Phosphorus Bronze Valve Guides
06-10-2005, 05:08 PM
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Phosphorus Bronze Valve Guides
Howdy,
I've been having some discussions with the owner of a Porsche 993 concerning what warning signs might offer owners of 993s with Phosphorus Bronze (PB for short) valve guide problems. After reviewing his test results and talking with the engineer at the lab to find out what would tell us PB valve guides were wearing rapidly enough to warrant concern or to possibly take action.
While Tim (the 993 owner) was concerned about the level of Phosphorus in
his report (<100) & I found after speaking with the Oil Engineer (for lack
of a better description) ;-) that the Phosphorus in the reports is an
additive used by the different oil companies and would not be an indication
of PB problems.
The alloy that makes up the PB contains Copper and the engineer said wear in
the PB valve guides would show up as a spike in the Copper level. Any
change in the Phosphorus level would be masked because the P level would
change whenever fresh oil were added.
Now, if there's a 993 owner out there with *known* valve guide problems in a
993, I'll give you a price break to analyze your oil to confirm that this is a valid way to look for PB Valve Guide problems in the real world. ;-)
So, for future reference, while the current charts showing sources of contamination tell us Copper indicates wear in bearings, rocker arm bushings, wrist-pin bushings, thrust washers, other bronze and brass parts at present, I will update these sources to include Phosphorus-Bronze components such as Porsche 993 Valve Guides. See http://members.rennlist.com/oil for the Chart as well as test results done over the past 2 years.
Let me know if you have any questions or comments about this.
I've been having some discussions with the owner of a Porsche 993 concerning what warning signs might offer owners of 993s with Phosphorus Bronze (PB for short) valve guide problems. After reviewing his test results and talking with the engineer at the lab to find out what would tell us PB valve guides were wearing rapidly enough to warrant concern or to possibly take action.
While Tim (the 993 owner) was concerned about the level of Phosphorus in
his report (<100) & I found after speaking with the Oil Engineer (for lack
of a better description) ;-) that the Phosphorus in the reports is an
additive used by the different oil companies and would not be an indication
of PB problems.
The alloy that makes up the PB contains Copper and the engineer said wear in
the PB valve guides would show up as a spike in the Copper level. Any
change in the Phosphorus level would be masked because the P level would
change whenever fresh oil were added.
Now, if there's a 993 owner out there with *known* valve guide problems in a
993, I'll give you a price break to analyze your oil to confirm that this is a valid way to look for PB Valve Guide problems in the real world. ;-)
So, for future reference, while the current charts showing sources of contamination tell us Copper indicates wear in bearings, rocker arm bushings, wrist-pin bushings, thrust washers, other bronze and brass parts at present, I will update these sources to include Phosphorus-Bronze components such as Porsche 993 Valve Guides. See http://members.rennlist.com/oil for the Chart as well as test results done over the past 2 years.
Let me know if you have any questions or comments about this.
06-10-2005, 10:10 PM
#2
RL Technical Advisor
Larry:
Just an FWIW,.......Porsche guides are NOT P-B.
We've done Porsche heads here since 1977 and they have used different materials beginning with a short-lived copper bronze material. I believe they use a Silicon Bronze but I've not done spectro analysis to confirm that.
We've used our own P-B guides since then and I can tell you hands-down that these have VERY different physical characteristics than any OEM guide I've touched in the past 30 years,...
IMHO, bronze parts found in oil filters and analysis originates from various bushings (piston pin, rocker arm, etc) and the distributor crank gear.
Phosphorus originates from engine oils (that REALLY varies) and byproducts of combustion. Ring sealing properties would play a large role in how much of this is discovered in oil analysis.
I'm no expert, but I've seen a LOT of engine internals over the past 30 years,....
Just an FWIW,.......Porsche guides are NOT P-B.
We've done Porsche heads here since 1977 and they have used different materials beginning with a short-lived copper bronze material. I believe they use a Silicon Bronze but I've not done spectro analysis to confirm that.
We've used our own P-B guides since then and I can tell you hands-down that these have VERY different physical characteristics than any OEM guide I've touched in the past 30 years,...
IMHO, bronze parts found in oil filters and analysis originates from various bushings (piston pin, rocker arm, etc) and the distributor crank gear.
Phosphorus originates from engine oils (that REALLY varies) and byproducts of combustion. Ring sealing properties would play a large role in how much of this is discovered in oil analysis.
I'm no expert, but I've seen a LOT of engine internals over the past 30 years,....
