Oil restricrors revisit

[afterburn 549]

Was looking and reading an other thread, and it was about oil P. (low)
I made the pt that oil rerstrictors might be the ans .
I "thought they were the way to go" but that was not the word there from a few ( and I do respect the few that said this )
So, to make a long story those that know,.. will you please define Yes , or No
Was it a blooper on Porsche's part to cover a problem, or, are they a great idea ?
thanx

[Flieger]

I thought Grady's point about the piston squirters needing to open earlier on larger 3.0, 3.2 engines being lugged was interesting. The 964 which first used them had a higher volume/pressure ratio on the oil pump. All the valvetrain parts need lubrication and the oil helps cool the head.

This may have been in the thread you were referring to and it was good enough to confirm my previous position that the restrictors are bad.

[afterburn 549]

Yes to me too, was some thing I never ever considered.
As far as bad , I will not fight city hall, I will change my wicked ways...Just at one time maybe it was a fad ? It was the big deal to do ?..Mine have been in at least 5 years...The valves have always measured fine at adj time.
How could some one like me be wrong.....again !! LOL

[Flieger]

Oh, it was certainly "the thing to do" right after the part superceeded the old unrestricted fitting. Many mechanics thought they were good and made the change when rebuilding. Porsche doesn't consider the old cars much so they said it was good for all Porsche engines.

After lots of miles and testing, more wear can be seen in the top end due to less lube and more heat.

It is like running bad, reformulated oil. It will not explode your motor but it will wear much more.

[afterburn 549]

So ... some where I missed the boat , the latest pelican tech bulletin ! I should have never put these In ! ?
These were for upping bottom End O.P. and popping the piston oil squatters At a lower RPM @ the sacrifice of cylinder cooling and cam wear ? ! ? ! ?
Well ,I will take them out...of course..but to date there has not been any significant cam wear in my case.....

[Henry Schmidt]

We have been using a version of the cam feed restrictor since the late 80s, even before Porsche first fitted them in 1991. We used to make them now we just buy them. Porsche reduction in cam tower oil flow from 18 gals to 12 gals only confirmed our understanding of the flow requirements of two valve top ends.
We see no down side to using these fittings.
Like with many theories, the theories don't match the actual data. Much like boat tailing cases, theories about extra wear and cooling shortfalls are not supported by the data.
Use the restrictors with confidence as we do in every engine (race or street). Perhaps 300-350 engines with no signs of unusual wear or cooling issues.

[afterburn 549]

Thanks Henry ! I think this was the consensus several years ago..after much debate.... just put them in.
I have been telling every one else to install them now for several years on this board
So I guess the next thing is proof of good or evil ?
In my case ..so far there has been no bad things erupting ..yet

[Gertvr]

Hi

I am new to this forum, been mostly researching on the Tech forum. Was about to post a new thread when I saw this thread.

I have a 78 RoW SC engine in my project car that is stock except for the Carrera tensioner upgrade. I had no oil leaks (well some small ones at the valve covers that i fixed) prior to installing the cam feed restrictors. Initially there was a small leak that was difficult to trace but it seemed to be from the chain housing cover. Long story short it got progressively worse and seems to be coming from the mating between the cam housing and the chain housing and now from both sides. Can this be as a result of this upgrade or just more abuse, as the car was not tracked before i got it, and has since been seeing a lot of track time.

Has anyone seen this before?


Thanks

Gert

[afterburn 549]

Hmm seems if anything the pressure would be less in there ..so, might be coincidental ?

[914/6]

did you user new sealing rings when installed the restrictors ?

[Gertvr]

Originally Posted by afterburn 549

Hmm seems if anything the pressure would be less in there ..so, might be coincidental ?

Im not a strong believer in coincidence You are right about the pressure since the flow is reduced, so I'm even more at a loss.

Originally Posted by 914/6

did you user new sealing rings when installed the restrictors ?

Yes, it was part of the kit and the area around the restrictors are dry.

It looks like i will have to pull the engine to fix these leaks. The cause might be more clear once the engine is out.

[WERK I]

Originally Posted by afterburn 549

......
So, to make a long story those that know,.. will you please define Yes , or No.....

High mileage engine- a BIG NO
I tried these restrictors on my 911 SC as an experiment. It had low oil pressure at idle, but not bad enough to illuminate the oil pressure light. After adding the restrictors, the engine developed an oil leak off the rear main seal immediately after the addition.

Rebuilt Normally aspirated engine - Yes

Rebuilt Turbo Engine - On the fence with this one. My engine - No
I guess it depends on the target HP of the engine.

[Henry Schmidt]

That's silly.
Adding the oil restrictors did not cause your rear main seal to leak, just like washing your car didn't cause it to rain.
The restricters do not create oil pressure. The seal was subjected to the same max pressure at rpm with either fitting.
The purpose of the restrictor is to reduce some of the unnecessary oil flying around in the heads and cam towers at high rpm. As a result, you can sometime experience a higher pressure at idle (3-5 lb.) with the restrictors.
Max oil pressure will not be increased at high rpm (4000+) because that pressure is controlled by the pressure relief and safety valves.
The only time you may see an increase in max pressure is if you rev your engine when it's cold. If you do that, you deserve more than a flywheel seal leak.

