is an anamoly. I'm not sure why it is there and it frankly should be removed. It is the ONLY exception like that and totallly contrary to class philosophy.

[LLoughman]

JeffYoung, thanks for sharing the insights on the logic behind this decision. I have been a long time follower of the IT forum and now think it’s time to give some feedback. Having run an ITS 240Z since 1997, about a year ago I noticed the standard aluminum rear drum was no longer available. While true you can find the steel version, there is a performance difference. As mentioned earlier there is an almost 50% weight penalty in rotating mass and the steel drums offer less heat dissipation (steel vs aluminum and cooling fins). Since I have experienced a rear shoe delaminating more than once, I will wait until some other fool runs the steel drums at Blackhawk (brake hawk) or Road America before I risk my fait at one of those venues with steel drums. If anyone has experience with the steel drum configuration at one of these tracks (and can run 1:22 at Blackhawk) please respond. Since we now have a known performance change running the 240Z without the available aluminum drums, what will be done to resolve this issue? Seems that acotyk has a point. Can someone explain the performance advantage of acotyk’s recommendation? Most of the braking (energy to heat transfer) is done by the front of the car and on all the Z cars this is done with a 2 piston caliper on a solid disk rotor up front. By the way using old parts like ebay aluminum drums is one of the reasons for a pedal to the floor failure that I had over the years and should be avoided at all cost.

As for the GM issue with the Olds/GA if JeffYoung’s comments are correct, than a safety issue as mentioned by Z3_GoCar does not make sense. If I recall correctly, the rule that allowed these GM cars to not only change from rear drum to disk but the bearings as well came long after their ITS classification. The argument here is simple, there is already precedence set to allow drum to disk conversions in ITS. I will be posting a notice to the comp board to either revoke the GM disk as stated in their reply to acotyk or to allow the drum to disk swap for the Z car or any other drum brake car. The board needs to be consistent on this “core philosophy” and in this case there is no sing of it.

Thank you acotyk for bringing up this issue.

JeffYoung or any of you other Z drivers, if you know of someone making the aluminum drums please post. By the way doesn’t a custom machined part by a non-oem type manufacturer for brake parts go against the “core philosophy”? Seems like a vintage concept.

If you were a lawyer, you could retire on arguing for/against inconsistent decisions by a governing body!

[Ron Earp]

Seems that acotyk has a point. Can someone explain the performance advantage of acotyk’s recommendation?

The ITAC and/or CRB doesn't have to explain the performance advantage of acotyk's recommendation. As I'm sure you are aware the GCR reads:

"To maintain the stock basis of Improved Touring.....No interchange of parts between assemblies is permitted, and all parts of an assembly shall be as originally produced for that assembly"

Their answer is pretty well spelled out in the introductory rules for Improved Touring.

Unfortunately the rear drums being no longer available forces the Z driver to make some choices. Race the car with available steel drums and accept the lower performance, or quit racing the car in Improved Touring.

I'll be cutting some holes in my backing plates and getting some air on those shoes and drums. I don't have rear brake ducting right now and race fine with the ally drums. I bet I can race fine with the steel drums using ducting.

[GKR_17]

I suspect the drums are cast iron, not steel. Using iron instead of aluminum is not a safety issue. Sure it will run hotter, but iron will take it where aluminum will not. Aluminum is very rarely used in brakes, and for good reason.

If you really want to talk safety I move we ban the stock drums.

[Ron Earp]

I suspect the drums are cast iron, not steel. Using iron instead of aluminum is not a safety issue. Sure it will run hotter, but iron will take it where aluminum will not. Aluminum is very rarely used in brakes, and for good reason.

If you really want to talk safety I move we ban the stock drums.

Yep, I think you're right on the cast iron. Been awhile since I looked though.

Now on the "ally drums" I'm pretty sure that is an ally drum, with fins cast in it, with a steel insert. Carbotechs can handle the heat and I was just talking with those guys a few weeks ago and they have a compound for shoes that can handle even more heat than the previous versions.

I'm not a Z historian but are these ally legal in the first place??? My 260Z shop manual doesn't show drawings of finned drums, but of round drums with no fins. Were the fins added by NIMSO for performance reasons and were they listed as an alternative part number by Datsun/Nissan?

I'm with you though. I'd like to ban the blasted things for selfish "don't want to ever work on a drum brake again" reasons, but I am logical enough to know that isn't something to pursue. Funny how one of my prime motivators for getting a new IT car is to get something that doesn't have drum brakes and carbs.

