401 Valve Seals Auction Question

[Guest ZombyWoof]

Any reason why these seals would not work in a '63 with a 401?

http://cgi.ebay.com/ebaymotors/1964-1965...bayphotohosting

[RivNut]

They'll work after you do some machining on the heads. The '66 engines were the only "nails" to come from the factory with vavle seals, and they were on the exhaust valves only.

Ed

[NTX5467]

As with ANY New Old Stock rubber-type part, it's as old as the vehicle it was designed to fit. How long they'd last could be debateable, considering their age--whether GM OEM replacement or aftermarket replacement items.

When anchored to the valve guide of the head, the valve stem slides in the hole (which the wire reinforcement helps to keep round and intact, as the other wire helps hold the rubber to the valve guide boss). This rubbing action might degrade the older rubber somewhat quickly, or at least sooner than if the rubber was newer and possibly more pliable.

If the valve guide to valve stem clearance is within certain specs, valve seals are not really needed. The reason they would be only on the exhaust side was to fix a "smoke on start-up" issue where residual oil might seep down the exhaust valve stem after the engine has stopped and then cause the resultant light smoke when the engine is first restarted and the oil burns off the exhaust valve head. Remember too, a certain amount of oil is necessary IN the valve guide for lubrication, so trying to make it "too dry" can be detrimental.

From my observations and experiences, if you try to "fix" an oil burning issue IF the oil is going down the valve guides, with new valve stem seals (or seals where there might not be any on particular vehicles), it's only a short-term fix as the additional "play" from the wider guide-to-stem clearances will soon wear the new seals and decrease their effectiveness. If you've got to machine the heads to use them on that particular model year, you'll have to remove the heads anyway, so a valve job and guide reconditioning could be done at the same time to ensure the new seals would last as they should. Personally, I like the bronze helicoil method of reconditioning valve guides as the interface of bronze and chrome valve stems are supposed to be very wear resistant--if and when any wear might happen, a new bronze helicoil insert and it's all good again.

If you want to bid on the parts, that's your money and how you spend it is of your determination.

Just some thoughts,

NTX5467

[Guest ZombyWoof]

NTX5467: Thank you for some great insights. My Riv suffers from the oil burn on startup. I had the engine rebuilt many years ago (early 90's) and new valve seals were not available and it was built without. If they're rubber, sounds like getting new ones when the time i$ right is a better option.