Valve seals for 1965 327 L79 engine
I am planning on replacing the valve seals, both intake and exhaust, on my1965 327 L-79 engine.
What are the current recommendations for manufacturer/product to use??
What are the current recommendations for manufacturer/product to use??
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Re: Valve seals for 1965 327 L79 engine
A good high quality viton seal, Manley, Howards, Felpro. Steer clear of chineasium big box fits-alls junk.
If the valves & guides have excessive wear new seals will work for a short period then start to leak again.
You are going to do this in situ right? Its doable. Make sure you keep track of the springs & keeps. They need to go back on the same valve stem which they were removed from. -
Re: Valve seals for 1965 327 L79 engine
I just replaced the seals on my 74 350-L48 which i believe are the same as used on your L79. I highly recommend the stud mounted valve spring compressor tool from Summit Racing (906784); It will save you a lot of grief.
I Installed both the standard seals (Felpro ss5112) and umbrella seals (Felpro ss10058). I used Felpro valve cover gaskets (vs12869T) which seal well. You might consider ordering a set of valve spring keepers (GM 12495503); they are easily lost when you pop them off. I had to wait a week because no one had them in stock. It's a good time to do a compression and leak down test as you will have all the plugs pulled.Comment
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Re: Valve seals for 1965 327 L79 engine
You really need to provided more information. First, why do you want to replace the valve seals? Oil consumption? If so, how many miles per quart?
Then you have to state what type of seals are installed. The OE type square section ring seals between the valve stem and retainer or some aftermarket type?
If the heads have ever been rebuilt they may have a different than OE seal type.
If oil consumption is high the valve guides might be worn and new seals may not improve the situation. Once the retainer is off lower the valve about a quarter to half inch and wiggle it. If you can feel much more than a barely perceptible wiggle the guides are worn and likely need to be rebuilt. At this point you can finish replacing all the seals to see if it helps as a stop-gap measure or pull the heads for a complete refresh.
DukeComment
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Re: Valve seals for 1965 327 L79 engine
Duke: the motor (L79 - 350 HP) was rebuilt in 2003, 30 over. It's giving small puffs of smoke on startup. Oil consumption is 1 - 1 1/2 quarts per 1K - 1.5k miles.
Seals are probably (from my memory) OE type; I bought all valve train parts from my local GM dealer.
Heads were given a "standard" rebuild, new push-in type guides were used.
I will give your "wiggle" test a try to determine if quides are worn.
Thanks for the advice.
MurrayComment
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Re: Valve seals for 1965 327 L79 engine
The oil consumption is not that bad. My SWC's 340 HP engine never got more than about 1500 miles per quart from new. Those chrome rings were slow to break in, and the loose fit forged pistons pass more oil than the tight fit cast pistons in cooking version small blocks.
When the car sits for days or weeks... whatever, oil can slowly leak down past the seals and guides and that gives you the little puff of smoke at startup. A better test is to find a steep hill and go down in a gear to give at least 3500 RPM on overrun for at least 10-15 seconds. Then at the bottom give the throttle a hard blip and look for blue smoke out the exhaust.
Some years ago my Cosworth Vega's oil consumption got down to about a quart every 150 miles or so. Overall engine performance was fine, but it was using a lot of oil and smoking. It was getting embarrassing. A neighbor told me the car "stunk".
I decided it was time to replace the valve seals, which weren't very good from the get go, and when I did the valve guide test the valves flopped back and forth like a wet noodles, so I knew it was off with the head for a complete refresh including new nickel-bronze valve guide inserts a better than OE seal (from a Honda), and a little bit of port massaging. Since then I've never driven it far enough between oil changes to get a handle on oil consumption.
If you decide to proceed and the engine has the OE type seals you can just buy them at NAPA or any other parts store since they are common to most Gen I small blocks from the fifties up. Most likely they are nitrile. If correct OE geometry Viton seals exist, I would go with them, but I don't know of any. Remember these seals have a square cross section and are not common off-the-self O-rings, but a unique design to the Chevy small block.
If anyone knows of OE geometry valve seals made from Viton rather than nitrile rubber give us a manufacturer and part number.
Duke
P. S. Back in the seventies/eighties if you saw an older Ferrari (fifties/sixties vintage) with a Columbo or Lampredi V-12 and it DIDN'T smoke you figured there had to be something wrong with it.
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