Did installing the oil line restrictors create a oil leak ??

hbkramer · 06-22-2006, 05:48 AM

79 SC, 71K/mi.:
I just added the oil line restrictors in the cam housings while updating to the oil fed tensioners.
So, I now have an engine with improved oil pressre,(approx 5 psi at speed- previously at 3-4).
In checking all the fittings/gaskets for oil leaks, cam covers, valve covers and new oil lines ,I found no leaks in my work, yeah!
But after a lengthly test drive I found a small oil leak at the rear of the engine(flywheel)

My question is:, Did installing the oil line restrictors ,which increased the oil pressure( 4 to 5 at speed) affect an otherwise happy and holding engine seal?
Thanks
Bruce

Mysterytrain · 06-22-2006, 10:47 AM

I had the restrictors installed on my engine after a rebuild. I really hated seeing 5 bar at start up, but I didn't see any leaks until I switched to Mobil 1 this spring. After a few hundred miles it appeared that my oil cooler seals began to leak. I decided I had enough and launched a two prong attack..drilled the restrictor openings to 3.5 mm and dumped the the mobil 1 for some 20/50 dino oil. My leak stopped and my oil pressures look much better. 4 bar cold & 1.5 bar warm at idle.

sammyg2 · 06-22-2006, 11:06 AM

No, the odds are that the restrictors did not cause your oil leak at the rear of your engine.
Guage reading you are seeing is not in psi, it is in bar.
1 bar = about 14.7 psi.
So 5 bar would equal about 74 psi.

hbkramer · 06-22-2006, 11:10 AM

Ron , thanks for the input. Glad to hear it was reversible,as once the seals go, I always believed they were gone,especially with increased internal pressure.
I will watch this, and may end up removing the rstrictors as you did,which takes all of 20 min. plus new crush washers.
Thanks
bruce

911pcars · 06-22-2006, 11:59 AM

Bruce,
IMHO, you assumed two independent variables as the cause of your oil leak. It's very possible that combination was the cause of your oil leakage. However, many owners report new oil leaks switching from dino to synthetic with no other changes.

What if you had adusted the ignition timing at the same time as well? I would have just switched back to dino oil and see if that cured the leak before backtracking.

In my case, the oil line restrictors didn't seem to encourage more oil leaks than the ones that existed before. :-)

Sherwood

hbkramer · 06-22-2006, 12:03 PM

Sammy, thanks for the correction, psi vs bar.
So, you dont think that an additional 1 bar /14.7 psi would stress a seal in a 70k mi engine. ??
If yo u over fill the oil level in the crank case the added volume is reported to have blown oil seals. I am guessing that the inc in oil volume and resulting oil pressure would have caused a failure. No?

Mysterytrain · 06-22-2006, 12:08 PM

No, I said I had no leaks with the restrictors just real high pressures.
Changing to M1 gave me leaks
Changed back the 20/50 GTX and luckily the leaks stopped.
Drilling the restrictors out to 3.5 mm and the insane cold start pressures were reduced.
Sorry if I wasn't clear on my thought process.

Wil Ferch · 06-22-2006, 01:32 PM

Well...how about this ???

Use of cam oil restrictors results in more pressure to the main bearing area.

Couldn't there be a case made whereby more pressure to the mains = more pressure to the crank "end" seals ????

- Wil

A Quiet Boom · A Quiet Boom's Garage

There is no pressure at the crank seals, at least not oil pressure. There may be some vacuum from the oil pump or possibly some pressure if the pistons have too much blowby.

Rick V · 06-22-2006, 03:21 PM

I did the same upgrade you just finished, (tentioners/restrictors) I found no extra leaking, and I use Mobile1 15w-50 That is what the car has been fed since day one. I changed my stuff out at around 100k.

hbkramer · 06-22-2006, 08:11 PM

Ch 4 p. 83 Wayne's Engine book on Oil pressure restrictors.
"oil pressure is higher at the main brgs,the rod brgs and piston squirters. oil pressure will inc 10-20 psi with the restrictors",
which A)reduces foaming in the cam housings,which B) allows the pump to pump it back to the oil tank quicker and also c) should give more accurate oil level readings.
No mention of any ill effects of this mod to older engines.

I did make a few assumptions with the onset of the leaks and forgot that i jack my car with a wood 4X6 block of wood on a floor jack under the sump.... this may also have contributed to my new leaks...I will keep an eye on it.
Bruce