Heat cycling is going to make any rubber harden, and you can't get around the
seal flattening under compression. The o-rings will eventually take the shape
of their space and start leaking as well. The oem seals were not only
compressed between the valve cover and washer, but the center of the seal is
slightly smaller than the shaft of the bolt. I've taken that into
consideration, and the lower washer will seat against the bolt shaft.
My oem seals went 9 years and 75k before starting to leak. That's pretty good
quality.
David
-----Original Message-----
>From: clubairth@bellsouth.net
>Sent: Jun 27, 2006 11:14 AM
>To: FlamingTaco <flamingtaco@earthlink.net>, shotimes@autox.team.net
>Subject: Re: [Shotimes] Valve cover bolt washers
>
>Yes. That's how the O-ring is listed for sizes at Lowe's. I guess you could
>specify the diameter of the rubber too. I still am looking for the standard
>size O-ring number? I think it's a 215 or 218 but have not been able to
>cross it over? You really don't want a washer. This is what's wrong with the
>factory style seal. The clamping force of the bolt will flatten things out.
>Look at the factory seals to see what I mean. The O-ring does a very good
>job of keeping the oil from migrating up the bolt stem.
>
> You really want a "Viton" O-ring but for this application I hardly think it
>needs anything special! That's what's used in good valve stem seals, like
>Fel-Pro. I wonder what the factory seals are made of? They get pretty hard
>and stiff with age. I find that I split them if I am not careful in taking
>them off. Several years ago I pulled them off and never broke any! Age/heat
>and use I guess.
>.
>.
>
>
>
>> Hold the phone... you stated "o-ring", but also "16mmOD x 11mmID" - this
>> would be a washer, correct? Using washers rather than o-rings is what I am
>> aiming for.
>>
>> Speaking of, anyone know their rubber? I queried a rubber mfg and was told
>> to use nitrile rubber for automotive applications (swithstands most
>> petroleum products), but I was turned off by the max operating temperature
>> of 120F. Wouldn't silicone rubber be the best (500F) and stand up ok to
>> engine oil?
>>
>> David
>>
>>
>
>>>
>>>This has already been done. All you need to do is add a O-ring under the
>>>head of the bolt in addition to the factory seals. Search the forum. You
>>>can
>>>get them at Lowe's. You need a 16mm OD X 11mm ID O-ring. Very common.
>>>Every
>>>valve cover I take off gets the O-ring trick!!
>>>.
>>>.
>>>.
>>>
>>>
>>>
>>>> While were on the subject, how many would be interested in washers to
>>>> seal
>>>> the valve cover bolts? I'm thinking $10/set would do well to cover my
>>>> costs. This would be for the six center bolts only, and they would be
>>>> used
>>>> in conjunction with the original seals.
>>>>
>>>> David
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