- junglejustice
- Verde
- Posts: 624
- Joined: Fri Nov 26, 2004 1:19 am
- Location: Granolaville, WA
Front Guibo Support;
Thought that I would post this for clarification of this piece. It's simple, but it works.
You can see that the bolts that come out of the flywheel go into rubber and then stop with just a nut on the other end and nothing holding their tips aligned (other than the rubber) They have the ability to flare under torque and at higher rpm the ends spread - this is what tears up the front donut.
The bolts that go through the holes in the donuts and to the shaft don't move as there the go through those metal strips and metal reinforcement/locator pins molded in there. Their ends can't flare...
This simple little plate keeps the flywheel bolts similarly in place and aligned.
You can see that the bolts that come out of the flywheel go into rubber and then stop with just a nut on the other end and nothing holding their tips aligned (other than the rubber) They have the ability to flare under torque and at higher rpm the ends spread - this is what tears up the front donut.
The bolts that go through the holes in the donuts and to the shaft don't move as there the go through those metal strips and metal reinforcement/locator pins molded in there. Their ends can't flare...
This simple little plate keeps the flywheel bolts similarly in place and aligned.
...to Alfa, or not to Alfa? That is the question...
- junglejustice
- Verde
- Posts: 624
- Joined: Fri Nov 26, 2004 1:19 am
- Location: Granolaville, WA
JJ,
Can you explain how the flywheel bolts flare? Don't the bolts tightly capture the spacers/sleeves molded into the donut?
From what I can recall from looking at a broken donut, dounts (and guibos ;-> ) are not just 6 spacers molded into a rubber disk. 3 of the spacers are attached to a 3-pointed spider with a big hole in the middle for the nose bearing. Not sure if the flywheel bolts fasten to the spider spacers or not though, but I suspect they do since these spacers are without locator pins.
Can you explain how the flywheel bolts flare? Don't the bolts tightly capture the spacers/sleeves molded into the donut?
From what I can recall from looking at a broken donut, dounts (and guibos ;-> ) are not just 6 spacers molded into a rubber disk. 3 of the spacers are attached to a 3-pointed spider with a big hole in the middle for the nose bearing. Not sure if the flywheel bolts fasten to the spider spacers or not though, but I suspect they do since these spacers are without locator pins.
Guibos
The 3 lugs that attach to the driveshaft yoke are free-floating.
The 3 lugs that attach to the flywheel are joined centrally to the middle of the donut. However, JJ has evidence that the driveshaft bolts are able to flare outward despite this.
I was considering using a plate like this on BOTH sides of the donut.
I think that the 1-piece driveshaft tends to really stress the front donut. I am tracking front donut lifespan now.
The 3 lugs that attach to the flywheel are joined centrally to the middle of the donut. However, JJ has evidence that the driveshaft bolts are able to flare outward despite this.
I was considering using a plate like this on BOTH sides of the donut.
I think that the 1-piece driveshaft tends to really stress the front donut. I am tracking front donut lifespan now.
Al Mitchell
Reale Motorsports
#82 E Production
Alfa Romeo GTV6
Reale Motorsports
#82 E Production
Alfa Romeo GTV6
My front donut recently fell apart at about 4000rpm causeing a fragment of it to put a nice hole in my exhaust( it sounded like a gunshot when it happened). When my mechanic showed me the donut the only thing left was the 3 holes for the driveshaft bolts. So I'm wondering if this plate would've helped prevent this from happening
Alex
84 GTV6
84 GTV6
JJ
I talked to my machinist today and arrived at a small dilema: what hardness/thickness of steel is needed to optimize this modification? If the steel is too soft or too thin, the holes for the bolts will become ovaled in time, right? Your photo shows steel that looks fairly thin, but what do I know?
James
I talked to my machinist today and arrived at a small dilema: what hardness/thickness of steel is needed to optimize this modification? If the steel is too soft or too thin, the holes for the bolts will become ovaled in time, right? Your photo shows steel that looks fairly thin, but what do I know?
James
- junglejustice
- Verde
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- Joined: Fri Nov 26, 2004 1:19 am
- Location: Granolaville, WA
You don't want it to be too thick as (in theory) you would be moving towards a solid coupling again and maybe compromise smoothness... In theory...
Thin. No problem. Just to support that forward rubber a bit. There isn't too much moving around up there once it is all bolted tight.
It time, yes, it may oval the holes and then you just replace it when you do donuts... It's not a cure-all; just a little extra help for high-powered cars...
More intended for a high-powered application that gets opened up regularly any way.
Thin. No problem. Just to support that forward rubber a bit. There isn't too much moving around up there once it is all bolted tight.
It time, yes, it may oval the holes and then you just replace it when you do donuts... It's not a cure-all; just a little extra help for high-powered cars...
More intended for a high-powered application that gets opened up regularly any way.
...to Alfa, or not to Alfa? That is the question...
- Maurizio
- Verde
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- Joined: Wed Dec 01, 2004 4:49 am
- Location: the Netherlands, 153.1km from the N'ring :-)
You actually could just use a good quality aluminum plate of 1 mm thick.
