1960s Valve cover gasket for 1966 Coupe de Ville

[Cadillac George]

I see there are two different thickness of gasket material available, 4mm and 6mm.  I purchased the FelPro which is 6mm but it just didn't seam to fit the cover correctly. Any suggestions would be appreciated.  Thanks.

["Cadillac Kid" Greg Surfas 15364]

What do you mean "didn't seem to fit the cover"?
Greg Surfas

[Cadillac George]

Greg, they were thicker than the original.  They were 6mm and the old ones were 4mm. Also, I could not get the tabs to go into the slots in the cover, the material was too thick.  I could not keep the gasket in place to get it in position when I tried to install them.  I gave up and ordered another brand then the FelPro which were thinner, but they didn't seal well. I may have warped the covers trying to stop the leaks with the thinner gaskets by over tightening the bolts. 

I have a granite surface plate in my shop so I will check the covers to make sure they are straight.  If not I will try to hammer them straight.  Then I'm going to try the FelPro with Permertex on both sides of the gaskets.  Also, plan to torque the bolts to 10 ft. Pounds.  I hope that will stop the leaks.  Any suggestions would be appreciated.   

["Cadillac Kid" Greg Surfas 15364]

George, FWIW when I do (any) rocker arm cover or pan gasket replacement I typically run a small bead of 3M Weatherstripping adhesive (yellow) along the cover where the gasket is going to sit and then as I locate the gasket along the cover "rail" I insert 1/4" bolts through the holes to keep the gasket in place while the adhesive dries. As fr as the tabs fitting into the notches in the cover, they could be trimmed.
Greg Surfas

[TJ Hopland]

If you didn't check for straightness I'm betting that is going to be where a lot of your problems are.  If you spend a half hour making sure the covers are straight that will likely help a lot.  A trick I have seen lately for those that don't have a surface plate is using the table of larger woodworking tools like a table saw or planer.  Lots of guys have those in their wood shops and are plenty flat for this sort of thing.

I have heard of the weatherstripping trick too.  Usually used to 'glue' the gasket to which ever side makes the most sense, often the cover.   Main reason that was done is so the gasket could be reused after it was removed for valve adjustments or head bolt re torques after a rebuild. 

[35-709]

"Also, plan to torque the bolts to 10 ft. Pounds."

10 ft./lbs. is WAY too much.  Don't do it --- you will always have problems.  The shop manual recommends 28 INCH pounds.  If you don't have a decent inch pound wrench, get one.  You might go a little higher with the thicker gaskets, 40 INCH pounds would be plenty --- no more!  There is no reason to "glue" (Permatex) the valve covers on.  Permatex (or a light film of hi-temp silicone) on the valve cover side (valve cover and its holes MUST be flat) should work fine.  Clean and dry surface on the engine side.  This will allow you to remove the valve covers without ruining the gasket as it will stay in place on the cover and make it easy to reuse --- done properly it will not leak.
It is permissible (shop manual recommended) to re-torque  the valve cover bolts after the engine has been run and cooled off, but again, only to the recommended specs.

[Cadillac George]

Greg,

Thanks for the heads up on the bolt torque.  I found that info online!  I now have a shop manual and will refer to it for my torque values. I have an inch pound torque wrench. Thanks

 I'm trying to get this 1966 coupe on the road after it sat in a garage for 20 years.  It's running on an external fuel tank plumbed  to the engine's fuel pump. Plan to drop the fuel tank, clean it and replace the rubber hoses.  I will check the solid lines too.  Any suggestions on what fuel to use?

I did drive it around my parking lot it moves in forward and reverse!  Going to pull the drums off to check the breaks.  Also, going to flush and bleed the brakes before I remove the drums.  Is there a YouTube video on the brake drum removable around.  I would guess the master and brake cylinders are shot, but let's see what I find when I get the drums off.  Thanks for all you expert advice.  I will keep you posted on my slow progress!  George

[35-709]

Fuel - the high compression 429 requires premium.  I have a particular dislike of ethanol-laced fuels in my older cars and run non-ethanol in my 472s, '72 460 Ford, and (now sold) '66 Bonneville exclusively unless I am on a trip.  On a trip I just grit my teeth and bear it, buying non-ethanol where and when I can.  Being in an east coast Florida town with lots of water craft around, I have no trouble getting non-ethanol where I live, I also have no trouble with pinging.  If I did, I would have no compunction about knocking the timing back a degree or two to avoid having to use ethanol fuel.  I also have electric aux fuel pumps in all old vehicles back by the gas tank to hopefully preclude the threat of vapor lock.

If the wheels turn free, the rear drums should just pull right off.  You might possibly want to loosen the rear brakes by turning the star wheel adjusters to loosen the brake linings up a little, also make sure the e.brake fully retracts when off.  But, as I noted, if they are turning they may well just pull right off.

With the strong possibility that the brake cylinders and master should be replaced/rebuilt, I would remove them first, check the lines for serviceability (leaks and severe rust), and then flush the lines.  No reason to flush the parts you are going to rebuild/replace anyway.  On an old car that is an unknown a complete brake overhaul is a must, don't try to patch it up.  Best of luck with it.
Geoff N.

 

[Cadillac George]

Geoff,

Thanks for the reply.  Trying to bleed the brake system, getting a lot of air in the front lines.  It looks like the breaks were replaced and the drum cylinders are not leaking.  I removed the master cylinder cover and saw that the rear break reservoir would squirt when I press the pedal but nothing from the front break reservoir. Should I replace the master cylinder?   Thanks for your help. 

[TJ Hopland]

edit: he started a new thread with the brake questions so I will just move my reply on that subject there.....