1970 Corvette LS5 454 4 speed consumes a lot of oil from day one

[Roger W.]

Re: 1970 Corvette LS5 454 4 speed consumes a lot of oil from day one

I have heard that teflon valve seals dry out and should only be used for race engines. Street engines should use Viton seals.

[Joe L.]

Re: 1970 Corvette LS5 454 4 speed consumes a lot of oil from day one

Hi Mark,
Thanks for the inquiry. Yes we did resolve my oil consumption problem in my 70 454. We had to replace all the valve stem seals, most were completely disintegrated except for a small black piece with a metal ring left. We were able to replace them all with the heads still on, by moving each piston all the way up or pressurizing the cylinder in case the valve dropped. I did notice a few times in the past years removing the valve covers and seeing broken black pieces sitting I the corners and always having oily spark plugs.

Chris------


What type of valve seal did the engine have and what type did you replace them with? The original valve seals for your application were a "pale yellow", rigid nylon (plastic), umbrella type seal that snapped into the valve cap (retainer). This is the ONLY type I recommend. Any other type will usually interfere with the original-type dual valve springs and "self-destruct" in short order.

[Joe L.]

Re: 1970 Corvette LS5 454 4 speed consumes a lot of oil from day one

Chris------

The attached shows the type of valve seal that was originally used on your engine. As I mentioned, with the stock dual valve springs, this is the only type of seal I recommend.

https://www.ebay.com/itm/163154611815?ul_noapp=true

[Mark E.]

Re: 1970 Corvette LS5 454 4 speed consumes a lot of oil from day one

Chris------

The attached shows the type of valve seal that was originally used on your engine. As I mentioned, with the stock dual valve springs, this is the only type of seal I recommend.

https://www.ebay.com/itm/163154611815?ul_noapp=true

But Joe, this part is discontinued. Is it a good idea to use this seal which may have been sitting on the shelf for years?

Earlier you recommended Fel-Pro SS 72513.

[Joe L.]

Re: 1970 Corvette LS5 454 4 speed consumes a lot of oil from day one

But Joe, this part is discontinued. Is it a good idea to use this seal which may have been sitting on the shelf for years?

Earlier you recommended Fel-Pro SS 72513.

Mark------

I used this eBay item to illustrate the type of seal; not to recommend purchase of this particular one. Besides there are only a few available and one needs 16.

This type of seal can only be used with the valve spring cap designed for it. So, one has to have both the right cap and the right seal. If one has the right caps, the seals can be replaced with the Fel-Pro part number mentioned. If one does not have the right caps, then one has to obtain them if they are to use the original style valve seal.

By the way, I don't think these caps/seals are necessarily deteriorated if they are NOS. The seals are nylon and weather storage well. It's engine heat and oil that deteriorate them.

[Mark E.]

Re: 1970 Corvette LS5 454 4 speed consumes a lot of oil from day one

Mark------

I used this eBay item to illustrate the type of seal; not to recommend purchase of this particular one. Besides there are only a few available and one needs 16.

This type of seal can only be used with the valve spring cap designed for it. So, one has to have both the right cap and the right seal. If one has the right caps, the seals can be replaced with the Fel-Pro part number mentioned. If one does not have the right caps, then one has to obtain them if they are to use the original style valve seal.

By the way, I don't think these caps/seals are necessarily deteriorated if they are NOS. The seals are nylon and weather storage well. It's engine heat and oil that deteriorate them.

The original caps and seals are one piece, right? So how are replacement Fel-Pro seals used with original caps? Are the old seals removed or cut off somehow?

Regarding using original caps/seals from old stock- Rubber and nylon hardens with exposure to air, if even a little. I'd feel better using old stock if the caps/seals were in air tight packaging.

[Joe L.]

Re: 1970 Corvette LS5 454 4 speed consumes a lot of oil from day one

The original caps and seals are one piece, right? So how are replacement Fel-Pro seals used with original caps? Are the old seals removed or cut off somehow?

Regarding using original caps/seals from old stock- Rubber and nylon hardens with exposure to air, if even a little. I'd feel better using old stock if the caps/seals were in air tight packaging.

Mark------

.

The seals "snap out of and into" the valve spring caps. They are a tight fit and the Fel-Pro replacements fit a tad looser than the originals but they will work fine.

[Mark E.]

Re: 1970 Corvette LS5 454 4 speed consumes a lot of oil from day one

Thanks Joe. Safe travels home.