Thru Bolt O-rings

[code7rpd]

In reading the engine rebuilding book by Wayne I read that black silicon can be used on the thru bolt o-rings. Should it be used on the o-ring on the bolt head side and the nut side? The pics in the book only show it on the bolt head side. Is it the recommended way to go?

[sand_man]

I'm in the process of rebuilding my '87 930 and I am NOT planning on using the black silicon. I've also read/heard that the blue o-rings are useless...try to find the green ones that I think might have been used on the 964 (not sure about the 964 part, but they are green).

Jeff

[porschett]

I got some o-ring lube (thanks Henry) and the green o-rings for my rebuild. Works great and non of that oozing of the o-ring after torque (unlike some of the blues I've seen). I think the green ones are cheaper than the blue ones also. Henry sells them for like .50 each.

[code7rpd]

I'll look for the green o-rings. What kinkd of o-ring lube did you get porschett?

[Mike Juzenas]

When I was in the Jerry Woods engine rebuilding course he used Down Corning 111 as O ring lube.

Cheers,

Mike

[ChrisBennet]

The O-rings that come in the gasket kit are blue - and suck. Get the green ones from Henry or EBS and lube them up with some Dow Corning 111. The 964 gasket kits come with the blue O-rings also but they seem to work OK in that application.

Perhaps Ralph can weigh in on what Andial uses for sealants.
-Chris

[DonE]

I used the blue o-rings from EBS (in their rebuild kit) and black sealant as recommended in "the book" for two rebuilds with no problems.

[ChrisBennet]

Last year I said to my buddy (who's built a lot of 911 motors) "I've used the blue O-rings for years and never had a problem." He told me: "Yes you did, you just didn't know it."

This is what can happen to the blue O-rings on the unbevelled side of the case through holes:



-Chris

[DonE]

Good pics. On the other hand, if there are no leaks, what's the difference or problem? Personally, I don't care about those blue thingies - no one sees them.

[cstreit]

I've used the blue ones for years as well.

The key is to make sure the washer doesn't spin when you torque down the through-bolt nuts. The washers are so soft and pliable, if the washer spins, it'll tear the o-ring up.

I have a helper hold them with a pair of needlenose... (That said, I use the greenies now for 1-man operation)

[code7rpd]

I just ordered a set of greens from EBS.

[speedkillz]

Dow 111 can be hard to find and for the amount you use the tube will out last uranium. I used Curl-T on mine. it lubes and seals worked great. The nut end gets the most twisted up from the torquing.

[ChrisBennet]

MSC carries it http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=1848217&PMT4NO=3400932


It's ideal for oil return tube O-rings and such. I just use 30W oil on the through bolt O-rings but I don't see why DC 111 wouldn't work even better.
-Chris

[len911]

I bought a pound of "knock off 111" from http://www.sspinc.com/prodspecs/prodspecs.cfm?spec=1212specs
Currently $19.95 for 1# tub...

Basically the same stuff as 111 per their data sheets vs. Corning's . Probably will last me a lifetime of "O-ring" lubing... Lou