Is a Top end rebuild Required for thru bolt o rings

[YermanCars]

Hi Guys,

I had a couple leaks that needed to be addressed one of them the camshaft o-ring

The others were case thru bolt o-rings

My car has 53k with great compression and leak down numbers

The pcar mech said that the top end needs to come off
to change the case thru bolt o-rings is this true?

Why do I have to spend 4k for some leaky orings

[Fishcop]

No, you can chage the through bolt O rings without splitting the case. Do it one at a time. There is argument over the use of silicone as an added insurance (Wayne recommends it in his book). I didn't use silicone and I don't have leaks. There is apparently a lot to be said for the green "Viton" brand rings in preference to the blue ones that come with a lot of rebuild kits.

The camshaft O ring unfortunately requires the cam to come out, ergo top end comes apart...

[Fishcop]

hmmm, I read the other responses on the rebuild page. I replaced mine during the early phase of a rebuild... If John Walker says it can't be done, then it can't be done...

[john walker's workshop]

the cylinders have to come off to access the o rings, so at that point, you might as well spend another 20 minutes and split the case. case halves tend to leak slightly at the bottom, on the bellhousing end, so you could fix that leak too.

[LeRoux Strydom]

My SC's engine came out last week for a bunch of other work. While the P&C's were out, we changed the through-bolt O-rings one at a time without splitting case. You can't do them without removing the cylinders, so you might as well then do the heads & valves.

LeRoux

[Superman]

If John says the cylinders have to come off, then the cylinders have to come off. I would agree that silicon grease is the stuff to use on o-rings. It keeps them 'new' and pliable for many years longer than they would otherwise.