In the process of restoring my 914/6, I want to have vented rear rotors, mostly because I'm going to have a big engine, but also because I think it's kinda cool.
The stash of parts I bought from Jon Lowe contained some rebuilt original 914/6 rear calipers.
It also contained some good condition 911 front calipers "A" calipers I think: 3 inch bolt spacing, steel, and with a spacer. They had 48 mm pistons.
To build rear calipers that have a spacer, there is one recipe that uses the spacers from the rear of 911 mid-year calipers, as well as other hardware. Those spacers are 10 mm. I don,t have such calipers and initial attempts at getting some were unfruitlful.
So, I took the spacers from the front calipers that I have, but they're 7.5 mm thick.
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I figured it might be easier to simply add a second thin spacer, rather than build a thicker one. Not sure it's going to be the final solution, but I had the thin stock handy. This is really a test piece:
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and:
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A calipers are 3.5" spacing (and made of steel).
If you have 3" spacing calipers that are on vented rotors they are probably M-calipers.
and bolted up.
As far as I'm able to measure, the two spacers clamped together end up being 10.3 mm thick. Close enough.
I still need to find some 7mm bolts that are 70 mm long. There's a good hardware store that I use, in town, but they did'nt have any in stock. Apparently they can get me some, in socket head format.
Also, the spacers have 8mm holes in them, but the 914-6 rear caliper uses 7 mm hardware, as noted above. Does anybody know the hole size in the spacers for the mid-year rear 911 calipers ?
Couple more things I will need will be the little rubber O-rings and the retainer spring.
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Finally I'll need to turn some longer pad retaining pins. It's a very simple turning and should not be a problem.
Not sure what I'll end up doing. Stay tuned.
Michel Richard
QUOTE (fiid @ Jan 15 2006, 06:41 PM) |
A calipers are 3.5" spacing (and made of steel). If you have 3" spacing calipers that are on vented rotors they are probably M-calipers. |
Michel...
Just do it right...
Rear 911 calipers are a dime a dozen. Years 70-84 oughta do the trick (not too many years to choose from). 6 o-rings per caliper? Hours fiddling with 2.8mm spacers? You should be able to find a core set for $50-70 bucks... what's your time worth? Also, 7mm hardware will be difficult (unless you get the $50.00 core 911 rear brakes, in which you can use that hardware and it's a perfect match to the hardware that was on your $1000.00 calipers!), so now your talking hardware store hardware for 914-6/GT calipers?
This is a serious car your putting together, those are some of the most sought after brakes in 914dom. I'd hate to see you move forward with that concoction, especially on something as important as 'brakes'. Please someone, send this man some toasted rear M-Calipers.
(sorry... I hope I don't offend. It's just my $0.02 and sometimes I don't know when to shut up)
E.
Forgot...
QUOTE |
Does anybody know the hole size in the spacers for the mid-year rear 911 calipers ? |
QUOTE |
Couple more things I will need will be the little rubber O-rings and the retainer spring. |
QUOTE |
Not sure what I'll end up doing. Stay tuned. |
Amen
Eric,
okay, okay, I'll do it right. I got your point, and you're correct.
Michel
Michel
I think I have the spacers and pins you need. I will check in the tomorrow. Send me an email of evrything you need though.
Brian,
Email sent.
Cheers
Has anyone ever checked to see if the parts from a Ferrari 308 would work? They are suppose to be the same caliper from ATE.
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As I understand it, it's the Ferrari guys who come and raid our calipers and parts, not the other way around. Ferrari parts are even more expensive than ours.
Yeah Michel!!
Yeah Brian!!
You probably don't have the pins, they have to be custom made with the one large pin diameter (one pair may work). Spacers and hardware would be the ticket, also, the 911 pad springs will also be needed.
Paul,
Those are the exact same caliper with one difference, the bleeders are 180 degrees oppositie the 914-6/GT caliper.
