VALVE COVER GASKET REPLACEMENT

[matt]

I am considering replacing the valve cover gaskets on my V12 275 because of oil leaks.I can also see leaks between the valve covers and timing chain cover. I am mot a mechanic but think I can tackle this one. Any imput would be greatly appreciated.I have been told that a rubber o ring can be placed in the timing chain/valve cover area and secured by shims. While the covers are off, I want to power coat them in the black crinkle finish. Thank you. matt

[matt]

I am considering replacing the valve cover gaskets on my V12 275 because of oil leaks.I can also see leaks between the valve covers and timing chain cover. I am not a mechanic but think I can tackle this one. Any input would be greatly appreciated.I have been told that a rubber o ring can be placed in the timing chain/valve cover area and secured by shims. While the covers are off, I want to powder coat them in the black crinkle finish. Thank you. matt

[tyang]

Hi Matt,

Another thing to consider, is to check for flatness of the mating surfaces where the valve cover meets the head. Leaks can also come from warped covers when some overzealous mechanic tried to tighten the covers down. Get a good straight edge, and see if the surfaces mate up. If they don't, find a large flat surface, tape some large sheets of sandpaper down, and start taking away material until the valve covers are flat.

Try not to use too much RTV to seal the gaskets, as the stuff the squeezes out and eventually works its way into the oil passageways and clogs things up, and you don't want that!

Good luck!

Tom

[fest]

I do not know if the 275 uses O-Rings
between the Valve Cover and the Timing Case
but
I am under the impression
that the O-Rings between the Valve Covers
and the Timing Case
cannot be replaced
without removing the Timing Case
(you probably do not wish to go there)

Therefore, you need to be quite careful
of these O-Rings when removing / installing the Valve Covers
to avoid damage to these O-Rings

the books I have referred to earlier
i.e. Bishop's and FAF's Guides
do a good job of explaining this procedure
e.g. use of shim stock to protect these O-Rings
when removing / installing Valve Covers
Bill Bradurski of the FCA Forum
is also a good source;
I have seen threads on this very subject

I am not aware of the 'shim' technique mentioned-
Perhaps someone well versed could elucidate?

I would advocate using caution
and also using some 'Red Paste'
(in sparing amounts)
to seal these O-Rings when replacing Valve Covers

[John Vardanian]

Matt,

Your problem is no big deal. This is how I tackled mine:

1. Remove the valve cover and the sprocket cover and clean and degrease all mating surfaces.
2. Carfuly cut away the top section of the o-ring
3. Shave off the leftover stubs so that the the ends in the half that stays in are flush with the cylinder head.
4. Smear some RTV in the groove of the sprocket cover where the o-ring goes and place a new o-ring in the groove. Let this sit long enough so the oring adheres to the sprocket cover (probably several hours or a day).
5. Cut off the new o-ring flush with the flat edge of the sprocket cover.
6. Dab on small globs of RTV (the size of a lentil bean) at the ends of the old o-ring that is on the engine and the new o-ring that is stuck on the sprocket cover. Also smear some RTV on the entire length of the new o-ring that is in the sprocket cover.
7. Place a new valve cover gasket on the head and slide on the sprocket cover (you may want to smear a little RTV on both sides of the gasket first).
8. Place a thin sheet of metal against the new o-ring and slide on the valve cover about half way down.
9. Pull out the thin sheet metal and drive the valve cover home.
10. Add the washers and the acorn nuts and tighten from the center outward to 5 ft/lb of torque.

You can find the thin sheet metal in a hardware store, or if you have an old cookie tin can you can cut out a 4'x4' section. You can also cut out a section from a plastic milk jug.

Important: there are two through bolts at the rear of the valve cover that fasten the distributor base to the valve cover. Don't forget to remove these before trying to lift of the valve cover.

Good luck.

john

[Racerrad]

Speaking of valve cover removal/replacement, anyone have an idea of where to find the plastic or bakelite knobs that screw into the cover for ease of removal?

Thanks, Rad

[matt]

Thank you for the help. I am still not sure about the sheet metal.Is it to hold the half o ring in place while you place the timing chain cover on? Does this half o ring go on the timing chain side or the valve cover side? I am sure if I took it apart I would see what is going on. As for the knobs for racerrad. You can get them from madenterprise.com. However,I have called to try to order things and got no reply.Give it a try. I found a shop in the Bay Area that does crinkle finish powder coating. I am going to check out a sample. The owner told me he knows exactly what I am looking for. Thanks again for your help. matt

[matt]

John: I think I figured it out. The sheet metal is placed between the timing chain cover and the valve cover while you slip the valve cover in place. This must be to avoid moving the half o ring out of its grove. This job seems like something I can do. I know the right way is to remove the front timing chain case and replace the entire ring but at this point I just want to stop the leaks. When the engine goes in for a rebuild (outch);thats when it will get done properly.

[John Vardanian]

Matt,

The sheet metal is to keep the o-ring from crinkling when you slide on the valve cover. Remember, first you slide on the sprocket cover with the half o-ring attached, then you slide on the valve cover.

john

[fest]

I forgot to add that
when replacing the Valve Cover Gaskets
it is a good idea to check the Valve Lash (Clearances)
and of course check all parts for undue wear, etc
(again the Bishop book has a good outline)