Excessive Oil Consumption - Every 993 0wner should read!
07-08-2015, 01:08 PM
#46
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Chuck
07-08-2015, 01:23 PM
#47
Drifting
Excessive Oil Consumption - Every 993 0wner should read!
It is clear that worn valve guides will cause plugged SAI ports however could ordinary carbon build up that exists in internal combustion engines be the cause for some plugged port cases and could techron or some other cleaner help address or prevent this issue? Is fuel quality at all at play here?
07-08-2015, 03:09 PM
#48
Drifting
It is clear that worn valve guides will cause plugged SAI ports however could ordinary carbon build up that exists in internal combustion engines be the cause for some plugged port cases and could techron or some other cleaner help address or prevent this issue? Is fuel quality at all at play here?
07-08-2015, 03:47 PM
#49
RL Community Team
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OK so I have been following this thread and came up with this scenario, Owner regularly inadvertently overfilling oil until what appears to be excessive oil condition is observed or the burning of the oil clogs the secondary air injector ports and a self-inflicted top end rebuild ensues.
Andy
Andy
Last edited by pp000830; 02-20-2019 at 07:04 PM.
07-08-2015, 03:48 PM
#50
OK so I have been following this thread and came up with this cenerio, Owner regularly inadvertantly overfilling oil until what appears to be excessive oil condition is observed or the burning of the oil cloggs the secondary air injector ports and a self inflicted top end rebuild ensues.
Andy
Andy
07-08-2015, 05:41 PM
#51
Banned
OK so I have been following this thread and came up with this cenerio, Owner regularly inadvertantly overfilling oil until what appears to be excessive oil condition is observed or the burning of the oil cloggs the secondary air injector ports and a self inflicted top end rebuild ensues.
Andy
Andy
07-08-2015, 05:47 PM
#52
Banned
Great read Bob, thanks for providing the link. I had already read the clean out procedure and seen the video. Hope at least all the '96 guys are satisfied with their solution. However, I was really hoping that people could come up with the solution to the basic issue of building carbon in the ports. From other reading, it seems that bad valve guides are an element. Further, it seems that the valve guide seals are to good stopping the guides from getting any oil until they wear badly and then the oil comes pouring through causing the carbon. Some suggested that the 5W oil can get through and some have suggested that the spring around the seal be removed. Guess that's for further exploration.
Chuck
Chuck
Just a bad design to satisfy US smog requirements. The crazy thing is once the car is warmed up the SAI is useless.
I do believe that if you are in a position to fully warm the car up each time it is started (or most of the time) this will reduce or even eliminate the carbon build up. And I do agree that if you at some point you get better value guides in this will help. And 5W should not be used in any case.
07-08-2015, 05:55 PM
#53
07-08-2015, 06:07 PM
#54
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02-15-2019, 04:13 PM
#55
If too full, the oil gets ingested into the SAI system, where at 45K miles the SAI check valve can and probably has been rendered ineffective for its intended purpose. This would allow hot exhaust gasses up into and throughout the SAI system, thereby coking the over filled oil that gets ingested from over filling the engine oil.
Could some less than scrupulous repair shops perform top end rebuilds, where not necessary and also propagate the soft Porsche valve guide material.
When extrapolating data, it is not accurate to state how many cars required, or were claimed to require top end rebuilds at a "repair" shop; as there are many vehicles into 100K - 200K miles, without necessitating a top end rebuild.
The only valid data is the # of vehicles actually requiring top end rebuilds against the number of vehicles imported or grey marketed into the US. This would EXCLUDE those engines exhibiting excessive oil consumption from overfilling the engine oil !
02-15-2019, 06:49 PM
#56
Yes indeed, but what is not known, is how full the oil level was kept for those 45000 miles...
If too full, the oil gets ingested into the SAI system, where at 45K miles the SAI check valve can and probably has been rendered ineffective for its intended purpose. This would allow hot exhaust gasses up into and throughout the SAI system, thereby coking the over filled oil that gets ingested from over filling the engine oil.
Could some less than scrupulous repair shops perform top end rebuilds, where not necessary and also propagate the soft Porsche valve guide material.
When extrapolating data, it is not accurate to state how many cars required, or were claimed to require top end rebuilds at a "repair" shop; as there are many vehicles into 100K - 200K miles, without necessitating a top end rebuild.
The only valid data is the # of vehicles actually requiring top end rebuilds against the number of vehicles imported or grey marketed into the US. This would EXCLUDE those engines exhibiting excessive oil consumption from overfilling the engine oil !
If too full, the oil gets ingested into the SAI system, where at 45K miles the SAI check valve can and probably has been rendered ineffective for its intended purpose. This would allow hot exhaust gasses up into and throughout the SAI system, thereby coking the over filled oil that gets ingested from over filling the engine oil.
