5mil spacer on 5 lug conversion Options

[Blown59]

If someone could educate me, it would be greatly appreciated. Ive done my CV shaft conversion for the 5 lug. My setup is this... 914 inner CV, 914 shaft, 4mil grind on the outer spline end, 944 CV, 944 stub, boxter wheel hub. I'm reading that I need a 5 mil spacer in one of two, possibly both locations. I dont see this as being necessary. One image shows a spacer on the stub placed where the stub shaft enters the bearing race and mates to the hub shaft... I dont see how this could possibly work. Second, I see information calling for the spacer to slide on the back of the hub stub for shaft input. To me, this would seem to prevent the stub shaft from fully seating, leaving a 5 mil gap inside the bearing race (maybe this is where the "other 5 mil spacer is supposed to go?).

This then brings me to my last question... If your space everything out 5 mil, arent you loosing 5 mil of spline engagement? I'm using boxter rear bearings as I understand they are identical in size to the 914, just actually better (more bearings?). As I line everything up, prior to assembly everything seems to fit as it should. Stub and hub join properly and sit flush. Bearing is correct size for distance between hub/stub. Plenty of engagement/support from sub/hub on inner bearing race wall. It doesnt appear there would be any engagement on the outter race wall from the sub or hub. And it doeant appear that the 914 sub engaged the bearing except on the inner race wall.

So, I dont see where the need is for the 5 mil spacer. I dont want to ruin bearings and have to disassemble if it doesnt function properly or worse case damage something in my attempt to drive it as is.

If I'm wrong or am not fully understanding something, can someone please correct my ignorance or lack of understanding? Or is it possible this may be an alternative setup to the 911 hubs without a ton of "extra bits"??

[Blown59]

Nothing?

[r_towle]

Not sure where the spacer is required, but is it possible to measure everything with calipers?

[Mueller]

http://www.914world.com/bbs2/index.php?sho...5853&st=200


My 5 lug conversion in link above using the 951 stub axle with 986 hub.
The 914 bearing is 40mm wide, the space between is greater than that.

Patrick Motorsports sells the spacers however I made my own.

[JFJ914]

If someone could educate me, it would be greatly appreciated. Ive done my CV shaft conversion for the 5 lug. My setup is this... 914 inner CV, 914 shaft, 4mil grind on the outer spline end, 944 CV, 944 stub, boxter wheel hub. I'm reading that I need a 5 mil spacer in one of two, possibly both locations. I dont see this as being necessary. One image shows a spacer on the stub placed where the stub shaft enters the bearing race and mates to the hub shaft... I dont see how this could possibly work. Second, I see information calling for the spacer to slide on the back of the hub stub for shaft input. To me, this would seem to prevent the stub shaft from fully seating, leaving a 5 mil gap inside the bearing race (maybe this is where the "other 5 mil spacer is supposed to go?).

This then brings me to my last question... If your space everything out 5 mil, arent you loosing 5 mil of spline engagement? I'm using boxter rear bearings as I understand they are identical in size to the 914, just actually better (more bearings?). As I line everything up, prior to assembly everything seems to fit as it should. Stub and hub join properly and sit flush. Bearing is correct size for distance between hub/stub. Plenty of engagement/support from sub/hub on inner bearing race wall. It doesnt appear there would be any engagement on the outter race wall from the sub or hub. And it doeant appear that the 914 sub engaged the bearing except on the inner race wall.

So, I dont see where the need is for the 5 mil spacer. I dont want to ruin bearings and have to disassemble if it doesnt function properly or worse case damage something in my attempt to drive it as is.

If I'm wrong or am not fully understanding something, can someone please correct my ignorance or lack of understanding? Or is it possible this may be an alternative setup to the 911 hubs without a ton of "extra bits"??

The 911 uses a RWB that is bigger in diameter and 5 mm wider. They machined the 911 5 lug hub 5 mm deeper than the 4 lug hub. The spacer is used to make up the 5mm. It goes on the hub on the hub side. This maintains brake disc and caliper alignment. If you don't use it you'll have 5mm of slop after you torque everything.

You are using a Boxster hub which should be dimensionally the same as the 4 Cyl hub so I think you should be ok.

[mepstein]

If someone could educate me, it would be greatly appreciated. Ive done my CV shaft conversion for the 5 lug. My setup is this... 914 inner CV, 914 shaft, 4mil grind on the outer spline end, 944 CV, 944 stub, boxter wheel hub. I'm reading that I need a 5 mil spacer in one of two, possibly both locations. I dont see this as being necessary. One image shows a spacer on the stub placed where the stub shaft enters the bearing race and mates to the hub shaft... I dont see how this could possibly work. Second, I see information calling for the spacer to slide on the back of the hub stub for shaft input. To me, this would seem to prevent the stub shaft from fully seating, leaving a 5 mil gap inside the bearing race (maybe this is where the "other 5 mil spacer is supposed to go?).

This then brings me to my last question... If your space everything out 5 mil, arent you loosing 5 mil of spline engagement? I'm using boxter rear bearings as I understand they are identical in size to the 914, just actually better (more bearings?). As I line everything up, prior to assembly everything seems to fit as it should. Stub and hub join properly and sit flush. Bearing is correct size for distance between hub/stub. Plenty of engagement/support from sub/hub on inner bearing race wall. It doesnt appear there would be any engagement on the outter race wall from the sub or hub. And it doeant appear that the 914 sub engaged the bearing except on the inner race wall.

So, I dont see where the need is for the 5 mil spacer. I dont want to ruin bearings and have to disassemble if it doesnt function properly or worse case damage something in my attempt to drive it as is.