You want to add stiffness in the radial direction of the bolts and a low stiffness in the nut direction so that the plate can form and take tolerances when assembling. The trick is that the plate has a in plane stiffness which is very large and makes sure the three bolts have to work together against the torque of the engine. It even changes the bending profile of the bolts, which makes the 4x stiffer.
Saluti,
Maurizio
You want to add stiffness in the radial direction of the bolts and a low stiffness in the nut direction so that the plate can form and take tolerances when assembling. The trick is that the plate has a in plane stiffness which is very large and makes sure the three bolts have to work together against the torque of the engine. It even changes the bending profile of the bolts, which makes the 4x stiffer.
Saluti,
Maurizio
Banned.. ? Daily donky.. ==> BMW 325d
E36M3 (3.0) Ringtool ==> definitely BANNED!
AR 75 TS Ringtool '90, AR Spider 2000 veloce '79
E36M3 (3.0) Ringtool ==> definitely BANNED!
AR 75 TS Ringtool '90, AR Spider 2000 veloce '79
You should probably stay away from aluminium...
This kind of fastener needs a very stable material to not relax with time, alu will just not do.
In my opinion you can use whatever gauge steel you can fit in there and it won't affect the function of the guibo at all unless the steel plate touches any other part then the guibo and the nut.
The flex occurs between the screws in the guibo and linking the three screws fron the driveshaft won't upset anything, they're already linked on the other side remember...
Maybe keep in mind that you want a perfectly symmetrical part as a heavy part would upset the balance of the shaft.
This kind of fastener needs a very stable material to not relax with time, alu will just not do.
In my opinion you can use whatever gauge steel you can fit in there and it won't affect the function of the guibo at all unless the steel plate touches any other part then the guibo and the nut.
The flex occurs between the screws in the guibo and linking the three screws fron the driveshaft won't upset anything, they're already linked on the other side remember...
Maybe keep in mind that you want a perfectly symmetrical part as a heavy part would upset the balance of the shaft.
Mats Strandberg
-Scuderia Rosso- Now burned to the ground...
-onemanracing.com-
-Strandberg.photography-
GTV 2000 -77 - Died in the fire.
155 V6 Sport -96 - Sold!
-Scuderia Rosso- Now burned to the ground...
-onemanracing.com-
-Strandberg.photography-
GTV 2000 -77 - Died in the fire.
155 V6 Sport -96 - Sold!
- Maurizio
- Verde
- Posts: 680
- Joined: Wed Dec 01, 2004 4:49 am
- Location: the Netherlands, 153.1km from the N'ring :-)
This kind of fastener needs a very stable material to not relax with time, alu will just not do.
A good point, on the nut side & washer side not a problem but the guibo has not such a nice contact surface.
Was thinking of making some supports for a long time.
Now I have the TS drive shaft out, it might bea good time to design something
Banned.. ? Daily donky.. ==> BMW 325d
E36M3 (3.0) Ringtool ==> definitely BANNED!
AR 75 TS Ringtool '90, AR Spider 2000 veloce '79
E36M3 (3.0) Ringtool ==> definitely BANNED!
AR 75 TS Ringtool '90, AR Spider 2000 veloce '79
Not to rub it in or anything but the contact area isn't really the point, alu will relax with time even if it had a very large contact area and a static environment.
That's just alu... You maybe can find a useful heat treated alloy but steel is so much easier.
That's just alu... You maybe can find a useful heat treated alloy but steel is so much easier.
Mats Strandberg
-Scuderia Rosso- Now burned to the ground...
-onemanracing.com-
-Strandberg.photography-
GTV 2000 -77 - Died in the fire.
155 V6 Sport -96 - Sold!
-Scuderia Rosso- Now burned to the ground...
-onemanracing.com-
-Strandberg.photography-
GTV 2000 -77 - Died in the fire.
155 V6 Sport -96 - Sold!
- Maurizio
- Verde
- Posts: 680
- Joined: Wed Dec 01, 2004 4:49 am
- Location: the Netherlands, 153.1km from the N'ring :-)
I'm just plain stubborn, (that's why I stick with alfa's) so for me it just depends on the applied N/mm^2 .
A plain example, how about alloy wheels.......
But one thing is true looking at fatigue steel wins!
But I don't want to start an huge discussion so guys take the easy and safe route use steel .
A plain example, how about alloy wheels.......
But one thing is true looking at fatigue steel wins!
But I don't want to start an huge discussion so guys take the easy and safe route use steel .
Banned.. ? Daily donky.. ==> BMW 325d
E36M3 (3.0) Ringtool ==> definitely BANNED!
AR 75 TS Ringtool '90, AR Spider 2000 veloce '79
E36M3 (3.0) Ringtool ==> definitely BANNED!
AR 75 TS Ringtool '90, AR Spider 2000 veloce '79
- junglejustice
- Verde
- Posts: 624
- Joined: Fri Nov 26, 2004 1:19 am
- Location: Granolaville, WA