Could some less than scrupulous repair shops perform top end rebuilds, where not necessary and also propagate the soft Porsche valve guide material.
When extrapolating data, it is not accurate to state how many cars required, or were claimed to require top end rebuilds at a "repair" shop; as there are many vehicles into 100K - 200K miles, without necessitating a top end rebuild.
The only valid data is the # of vehicles actually requiring top end rebuilds against the number of vehicles imported or grey marketed into the US. This would EXCLUDE those engines exhibiting excessive oil consumption from overfilling the engine oil !
02-15-2019, 08:28 PM
#57
Racer
I had my top-end rebuilt at about 55k miles. The engine had to come out to have the case re-sealed (leaking from the through-bolts), because the car had sat idle for at least 2 years before I acquired it. While they were in there, I had the top-end rebuilt as well, using after-market valve guides. Now, many years and 40k miles later, I drive 5k miles per year without having to top-off the oil between each oil change. As for the oil fill-level, I set the oil level so that it is near the top marker when at maximum temperature. Some might call this over-filling; but, 5k miles later the oil level only drops to about the middle of the range, which I believe is well under 1 quart per 5k miles. I wonder how many 993 owners without top-end rebuilds can go 5k miles without having to top-off the oil level?
Last edited by Ivan J; 02-15-2019 at 09:33 PM.
02-16-2019, 03:17 AM
#58
Such an intelligent response requires none; since the point was missed completely...
The oil level gauge needs to be calibrated by the owner, with regards to the actual oil level on the dip stick or its unreliable as to the actual engine oil level of the car.
There are contributing causes, and then there is a root cause to clogged SAI ports. I will put $10k on the root cause of overfilling engine oil as opposed to worn valve guides as being the root cause of clogged SAI ports...Go strong or go home!
Contrary to the OP's belief, he was not the catalyst to the contributing vs root cause of the SAI port issue, but is rather parroting what has already been challenged to Steve Weiner's original proclamation of soft valve guides as being the primary cause of clogged SAI ports.
Mr. Weiner even went as far as to accept the root and contributing causes, since it was far more likely that engine oil overfills were coking the SAI ports, rather than worn valve guides.
The oil level gauge needs to be calibrated by the owner, with regards to the actual oil level on the dip stick or its unreliable as to the actual engine oil level of the car.
There are contributing causes, and then there is a root cause to clogged SAI ports. I will put $10k on the root cause of overfilling engine oil as opposed to worn valve guides as being the root cause of clogged SAI ports...Go strong or go home!
Contrary to the OP's belief, he was not the catalyst to the contributing vs root cause of the SAI port issue, but is rather parroting what has already been challenged to Steve Weiner's original proclamation of soft valve guides as being the primary cause of clogged SAI ports.
Mr. Weiner even went as far as to accept the root and contributing causes, since it was far more likely that engine oil overfills were coking the SAI ports, rather than worn valve guides.
Last edited by nine9six; 02-16-2019 at 03:39 AM.
02-16-2019, 09:13 AM
#59
Rennlist Member
Such an intelligent response requires none; since the point was missed completely...
The oil level gauge needs to be calibrated by the owner, with regards to the actual oil level on the dip stick or its unreliable as to the actual engine oil level of the car.
There are contributing causes, and then there is a root cause to clogged SAI ports. I will put $10k on the root cause of overfilling engine oil as opposed to worn valve guides as being the root cause of clogged SAI ports...Go strong or go home!
Contrary to the OP's belief, he was not the catalyst to the contributing vs root cause of the SAI port issue, but is rather parroting what has already been challenged to Steve Weiner's original proclamation of soft valve guides as being the primary cause of clogged SAI ports.
Mr. Weiner even went as far as to accept the root and contributing causes, since it was far more likely that engine oil overfills were coking the SAI ports, rather than worn valve guides.
The oil level gauge needs to be calibrated by the owner, with regards to the actual oil level on the dip stick or its unreliable as to the actual engine oil level of the car.
There are contributing causes, and then there is a root cause to clogged SAI ports. I will put $10k on the root cause of overfilling engine oil as opposed to worn valve guides as being the root cause of clogged SAI ports...Go strong or go home!
Contrary to the OP's belief, he was not the catalyst to the contributing vs root cause of the SAI port issue, but is rather parroting what has already been challenged to Steve Weiner's original proclamation of soft valve guides as being the primary cause of clogged SAI ports.
Mr. Weiner even went as far as to accept the root and contributing causes, since it was far more likely that engine oil overfills were coking the SAI ports, rather than worn valve guides.
