240,260,280Z drum brakes

[DatsunDoc]

It becomes a safety issue when you can't buy new ones.

[John Coffey]

As long as you can find used ones that are not at their wear limit, you still have a supply. I've probably got 20 on a shelf here in the shop.

[jmortensen]

As long as you can find used ones that are not at their wear limit, you still have a supply. I've probably got 20 on a shelf here in the shop.

There are also other options to source drums that fit. 510 iron drums fit, and I think it's Triumph TR4 (could be wrong on the model here) guys who were stealing the aluminum drums for less unsprung weight, so whatever model it was, their iron drums should also fit.

You can make an argument for being able to change them out, but I don't think safety is going to be the main point of that argument.

[gira]

Gees guys, I thought you were on the same team as I. You act like Mazda guys for heavens sake. Thanks Datsun Doc for understanding. The issue is we continue to have them crack under stress, can't turn them, aren't supposed to use parts from other cars, the supply is finite, and we're the only IT cars with those crap rear brakes. Why do you think they changed them for EP? I really would have thought I'd have a more favorable response from other racers that would like to go a long enduro without changing shoes. Try it hot and see how long you sit on pit road. I am not saying they don't work! They simply aren't as good as what we compete against. Lot's of us don't have a huge supply of used drums on the shelf, and we have to agree the supply is finite unless somebody ponies up and builds a batch. I ain't gonna use steel as that is a performance disadvantage.

Greg Ira

[jmortensen]

Gees guys, I thought you were on the same team as I. You act like Mazda guys for heavens sake. Thanks Datsun Doc for understanding. The issue is we continue to have them crack under stress, can't turn them, aren't supposed to use parts from other cars, the supply is finite, and we're the only IT cars with those crap rear brakes. Why do you think they changed them for EP? I really would have thought I'd have a more favorable response from other racers that would like to go a long enduro without changing shoes. Try it hot and see how long you sit on pit road. I am not saying they don't work! They simply aren't as good as what we compete against. Lot's of us don't have a huge supply of used drums on the shelf, and we have to agree the supply is finite unless somebody ponies up and builds a batch. I ain't gonna use steel as that is a performance disadvantage.

I'm on the team where when you see something that doesn't make sense, you say "Hey, that doesn't make sense." It may be that we're not on the same team. If Mazda guys use arguments that make sense, then I'm on that team. ;-)

I don't race in IT and I have rear disk brakes on my car. It's pretty tough to argue that the rear drums aren't safe after 40 years of continuous track time though. I agree 100% with the bolded part of your last statement, but saying that is a lot different than saying that the rear drums aren't safe.

FWIW, there was some debate about the steel vs aluminum a while back. I never paid much attention as I don't run drums, but I think the idea was that some Z racers were going to iron drums because they stayed rounder under extreme conditions, and that was more advantageous than reducing unsprung weight by running the aluminum drums. Like I said though, I didn't pay that much attention so you'd have to dig around to find more info than that if you're so inclined...

[WingZr0]

Plain and simple, if your allowed to mod an engine to go faster than the brakes will

allow to stop then you should be allowed to mod or replace the brakes.

Gutting a car alone already means you going faster than factory and everyone

knows stock brakes ain't made for the race track.

Stock brakes should only be used on cars maintaining a certian amount of stock

performance, speed wise.

Notice, very important, speed wise.

So they should go ahead and change the rules at least for one year to see how the

entriants compete when allowed a certain level of said amount of brake upgrades.

It's a safety issue of course and on top of that a legal one when it flies in the face of

NEGLECT !

As in a neglect to listen to legitimate concerns from the racers on the course.

~Z~

BTW way Greg, nice layout in the Grass Roots Motorsports issue

I bought it in downtown Sacramento after photocopying Dean Nakatsu's and figured

it was you from the club while reading.

Great Job on those!

~Z~

Edited August 19, 2009 by WingZr0

[DatsunDoc]

I race in vintage (CP) and it's actually even worse than IT on brakes. The car is faster down the straights and you have to slow more for the corners since the tires aren't as good. Turning drums and rotors isn't an option IMO. You can't afford the reduction in mass and they crack. Aluminum helps dissipate the heat better than solid iron drums. That's why they designed them that way. The lack of new drums is very disappointing to hear.

Mike Unger

[John Coffey]

Gees guys, I thought you were on the same team as I.

I'm on the same team but that doesn't mean I have to agree with you. :-)

I've run IT sprint races and 3 hour enduros and never encountered a cracked rear drum. Lots of cracked front rotors but the rear drums have never really been an issue. I do know other Z racers who have cracked the lining of the drum but they've admitted to turning the drum beyond the minimum stamped on it before the event.

Maybe the tracks and driver's here on the west coast are easier on brakes, maybe we run different shoe material, I don't know. You do know that a complete rear drum, shoes, backing plate, springs, wheel cylinder, etc. weighs in at 12lbs. 9.3 oz. right? You're not going to beat that with any disc brake install. And yes I've make a shoe change during a mandatory 10 minute enduro pit stop. Its hot but it can be done by two people if they practice, the drums are modified with two 1" holes to access the adjuster, and the adjuster linkage is modified.

Also, having been on a vintage racing comp committee and dealing with Porsche guys crying "SAFETY" whenever they wanted a mod makes me very skeptical of anyone making a safety claim as part of a rules change.

So, yes we're on the same team and no I don't think the rule needs to be changed for IT.

[gira]

My last post about this I hope. This isn't tiddlywinks or farting around on a trackday. The last 12 hour enduro I did was 10/10ths the entire time. This is as hot a competition as you can get in my opinion. Again, I don't believe the overall stopping distance will decrease, so laptimes in cool brake qualifying won't change.

Finite supply breeds used service limits and perhaps that's why ours have cracked. It still isn't getting better as time goes by. We run a typical green Carbotech shoe which I an certain many WestCoast guys run and yes, we push the brake pedal the same as you surfer dudes.

I was unaware of the weight of the drum assembly and frankly don't care because the problem still remains.

10 minute pitstop mandatory?? We don't have those. My team can do a hot shoe change in 10 minutes, infortunately that's 8 minutes longer on pit road than I'd like or have to stay. We are also able to go to the 6 hour mark in a 12 or 24 hour enduro.

OK since these drums are all over the place- WHERE CAN I BUY SOME? NOT STEEL!

Greg Ira

[John Coffey]

Enduros should be under a different rule set then IT IMHO. Here in Cal Club they have supplemental rules for any of the Enduro events and its far easier to get a rule change there then in the national level IT rule set. Maybe that's where you should make your first effort at a competition adjustment. After a couple years you can use that as backup for your proposed national rule change.

New aluminum drums are NLA as has been said here. Used drums are on every S30 and you just need to start harvesting and stacking them on a shelf. Another alternative is having the used drum surfaces built up using a plasma spray. That will also let you add a high Manganese steel which will wear better and provide more friction.

[jmortensen]

Possible source for circumferentially finned aluminum drums for Z cars. I figure if the Triumph guys were using Z drums, the Z should be able to use the Triumph drums. Looks relatively expensive but if legal might be an advantage in heat dissipation.

http://www.racemettleltd.co.uk/drum.html

Edited February 4, 2010 by jmortensen

[Zedyone_kenobi]

I was reading this again and noticed that it was mentioned you cannot turn the factory drums. I just had my aluminum drums turned, They came in at 9.015" and 9.005" when the allowable ID is 9.055"

Should I be concerned. My car is currently used for only street driving, but I am taking it to a track day in March and want to start autocrossing it.