06-11-2005, 12:51 PM
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Hi Steve,
You wrote:<<I'm no expert, but I've seen a LOT of engine internals over the past 30 years>>> I'm pretty certain you *are* an expert for what I've read about your capabilities!
Actually, I was basing my comments on info I rec'd from others but we were obviously mistaken - but I certainly respect and believe you - I know you're very familiar with these cars/engines. When I started researching this issue for a customer I asked the Rennlist Email List about the material of construction of the 993 valve guides and the only reply I got said they were pretty sure they were PB -
In any case, I'd still like to find an early warning for the valve guide wear problem.
I thought this was a wide spread problem with the 993's but maybe that's not the case? So, do the silicone-bronze valves guides experience premature wear? Is that a reason for suggesting the bottom shield on the engine be removed? Actually, if the guides are SB, my comments about a spike in the copper is still valid - since the Bronze in the Silicon Bronze is still an alloy containing Copper, a spike in the Copper content would still be the factor that suggests abnormal wear in the valve guides.
You're absolutely correct about the Phosphorus being one of the many additives used by the Oil Manufacturers (it's also used in Coolant). ;-) (Which I also said in my original post).
Sorry about mistakenly calling the guides PB - it looks like I should have said Silicone-Bronze.
So, is my point about the Copper spiking a reasonable conclusion to suggest the valve guides are worn? I know this is a less than *conclusive* finding since other components are made of copper (and bronze) and they'd also release copper when worn.
Or should I drop the whole thing?? ;-)
You wrote:<<I'm no expert, but I've seen a LOT of engine internals over the past 30 years>>> I'm pretty certain you *are* an expert for what I've read about your capabilities!
Actually, I was basing my comments on info I rec'd from others but we were obviously mistaken - but I certainly respect and believe you - I know you're very familiar with these cars/engines. When I started researching this issue for a customer I asked the Rennlist Email List about the material of construction of the 993 valve guides and the only reply I got said they were pretty sure they were PB -
In any case, I'd still like to find an early warning for the valve guide wear problem.
I thought this was a wide spread problem with the 993's but maybe that's not the case? So, do the silicone-bronze valves guides experience premature wear? Is that a reason for suggesting the bottom shield on the engine be removed? Actually, if the guides are SB, my comments about a spike in the copper is still valid - since the Bronze in the Silicon Bronze is still an alloy containing Copper, a spike in the Copper content would still be the factor that suggests abnormal wear in the valve guides.
You're absolutely correct about the Phosphorus being one of the many additives used by the Oil Manufacturers (it's also used in Coolant). ;-) (Which I also said in my original post).
Sorry about mistakenly calling the guides PB - it looks like I should have said Silicone-Bronze.
So, is my point about the Copper spiking a reasonable conclusion to suggest the valve guides are worn? I know this is a less than *conclusive* finding since other components are made of copper (and bronze) and they'd also release copper when worn.
Or should I drop the whole thing?? ;-)
06-11-2005, 01:47 PM
#4
Rennlist Member
I seriously doubt the value in testing oil to determine the amount of wear in the valve guides even if the guide material can be detected in the test..
Oil analysis, at best, can tell you the rate of wear, but can't tell you the total amount of wear.
Think of it this way, the speedometer needle can tell you your instantaneous speed at any given moment, but the speedometer can't tell you how far you have driven. You need to look at the odometer to determine that. The oil test only tells you the rate of wear at that change interval you test the oil, but not the total amount of wear.
If you did an oil analysis with every oil change you might be able to calculate the accumulative wear based on the sample size, the amount of oil changed, and the number of oil changes made. If you made that calculation for each change, then you might be able to make a call.
It seems that the best way, baring dismantling the valve covers and physically checking, is to track the car's oil consumption of the car. oil is consumed in one of the following ways; leaks, ring wear, or valve guide/seal wear.
Since the amount of ring wear appears to be nonexistent for these cars, that leaves leaks, which are fairly obvious, and consumption via valve seals and guides.
Steve, have you accumulated any data on the longevity of the Phosphor Bronze guides versus the OEM material? It would be interesting to know.
Are there any other downsides to the phosphor bronze?
Marv
Oil analysis, at best, can tell you the rate of wear, but can't tell you the total amount of wear.
Think of it this way, the speedometer needle can tell you your instantaneous speed at any given moment, but the speedometer can't tell you how far you have driven. You need to look at the odometer to determine that. The oil test only tells you the rate of wear at that change interval you test the oil, but not the total amount of wear.
