Early Car Update to Restricted Cam Oil Line Fitting ???

[JCR]

Has anyone performed this modification? See below link to .pdf tech article from Dieter's (450kb).

Cam Oil Line Fitting Update


I'm looking to get my oil pressure up, and this seems to be a recommended way to do it - with additional benefits. I run 20W 50 dino oil and am a bit concerned with having enough flow before oil is up to temp.

I've searched the topic, and haven't found much here or on Pelican. Any of the typical excellent advice from the registry gurus is much appreciated!

[HarryD]

Has anyone performed this modification? See below link to .pdf tech article from Dieter's (450kb).

Cam Oil Line Fitting Update


I'm looking to get my oil pressure up, and this seems to be a recommended way to do it - with additional benefits. I run 20W 50 dino oil and am a bit concerned with having enough flow before oil is up to temp.

I've searched the topic, and haven't found much here or on Pelican. Any of the typical excellent advice from the registry gurus is much appreciated!

I am nothing close to an expert, but I must be totally ignorant as to why you want to put restrictors on an oil system (unless of course you think the folks who designed these systems in the first place were dumb).

His statemetn that the flows look ok is very scary as how many people can visually tell the difference between 1 gpm vs 2 gpm out of an spray nozzle anyway. I know I can't.

That said, what the restrictors appear to be doing is create a backpressure in the main oil line to force more oil to the lower (crank and rod) bearings at the expense of reduced flow to the cams. This has a byproduct of raising the APPARENT Oil pressure since the transmitter is on the high pressure side of the Oil restrictor. You have not changed the source of the pressure (the pump) so it is already doing all it can.

I am also concerned that by reducing oil flow closer to the top of the engine, you are reducing an opportunity for using the oil to move excess heat to the oil cooler.

While I know there are cases where the lower bearing have failed due to inadequate lubrication, I sincerely doubt this was a original design defect that requires this type of "half---ed" fix. If that was the case, how do many of these engines give 150-200+k miles of service prior to bottom end rebuild?

Like I said, I must have missed something.

[RandyWebb]

Harry, What you missed is PAG's TSB on this. They say to do it. The Dieter guy didn't think it up.

But, I have had engine builders say not to do it (on a carb'd hot rod engine).

That's all I know - except that you are reducing foaming (good) and reducing flow to the cams in order to get more flow to the crank area I guess. I would do it on a stock engine. There was a short article in Pano or Excl. a few months ago on this.

Maybe some engine builders slike Steve W. will weigh in on this. However, all the builders in North America don't have the engineering resources that PAG does. If they say to do something, I would take it seriously. That does not mean to do it always - as they are prob. not evaluating modified engines or ones using oil types that are no longer recommended (dino oils).

[HarryD]

Harry, What you missed is PAG's TSB on this. They say to do it. The Dieter guy didn't think it up.

But, I have had engine builders say not to do it (on a carb'd hot rod engine).

That's all I know - except that you are reducing foaming (good) and reducing flow to the cams in order to get more flow to the crank area I guess. I would do it on a stock engine. There was a short article in Pano or Excl. a few months ago on this.

Maybe some engine builders slike Steve W. will weigh in on this. However, all the builders in North America don't have the engineering resources that PAG does. If they say to do something, I would take it seriously. That does not mean to do it always - as they are prob. not evaluating modified engines or ones using oil types that are no longer recommended (dino oils).

Randy,

I have seen the article and I can see where they are coming from. Like you said, the PAG engineers have vast resources for this type of thing and we need to respect their findings/recommendations. Indeed, most often the factory engineers have already beat to death all of the objections we can think of (plus the ones we haven't) in order to get their recommendations published. In most cases, they do an excellent job.

Still I have to wonder why my stock 2.4L T engine using 20W-50 dino (changed every ~3000 miles) would benefit from this change. I asked my wrench about this update and he too was not sure why I would benefit.

I guess my real question is that if this was such an important change, why was it not identified as needed until 1991? What is the history that led us here? Is this an issue like the tensioners that was apparent early on but not addressed due to more pressing concerns or just part of the normal evolution of things?

Like most things in life, you pay your money and you take your chances....

[HarryD]

Here is a thread from Rennlist on this topic.

http://forums.rennlist.com/rennforum...il+restrictors

Any thoughts?

[RandyWebb]

Those are all valid questions. But the answers can range from modern oils after 1991 to a new junior engineer who poked around into things nobody had thought to do. Maybe she had a statistics background and found something nobody had ever looked for before. It could be almost anything. I would scrutinize the TSB carefully as to what cars it applies to.

We can all agree that foaming is bad.

And, we can all agree that wear on the crank is usually not a problem in the first 200,000 miles. So....

[HarryD]

Randy,

Glad we can agree on things.

Now I need to go look and see if I have the updated restrictors or not.

[pwd72s]

I believe in the old

: "If it still works, don't (mess) with it" theory. The factory design has worked since 1972. I'm not going to "mess" with it.

[Jens]

Anything and everything we can do to these classic cars to make them last longer is always a good thing. The 911 has ALWAYS been about development...every year and even mid year since dat one. If this pans out to be an actual, functional improvement and not change the character of the classic, then I'm doing it. I'm dying to hear the technical analysis...and benefit if any.

[pwd72s]

Anything and everything we can do to these classic cars to make them last longer is always a good thing. The 911 has ALWAYS been about development...every year and even mid year since dat one. If this pans out to be an actual, functional improvement and not change the character of the classic, then I'm doing it. I'm dying to hear the technical analysis...and benefit if any.

DITTO! I've read of the change, but not enough to convince me to do it...and I did convert my '72 to the Carrera tensioners. So I'm not totally hung up on originality, but want to be damned sure that any modification would be a true improvement, not the latest fad...