Race Engine Forum UK

Hello, I just completed a rebuild of my 1608 engine with:
new gasket / seal set
piston rings
valve seals
etc...
I am keeping everything stock, rebuild went well except that my cam exhaust seal is leaking behind the front pulley. The seal I obtained from my supplier was mfg. by AKRON, I obtained a new seal mfg. by BECK/ARNLEY and still have the same problem.
No problems are seen on a close visual inspection of seal surface and my oil pressure is within normal range.
I was told that this a well known leak point and may have to live with it, I never had the problem before the rebuild and I am not happy with that answer. Can you provide a seal that may correct my problem? Any information would be appreciated.
Thank you

This is most commonly where the block face or head face has been 'dressed' with carborundun paper or similar and debris has become trapped in the oil feed holes to the head. There are 6 on the block. The debris gets forced into the cam front journal housing by oil pressure and tears into the cam nose, housing and seal. Leak from the cam seal generally results.


G

Thank You for your fast and informative response, could you suggest the best way to correct the problem or is another rebuild in my future?
Thank You

Pull the camboxes and remove both seals, polish the cam journals with light oil and fine Scotchbrite, clean with brake cleaner or similar solvent and do the same to the camboxes esp front journal housing. Reassemble with new seals but be sure to use OE type with polymer coated case.

Sorry I am in a hurry - I can offer pics tomorrow if_u_need.

G

Thank you for the helpful response. At your convenience, If you could post pictures it would be greatly appreciated.
Thank you again

Photo captions should tell you most of the story..

Worth mentioning that in addition to the debris cause I remarked on already, dry start or over-tightened cambelt can cause scuffing damage too. Always use engine oil and a tiny bit of molybdenum grease in the cambox bores on reassembly. Naturally the seal inner diameter & cam nose needs a bit of oil on it too.

G

The thing worth mentioning is straightness of the seal in the housing. This size oil seal can tolerate only 0,20 mm diagonal declination (hope my words are right ones). After that it's gonna worn out fast and leak for sure. So make sure the seal is perfectly in place and straight.

As Guy also mentioned, Viton seals are the best. They can tolerate up to 200 deg. C of heat and thet don't really deteriorate. I'm also used NBR (nitrile rubber) ones with great success in street use when stress is much more lower than in racing.

... As a a rule I use OE ones that ....

Hey Guy thank you for sponsoring my company. We produce the OEM types you will find cfw on the OEM or Corteco on the aftermarket types. They are out of the same tooling.

For user who are interested to learn more radial shaft sealings.

Technical handbook: http://www.simrit.de/files/000013AE.pdf
Catalogue: http://www.simrit.de/files/00001387.pdf


Nils