If you did an oil analysis with every oil change you might be able to calculate the accumulative wear based on the sample size, the amount of oil changed, and the number of oil changes made. If you made that calculation for each change, then you might be able to make a call.
It seems that the best way, baring dismantling the valve covers and physically checking, is to track the car's oil consumption of the car. oil is consumed in one of the following ways; leaks, ring wear, or valve guide/seal wear.
Since the amount of ring wear appears to be nonexistent for these cars, that leaves leaks, which are fairly obvious, and consumption via valve seals and guides.
Steve, have you accumulated any data on the longevity of the Phosphor Bronze guides versus the OEM material? It would be interesting to know.
Are there any other downsides to the phosphor bronze?
Marv
06-11-2005, 02:45 PM
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Hi Marv,
You're right about the tests not showing the total amount of wear - great analogy about the speedo and odometer. Also, when oil is being used at a high rate it further complicates the Oil Analysis process. Since fresh oil is being added to compensate for that used (hopefully), a fresh load of additives is being introduced with each quart added and the concentration of any contaminates is being diluted as well. This is why it's so important to report the amount of oil added since the last oil change when submitting a oil sample. This is also why Oil Analysis is a tool best used for long term information.
While you can't determine the accumulated amount of wear of any component from an analysis, it's still useful in determining the overall health of the engine. Also, if a high concentration of any comtaminant (such as copper) is found, it only means an additional test is suggested. This is due in part to the possibility of the sample being exposed to contaminants from outside sources. We've had high levels of a contaminant reported and later found that work had been done - such as drilling or sanding - while the engine was nearby and partly exposed by having a valve cover off, oil cap off, or even is running near an operation that is producing airborne particles.
Once that kind of error is eliminated, the oil analysis can point to potential problem areas or even indicate everything is in the normal range.
You're right about the tests not showing the total amount of wear - great analogy about the speedo and odometer. Also, when oil is being used at a high rate it further complicates the Oil Analysis process. Since fresh oil is being added to compensate for that used (hopefully), a fresh load of additives is being introduced with each quart added and the concentration of any contaminates is being diluted as well. This is why it's so important to report the amount of oil added since the last oil change when submitting a oil sample. This is also why Oil Analysis is a tool best used for long term information.
While you can't determine the accumulated amount of wear of any component from an analysis, it's still useful in determining the overall health of the engine. Also, if a high concentration of any comtaminant (such as copper) is found, it only means an additional test is suggested. This is due in part to the possibility of the sample being exposed to contaminants from outside sources. We've had high levels of a contaminant reported and later found that work had been done - such as drilling or sanding - while the engine was nearby and partly exposed by having a valve cover off, oil cap off, or even is running near an operation that is producing airborne particles.
Once that kind of error is eliminated, the oil analysis can point to potential problem areas or even indicate everything is in the normal range.
06-11-2005, 03:23 PM
#6
RL Technical Advisor
Hi Larry:
LOL,..This is a very complex subject and I'd be happy to talk to you on the phone to clarify some things you brought up, if you wish.
IMHO oil analysis, while a VERY useful and important tool, will not address/indicate anything about guide wear. There are a lot of variables at work with this issue.
Marv:
Regarding your question on P-B guide wear, all I can say is that I've not had to re-do any heads that we've installed & fitted these guides in the past 20 years. Some have come back for bent valves from an over-rev, but guide to stem clearances remained VERY close to original spec.
The OEM material is junk and Porsche has been very inconsistent (sloppy) with guide-to-stem clearances in the manufacturing process,......
LOL,..This is a very complex subject and I'd be happy to talk to you on the phone to clarify some things you brought up, if you wish.
IMHO oil analysis, while a VERY useful and important tool, will not address/indicate anything about guide wear. There are a lot of variables at work with this issue.
Marv:
Regarding your question on P-B guide wear, all I can say is that I've not had to re-do any heads that we've installed & fitted these guides in the past 20 years. Some have come back for bent valves from an over-rev, but guide to stem clearances remained VERY close to original spec.
The OEM material is junk and Porsche has been very inconsistent (sloppy) with guide-to-stem clearances in the manufacturing process,......
06-11-2005, 03:45 PM
#7
Rennlist Member
I have been told by companies that do analysis that it principle use is to determine when to change the oil.
Municipalities use this method for their fleets as a tool to minimize oil changes and save money. Us regular folks don't have the issue with only a few cars and it is simpler to change the oil at chronological and mileage intervals.
Marv
Municipalities use this method for their fleets as a tool to minimize oil changes and save money. Us regular folks don't have the issue with only a few cars and it is simpler to change the oil at chronological and mileage intervals.