[dspillrat]

Every 240 I've ever pulled apart, had fins.......

Now I have seen 3 vented rotors as well....vented rotor caps that is.....

Didn't realize the olds came with drums.... I Need a letter penned Jeff...

David

[GKR_17]

I'm with you though. I'd like to ban the blasted things for selfish "don't want to ever work on a drum brake again" reasons, but I am logical enough to know that isn't something to pursue.

I was really kidding, but was trying to say that if safety is the arguement then make them run the iron drums. I vote a big no to the disc swap. Not sure how to handle the Olds, I'd rather it get pulled than be a precident further creep.

[JeffYoung]

Somebody send a letter in....we need to get that Olds exception deleted.

[pballance]

Yep, I think you're right on the cast iron. Been awhile since I looked though.

Now on the "ally drums" I'm pretty sure that is an ally drum, with fins cast in it, with a steel insert. ................

I'm not a Z historian but are these ally legal in the first place??? My 260Z shop manual doesn't show drawings of finned drums, but of round drums with no fins. Were the fins added by NIMSO for performance reasons and were they listed as an alternative part number by Datsun/Nissan?

...............

They were all finned Ron. Aluminum drum with steel insert. They can be re-sleeved if you will. Not cheap but it can be done. I think JohnC at Betamotorsports was looking into that for one of his customers. Also, the new aftermarket's are cast and are without fins.

My drum backing plates are vented and there was evidence of a rear ducting system being attached to the rear control arms at one time. One of the previous owners of my car ran it in enduros on the west coast.

While I agree it would be nice to do away with the drums, as a Z racer I wll argue that it is against the class philosophy and an allowance should not be made. Like Jeff, I have another Z waiting in the wings that actually has discs all the way around

BTW, I will try to get a picture or two up for the Nissan fans. I have a buddy that has a Nissan IMSA GTP in his shop. Pretty neat car.....

[spawpoet]

"My drum backing plates are vented and there was evidence of a rear ducting system being attached to the rear control arms at one time. One of the previous owners of my car ran it in enduros on the west coast."



It was always my understanding that the cast drums were preferred on z's for enduros anyways. I don't know from personal experience, and have no idea if it's true, but the internet lore was always use the alloy drums for auto-x and sprint races, and the cast for the long races because they dealt with extended periods at high temp better.

[Eagle7]

They were all finned Ron. Aluminum drum with steel insert.

If that's the case, then how can a steel aftermarket drum be considered a legal equivalent?

[Knestis]

... If you were a lawyer, you could retire on arguing for/against inconsistent decisions by a governing body!

LMAO. Jeff's a lawyer.

...I will be posting a notice to the comp board to either revoke the GM disk as stated in their reply to acotyk or to allow the drum to disk swap for the Z car or any other drum brake car. ...

Please DO ask that the GM exception be removed. It got poked into the ITCS long before recent efforts to be consistent on this and other issues, so it's time has come and gone.

EDIT - a little more history on the ITCS... The entire IT category suffered from a wicked case of benign neglect between its inception in the mid '80s and about 10 years ago. A lot of things have been fixed since then but this rear brake exception isn't one.

K

[JeffYoung]

L --

No problem on the info. I wish more detail was listed with the decisions in Fastrack.

I run steel drums (came stock so I have to) on the TR8 and I delaminate shoes and burn up wheel cylinders occasionally. I have on the list of things to do (as does Ron) to run ducting to the rear brakes. We have a very brake intensive track here (CMP -- I'll put it up against any track in the US for being hard on brakes) and we survive.

So, I think there are ways around this other than allowing alternate rear brakes. As you can see, the one time this was done (incorrectly) for the Olds, it opened a can of worms that could really do damage to the core philosophy of IT. It is critical, in my view, that we toe the line and not allow "safety" or "NLA" issues to cause us to allow alternate parts. If we start with that, THAT is the path to production and/or AS, etc.

If you write a request to have the Olds rear brake/hub allowance rescinded, I will support that 100%.

If you have any other questions, let me know, and thanks again for the polite and considered post. It is appreciated.