[WERK I]

Originally Posted by Henry Schmidt

That's silly.
Adding the oil restrictors did not cause your rear main seal to leak, just like washing your car didn't cause it to rain.
The restricters do not create oil pressure. The seal was subjected to the same max pressure at rpm with either fitting.
The purpose of the restrictor is to reduce some of the unnecessary oil flying around in the heads and cam towers at high rpm. As a result, you can sometime experience a higher pressure at idle (3-5 lb.) with the restrictors.
Max oil pressure will not be increased at high rpm (4000+) because that pressure is controlled by the pressure relief and safety valves.
The only time you may see an increase in max pressure is if you rev your engine when it's cold. If you do that, you deserve more than a flywheel seal leak.

Geez Henry, cool your jets. I'm just telling everyone what happened.

I don't drive spiritedly until the oil temp gets up to normal operating temp with any engine.
The rear main wasn't leaking before the change and I noticed the drip the day after a trip. It was a "high mileage" with 76K miles on odometer. Maybe a coincidence? Probably not. The oil seal was probably near the end of its lifespan and the leak wasn't severe......maybe a drop or two. Everyone that had done the mod in previous threads, saw an increase of pressure at idle of a few pounds and about 5-10 pounds at RPM ranges 3K and up.

[afterburn 549]

Well..when this is done ( this thread ) I am going to file it as done no mater what the out come
Knowing what I think I know..the oil in the cam towers is just left over from the spray tubes..there is probably some thrown up in the chain boxes via a chain ride...
The rear seal sees what it saw in the 1 st place so...it seems to me the leaks are an other issue.
By the way..when this idea was hashed over a couple years ago...even the oil, amount of and volume (being less )several other things were addressed and it all came out a plus all across the board by smarter minds then me.
Wish i could find the thread..but this search button is...not user friendly.
Like said I installed mine shortly after break in with no problems.....so far

[Henry Schmidt]

Originally Posted by WERK-I

Geez Henry, cool your jets. I'm just telling everyone what happened. .........edit.........

Well Dave, what you were telling everyone was don't use restrictors on an old engine "BIG NO" because they caused your flywheel seal to leak.
My comment was that your conclusion may be flawed. Your observation may have been accurate but your reasoning [cause and effect] is suspect.

[WERK I]

Henry, thanks for your reply. Well, I think "cause and effect" would apply. If you increase the amount of oil to the mains that are on the edge of their specifications(worn), more oil is going to be passed out through the mains to a worn rear main seal that is probably on the edge as well.

I guess what I'm trying to get at is this; Don't use the restrictors on a high mileage engine just to get the oil pressure up. Fix the problem, not mask the symptoms.

[afterburn 549]

OK , for fun lets say your mains are worn, really worn., The crank is wobbling around in there doing the Watusi, the Freddie, the Twist. Would not that equal less pressure to the system now that you are hemorrhaging everywhere out all of the mains ?
Now all the mains , Not just one has oil taking the path of least resistance, to the bottom of the case.
So there would be less oil to the last main too and with a big drain hole there..a EZ path to the bottom....
So by this theory it would be more dangerous to use these in a "fresh" Eng then a old worn tired thing....because there would be more pressure in the system ?
Porsche did not think so.
Did they make a mistake ?
redesign the oiling system ?

[WERK I]

Originally Posted by afterburn 549

OK , for fun lets say your mains are worn, really worn., The crank is wobbling around in there doing the Watusi, the Freddie, the Twist. Would not that equal less pressure to the system now that you are hemorrhaging everywhere out all of the mains ?
Now all the mains , Not just one has oil taking the path of least resistance, to the bottom of the case.
So there would be less oil to the last main too and with a big drain hole there..a EZ path to the bottom....
So by this theory it would be more dangerous to use these in a "fresh" Eng then a old worn tired thing....because there would be more pressure in the system ?
Porsche did not think so.
Did they make a mistake ?
redesign the oiling system ?

Thanks for rational and logical response. I see this thread is taking the same insulting twist as in the previous thread about the oil restrictors. Porsche added the restrictors in the 964 engine because the increased size of the piston squirters which run off the mains. The Porsche air cooled engine oiling system is not perfect and it had been tweaking it for years.
I tried the restrictor as an experiment and that was the result. I put the restrictors in to see what the delta would be on an engine with relatively high mileage. Argue and insult all you want, but that is what happened. I'm a firm believer in "cause and effect" and in this case it was undeniable. Why anyone would want to put them in an engine that is running perfectly fine for thousands of miles, is beyond me.

[afterburn 549]

Insulting ? Sir, I was speaking same as over a cup of coffee or a beer
NEVER no insult intended................where did you get that ?