Hi, this is my first post on this site! Looks like a great place and a wealth of knowledge. I've got a Cosworth YB N/A in my Westfield.

Got a slight leak on my Cosworth YB. Definitely from high up at the front so replaced the rocker cover gasket (Cometic) and new half moon seals off ebay like this http://www.ebay.co.uk/itm/COMETIC-CO...item4604945754

Also put some Loctite 5910 on the corners where the half moons touch the cam cover gasket.

Anyway, to cut a long story short it's still leaking and I can see a small stream of oil running down the front of engine. Anyone got any experience with the half moon seals from above link? Can leaking half moons still mean a dry looking rocker cover? as I can't see any obvious signs of the cover weeping now. Or is it more likely to be cam seals - it's got to be somewhere in the general area though. Any thoughts?

Cheers

 

had this on my saff and it was the cam seals.

 

Try cam seals. I also always fit genuine half moons as I find aftermarket ones to be to slim

 

Thanks. Sorry to sound stupid but is there a best way to removing cam seals?

 

You have to take ti all apart get seals out.
Haveing the same problem here as replaced camseal half moons ect and still leaking.
Goto-do as advise by HT raceing is to ell seal the front cam bearing suports underneath!
As oil will crap out under.
let me know and when done let you know if this works.
pete 241 coz Mk1 race project...

 

Hi Robo,
I run a YB Turbo in a Dax Sprint and Hillclimb car. We had the same problem some time ago. We ended up fitting a cometic gasket plus the half moons. We also used a very good gasket seal product called Wellseal. Its not cheap (Ł20) ish but is very good. We put the wellseal on the underside of the half moons and the cometic gasket with a bit extra around the area where the half moons join the gasket.
My engine is around 300bhp and we have struggled to keep the oil in it ! and are currently reviewing the breather setup.
The place to look closely is where the half moons join the cometic just behind the cam pulleys.

 

You can remove them by removing the cam pulleys (at least on 2WD you can) remember to use VITON seals, otherwise you are just going to have the same problem.

But as said the half moon seals (You will need to remove the cam cover for these) also cause problems and aftermarket ones aren't always the correct dimensions which causes the issue.

Worn 'spacers' can also cause leaks.

Martin

 

I had this on mine but noticed one or the cam seals had pushed out slightly so I pushed it back in gave it all a good clean with some brake cleaner and has been leak free since.