Eric,
Did all 911 rear calipers, in 1976, have the spacer ? i.e. did all 911s have ventred rear rotors ?
Because I just bid on a pair on ebay and I could'nt tell in the picture. Did not reach reserve, but I'll still try to buy them.
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1,1&item=8028873146&sspagename=STRK%3AMEDW%3AIT
Michel
Those are exactly what you need.
Yes, they have the 10mm spacers.
So where did you find 11.5 grade m7 hardware? I searched and searched, but couldn't find any.
This place list 7mm hardware
http://www.aaronsmetricscrews.com/default.htm
QUOTE (9146986 @ Jan 16 2006, 11:30 AM) |
So where did you find 11.5 grade m7 hardware? I searched and searched, but couldn't find any. |
Michel,
I found the spacers,pins, and bolts I have. They are 14mm spacers. Let me know if you still want them.
..
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Hmm, 14mm spacers would work for the later 24mm vented rotors.
I have a 914/6 coversion which has the 911 vented calipers in the rear. I got a set of spacers a long time ago from Stephens Maching that allowed the use of the stock 914 rear caliper.
When using the 911 vented caliper you will also have to turn down the diameter of the disc to fit the caliper regardless of which you use.
If you can get those m7 in a socket head, which is a hex socket head, that's cool too, probably better. I'd be good for a few sets of 8.
QUOTE (9146986 @ Jan 16 2006, 05:47 PM) |
If you can get those m7 in a socket head, which is a hex socket head, that's cool too, probably better. I'd be good for a few sets of 8. |
Ok,
I decided to do something a little productive. I was thinking about Eric a couple of times while doing this.
I decided to turn some pad retaining pins. I got one done. I find it's very difficult to take a picture of a piece spinning in a lathe, but here it is.
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Please be gentle with me if you're going to critique my machining technique. All I know is it results in a pin. Longer just-machined pin next to stock one. Small transverse hole still to be drilled.
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Brian,
Thank you for looking.
I will try to find the proper 10 mm spacers first. But please keep in touch.
Cheers,
Michel
QUOTE |
Please be gentle with me if you're going to critique my machining technique. |
QUOTE |
Brian, Thank you for looking. I will try to find the proper 10 mm spacers first. But please keep in touch. Cheers, Michel |
Michel,
Jimmy Wilkerson made the spacers for my calipers. I believe he still have complete sets of spacers for 914-6 calipers as well as 914-4 calipers.
His e-mail address is Gemi283@webtv.net
Two things,
1) The hardware store called and they say they can't get any 7mm socket head bolts, any length. I asked if they could get Torx head, or other similar, and apparently not. Oh well.,
2) finished making the pins:
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And this is how they will look when installed. Eric, the additional 2.8 mm spacers are there only for mock-up purposes. I will get proper 10 mm spacers.
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QUOTE (rickyhgarcia @ Jan 16 2006, 08:32 PM) |
Michel, Jimmy Wilkerson made the spacers for my calipers. I believe he still have complete sets of spacers for 914-6 calipers as well as 914-4 calipers. His e-mail address is Gemi283@webtv.net |
why don't you just order one of Eric's kits?
QUOTE (Jeroen @ Jan 17 2006, 07:33 PM) |
why don't you just order one of Eric's kits? |
really? is putting vented rotors on /6 calipers different than /4's? dont wanna hear that.
Some 911 caliper bolts are available from Porsche. I guess I'd look at sourcing the next size OEM, and drilling and tapping.
I've done a ton of research into the 308/914-6 caliper connection. Let me know if you have any questions regarding that.
Nice pins, BTW.
McMaster car sells M7 bolts, if that helps.
Just looked at the McMaster Carr website. They do have 7mm hardware, but not socket head cap screws, at all, and not standard hex head in anything above 50 mm.
It looks like the closest they have is 8mm by 70mm. That would probably mean drilling the bolt holes in the caliper oversisze, and I don't want to do that to my unobtanium 914/6 calipers unless there is zero other choice.