Marv
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06-11-2005, 04:57 PM
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I have had an interesting result show up in oil analysis on my M3 - higher than expected silicon indicating atmospheric 'dirt' getting through the ITG filter that came with my aftermarket cold-air intake ... this was eliminated when I went with a Dinan setup (and supercharger :-)).
At the same time, the analysis did not show any abnormal wear of other components, and this engine had to be rebuilt for oil-ring failure at 90,000miles attributed to inadequate initial breakin due to earlier switchover to synthetic lubricants.
Just a datapoint on oil analysis.
At the same time, the analysis did not show any abnormal wear of other components, and this engine had to be rebuilt for oil-ring failure at 90,000miles attributed to inadequate initial breakin due to earlier switchover to synthetic lubricants.
Just a datapoint on oil analysis.
06-11-2005, 05:09 PM
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Hi Steve,
Excellent info. What brand are the guides you use? or do you have them made?
Thanks for the offer to discuss this on the phone - you're right about this being complex! What started out as an attempt to find a way to predict valve guide wear has turned out to be an impossibility. At least when trying to use Oil Analysis in that respect.
It's nice to have a pro available to answer these kinds of questions.
Excellent info. What brand are the guides you use? or do you have them made?
Thanks for the offer to discuss this on the phone - you're right about this being complex! What started out as an attempt to find a way to predict valve guide wear has turned out to be an impossibility. At least when trying to use Oil Analysis in that respect.
It's nice to have a pro available to answer these kinds of questions.
06-11-2005, 05:17 PM
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Hi Doug,
Sometimes a high silicone content can be from something as simple as a air filter not being seated properly. Glad to hear the Dinan fixed.
BAD, as far as switching to synthetic after a rebuild - I rebuilt my Mercedes diesel and used many new parts - such as pistons, sleeves, rings, water pump, oil pump and all the other stuff needed to make it as close to "new" as I could. Naturally the machine shop used was a *big* help. Anyway - I used dino oil for the first 1000 miles before switching to Mobil 1. It's got 284k on it with 30k since the rebuild - doesn't use/leak/burn *any* oil even after a high speed (70-75) run.
BTW, one thing oil analysis has shown is even new vehicles can have high levels of contaminants from the assembly and manufacturing process - we've seen this in Mercedes, Ferrari and Porsche as well as others. Which has made me a big proponent of a early oil change for new cars.
Thanks for sharing your info about the oil analysis -- very helpful -
Sometimes a high silicone content can be from something as simple as a air filter not being seated properly. Glad to hear the Dinan fixed.
BAD, as far as switching to synthetic after a rebuild - I rebuilt my Mercedes diesel and used many new parts - such as pistons, sleeves, rings, water pump, oil pump and all the other stuff needed to make it as close to "new" as I could. Naturally the machine shop used was a *big* help. Anyway - I used dino oil for the first 1000 miles before switching to Mobil 1. It's got 284k on it with 30k since the rebuild - doesn't use/leak/burn *any* oil even after a high speed (70-75) run.
BTW, one thing oil analysis has shown is even new vehicles can have high levels of contaminants from the assembly and manufacturing process - we've seen this in Mercedes, Ferrari and Porsche as well as others. Which has made me a big proponent of a early oil change for new cars.
Thanks for sharing your info about the oil analysis -- very helpful -
06-11-2005, 05:41 PM
#11
RL Technical Advisor
Originally Posted by Larry T
Hi Steve,
Excellent info. What brand are the guides you use? or do you have them made?
Thanks for the offer to discuss this on the phone - you're right about this being complex! What started out as an attempt to find a way to predict valve guide wear has turned out to be an impossibility. At least when trying to use Oil Analysis in that respect.
It's nice to have a pro available to answer these kinds of questions.
Excellent info. What brand are the guides you use? or do you have them made?
Thanks for the offer to discuss this on the phone - you're right about this being complex! What started out as an attempt to find a way to predict valve guide wear has turned out to be an impossibility. At least when trying to use Oil Analysis in that respect.
It's nice to have a pro available to answer these kinds of questions.
Our P-B guides are made just for us.
Marv is right; oil analysis is a great tool for determining proper oil change intervals and an indication of impending engine internal "difficulties".
In my experience, high silicon content is indicative of dirt in the engine. Thats usually a case of insufficient filtering for the environment and in some cases, a poorly fitting element. I've never seen ring failures from improper breakin caused by synthetic oils.
