85 to 95 Cam Gears 928 105 530 01 NLA - Update
12-15-2010, 01:53 PM
#166
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12-15-2010, 01:59 PM
#168
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For what it's worth, I think I was the 'first return' mentioned above. I said that the coating on the gears was worn through, and that in the Rennlist experience that meant the gears were done. I was offered a refund and an arrangement for Fedex to pick up the gears, no hassle, no questions asked. dC was very courteous throughout. Seems fair enough to me.
12-15-2010, 02:01 PM
#169
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Quick update on the project.
We are having both steel and alloy cam gear prototypes made.
A few questions for feedback please.
Cost reduction ---
1) There are two marks on the front face of the cam which seem to mark the orientation of the rotor. I do not see these as necessary as the rotor can only be put on in one position. Any reason to keep the marks??
2) On the front edge of the gear opposite the actual timing mark (rear of gear) there is a larger timing mark. I have never seen the reason for this. Is it needed??
Weight -----
1) I see the big advantage of going back to a steel gear from a wear point. Porsche already did this on the oil pump gear. Weight could be circa twice that of the alloy gear. Current weight is 13.5 Oz. So if the steel gear weighs circa 27oz how much of an issue is that for stock cars?? Cost will also be more but probably fit and forget.
We are also looking at an alloy gear with steel teeth.
Comments please?
We are having both steel and alloy cam gear prototypes made.
A few questions for feedback please.
Cost reduction ---
1) There are two marks on the front face of the cam which seem to mark the orientation of the rotor. I do not see these as necessary as the rotor can only be put on in one position. Any reason to keep the marks??
2) On the front edge of the gear opposite the actual timing mark (rear of gear) there is a larger timing mark. I have never seen the reason for this. Is it needed??
Weight -----
1) I see the big advantage of going back to a steel gear from a wear point. Porsche already did this on the oil pump gear. Weight could be circa twice that of the alloy gear. Current weight is 13.5 Oz. So if the steel gear weighs circa 27oz how much of an issue is that for stock cars?? Cost will also be more but probably fit and forget.
We are also looking at an alloy gear with steel teeth.
Comments please?
__________________
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014
928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
12-15-2010, 02:25 PM
#172
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...Weight -----
1) I see the big advantage of going back to a steel gear from a wear point. Porsche already did this on the oil pump gear. Weight could be circa twice that of the alloy gear. Current weight is 13.5 Oz. So if the steel gear weighs circa 27oz how much of an issue is that for stock cars?? Cost will also be more but probably fit and forget.
We are also looking at an alloy gear with steel teeth.
Comments please?
1) I see the big advantage of going back to a steel gear from a wear point. Porsche already did this on the oil pump gear. Weight could be circa twice that of the alloy gear. Current weight is 13.5 Oz. So if the steel gear weighs circa 27oz how much of an issue is that for stock cars?? Cost will also be more but probably fit and forget.
We are also looking at an alloy gear with steel teeth.
Comments please?
The only thing I can think of is since the steel weighs more, there is a higher moment of inertia, meaning the sprocket in motion produces more rotational forces - it requires more to start and stop the sprocket.
This could potentially create more stress on the cams, during acceleration and decellaration and in particular, abrupt engine stall/stop.
This may not me a problem, and the belt connects the gears and everything else into a system which spins in unison.
The belt stretches under load, no?
If so, it is possible the cams may see stresses as the sprocket overcomes its moment of inertia, during a fraction of time the belt stretches, prior to overcoming the moment the complete belt system begins to spin in unison.
Did the change to alum. happen around the same time the 928 changed to 32V?
Caveat: This is my "shadetree engineer" statement, and I have no direct experience in automotive engine design.
12-15-2010, 02:38 PM
#173
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Surface hardening?. If that's the case it wasn't hard enough or deep enough and they are all bad used, every one of them I've ever seen has wear from the belt to one degree or another. This cogged belt setup isn't specific to 928's, nearly everything uses them, a little shining wear isn't usually cause for alarm as long as the gears aren't eaten into. That is usually a sign of something else wrong when it happens, or you have many many hundreds of K's on it. I'm open to the idea of the 928 being "different" though, and as I said returns are no issue.
12-15-2010, 02:54 PM
#174
Former Sponsor
Quick update on the project.
We are having both steel and alloy cam gear prototypes made.
A few questions for feedback please.
Cost reduction ---
1) There are two marks on the front face of the cam which seem to mark the orientation of the rotor. I do not see these as necessary as the rotor can only be put on in one position. Any reason to keep the marks??
2) On the front edge of the gear opposite the actual timing mark (rear of gear) there is a larger timing mark. I have never seen the reason for this. Is it needed??
Weight -----
1) I see the big advantage of going back to a steel gear from a wear point. Porsche already did this on the oil pump gear. Weight could be circa twice that of the alloy gear. Current weight is 13.5 Oz. So if the steel gear weighs circa 27oz how much of an issue is that for stock cars?? Cost will also be more but probably fit and forget.
We are also looking at an alloy gear with steel teeth.
Comments please?
We are having both steel and alloy cam gear prototypes made.
A few questions for feedback please.
Cost reduction ---
1) There are two marks on the front face of the cam which seem to mark the orientation of the rotor. I do not see these as necessary as the rotor can only be put on in one position. Any reason to keep the marks??
2) On the front edge of the gear opposite the actual timing mark (rear of gear) there is a larger timing mark. I have never seen the reason for this. Is it needed??
Weight -----
1) I see the big advantage of going back to a steel gear from a wear point. Porsche already did this on the oil pump gear. Weight could be circa twice that of the alloy gear. Current weight is 13.5 Oz. So if the steel gear weighs circa 27oz how much of an issue is that for stock cars?? Cost will also be more but probably fit and forget.