The other alternative is to use the hardware off of core 911 calipers.
Michel
I've been working on both conversions for about 6 years. Pins and spacers are different between the /4 and /6 calipers. Bolts are only available from core 911 calipers or if I have them custom made in the UK. Well, okay, I could get them made here for $14 each (minimum 50). They are grade 9.8, and the only others I could find were grade 8, and half the tensile strength. If there is sufficient interest I could place the order for the 100 minimum in the UK.
CODE |
why don't you just order one of Eric's kits? |
QUOTE |
I guess I'd look at sourcing the next size OEM, and drilling and tapping. |
I agree with Eric. Find some junk 911 rear calipers. I've stripped about 10 calipers so far. Perhaps someone in California can raid a yard or two for us. Not too many left to raid in Utah or Ontario. Give Eric and myself a note if you can help.
I phoned Parts Heaven and talked to Jeff. He agreed to take core calipers apart and to ship just the spacers and the bolts. US$ 40 !
I'll report when they arrive.
I then use regular 911 rear vented rotors, right ? If memory serves, the only thing that might happen is the need to turn down the outer diameter a couple of mm.
If all works out well in that area, the plan is to get spreader springs, the rotor spacers and longer studs from Eric.
Turn the 911 rear rotor down to 286mm from 290mm.
I know it is not much but the extra weight and unused surface is detrimental. Also provides the needed clearance.
I figured out that the pins that I made with the bosses were not ideal.
It looks like part of the job of those pins is to help center the spreader spring. So I turned another pair with a shorter mid-section.
Here's a picture of an orginal short pin (bottom) my first attempt (middle) and this morning's style of pin. This morning, I made the bosses longer and the mid-part the same length as on the original.
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And here's what the new pin looks like in the caliper. Once more, the spacers betwen the caliper halves in this picture are for mock-up purposes only.
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Got my spacers and bolts from Parts Heaven, and I'm pretty happy.
Here's what I got, four of these spacers, and eight bolts:
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And the calipers, assembled.
I still need to get the seals and new spreader springs from Eric Shea, but this is beginning to look like proper calipers. Note that the bolts are the appropriate length,
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Here is how I utilized 914-6 calipers with 911 caliper spacers and vented rear rotors. In addition to splitting the calipers and 911 caliper spacers, I used a spacer between the caliper mounting bolts. I also wanted to use the stock dust shields so a spacer was fabbed between the dust shield and mounting bracket. DH
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Way ta go Michel
Kargeek (sorry no name in the sig)... I'm shocked that a spaced -6 caliper doesn't hit the arm with those spacers on the caliper ears. 914 calipers are usually so tight that customers have to take off the 10mm rear adjuster cap just to get the caliper to mount...
[QUOTE]Kargeek (sorry no name in the sig)... I'm shocked that a spaced -6 caliper doesn't hit the arm with those spacers on the caliper ears. 914 calipers are usually so tight that customers have to take off the 10mm rear adjuster cap just to get the caliper to mount...
Eric, I did this conversion 18 years ago with NOS 6 calipers, swapmeet 911 calipers for spacers and a local porsche shop supplied me the mounting spacers. I don't remember a problem with clearance...I haven't had the car apart since. Dave Hall-aka, Kargeek.
Dave... amazing. I can see the picture so I'z gots ta believe it.
QUOTE (Kargeek @ Jan 31 2006, 07:55 PM) |
Eric, I did this conversion 18 years ago with NOS 6 calipers, swapmeet 911 calipers for spacers and a local porsche shop supplied me the mounting spacers. I don't remember a problem with clearance...I haven't had the car apart since. Dave Hall-aka, Kargeek. |
Michel,
Check EricĀ“s work on my set of 914-6 GT rear calipers:
http://www.914world.com/bbs2/index.php?showtopic=52486&st=0&gopid=690080entry690080
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