shazam74

Last night I got ambitious and started doing some over do work on my dad's, now my Vette. It has been if ignored for a bit and I knew the valve covers were leaking pretty good. Out came the degreaser and a full wipedown. I pulled off all the bits to get to the passenger side cover and when I went for the bolt, it was less than hand tight and the cover almost pulled off. The previous owner (before my dad) did rtv along with a rubber gasket and did a hell of a messy job with the rtv. I cleaned it all up and installed the FelPro dry as it driected. To my horror, upon installing the bolts, they barely catch a tread or two, but I got them down by pressing slightly on the cover. I did the other side pulling of the washer motor (so much easier) and that side was an even bigger pain trying to wrench down. I did the thermostat too since I had it and about 10 gaskets for it as well. I wasn't happy about the bolts, but I buttoned it up, wiped it down, and finished up around 1:30 am.

This morning I fire it up, watch some of the old oil burn off from the header, and take it for ride hoping the bolts hold. No leaks on the thermostat and it's working fine but low and behold the one bolt that was a PITA to get down had oil dripping from it's side. So doing more research and finding out that from the factory they used rtv which explains the shorter bolts. So that said, what have you guys done when you swapped the gaskets? Did you just go rtv, did you get a slightly longer bolt and run with a rubber gasket? If you did the bolt you mind telling me the size and if you remember where you got them? I'm sort of leaning towards finding slightly longer bolts first before I pull it all back apart and start from scratch. I love how simple and easy the car is to get too, but I'm hoping to only have to do the job once.

I still have a possible leak in the timing chain cover, the rack is squirting out the right front boot, and of course all the bushings are toast so any thoughts on an easy win for the valve cover gasket is appreciated.

mazdaverx7

When I replaced the valve cover gaskets in my first 84, I used blue silicone Moroso brand gaskets. I got longer bolts and they worked perfectly along with the new gasket. Never leaked another drop of oil from the valve covers while under my ownership. I don't remember the size of the bolts but I do remember that I bought stainless bolts and washers that were slightly longer.

I was never a fan of the cork gaskets which I believe that the car originally came with. They dry out too easily and are very prone to leaking.

Joe C

there's been a lot of discussion lately on iron head L98's (85-E86) with leaking valve covers. the L98's use 1/4-20 studs vs bolts to secure the VC's. my question - 1984 L83's - what was factory OE - bolts or studs? in 1985, GM issued a TSB that added gaskets (vs. using RTV) and part of the kit was longer studs. i'm not up on the L83 configuration - was any kind of valve cover TSB issued for the 1984 L83 corvette? if RTV was the original sealant, it seems to me that adding a gasket will require longer bolts to compensate for the gasket thickness. some calculating would be required for the proper length bolts - if bolts were OE, that is. finally, as with all VC, proper torque of the hardware is a necessity.

edit: just checked the factory parts manual. seems the 1984 corvette calls out 1/4-20 x 1.0 bolts (w/ M7x16 washers), and no gasket callout. knowing that, maybe slightly longer bolts are necessary when using gaskets. SBC gaskets typically run .125-.250 thickness.

if the OP is looking for a quality gasket set, I highly recommend fel-pro 1628. top of the line (blue) silicone rubber - .250" thickness. i'd also consider an upgrade and retrofit to studs, similar to the L98.

shazam74

Ah thanks guys. I can not seem to find a lot of love for the L83 so I appreciate all the thoughts and suggestions.

I found some flanged 1/4-20 X 1 1/4 bolts and also 1 1/2 in to test out with washers.

Joe C I totally never thought about throwing in studs and I'm smacking my head for it. It would have made alignment of the gaskets so much easier. With studs in, would you think there would be more clearance issues with removal ( basically needing to remove more around the engine than the bolts)? I can tell you that this is the route I may go if I have to pull this apart again.

Thanks for your help guys. I'm sure you'll see me post often when money permits for my coming projects.
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Joe C

there shouldn't be issues using studs in place of bolts. these studs will handle gaskets up to .250" - I went this route with my 85 and fel-pro 1628 gaskets. worked like a champ and leak free.

get a set of these moroso studs. should solve any problems...



clean the threaded holes in the head, and set them using a dab of blue thread locker - snug or around 50 inch pounds.

shazam74

Thank you so much. As of right now the maiden cruse with the longer bolts seems to be holding tight. I'm going to pick these studs up for the next time the covers come off.