We are also looking at an alloy gear with steel teeth.
Comments please?
Note that Roger and I are not normally in competition...nor do I like this idea...but I've been working on this for two months..so I don't want to stop.
I sent a PM to Roger asking if this was a "good" idea, but he has not responded, but continued plowing ahead. I was willing to share what I knew about the gears and see if somehow we could talk and figure this out...not happening, apparently.
I'll just say this....generally parts guys should concentrate on selling parts and keep away from the engineering/production of pieces, of which they have little knowledge. Very seldom do things turn out well....
12-15-2010, 02:57 PM
#175
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1) There are two marks on the front face of the cam which seem to mark the orientation of the rotor. I do not see these as necessary as the rotor can only be put on in one position. Any reason to keep the marks??
2) On the front edge of the gear opposite the actual timing mark (rear of gear) there is a larger timing mark. I have never seen the reason for this. Is it needed??
2) On the front edge of the gear opposite the actual timing mark (rear of gear) there is a larger timing mark. I have never seen the reason for this. Is it needed??
2) Yes?
12-15-2010, 03:00 PM
#176
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Quick update on the project.
We are having both steel and alloy cam gear prototypes made.
A few questions for feedback please.
Cost reduction ---
1) There are two marks on the front face of the cam which seem to mark the orientation of the rotor. I do not see these as necessary as the rotor can only be put on in one position. Any reason to keep the marks??
We are having both steel and alloy cam gear prototypes made.
A few questions for feedback please.
Cost reduction ---
1) There are two marks on the front face of the cam which seem to mark the orientation of the rotor. I do not see these as necessary as the rotor can only be put on in one position. Any reason to keep the marks??
2) On the front edge of the gear opposite the actual timing mark (rear of gear) there is a larger timing mark. I have never seen the reason for this. Is it needed??
Weight -----
1) I see the big advantage of going back to a steel gear from a wear point. Porsche already did this on the oil pump gear. Weight could be circa twice that of the alloy gear. Current weight is 13.5 Oz. So if the steel gear weighs circa 27oz how much of an issue is that for stock cars?? Cost will also be more but probably fit and forget.
1) I see the big advantage of going back to a steel gear from a wear point. Porsche already did this on the oil pump gear. Weight could be circa twice that of the alloy gear. Current weight is 13.5 Oz. So if the steel gear weighs circa 27oz how much of an issue is that for stock cars?? Cost will also be more but probably fit and forget.
12-15-2010, 03:02 PM
#177
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Note that both Roger and I are making cam gears...for some reason, way beyond me. Doesn't seem like that big of a market....
Note that Roger and I are not normally in competition...nor do I like this idea...but I've been working on this for two months..so I don't want to stop.
I sent a PM to Roger asking if this was a "good" idea, but he has not responded, but continued plowing ahead. I was willing to share what I knew about the gears and see if somehow we could talk and figure this out...not happening, apparently.
I'll just say this....generally parts guys should concentrate on selling parts and keep away from the engineering/production of pieces, of which they have little knowledge. Very seldom do things turn out well....
Note that Roger and I are not normally in competition...nor do I like this idea...but I've been working on this for two months..so I don't want to stop.
I sent a PM to Roger asking if this was a "good" idea, but he has not responded, but continued plowing ahead. I was willing to share what I knew about the gears and see if somehow we could talk and figure this out...not happening, apparently.
I'll just say this....generally parts guys should concentrate on selling parts and keep away from the engineering/production of pieces, of which they have little knowledge. Very seldom do things turn out well....
Roger, what are your thoughts on this?
12-15-2010, 03:05 PM
#178
Rennlist Member
Does anyone know what Al alloy Porsche used for these gears? Some alloys, like 7075T6 or the 2024 series, have a surface treatment in mill stock form that prevents corrosion, and is pretty hard as well. And I think it has to be one of the alloys like this - these are the hardest, and hardness seems to be required by the application. If so, then just anodizing isn't going to be adequate I don't think. No engineer here, just had to look into this when I was building musical instruments.
12-15-2010, 04:11 PM
#179
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I have the greatest respect for Greg but I do not see that we are in competition anywhere.
I see no products that Greg makes that compete with me at all.
He makes bespoke parts for high performance engines.
I sell large volumes of parts for the general 928 market.
He sees a small market for cam gears and I see a very large market for cam gears.
I have no skill at all with making cam gears but have a group of experts who do.
What I am very good at is making the best commercial deal for the supply of a basic cam gear that meets or exceeds the required parameters at a price that is acceptable to the 928 community.
Also in that goal is my need to make a respectable margin for my business.
Underneath all of that is I am passionate about 928's and will do all I can to keep them on the road.
Engineers should stay out of business and leave it to businessmen - that's a joke Greg.
I see no products that Greg makes that compete with me at all.
He makes bespoke parts for high performance engines.
I sell large volumes of parts for the general 928 market.
He sees a small market for cam gears and I see a very large market for cam gears.
I have no skill at all with making cam gears but have a group of experts who do.
What I am very good at is making the best commercial deal for the supply of a basic cam gear that meets or exceeds the required parameters at a price that is acceptable to the 928 community.
Also in that goal is my need to make a respectable margin for my business.
Underneath all of that is I am passionate about 928's and will do all I can to keep them on the road.
Engineers should stay out of business and leave it to businessmen - that's a joke Greg.
12-15-2010, 05:06 PM
#180
In respect to steel gears, no problem, they may need the black zinc treatment like the ATI dampers. Also in steel you can cut more material out, so that you can come out at the same weight. Seen this quite a lot. Nascar engine blocks are iron or compacted graphite iron weigh the same as an alloy block or there abouts.
Greg
Greg