Yet another 308 camshaft question. I have literally spent days reading many very good threads about 308 cams, cam timing and degreeing, etc. Lots of really great information, and I am still reading. So here we go: 1978 GTB, the cams are off and I am ready to put them back on. Some threads on this great site state that it is easier to replace the cam seals when the cams are off. One says that you slide the seal over the lobes on the cam before you bolt it in place. So, here's my question: Don't the seals need to be installed using a drive-tool after the valve cover is in place ? And if so, the cam timing pulley need to come off anyway !? How are you all installing the seals when the cams are OFF ? If this can be done without having to remove the belt pulleys from the cams it will save me some work for sure, but I want to do it correctly to avoid more leaks. Funny thing is it seems that the old leaky seals I removed appeared to possibly have been installed BEFORE the valve cover was bolted in place. I see some funny pinch marks on the old seals at the seam between valve cover and head. Thanks H
And therein lies the answer to your question. But you still need the pulley off to degree the cams and pin the pulley in the right position to index the belt teeth.
The front cam seals go on before you install the cam. You really can't get them in once the cover is in place and everything is torqued down. When I did it, I put the fronts on, set the cam in place, put the caps in loosely, then slipped the rear seals on before tightening the caps. I also put a very thin coating of RTV sealant on the lower "U" before setting the seals in place. So far, they have been totally free of leaks. I used the factory timing marks as an initial starting point to set the cams, and then degreed them once everything was in place.
Steve: So, this means you are NOT using a drive tool, and you are indeed installing the cam seals before bolting everything down, including the valve covers. .... and of course could leave your cam pulleys on the cams while installing the cam seals. And it works for you, no leaks. Must be the sealant you use that saves you from more leaks. Some past threads I've read has data supporting DRY seal installs being successful, and some other cam seal installs with sealants etc have experienced that the seals pop out. What to do, what to do ....... H
As I said, I used a very thin coating of RTV. If you put too much on, then yes, the seal might well slide out on you (guess how I found that out). I left the timing belt pulleys on the cams, slipped the seals on from the back and it all went together very nicely.
Essentially, the parting line is the point of eventual leaks, therefore, a small dab of threebond 1211 at the split line oc the vc and head on the 9 and 3 positions will address the eventual leak issue, while staying dry at the remainder of the circumference will keep"them in place" as you wish to call it.... good luck, CIAO!
I used Permatex Aviation gasket cement on the ouside of the cam seals to both seal them and hold them in place. Then use a small amount of RTV where the cam cover gasket meets the cam seal. All good no leaks and the seals haven't popped out.
Like a dumbass (Doh!), I put a light coating of RTV on my cam seals the first time, thought I had read it somewhere though it went against everything I knew. When I put the cam covers on I watched the seals push out, and pushing them back in was only a game, they just pushed back out again a few minutes later. All four of them. In the end I had to pull the cam covers off and clean it all up with lacquer thinner. Just a dab at the cam cover gasket seam, otherwise dont put anything on them anywhere. On paper gaskets I work a lil dab of RTV into the surface and let it set up. They come back apart better later on, and they dont usually leak for a long time. You can leave the pulleys on and slip the seals over the cams, but if your going to degree them you need the pulleys loose.
Thanks a lot everyone ! This gives me what I need to proceed. Regarding degreeing my cam, I somehow need to figure out what cam I have, in another thread ... H
