I need a source for cross drilled front brake rotors for 4 my lug 1974 porsche 914.


I have thus far only found Zimmerman for 1970 through 1972! but for Cheap= <$50.00! Some one also tried telling me that all 914 brake rotors are the same from 1970 - 1976?

What gives?

"Someone" was pulling your leg. The 73-76 rotors are different; they will not fit correctly on the early struts with early calipers.

Cross-drilling a solid rotor, like the ones on a 914-4, is useless IMHO. Plus it leads to cracking, which lets you throw away the rotor when you notice the crack.

Pelican used to carry the cross-drilled Zimmerman ones; not sure if we still do.

--DD

Now if only someone made a kit for 4-lug vented and cross-drilled or slotted rotors

I have the 4 bolt ALLOY hubs and are using gas slotted rotors that also have had the cold treatment. My shop said the early carrera rotors are also available cross drilled but that is pretty useless unless you are racing in the mud or heavy rain or something (that should start the fur flying). Anways I'd say get a set of them.

QUOTE (Brando @ Jan 10 2006, 06:47 PM)

Now if only someone made a kit for 4-lug vented and cross-drilled or slotted rotors

Like DDD said, a waste of time and money. Cross drilling and/opr slotting provides NO improvement in stopping or cooling. In fact, there are well researched studies out there that prove the opposite is true. The Cap'n

QUOTE (Cap'n Krusty @ Jan 10 2006, 07:28 PM)

QUOTE (Brando @ Jan 10 2006, 06:47 PM) Now if only someone made a kit for 4-lug vented and cross-drilled or slotted rotors  :idea: Like DDD said, a waste of time and money. Cross drilling and/opr slotting provides NO improvement in stopping or cooling. In fact, there are well researched studies out there that prove the opposite is true. The Cap'n

So, no vented 4-lug rotors around because they're a waste of time and money? Compared to a full 5-lug conversion for vented rotors and different calipers?

QUOTE

Cross drilling and/opr slotting provides NO improvement in stopping or cooling. In fact, there are well researched studies out there that prove the opposite is true. The Cap'n

Love to see them


If your looking to run drilled solid discs, please let met know... so Ill be off the road when your driving

WOW!

pretty strong opinions on this subject. Atleast from the contributing members!

Sounds pretty unanymous here!

But I am confused as to why there is a market and a production line of solid brake rotors with the inferred liability?

I seek enlightenment.
Is cross drilling vented rotors o.k. but not solid? If so then why? Aren't vented rotors as... if not more likely to rust and or stress crack if not more so because of decreased wall thickness per side? I see the obvious benefits of Vented rotors over solid cross drilling aside.

But aside from spending several thousand dollars in doing a tire / wheel / brake conversion....etc. to accomodate a vented rotor upgrade.

I pose the question: I have seen some very expensive high performance cars oem w/ cross drilled vented rotors and are the physics and benefits of the vented rotor that different as to make it a benefit in the vented variety and a liability or hazard when solid?

Just playing the devil's advocate here anyone can sing to the choir.

thanks for the input. This site is great!

I've run the drilled, non-vented front discs on my VW Vanagon 4WD / 3.2 911 engine power. It dramatically stopped the 5,000 lb brick much better than the solid discs. However since there is NO where for the hot (braking) gasses to escape from, the discs get very hot -very fast. The discs actually would wear in a "Washboard" pattern-and the brake pads had a mated washboard look as well.
The drilled rotors had a life of 12,000 miles, so they got changed every year, cause they could not be turned/ cleaned up to spec.
Also note that heat can set up cracks between the drilled holes- and that's a situation you don't need

Last year, I ordered a catalog from FVD in Florida,
http://www.fvd-web.com/fvd-usa/

their catalog 'lists' Cross Drilled Brake Rotors for the 914.


One of their guys hangs out (and sponsors) over on 6speedonline.com

I sent this guy an email asking.... "Hey do you guys in fact carry these
rotors for the 914????

He said he'd check on it and came back and said Yes they did.

I said, now you know the 914 is 4-LUG right?
"Yep, we know that".

You could check with them.

I was just wondering if this would be good

It sounds like "No".

Do any production cars use a drilled or slotted solid rotor?

