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'62 valve cover screws pop!

Started by Rob Leonard, July 18, 2017, 05:54:32 PM

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Rob Leonard

My attempted fix leaky valve cover gaskets on my '62's 390 went sideways today.
In the past I've slowed the leaks by hand tightening the four screws on each cover. I decided to torque them down today - to the specified 30 pounds. Well, two of the screws popped their heads - the second when I was backing it off for fear that they all would pop due the specified tightness.
Now I need to drill-out the two headless screws and replace all eight screws with new ones.
Where can I get quality replacement screws?
Thanks, Rob Leonard

Jeff Rosansky CLC #28373

#1
That is an awfully small screw. Did you say 30 pounds or 30 inch pounds?
Jeff
Jeff Rosansky
CLC #28373
1970 Coupe DeVille (Big Red)
1955 Series 62 (Baby Blue)
Dad's new 1979 Coupe DeVille

Rob Leonard

I too thought 30 pounds was an awful lot of pressure.
I think I misread the shop manual - It says 30 foot pounds for the "Rocker arm cover to cylinder head" screw.
I should have gone with my judgement...

Dan LeBlanc

It's an error in the shop manual.  It should be inch pounds.
Dan LeBlanc
1977 Lincoln Continental Town Car

Bobby B

Quote from: Jeff Rose                                         CLC #28373 on July 18, 2017, 06:09:40 PM
That is an awfully small screw. Did you say 30 pounds or 30 inch pounds?
Jeff

30 ft./lbs.??? Are you sure?? You snapped them. Go back and check your reference.....Most valve covers are 3-5 ft./lbs or 36-60 in/lbs. This mistake is usually made over and over again on valve covers and water pump bolts. Didn't you feel them stretching? A 1/4" wrench is all that's need for that small of a bolt. The worst thing you could do to most valve cover gaskets is overtighten them and distort the gasket to the point of no return. Clean both surfaces up, and if you're using an old school cork or equivalent type gasket, put a nice thin coat of Permatex Aviation, No.2, Gasgacinch, etc. on the valve cover surface and the gasket surface that mates to the valve cover only. Once they set up, place the gasket in the valve cover recess, and install the gasket with NOTHING on the engine side at all. Go lightly with a 1/4" wrench by feel, or use a torque wrench if you're unsure. Sealer on one side only allows you to remove the valve cover at any time for servicing, without ruining the gasket or spending hours scraping with towels in the valvetrain. Modern gaskets might use NO sealer at all, as they are made up of different compositions. I stay away from rubber gaskets for valve covers. I've never been able to get them to seal properly without squishing. Some  brand gaskets have metal bushings in the holes so you can't over tighten them. I've had the best luck with the plain 'ol cork gasket when it comes to old school motors. Never a leak....Check the covers while you have them off because you might have distorted them, so you might need to flatten those surfaces back to normal and peen over your bolt holes since you most likely made them concave now and they will never seal. Take your time and you won't have any leaks....Good luck,
                                                                                                                                                 Bobby
1947 Cadillac Series 62 Convertible Coupe
1968 Mustang Convertible
1973 Mustang Convertible
1969 Jaguar E-Type Roadster
1971 Datsun 240Z
1979 H-D FLH

Rob Leonard

Thanks guys. Good advice.
My original question remains:
Where can I get replacement screws?

russ austin

I have original screws.  Shoot me an email;  russ85747@hotmail.com
R.Austin

The Tassie Devil(le)

Don't forget that you will need to re-shape the distorted rocker cover flanges as well.

The Shop Manuals have been known to contain some inaccurate information.   BUT, not very often.

The '72 Shop Manual shows the Torque for the Head Bolts as 155 Ft.Lbs. in one part, and 105 Ft.Lbs. in another part.   It must have been a typo, that the checkers didn't discover before it went to printing.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

David Greenburg

Definitely a shop manual typo. It's inch-lbs.  I posted on the discrepancy a while back after comparing '59, '60, and '61 torque specs.
David Greenburg
'60 Eldorado Seville
'61 Fleetwood Sixty Special

P. Manoogian

Do yourself a favor when doing 390 valve covers - get a tube of black Permatex Ultra and follow the directions to a "T." You will be happy.
1961 Eldorado - Shell Pearl/Mauve
1962 Corvette 327 - 250 HP Automatic Triple Black
1963 Impala SS Convertible - 283 Automatic Black Red Gut White Top
1965 Impala SS Coupe  - 502 Turbo 400 - Crocus Yellow
1974 Corvette L84 4spd Coupe - White / Black Leather

savemy67

Hello Rob, (and all),

I have come across a few errors in my '67 shop manual, so I do not doubt that other years may have an error or two.  When in doubt, refer to any torque specification web site (that is published by a reputable fastener or engineering entity) for the correct value for the size fastener being used.

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

Rob Leonard

Thanks to all.
I have cork/rubber valve gaskets and four new cover screws coming in the mail.
I picked up some black Permatex Ultra. I will correctly reform the valve cover rails and screw flanges before installing.
I really appreciate you help. Rob

Bob Schuman

Check the entire flange surface of the valve covers for flatness on a flat surface (a ktichen countertop works well when the wife is not at home). I recently used that to find the ends of my valve covers were bent upward enough that no gasket would have sealed.
Bob Schuman
Bob Schuman, CLC#254
2017 CT6-unsatisfactory (repurchased by GM)
2023 XT5