We use synthetic oils from the very start and perform this procedure on our engine dyno under carefully controlled conditions. IMHO, few people really know how to properly break-in a new engine. It REALLY tests ones patience.
06-11-2005, 06:25 PM
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Steve,
Thanks for all that you contribute to this board. While it's a little late discussing proper break-in on my 96 993 w/ 82K miles I am curious how one might go about it.
Thanks for all that you contribute to this board. While it's a little late discussing proper break-in on my 96 993 w/ 82K miles I am curious how one might go about it.
06-11-2005, 06:45 PM
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Hi Steve,
Thanks for the info - do the OEM guides for earlier 911s (since we started out talking about 993 guides I assume you were talking about 993s) have the same. hmm...limitations? If I decide to rebuild my '74 911 one day would the OEM be acceptable or would it be advisable to get yours?
You're right about using synthetic from the beginning - that's what Porsche does and I probably would have ended up with the same results if I'd started with synthetic. As far as break-in, I did a series of runs where I got up to about 30mph then accelerated *hard* up to 50-60, then coasted back down to 30 and repeated the process over & over. I did this 30 or more times during the 1st 1000 miles. I also made sure not to drive at a constant speed for very long - varying speeds is very important in seating the rings properly. Not sure how much it contributed to the current, excellent condition but it didn't hurt. I've heard the old saying about "driving it hard from day one" but I don't follow that suggestion.
If you have time to tell us about your break-in procedures I'm sure a lot of people would be interested.
Thx,
Larry T
The Oil Analysis Co.
www.youroil.net
Thanks again for sharing your expertise -
Thanks for the info - do the OEM guides for earlier 911s (since we started out talking about 993 guides I assume you were talking about 993s) have the same. hmm...limitations? If I decide to rebuild my '74 911 one day would the OEM be acceptable or would it be advisable to get yours?
You're right about using synthetic from the beginning - that's what Porsche does and I probably would have ended up with the same results if I'd started with synthetic. As far as break-in, I did a series of runs where I got up to about 30mph then accelerated *hard* up to 50-60, then coasted back down to 30 and repeated the process over & over. I did this 30 or more times during the 1st 1000 miles. I also made sure not to drive at a constant speed for very long - varying speeds is very important in seating the rings properly. Not sure how much it contributed to the current, excellent condition but it didn't hurt. I've heard the old saying about "driving it hard from day one" but I don't follow that suggestion.
If you have time to tell us about your break-in procedures I'm sure a lot of people would be interested.
Thx,
Larry T
The Oil Analysis Co.
www.youroil.net
Thanks again for sharing your expertise -
06-11-2005, 07:18 PM
#14
RL Technical Advisor
Hi Larry:
All OEM guides seem to be the same crap; even the newest GT-3's and GT-3 race engines use the same material. We sold a bunch of our guides to Porsche Motorsports last year,..
If you rebuild your 2.7,...I'd strongly recommend something better, whether its our P-B ones or another product would be your call. Beyond that, any guide must be hand-honed and fitted correctly to ensure a long life.
I subscribe to your break-in technique. Basically, thats correct as one just monitors oil temps and keeps things cool during this process. It takes a lot of discipline to do this and honestly, its not much fun. Leakdown testing and oil consumption tells you when everything is seated and its "ready to go".
At this juncture, I must say that street engines and race engines are not the same with regard to longevity and in the genre of competition engines, certain tolerances are loosened to prevent problems since these always get a minimal running-in before being run very hard. Street engines are expected and should last for hundreds of thousands of miles (with correct maintenance) so extra care is taken during that process.
When I get a moment, I'll write up a break-in procedure for street engines and post it on my website.
All OEM guides seem to be the same crap; even the newest GT-3's and GT-3 race engines use the same material. We sold a bunch of our guides to Porsche Motorsports last year,..
If you rebuild your 2.7,...I'd strongly recommend something better, whether its our P-B ones or another product would be your call.
Beyond that, any guide must be hand-honed and fitted correctly to ensure a long life.I subscribe to your break-in technique. Basically, thats correct as one just monitors oil temps and keeps things cool during this process. It takes a lot of discipline to do this and honestly, its not much fun. Leakdown testing and oil consumption tells you when everything is seated and its "ready to go".
At this juncture, I must say that street engines and race engines are not the same with regard to longevity and in the genre of competition engines, certain tolerances are loosened to prevent problems since these always get a minimal running-in before being run very hard. Street engines are expected and should last for hundreds of thousands of miles (with correct maintenance) so extra care is taken during that process.
When I get a moment, I'll write up a break-in procedure for street engines and post it on my website.