Jeff

JeffYoung, thanks for sharing the insights on the logic behind this decision. I have been a long time follower of the IT forum and now think it’s time to give some feedback. Having run an ITS 240Z since 1997, about a year ago I noticed the standard aluminum rear drum was no longer available. While true you can find the steel version, there is a performance difference. As mentioned earlier there is an almost 50% weight penalty in rotating mass and the steel drums offer less heat dissipation (steel vs aluminum and cooling fins). Since I have experienced a rear shoe delaminating more than once, I will wait until some other fool runs the steel drums at Blackhawk (brake hawk) or Road America before I risk my fait at one of those venues with steel drums. If anyone has experience with the steel drum configuration at one of these tracks (and can run 1:22 at Blackhawk) please respond. Since we now have a known performance change running the 240Z without the available aluminum drums, what will be done to resolve this issue? Seems that acotyk has a point. Can someone explain the performance advantage of acotyk’s recommendation? Most of the braking (energy to heat transfer) is done by the front of the car and on all the Z cars this is done with a 2 piston caliper on a solid disk rotor up front. By the way using old parts like ebay aluminum drums is one of the reasons for a pedal to the floor failure that I had over the years and should be avoided at all cost.

As for the GM issue with the Olds/GA if JeffYoung’s comments are correct, than a safety issue as mentioned by Z3_GoCar does not make sense. If I recall correctly, the rule that allowed these GM cars to not only change from rear drum to disk but the bearings as well came long after their ITS classification. The argument here is simple, there is already precedence set to allow drum to disk conversions in ITS. I will be posting a notice to the comp board to either revoke the GM disk as stated in their reply to acotyk or to allow the drum to disk swap for the Z car or any other drum brake car. The board needs to be consistent on this “core philosophy” and in this case there is no sing of it.

Thank you acotyk for bringing up this issue.

JeffYoung or any of you other Z drivers, if you know of someone making the aluminum drums please post. By the way doesn’t a custom machined part by a non-oem type manufacturer for brake parts go against the “core philosophy”? Seems like a vintage concept.

If you were a lawyer, you could retire on arguing for/against inconsistent decisions by a governing body!

[Xian]

While true you can find the steel version, there is a performance difference. As mentioned earlier there is an almost 50% weight penalty in rotating mass and the steel drums offer less heat dissipation (steel vs aluminum and cooling fins). Since I have experienced a rear shoe delaminating more than once,

OK, so steel drums are bad b/c of less heat dissipation. Nevermind that I'm sure you could have custom shoes whipped up that would work at the higher heat but I follow your train of thought.

Most of the braking (energy to heat transfer) is done by the front of the car

Uhhhh... so how much heat can the rear be making?

Christian, who races a car with rear drums and will beat the "horses for courses" drum some other time.

[JLawton]

I will be posting a notice to the comp board to either revoke the GM disk as stated in their reply to acotyk

Man, that's REALLY gonna piss off all those Achieva racers............




.

[John Herman]

Man, that's REALLY gonna piss off all those Achieva racers............




.

And the Calais drivers. BTW, this was a carryover from the late SS days, not an IT "derived" rule.

[Eagle7]

And the Calais drivers.

So when are you going to dust that thing off and drive it?

[John Herman]

So when are you going to dust that thing off and drive it?

Once I get just a little bit farther in this school thing which has forced me into retirement, I hope to get back out there. Hopefully, maybe, I'll get it out to Grattan to do a couple of test days this summer, but I still need to but the engine back together.

[Eagle7]

...Hopefully, maybe, I'll get it out to Grattan to do a couple of test days this summer, but I still need to but the engine back together.

Wohoo! I'll try not to hit you.

[Steve Barth]

I have been racing 240Z's since 1990 and have owned them even longer. The aluminum finned drum brakes are shown/pictured in several places in the original shop manual, they are also noted in the factory sales brochures I have. They are original equipment. Since the factory aluminum units are no longer available I feel changing over to the later 280ZX rear disc would be ok. Yes, I know it pushes the upadate back date rule. But SCCA "let the horse out of the barn" twenty years ago when they allowed the General Motors guys to change over from rear drums and bearings and axle assembly on the Olds Calais and Acheivea to disc. So a precedent has been set. I do not want to reverse that decision because it would take out many needed competitors and participatants in the club. I we should look forward and as any of these vehicles age and parts are no longer avaliable. I feel an update is neccessary to keep grassroots motorsports alive and going forward.
Thanks
Steve Barth Ann Arbor,Mi - Detroit/GreatLakes Region
ITS Datsun 240Z