If I'm wrong or am not fully understanding something, can someone please correct my ignorance or lack of understanding? Or is it possible this may be an alternative setup to the 911 hubs without a ton of "extra bits"??

The 911 uses a RWB that is bigger in diameter and 5 mm wider. They machined the 911 5 lug hub 5 mm deeper than the 4 lug hub. The spacer is used to make up the 5mm. It goes on the hub on the hub side. This maintains brake disc and caliper alignment. If you don't use it you'll have 5mm of slop after you torque everything.

You are using a Boxster hub which should be dimensionally the same as the 4 Cyl hub so I think you should be ok.

If you use a 70-72 lug centric rear 911 hub, it uses the same bearing as a 914 and no spacer is needed. the mid and later hubs use a larger, wider bearing so to use the later hub, you need a 5mm spacer between the bearing and the hub to make up for the 5mm longer bearing seat. PMS has them for sale or you can make them on a lathe. You still use the 914/early 911 bearing with the later hub so it fits into the 914 trailing arm.
I don't know how the 944 hub measures compared to the 914 or 911 hub but it should be easy to check next to a stock 914 hub.
I don't know about spline engagement because using the 911 rear hub requires the use of custom length axles for Sway Away. They carry the axle as a stock part number 2420.

More info on this classic thread - http://www.914world.com/bbs2/index.php?showtopic=91963

[Blown59]

The 911 uses a RWB that is bigger in diameter and 5 mm wider. They machined the 911 5 lug hub 5 mm deeper than the 4 lug hub. The spacer is used to make up the 5mm. It goes on the hub on the hub side. This maintains brake disc and caliper alignment. If you don't use it you'll have 5mm of slop after you torque everything.

You are using a Boxster hub which should be dimensionally the same as the 4 Cyl hub so I think you should be ok.

This was my understanding too, but in the midst of all the different information, I didnt want to be wrong and cause damage to anything.

Ive attached a few pics for references:
[attachmentid=741
019]

[Blown59]

Given a minor bit of possible inaccuracy in reading the tape and the conversion of 2 5/8 inches to mm... We are looking at 66.675 mm from hub face to the face of the stub input. Unfortunately, I dont have access to the 914 hubs right now, they're in storage.

And in measuring my bearing, I get 1 19/32 inches or by that conversion 40.481mm. If I use 1 18/32 inches that converts to 39.688mm. So, I'm assuming this setup is a go? Id just like to confirm hub face to stub input face from a 914 hub if someone has those measurements.

This pic added for good measure:

If this works as I hope, it will be a more cost effective rear hub conversion. 944 stubs can be had for $15-30, boxter bearings are cheap, boxter hubs already removed from the assembly are about $30-35 each. No more need in hunting expensive and harder to come by early 911 hubs.

[mepstein]

I know it's been tried/done before but not done much. I'm not sure the reason why. I think Mike Mueller is doing it now. If so, he would know all the details.
@Mueller

[Blown59]

I know it's been tried/done before but not done much. I'm not sure the reason why. I think Mike Mueller is doing it now. If so, he would know all the details.
@Mueller

I had a look over link he attached for his thread. In looking at his hub, it has a different part number than mine does. My hub is from a boxter front, that may be the difference in spacing?? I attached a pic above of my hub with part number. The idea or hope was to find a more coat effective alternative and not need to machine parts.

[Mueller]

If the front Boxster hub fits that might be better than using the rear one.
With my set up I am using 100mm CV joints which will bolt up to the 944 stub axle I am using.

If you still have the old wheel bearings and a Dremel or similar you can grind the ID of the bearing for trial fittings.

[TravisNeff]

If I remember right, I used one on the outside and one on the inside. 951 stub axle, 911sc hub. Needed it on the outside as the hub would hit the bearing retainer plate. It's been a while and I had to take it apart and put it back together a few times to get it all right.

[Blown59]

If the front Boxster hub fits that might be better than using the rear one.
With my set up I am using 100mm CV joints which will bolt up to the 944 stub axle I am using.

If you still have the old wheel bearings and a Dremel or similar you can grind the ID of the bearing for trial fittings.

Axle build is the same except I retained the 914 inner. Thats pretty much a standand I think sans Sway Aways.

I dont have the old bearings, but based on my measurements above, I'm pretty sure the bearing is 40mm. Boxster/914 bearings are interchangeable. It doesnt appear ill have an issue fitting the swing arm.

I guess I was more confused, thinking the 5mil spacer was to push the hub out 5mil further for proper shaft spacing between the hub and the trans. I was more affraid if I installed the shaft I was going to have side to side play in my shaft or "stretch" the CVs out too much. It seems ill be okay. I still have a few weeks before my rear is reassembled, so maybe I'll come up with some measurements of a spare 914 axle/hub combo before install. I just dont have those readily available at this time.

Im hoping this proves to be a very simple and cost effective upgrade for future conversions.

[Mueller]

If the front Boxster hub fits that might be better than using the rear one.
With my set up I am using 100mm CV joints which will bolt up to the 944 stub axle I am using.

If you still have the old wheel bearings and a Dremel or similar you can grind the ID of the bearing for trial fittings.

I milled the inside flange down flat, then took some material off the top of the side flanges...when I installed them I flipped them over and put them on upside down.

[Blown59]

I milled the inside flange down flat, then took some material off the top of the side flanges...when I installed them I flipped them over and put them on upside down.

You lost me... Milled what flange? Flipped what?

[Mueller]

The bearing retaining part.
Unmodified in picture.

With your front hub it might be okay, no idea.

[Blown59]

Ahh... Yes, I'm thinking the bearing flange will be fine. I dont forsee clearance issues.