5-lug upgrade: which parts needed?

Dennis Marer · 01-10-1999, 12:05 AM

It appears that many/most of the front suspension parts are identical between the 914 and 911. I'm not sure about the A-arms or tie rod connections - would the 911 "hub" assembly fit onto a 914 A-arm?

(What is that thing called, anyway?)

Just wondering what the minimum parts you'd need to swap out to get the 5-lugs and better braking. Thanks!

dman007 · 01-10-1999, 06:13 AM

You will probably get better and more detailed answers from someone else but I will tell you what I know.

If you are trying to go the cheapest way you can, you just take the stock 914 rotors and have them redrilled for 5 bolt. You probably have more people doing this way than anything. It is my understanding that this is an OK way to go. If you want to spend more and can find a front 911 suspension, it will bolt right in. You might want to check with Wayne to see what he has. If that does not pan out, I have seen all of the items mentioned about for sale used on the internet. You can also find 914-6 rear hubs(5 bolt), rotors, etc. for sale on the net.

As far as braking goes, a very popular brake upgrade is going with BMW 320i calipers. I believe Wayne has a tech article on just how to do this upgrade. You should also go with a larger 19mm master cylinder at the same time. I hope this is helpful.

halbl · 01-10-1999, 07:59 AM

There is a complete Tech article on this subject elsewhere on this site, complete with pictures. Pelican sells the parts and has the machine shop to permorm the modifications.

Dennis Marer · 01-10-1999, 11:26 AM

I've read the tech article on upgrading to 5-lug, and know all the options. I would like to pursue the conversion to a 911 suspension, so let me re-ask my question:

It appears (at least from pictures) that many of the suspension parts are identical - hence, not all of them would need to replaced if a swap were done. For example - is the A-arm shared between the 914 and 911, or would it need to be replaced too?

All bushings, the shocks and springs, and a sway bar are known to be interchangeable.

Torsion bars are different (splines) as well as calipers, rotors, and the 5-lug hub assembly.

What else is there to change? Perhaps someone who has performed the swap could post their experiences with details about what parts *need* to be cannibalized off a 911, and what parts can be left alone. Thanks!

dman007 · 01-10-1999, 04:25 PM

It is my understanding that the 911 suspension is a direct bolt in with no modifications necessary. If you get into much later models, there may be something required.

Dennis Marer · 01-10-1999, 04:34 PM

Yes, that's what just the tech article says. But how *much* of the suspension needs to be replaced? Everything, including steering rack and A-arms? Just the strut and hub assembly?

The less I have to replace the easier it is going to be to find quality and affordable parts. Replacing the entire suspension (when only a handful or parts is necessary) is what I'd like to avoid.

Anybody out there actually done this surgery?

Jim Philpot · 01-10-1999, 05:37 PM

It appears that the conversion of the front end has been beaten to death!

This still leaves the rear end to be addressed. Conversion of the rear can be accomplished one of three ways:

1-- Have later model rear hubs re-drilled and have five studs pressed in.

2-- Have early model rear hubs re-drilled and have five studs pressed in.

NOTE---the difference here is that the early model hub castings had, in addition to raised bosses for the four holes, extra bosses for use with five holes(to permit the castings to be used for either the -4 or the -6 version). There is some concern about the use of later hubs, without the extra bosses, since the four additional holes to be drilled will be in fairly thin metal, and may not provide sufficient strength to retain the studs. I had my conversion done by FAT using later hubs and they didn't seem to be that concerned. I don't plan to expose my car to autox or race conditions, and, therefore I'm not concerned either. It probably should be considered, however, by anyone contemplating severe usage of the car.

3-- Purchase 914-6 rear hubs. The problem with this approach is that you will also have to purchase 914-6 stub axles, since the splines of the 914-4 stub axle will not fit the 914-6 hub splines.

With all of these approaches, you must, of course, either have your rear rotors re-drilled for the five holes, or purchase 914-6 rotors. You will also have to drill new holes for the small flathead screws that attach the rotor to the hub.

Jim Philpot · 01-10-1999, 05:40 PM

It appears that the conversion of the front end has been beaten to death!

This still leaves the rear end to be addressed. Conversion of the rear can be accomplished one of three ways:

1-- Have later model rear hubs re-drilled and have five studs pressed in.

2-- Have early model rear hubs re-drilled and have five studs pressed in.

NOTE---the difference here is that the early model hub castings had, in addition to raised bosses for the four holes, extra bosses for use with five holes(to permit the castings to be used for either the -4 or the -6 version). There is some concern about the use of later hubs, without the extra bosses, since the four additional holes to be drilled will be in fairly thin metal, and may not provide sufficient strength to retain the studs. I had my conversion done by FAT using later hubs and they didn't seem to be that concerned. I don't plan to expose my car to autox or race conditions, and, therefore I'm not concerned either. It probably should be considered, however, by anyone contemplating severe usage of the car.

3-- Purchase 914-6 rear hubs. The problem with this approach is that you will also have to purchase 914-6 stub axles, since the splines of the 914-4 stub axle will not fit the 914-6 hub splines.

