rope rear main install
Updated: Oct 29, 2021
not all of these engines can take a rubber seal, due to offset seal grooves causing journal misalignment, as well as inconsistent seal groove depths, that the plus and minus tolerances of a rope seal will be forgiving of. After all, these engines were never designed to have a rubber seal. I went to install the rubber seal on this one and was not satisfied with the contact area that the seal made with the journal so I went with a rope on this perticular one. Ropes are also more forgiving if the journal isnt flawless. That being said. If theres heavy pitting to the journal, it should be welded up, machined back down and the whole crank ground undersized after, to correct any warpage... Or just use a better crank. Polish seal journal to 2k grit. Now open up your seal package. Hammer seal flat with a clean body hammer before rolling it into your seal groove with a smooth hammer handle. Then use the razor in your kit to cut the seal flush with the cap/block. DO NOT PUT GREASE on a rope seal. The seals come pre lubricated. The rope seal is essentially a sponge that holds oil. once crank is st in, rotate the crank and check for rope contact area. you will see a wet strip, indicating seal to journal contact. Putting grease or heavy assembly fluid on it will seal the pores and ruin the seal. After the crank is installed, you will see oil gush out the ends. Thats normal. Clean it off with carb cleaner on a towel. Then I put "Indian Head" in between block and cap surface. Its a very watery viscocity sealer that will not interfere with bearing crush. Do not use rtv sealer under the cap!. Then I use a very minimal amount of rtv in the side seals. Just enough to make them wet and not pinch out under the cap. Offset the side seal on the cap, so as it slides into the block, they even out in the process. Gently hammer in your side steaks on the capside of the seal slot after torquing the cap down to 110ft pounds. And you are done. cut off excess side side rubber that sticks above the top. Rope seals constantly seap a little unlike a rubber seal... However they are a much heartier and durable seal. once a rubber seal leaks, it leaks A LOT. theres no "in between." as for acceptable drag: crank should not be locked up solid to where you cannot turn it easily with a wrench after assy!. its not a rocket science and there's no "calculated measurement" for acceptable drag. you just have to go by feel. a little on the tight side is better than too loose. either way, the drag of the rope seal should be notable.
So theres pro's and cons to both. When you get done, there should be a significant amount of drag on the crank. Crank should not be locked up solid, however.