Thanks


KT

QUOTE (Brando @ Jan 10 2006, 08:33 PM)

QUOTE (Cap'n Krusty @ Jan 10 2006, 07:28 PM) QUOTE (Brando @ Jan 10 2006, 06:47 PM) Now if only someone made a kit for 4-lug vented and cross-drilled or slotted rotors  :idea: Like DDD said, a waste of time and money. Cross drilling and/opr slotting provides NO improvement in stopping or cooling. In fact, there are well researched studies out there that prove the opposite is true. The Cap'n So, no vented 4-lug rotors around because they're a waste of time and money? Compared to a full 5-lug conversion for vented rotors and different calipers?

dude...

mueller hubs. allow you to use 911SC or carrera ? rotors with a 4 x 130 wheel. uses stock bearings etc, just allows you to use vented 911 rotors and MAINTAIN F O U R L U G wheels

here you go.....4 lug vented (and drilled if you want or slotted)

billet hubs (see 914 store)


+
(drilled rotor available @ Vertex Auto for $79 plus other places)

I got 4 lug cross-drilled rotors for my car from a company called Troutman in Temecula, Ca. I don't have a number but they sometimes have an add in Excellence. I only use them cause they look cool. My car still looks better than Aarons even with his cheap ass paint job.
Elliot

QUOTE (Mueller @ Jan 10 2006, 11:42 PM)

here you go.....4 lug vented (and drilled if you want or slotted) billet hubs (see 914 store) + (drilled rotor available @ Vertex Auto for $79 plus other places)

Mueller,

I'll start saving...

Mueller,

I know these billet hubs are for the '73 and up models, but what would be the problem if you would try to fit them on an early model?

I ask as I would like to know if they would fit a VW412S (my other car), which uses the same rotors as the early 70-72 914...

Just look at it as maybe a possibility to expand the market for them

Best regards,
Walter

QUOTE (pnewman @ Jan 10 2006, 08:32 PM)

Is cross drilling vented rotors o.k. but not solid? If so then why? Aren't vented rotors as... if not more likely to rust and or stress crack if not more so because of decreased wall thickness per side? I see the obvious benefits of Vented rotors over solid cross drilling aside.

Cross drilling vented rotors at least gives the hot gases from the brake pads somewhere to go. When you drill solid rotors, there's nowhere for it to go. I am surprised that Marty (Maltese Falcon) found the braking distances shorter using solid drilled rotors, but am not surprised to hear of the accelerated (and weird) wear patterns.

Most or all of the cars you see today with cross-drilled rotors actually have the holes cast into the metal from the beginning. This greatly reduces the risk of cracks (though they should still be checked periodically).

Gas-slotting, from what I can tell, has potential benefits without most or any of the risks from cross-drilling. That's true for both solid and vented rotors.

--DD

Thanks for the info Dave. Slotted seems to be a good (reduced cracking possibility solution for improving braking over cross drilled.

Now where can I get some 74 / 4 lug replacements slotted or vented or cross-drilled discs.... with only replacing the rotors themselves: i.e. direct fit?

I contacted Vertex and someone there emailed me stating that they sell only replacement discs.


thanks,

QUOTE (Walter @ Jan 11 2006, 01:50 PM)

Mueller, I know these billet hubs are for the '73 and up models, but what would be the problem if you would try to fit them on an early model? I ask as I would like to know if they would fit a VW412S (my other car), which uses the same rotors as the early 70-72 914... Just look at it as maybe a possibility to expand the market for them Best regards, Walter

not too sure about the early struts, I'm thinking it would just require a 1/8" to 1/4" spacer for the wheel bearings.....if I can get a hold of an early strut and hub I'd be happy to look into it.

QUOTE

Now where can I get some 74 / 4 lug replacements slotted or vented or cross-drilled discs.... with only replacing the rotors themselves: i.e. direct fit?

Like Elliot mentioned, try Troutman for drilled /4 rotors.....I'd be hesitant to run slotted /4 rotors since they are already on the thin side....no one makes a vented /4 rotor that is a direct bolt-on

You might find a machine shop that'll drill (and chamfer !!!) brand new rotors for you. I've seen ads in either magazines or the internet for places that'll do custom drilling of new rotors..not sure if you supply the rotors or if they do. I woudn't do it at my shop due to liabilities.......

QUOTE (pnewman @ Jan 18 2006, 12:36 PM)

Now where can I get some 74 / 4 lug replacements slotted or vented or cross-drilled discs.... with only replacing the rotors themselves: i.e. direct fit?

Vented, you won't get that way. Vented rotors are much thicker than solid, so you will need at the very least to replace your brake calipers with ones built to go over vented rotors.

The front rotors are also a challenge, because the rotor (disk) is a part of the front hub. They're one solid piece of metal, so you replace the whole shebang at one time. Unless you change over to a 911 front suspension, or go with the Magic Billet Hubs (the ones Mueller was referring to).

I don't know of anyone who makes 914-4 rotors with "cross-drilled" holes cast into them.

Any worthwhile machine shop can slot a set of rotors.

--DD

Dave always is well informed...damn...

How about these;

74 Crossed Drilled Zimmermann Rotors