With all of these approaches, you must, of course, either have your rear rotors re-drilled for the five holes, or purchase 914-6 rotors. You will also have to drill new holes for the small flathead screws that attach the rotor to the hub.

Dennis Marer · 01-10-1999, 05:46 PM

Yes...beaten to death, but still unanswered!

I was hoping for info above and beyond what's in the tech report.

I have received an e-mail from someone who performed the front end conversion which says the strut and hub assembly are all that need replacing. I will budget accordingly...

For the rear, a simple 4-lug to 5-lug adaptor will probably be sufficient. No plans to upgrade the rear brakes.

Dave at Pelican Parts · Dave at Pelican Parts's Garage

As far as the A-arms go, that is a maybe. You can use the 911 A-arms, but then you need the 911 torsion bars and torsion bar front caps. Or you can use the 914 A-arms.

I have heard that the crossmember can be left as-is (steel), or replaced with the aluminum one from the 911. (This may not apply to early 911 parts, not sure.)

I hope this is at least a partial answer.

--DD

Dennis Marer · 01-11-1999, 03:12 PM

I checked out Pelican Parts' listings for 914 and 911 A-arms, and the part numbers are the same...however, the prices are different! I'm sure that's just a typo...but at least it provides substance to the theory that they're interchangable.

I'm going to go with the approach that if it bolts on, it's going to work.

01-11-1999, 06:51 PM

ok here we go...if all you want is 5 lug rotors, and you arent concerned about bigger brakes or any of that neat stuff but will end up w/ bigger front brakes...the easiest way to do this conversion is to buy 4 to 5 lug converters for the rear, and find a 911 w/ good suspension and buy the front strut assemblies, w/ the rotor and caliper attached, this will also give you 911 front brakes, id look for one from a early, mid 70's 911, just because the shocks are similar in performance, you wil also need a 19mm master cylinder for the 911 brakes
if you would like to keep your 5 lug hubs, do not have your rotors drilled for the 5 pattern, because when your rotors wear out, the 5 pattern is gone, until you get new rotors and have them drilled out
the nicest thing to do is to upgrade the whole car to 911 suspension, but also the hardest and most expensive usually, the cv joints and everything are different
do not go w/ the idea of buying 914-6 stuff.....VERY rare!
ive done the conversion, i did the converters and front strut assembly, it was easy and very inexpensive....and an easy bolt in substitution....

Dennis Marer · 01-12-1999, 09:19 AM

Excellent! Thanks for the words of wisdom...

Victor Frisbee · 01-12-1999, 06:13 PM

Who said the front end swap was beaten to death.

BE AWARE

1) If you are going to 'swap' the shock/spindle assy and not the entire front end, you must have a '72 - '76 914. The ball joint on a '71 is different and will not work with the 911 components.

2) The 911 center section is slightly different than the 914 and therefore requires a different cover plate for the bottom. Get this item if you swap the entire front end.

3) The width of the outer bearing carriers (the alloy gizmo with the 5 studs in it) on 911 front ends comes in at least 2 different widths, approx. 1" and 2". This is an important consideration for wheel/tire clearence issues.

4) I understand the LIMITED budget issues, we all suffer from them. My advise would be to add turbo tie rods at the same time. The turbo tie rod eliminate the rubber union in the steering linkage and therefore increase accuracy and feel. Do it now and you will only have to get the front end aligned once.

5) If you are going to lower the car from stock ride height don't forget the spacer kit for the steering rack to eliminate 'bump steer'.

Victor Frisbee · 01-12-1999, 06:14 PM

Who said the front end swap was beaten to death.

BE AWARE

1) If you are going to 'swap' the shock/spindle assy and not the entire front end, you must have a '72 - '76 914. The ball joint on a '71 is different and will not work with the 911 components.

2) The 911 center section is slightly different than the 914 and therefore requires a different cover plate for the bottom. Get this item if you swap the entire front end.

3) The width of the outer bearing carriers (the alloy gizmo with the 5 studs in it) on 911 front ends comes in at least 2 different widths, approx. 1" and 2". This is an important consideration for wheel/tire clearence issues.

4) I understand the LIMITED budget issues, we all suffer from them. My advise would be to add turbo tie rods at the same time. The turbo tie rod eliminate the rubber union in the steering linkage and therefore increase accuracy and feel. Do it now and you will only have to get the front end aligned once.

5) If you are going to lower the car from stock ride height don't forget the spacer kit for the steering rack to eliminate 'bump steer'.

Dennis Marer · 01-12-1999, 09:12 PM

Good advice - I had settled on a '73 or later because of the side shifter transmission. Wheel/tire clearance issues are not going to be a problem - but I'll keep a heads and and see if I can find both types and compare them. Thanks!

As far as budget, I have a pretty sizable chunk to do the whole car. Unfortunately, most of that will go towards a new power plant...notice I didn't say "engine".

I'd like to save $$$ where I can, to be frugal but not "cheap". If it ain't broke, don't fix it!