I am replacing the valve cover gaskets and noticed that several rockers appear to be loose, what steps should I follow in order to torque them correctly, also when putting back the valve covers, what is the torque for the valve cover bolts? I have a 1985 vette with 86,000 miles.

 

If the rocker arms are not making noise, you shouldn't worry about them.

 

STOP! Don't start tightening your "loose" rockers, they don't need to be tightened. You SHOULD see rockers that aren't tight, those rockers are on the valves that are in the closed position. The only time you torque them is if they have been removed for service, and then there is a very specific sequence you follow to adjust all of the rockers, which is outlined in the service manual.

As for that torque? 50-80 lbs in will do it. Note the INCH lbs, not ft. lbs

 

Check your valve covers for straightness around the edge and make sure the area around the bolt holes hasnt been warped out of shape. Its definitely a case of more is not better.

 

Having an 1985 and having torqued the valve cover bolts using information from my 1985's service manual, I am pretty sure it had in print 50 inch pounds of torque.

 

- per the 85's FSM, 50 inch-pounds is correct, HOWEVER, the torque spec is based on using RTV silicone sealer on the valve covers, NOT gaskets as the OP indicated. if I were using gaskets, especially fel-pro silicone, I might use a higher torque value - maybe 90 inch pounds. as a side note, the iron head L98, and the corresponding valve covers are designed for RTV sealant, not gaskets.

BTW, my (factory original) 85 uses nuts, not bolts to secure the VC's....

 

thanks for the help and information, I stand corrected as my 85 vette also has nuts to secure the VC's.

 

The best luck I've had is with extra thick cork and no RTV at all. And recheck the bolts on occasion. Even using the right stuff, previously it finds a way through, and it's so hard to remove and clean off.

85s came with a thin cork valve cover gasket plus silicone adhesive from the factory btw.

I don't even use RTV on the thermostat neck.

 

the FSM makes no mention about a thin cork gasket - only RTV silicone....

 

There's a GM part number and it's in their parts book and diagram.

Also I remember I did use RTV between the gasket and cover, just not on the head surface.

 

When I replaced the valve cover gaskets I used Fel-Pro gaskets and torqued to 50 inch pounds. This was years ago. No leakage problems that I have seen. Will take another look tonight.

 

you seem to be correct on a P/N (#14088564) callout for a 85-86 (iron head) gasket, but as I said, the FSM procedure does not callout a gasket, only RTV silicone. after looking into this, there seems to be a TSB issued sometime in December 1985 that covers the installation of a gasket on iron head L98's ( TSB 85163 DEC 85 Engine - Valve Cover Oil Leaks, New Gasket ). can't seem to find a copy on line though. I guessing, iron heads originally came from the factory with RTV silicone, but at some point, a TSB was issued to address leaking valve cover issues. guess you learn something new everyday....

 

just got this on another thread - a big thanks to forum member "chevyowner"


TECHNICAL SERVICE BULLETIN

Reference Number(s): 85-163, Date of Issue: 11/15/85
ROCKER ARM COVER OIL LEAKS - NEW GASKET P/N'S RELEASED
Model(s): 1985 Chevrolet Corvette L98 5.7L Engine (VIN Code 8)
Bulletin No.: Chevrolet 85-163
Date: 11/15/1985

SERVICE INFORMATION
TO: ALL CHEVROLET DEALERS

Some 1985 Corvette engines may experience rocker arm cover engine oil leaks which may be caused by
improperly applied RTV sealant. A new rocker arm cover gasket, entered production in June, 1985. All 1985
vehicles produced after VIN Code: F5135076 have gaskets, replacing RTV. The following is a list of Part

Numbers released for service:
P/N Component Quantity
14101065 Rocker Arm Cover Gasket 1 Per Bank
14105964 Fastener Kit 4-Studs 4-Washers 4-Nuts

NOTE: The aluminum washer must be placed between the rocker arm cover and the
steel nut to prevent galvanic corrosion.

When service installation is required on both right and left rocker arm covers, two (2) 14101065 gaskets and
two (2) 14105964 fastener kits must be ordered. The 1985 Corvette Shop Manual, Section 6A 1-6, details the
procedures to be followed for removing rocker arm covers.

**************************************** *****************



well, I guess I've had this wrong for years. my VIN sequence is 36411, which indicates my 85 came from the factory with gaskets and studs/washers/nuts, which it does. I have been using RTV only for years, and have never had a problem with leaking, and I still stand by my statement that the 85's VC's were originally designed for RTV silicone only, and properly applied RTV to VC's will not leak.

my only saving grace is -


i'll be tearing into my 85 soon, and I may just use fel-pro silicone gaskets, then again, I may not. I've been using RTV (only)since I bought the cat in 96, and have not experienced a leaking issue. anyway, this is one of those little details that makes this hobby fun!

 

I used the Felpro gaskets on my iron head '85. I RTVed the gasket to my valve cover as mentioned and none between the gasket and head. I have cheated tho, I bought cast aluminum valve covers and I tighten the snot out of them. They have been on and off the car a bunch in the last 5 years and I still have no leaks. I highly recommend the Felpros.

 

One might also say they were originally designed incorrectly, hence the TSB. I wonder if GM assembled the early 86 ironheads with gaskets.

 

I don't think they were designed incorrectly. as the TSB implies, "improperly applied" RTV. since 85's built after VIN 35076, have gaskets, most likely, gaskets continued thru iron head 86's. it wouldn't make sense, to go back to straight RTV in 86. I wonder if 84 X-fires have gaskets, or factory applied RTV? FWIW, I've applied RTV, "by the book," and never had a "leak" issue.

 

My '84 FSM does not mention VC gaskets, only RTV #1052366 or equiv. Torque to 50 in. lb.

 

it's interesting that the TSB only addresses 85 corvettes, and does not include 84's. makes you wonder what the difference is....

 

Are the '85 VC's magnesium like the '84's?

 

yes, magnesium, up thru 92.